CN101646290B - Led drive circuit - Google Patents

Led drive circuit Download PDF

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Publication number
CN101646290B
CN101646290B CN2009101592886A CN200910159288A CN101646290B CN 101646290 B CN101646290 B CN 101646290B CN 2009101592886 A CN2009101592886 A CN 2009101592886A CN 200910159288 A CN200910159288 A CN 200910159288A CN 101646290 B CN101646290 B CN 101646290B
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resistance
constant
current
circuit
temperature coefficient
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CN101646290A (en
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丸山康弘
小路弘之
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Sharp Corp
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Sharp Corp
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Abstract

An LED drive circuit that drives an LED is provided with: a rectifying circuit that converts an alternating voltage into a pulsating current; a constant current circuit; and an over-temperature protection portion that limits an output of the constant current circuit, wherein the LED and the constant current circuit are connected in series on an output side of the rectifying circuit.

Description

Led drive circuit
Technical field
The present invention relates to the led drive circuit of driving LED (light-emitting diode).
Background technology
LED is because of its low-power consumption and feature of long life, in more and more wide field---be not only display unit and in lighting apparatus etc.---is applied.In lighting apparatus, use a plurality of LED to obtain required illumination.
Then its life-span can shorten LED if receive the electric current that surpasses load current value.Therefore, LED need drive with constant current, the electric current restriction perhaps is set makes that not having the electric current that surpasses predetermined size flows through wherein.
General lighting apparatus uses commercial AC 100V power supply mostly.Thereby, if use the LED lighting apparatus to replace incandescent lamp etc., then preferably should be such as general lighting apparatus, the LED lighting apparatus is arranged to also use commercial AC 100V power supply.
The example (referring to JP-A-2000-260578) of the configuration of the conventional led drive circuit that can in the LED lighting apparatus, use shown in Figure 20.Conventional led drive circuit shown in Figure 20 is with constant current driven LED, and is provided with: bridge diode 2; Resistance R 20_2; And constant-current circuit A20.Constant-current circuit A20 is provided with: NPN transistor Q20; Resistance R 20_1; And Zener diode ZD20.
The input side of bridge diode 2 is connected to commercial AC 100V power supply 1; The outlet side of bridge diode 2 is connected to led module 3; This led module 3 is the modules with a plurality of LED coupled in series; That is, cathode output end that is had from bridge diode 2, reaches resistance R 20_1 and is connected in series in proper order with this led module 3, NPN transistor Q20.The end of resistance R 20_2 is connected to the tie point that bridge diode 2 and led module 3 link together.The base stage of NPN transistor Q20 is connected to the other end of resistance R 20_2 and the negative electrode of Zener diode ZD20.The anode of Zener diode ZD20 is connected to the tie point that resistance R 20_1 and bridge diode 2 link together.
Utilize this configuration, the AC voltage of exporting from commercial AC100V power supply 1 carries out full-wave rectification by bridge diode 2, thereby obtains the pulsating voltage that its peak value is about 141V.In constant-current circuit A20, the base potential of NPN transistor Q20 is through the Zener voltage V of Zener diode ZD20 ZAnd become constant by clamper.Therefore, be V if make the base stage of NPN transistor Q20 and the voltage between the emitter BEO20, then the voltage of resistance R 20_1 is represented as (V Z-V BEQ20), and if to make the resistance value of resistance R 20_1 be R 20_1, the electric current that then flows through resistance R 20_1 is represented as (V Z-V BEQ20)/R 20_1, the electric current that resistance R 20_1 is flow through in this expression is constant.That is, the electric current that flows through led module 3 is constant, and is represented as (V Z-V BEQ20)/R 20_1
Usually, the voltage of Zener diode presents positive temperature characterisitic (that is, along with temperature raises; Voltage rises), and the voltage between transistorized base stage and the emitter presents negative temperature characterisitic (that is, along with temperature raises; Voltage descends); And resistance presents positive temperature characterisitic (that is, along with temperature raises, resistance value rises).Therefore, constant-current circuit A1 presents positive temperature characterisitic (that is, along with temperature raises, constant current value rises).Thereby in conventional led drive circuit shown in Figure 20, the electric current that the temperature rising may cause dropping on outside the predetermined value flow among the LED.
In conventional led drive circuit shown in Figure 20, all be not provided for temperature at led module 3 or led drive circuit self rise carry out overtemperature protection under the condition with higher components and parts or circuit.Thereby, if if its ambient temperature rises highly singularly or the anode terminal of led module 3 and cathode terminal between be short-circuited, then the worst led module 3 or the led drive circuit of may causing damages.And if apply excessive load, then incandescent lamp will lose efficacy and its filament disconnection with open circuit mode, and each free semiconductor components and devices of led module 3 and led drive circuit constitutes, and will lose efficacy with short-circuit mode.Therefore, must led drive circuit be made for,, also can not smolder or on fire even at led module 3 or constitute under the worst condition that arbitrary components and parts of led drive circuit are short-circuited.
The protection device and the temperature sensing device that have multiple general use are such as POSISTOR (semistor) ((registered trade mark) made by Japanese Murata Manufacturing Co. Ltd.).Yet; These devices all have lower rated voltage and lower rated power; And do not generating constant DC voltage, the substitute is source power supply is connected directly under led drive circuit and the situation with the pulsating current driving LED, its application is restricted.
Summary of the invention
The object of the present invention is to provide with the pulsating current driving LED and have the led drive circuit of overheat protective function.
To achieve these goals, led drive circuit driving LED of the present invention, and comprise: the rectification circuit that alternating voltage is converted to pulsating voltage; Constant-current circuit; And the overtemperature protection portion that the output of constant-current circuit is limited, wherein LED and constant-current circuit are connected in series on the outlet side of rectification circuit.
And this overtemperature protection portion can comprise: the PNP transistor; And resistance, this resistance has negative temperature coefficient, and is arranged between transistorized base stage of PNP and the emitter.And the transistorized emitter and collector of PNP can be connected to the path of circulate among from the constant current of constant-current circuit output.In either case; For example; Overtemperature protection portion also can comprise constant-current source; This constant-current source is connected in series with the resistance with negative temperature coefficient, and wherein the magnitude of voltage between transistorized base stage of PNP and the emitter is the product that multiplies each other and obtain through with the constant current value of constant-current source and the resistance value with resistance of negative temperature coefficient.Perhaps this overtemperature protection portion also can comprise: resistive element; This resistive element is connected in series with the resistance with negative temperature coefficient, and wherein the magnitude of voltage between transistorized base stage of PNP and the emitter is the product that current value and the resistance value with resistance of negative temperature coefficient of the electric current through will flowing through resistance with negative temperature coefficient and resistive element multiplies each other and obtain.
Perhaps, this overtemperature protection portion can comprise: NPN transistor; And resistance, this resistance has negative temperature coefficient, and is arranged between the base stage and emitter of NPN transistor, and wherein the emitter and collector of NPN transistor is connected to the path of circulate among from the constant current of constant-current circuit output.
And this led drive circuit also can comprise switching circuit, and this switching circuit switches the conducting and the disconnection of constant-current circuit, and wherein LED, constant-current circuit and switching circuit are connected in series on the outlet side of rectification circuit, and overtemperature protection portion control switch circuit.In this case, for example, this overtemperature protection portion can comprise: bipolar transistor, and this bipolar transistor is presented bias current to the control terminal of switching circuit; And resistance, this resistance has negative temperature coefficient, and the one of which end is connected to the base stage of bipolar transistor, and wherein the base stage of bipolar transistor and the magnitude of voltage between the emitter change according to the resistance value with resistance of negative temperature coefficient.Perhaps, this overtemperature protection portion can comprise: NPN transistor, and this NPN transistor will be pulled out to the bias current that the control terminal of switching circuit is presented; And resistance, this resistance has positive temperature coefficient, and the one of which end is connected to the base stage of NPN transistor, and wherein the base stage of NPN transistor and the magnitude of voltage between the emitter change according to the resistance value with resistance of positive temperature coefficient.And; This overtemperature protection portion also can comprise: constant-current source; This constant-current source is connected in series with the resistance that has the resistance of negative temperature coefficient or have a positive temperature coefficient, wherein the base stage of bipolar transistor or NPN transistor and the magnitude of voltage between the emitter be through with the constant current value of constant-current source with have the resistance of negative temperature coefficient or have the product that the resistance value of the resistance of positive temperature coefficient multiplies each other and obtains.Perhaps; This overtemperature protection portion also can comprise resistive element; This resistive element is connected in series with the resistance that has the resistance of negative temperature coefficient or have a positive temperature coefficient, wherein the base stage of bipolar transistor or NPN transistor and the magnitude of voltage between the emitter be through will flow through resistance with negative temperature coefficient or have positive temperature coefficient resistance and resistive element electric current value with have the resistance of negative temperature coefficient or have the product that the resistance value of the resistance of positive temperature coefficient multiplies each other and obtains.
Perhaps, in drive circuit of the present invention, this overtemperature protection portion can comprise: NPN transistor, and this NPN transistor will be pulled out to the bias current that constant-current circuit is presented; And resistance, this resistance has positive temperature coefficient, and is arranged between the base stage and emitter of NPN transistor.And; For example; This overtemperature protection portion also can comprise: constant-current source; This constant-current source is connected in series with the resistance with positive temperature coefficient, and wherein the base stage of NPN transistor and the magnitude of voltage between the emitter are the products that multiplies each other and obtain through with the constant current value of constant-current source and the resistance value with resistance of positive temperature coefficient.Perhaps; This overtemperature protection portion also can comprise: resistive element; This resistive element is connected in series with the resistance with positive temperature coefficient, and wherein the base stage of NPN transistor and the magnitude of voltage between the emitter are the products that value and the resistance value with resistance of positive temperature coefficient of the electric current through will flowing through resistance with positive temperature coefficient and resistive element multiplies each other and obtain.In either case; This overtemperature protection portion also can comprise: another resistance; This another resistance has positive temperature coefficient, and is arranged with the resistance branch with positive temperature coefficient, and another resistance that wherein has positive temperature coefficient is arranged on to constant-current circuit to be presented on the path of bias current.
Perhaps, in drive circuit of the present invention, this overtemperature protection portion can comprise: npn bipolar transistor, and this npn bipolar transistor is presented bias current to the bias current terminal of constant-current circuit; Control is with the npn bipolar transistor and first constant-current source, and this control is connected to the base stage of npn bipolar transistor respectively with the npn bipolar transistor and first constant-current source, and is used to control bias current; Resistance, this resistance has positive temperature coefficient, and the one of which end is connected to the base stage of control with NPN transistor; And second constant-current source; This second constant-current source is connected in series with the resistance with positive temperature coefficient, and wherein control is through with the constant current value of second constant-current source and have the product that the resistance value of the resistance of positive temperature coefficient multiplies each other and obtains with the base stage of NPN transistor and the magnitude of voltage between the emitter.Perhaps, overtemperature protection portion can comprise: npn bipolar transistor, and this npn bipolar transistor is presented bias current to the bias current terminal of constant-current circuit; Control is with npn bipolar transistor and resistive element, and this control is connected to the base stage of npn bipolar transistor respectively with npn bipolar transistor and resistive element, and is used to control bias current; Resistance, this resistance has positive temperature coefficient, and the one of which end is connected to the base stage of control with NPN transistor; And constant-current source; This constant-current source is connected in series with the resistance with positive temperature coefficient, and wherein control is through with the constant current value of constant-current source and have the product that the resistance value of the resistance of positive temperature coefficient multiplies each other and obtains with the base stage of NPN transistor and the magnitude of voltage between the emitter.Perhaps, this overtemperature protection portion can comprise: npn bipolar transistor, and this npn bipolar transistor is presented bias current to the bias current terminal of constant-current circuit; Control is with the npn bipolar transistor and first resistive element, and this control is connected to the base stage of npn bipolar transistor respectively with the npn bipolar transistor and first resistive element, and is used to control bias current; Resistance, this resistance has positive temperature coefficient, and the one of which end is connected to the base stage of control with npn bipolar transistor; And second resistive element; This second resistive element is connected in series with the resistance with positive temperature coefficient, and wherein control is the product that the value of the electric current through will flowing through the resistance with positive temperature coefficient and second resistive element and the resistance value with resistance of positive temperature coefficient multiply each other and obtain with the base stage of NPN transistor and the magnitude of voltage between the emitter.
And for example, this constant-current circuit can comprise: first resistance; Zener diode; And first bipolar transistor, the emitter of this first bipolar transistor is connected to an end of first resistance, and the base stage of this first bipolar transistor is connected to an end of Zener diode.Perhaps, this constant-current circuit can comprise: first bipolar transistor; Second bipolar transistor; First resistance, an end of this first resistance is connected to the base stage of second bipolar transistor; And second resistance; This second resistance is arranged between the base stage and emitter of first bipolar transistor; Wherein the base stage of the collector electrode of first bipolar transistor and second bipolar transistor links together, and the emitter of the base stage of first bipolar transistor and second bipolar transistor links together.
And for example, this switching circuit can comprise: thyristor or bidirectional triode thyristor; And first resistance, this first resistance is arranged between the gate pole and negative electrode of thyristor or bidirectional triode thyristor.
And; Comprise also that at led drive circuit switching circuit, this switching circuit switch under the situation of conducting and disconnection of constant-current circuit; Wherein LED, constant-current circuit and switching circuit are connected in series on the outlet side of rectification circuit; Thereby overtemperature protection portion control switch circuit, this switching circuit comprises: thyristor or two-way one pole thyristor; And first resistance; This first resistance is arranged between the gate pole and negative electrode of thyristor or bidirectional triode thyristor; This overtemperature protection portion can comprise: resistance; This resistance has positive temperature coefficient, and is arranged on the path that is used for presenting to the gate pole of thyristor or bidirectional triode thyristor bias current; And resistive element, this resistive element is arranged between the cathode output end of gate pole and rectification circuit of thyristor or bidirectional triode thyristor.And this overtemperature protection portion also can comprise: electric capacity, this electric capacity and resistive element are connected in parallel.
And; Comprise that at led drive circuit switching circuit, this switching circuit switch under the situation of conducting and disconnection of constant-current circuit; Wherein LED, constant-current circuit and switching circuit are connected in series on the outlet side of rectification circuit; Thereby overtemperature protection portion control switch circuit, switching circuit comprises: thyristor or bidirectional triode thyristor; And first resistance; This first resistance is arranged between the gate pole and negative electrode of thyristor or bidirectional triode thyristor; This overtemperature protection portion can comprise: resistance, and this resistance has positive temperature coefficient, and the one of which end is connected to the gate pole of thyristor or bidirectional triode thyristor; And resistive element, this resistive element is arranged between the cathode output end of the other end and rectification circuit of the resistance with positive temperature coefficient.And; This overtemperature protection portion also can comprise: another resistance; This another resistance has positive temperature coefficient; And be arranged with the resistance branch with positive temperature coefficient, another resistance that wherein has positive temperature coefficient is arranged on to the gate pole of thyristor or bidirectional triode thyristor to be presented on the path of bias current.
And, when constant-current circuit reaches predetermined temperature or when higher, this overtemperature protection portion can limit the output of constant-current circuit.
And, when led module reaches predetermined temperature or when higher, this overtemperature protection portion can limit the output of constant-current circuit.
Description of drawings
Fig. 1 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the first embodiment of the present invention.
Fig. 2 is the diagrammatic sketch that the configuration of led drive circuit according to a second embodiment of the present invention is shown.
Fig. 3 is the diagrammatic sketch of configuration that the led drive circuit of a third embodiment in accordance with the invention is shown.
Fig. 4 is the diagrammatic sketch of configuration that the led drive circuit of a fourth embodiment in accordance with the invention is shown.
Fig. 5 is the diagrammatic sketch that the configuration of led drive circuit according to a fifth embodiment of the invention is shown.
Fig. 6 is the diagrammatic sketch that the configuration of led drive circuit according to a sixth embodiment of the invention is shown.
Fig. 7 A is the diagrammatic sketch of example that the configuration of led drive circuit according to a seventh embodiment of the invention is shown.
Fig. 7 B is the diagrammatic sketch of another example that the above-mentioned configuration of led drive circuit according to a seventh embodiment of the invention is shown.
Fig. 8 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the eighth embodiment of the present invention.
Fig. 9 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the nineth embodiment of the present invention.
Figure 10 is the diagrammatic sketch of example that the configuration of constant-current circuit is shown.
Figure 11 is the diagrammatic sketch of another example that the configuration of constant-current circuit is shown.
Figure 12 is the diagrammatic sketch of another example that the configuration of constant-current circuit is shown.
Figure 13 is the diagrammatic sketch of another example that the configuration of constant-current circuit is shown.
Figure 14 is the diagrammatic sketch of example that the configuration of switching circuit is shown.
Figure 15 is the diagrammatic sketch of another example that the configuration of switching circuit is shown.
Figure 16 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the tenth embodiment of the present invention.
Figure 17 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the 11st embodiment of the present invention.
Figure 18 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the 12nd embodiment of the present invention.
Figure 19 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the 13rd embodiment of the present invention.
Figure 20 is the diagrammatic sketch that conventional led drive circuit is shown.
Figure 21 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the 14th embodiment of the present invention.
Figure 22 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the 15th embodiment of the present invention.
Figure 23 is the diagrammatic sketch that illustrates according to the configuration of the led drive circuit of the 16th embodiment of the present invention.
Embodiment
Each embodiment according to led drive circuit of the present invention below will be described with reference to the drawings.Led drive circuit according to the present invention is used to lighting apparatus, electronic display system etc.
< first embodiment >
Shown in Fig. 1 according to the configuration of the led drive circuit of the first embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 1 comprises: bridge diode 2; Constant-current circuit A1 and B1; PNP transistor Q1; Resistance R 1; And such as the negative temperature coefficient resister RN1 of NTC thermistor (below be called " NTC resistance R N1 ").
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A1 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A1 is connected to another output of bridge diode 2.The emitter of PNP transistor Q1 is connected to the negative electrode of led module 3, and the collector electrode of PNP transistor Q1 is connected to the bias current terminal T3 of constant-current circuit A1 through resistance R 1.And NTC resistance R N1 is arranged between the base stage and emitter of PNP transistor Q1, and constant-current circuit B1 is arranged between another output of base stage and bridge diode 2 of PNP transistor Q1.
PNP transistor Q1 is driven by constant-current circuit B1, and presents bias current to the bias current terminal T3 of constant-current circuit A1.In the led drive circuit of present embodiment shown in Figure 1; Through to limiting to the bias current that the bias current terminal T3 of constant-current circuit A1 presents through resistance R 1 by PNP transistor Q1; Thereby the output of restriction constant-current circuit A1, thereby this constant-current circuit A1 presents constant current driving LED module 3 to led module 3.Utilize this design, the load of PNP transistor Q1 reduces, thereby smaller transistor is used for PNP transistor Q1 becomes possibility, to limit the output of constant-current circuit A1.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A1) set to constant-current circuit A1.
In the led drive circuit of present embodiment shown in Figure 1, along with ambient temperature rises, the resistance value of NTC resistance R N1 reduces, and causes the base stage of PNP transistor Q1 and the voltage between the emitter to reduce.Therefore, the bias current of presenting to the bias current terminal T3 of constant-current circuit A1 reduces, and consequently the constant current value of constant-current circuit A1 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 1 reaches predefined specified level or when higher, PNP transistor Q1 is placed in off-state, does not consequently present bias current to the bias current terminal T3 of constant-current circuit A1.Therefore, constant-current circuit A1 is placed in off-state.
NTC resistance R N1 is being arranged under the base stage and the situation between the emitter of PNP transistor Q1; Through setting its resistance value for suitable value; For NTC resistance R N1, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
And constant-current circuit B1 presents base current to PNP transistor Q1, and the 1/h of its constant current value bias current of equaling to present to the bias current terminal T3 of constant-current circuit A1 FE(h here FEBe the h parameter of PNP transistor Q1).The overtemperature protection operation that will cause PNP transistor Q1 to be in off-state is taken into account; Through setting its constant current value for suitable value; For constant-current circuit B1, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
< second embodiment >
According to a second embodiment of the present invention the configuration of led drive circuit shown in Fig. 2.The led drive circuit of present embodiment shown in Figure 2 is provided with: bridge diode 2; Constant-current circuit A2 and B2; PNP transistor Q2; Resistance R 2; And negative temperature coefficient resister (below be called " NTC resistance ") RN2.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The negative electrode of led module 3 is connected to the emitter of PNP transistor Q2.The constant current terminal T1 of constant-current circuit A2 is connected to the collector electrode of PNP transistor Q2, and the constant current terminal T2 of constant-current circuit A2 is connected to another output of bridge diode 2.And the collector electrode of PNP transistor Q2 is connected to the bias current terminal T3 of constant-current circuit A2 through resistance R 2.And NTC resistance R N2 is arranged between the base stage and emitter of PNP transistor Q2, and constant-current circuit B2 is arranged between another output of base stage and bridge diode 2 of PNP transistor Q2.
PNP transistor Q2 is driven by constant-current circuit B2.Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A2) set to constant-current circuit A2.
In the led drive circuit of present embodiment shown in Figure 2, along with ambient temperature rises, the resistance value of NTC resistance R N2 reduces, and causes the base stage of PNP transistor Q2 and the voltage between the emitter to reduce.Thereby the constant current value of constant-current circuit A2 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 2 reaches predefined specified level or when higher, PNP transistor Q2 is placed in off-state, thereby constant-current circuit A2 is placed in off-state.
NTC resistance R N2 is being arranged under the base stage and the situation between the emitter of PNP transistor Q2; Through setting its resistance value for suitable value; For NTC resistance R N2, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
And constant-current circuit B2 presents base current to PNP transistor Q2, and its constant current value equals the 1/h of the output current of constant-current circuit A2 FE(h here FEBe the h parameter of PNP transistor Q2).The overtemperature protection operation that will cause PNP transistor Q2 to be in off-state is taken into account; Through setting its constant current value for suitable value; For constant-current circuit B2, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
< the 3rd embodiment >
The configuration of the led drive circuit of a third embodiment in accordance with the invention shown in Fig. 3.The led drive circuit of present embodiment shown in Figure 3 is provided with: bridge diode 2; Constant-current circuit A3; PNP transistor Q3; Resistance R 3_1 and R3_2; And negative temperature coefficient resister (below be called " NTC resistance ") RN3.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A3 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A3 is connected to another output of bridge diode 2.And the emitter of PNP transistor Q3 is connected to the negative electrode of led module 3, and the collector electrode of PNP transistor Q3 is connected to the bias current terminal T3 of constant-current circuit A3 through resistance R 3_1.And NTC resistance R N3 is arranged between the base stage and emitter of PNP transistor Q3, and resistance R 3_2 is arranged between another output of base stage and bridge diode 2 of PNP transistor Q3.
PNP transistor Q3 is driven by NTC resistance R N3 and resistance R 3_2, and presents bias current to the bias current terminal T3 of constant-current circuit A3.In the led drive circuit of present embodiment shown in Figure 3; Through to limiting to the bias current that the bias current terminal T3 of constant-current circuit A3 presents through resistance R 3_1 by PNP transistor Q3; Thereby the output of restriction constant-current circuit A3, thereby this constant-current circuit A3 presents constant current driving LED module 3 to led module 3.Utilize this design, the load on the PNP transistor Q3 reduces, thereby smaller transistor is used for PNP transistor Q3 becomes possibility, to limit the output of constant-current circuit A3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A3) set to constant-current circuit A3.
In the led drive circuit of present embodiment shown in Figure 3, along with ambient temperature rises, the resistance value of NTC resistance R N3 reduces, and causes the base stage of PNP transistor Q3 and the voltage between the emitter to reduce.Therefore, the bias current of presenting to the bias current terminal T3 of constant-current circuit A3 reduces, and consequently the constant current value of constant-current circuit A3 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 3 reaches predefined specified level or when higher, PNP transistor Q3 is placed in off-state, does not consequently present bias current to the bias current terminal T3 of constant-current circuit A3.Therefore, constant-current circuit A3 is placed in off-state.
NTC resistance R N3 is being arranged under the base stage and the situation between the emitter of PNP transistor Q3; Through setting its resistance value for suitable value; For NTC resistance R N3, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
And resistance R 3_2 presents base current to PNP transistor Q3, and the 1/h of the electric current that the flows through resistance R 3_2 bias current that equals to present to the bias current terminal T3 of constant-current circuit A3 FE(h here FEBe the h parameter of PNP transistor Q3).The overtemperature protection operation that will cause PNP transistor Q3 to be in off-state is taken into account; Set suitable value for through the current value that will flow through resistance R 3_2; For resistance R 3_2, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
Can with configuration shown in Figure 2 is made amendment from the modification that Fig. 1 to Fig. 3 carried out identically.That is, constant-current circuit B2 can be replaced by the resistance with suitable resistance value.
< the 4th embodiment >
The configuration of the led drive circuit of a fourth embodiment in accordance with the invention shown in Fig. 4.The led drive circuit of present embodiment shown in Figure 4 is provided with: bridge diode 2; Constant-current circuit A4; NPN transistor Q4; Resistance R 4_1 and R4_2; And negative temperature coefficient resister (below, be called " NTC resistance ") RN4.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A4 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A4 is connected to the collector electrode of NPN transistor Q4.The emitter of NPN transistor Q4 is connected to another output of bridge diode 2.And the negative electrode of led module 3 is connected to the bias current terminal T3 of constant-current circuit A4 through resistance R 4_1.And resistance R 4_2 is arranged between the base stage of negative electrode and NPN transistor Q4 of led module 3, and NTC resistance R N4 is arranged between the base stage and emitter of NPN transistor Q4.
NPN transistor Q4 is driven by resistance R 4_2 and NTC resistance R N4.Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A4) set to constant-current circuit A4.
In the led drive circuit of present embodiment shown in Figure 4, along with ambient temperature rises, the resistance value of NTC resistance R N4 reduces, and causes the base stage of PNP transistor Q4 and the voltage between the emitter to reduce.Thereby the constant current value of constant-current circuit A4 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 4 reaches predefined specified level or when higher, NPN transistor Q4 is placed in off-state, thereby constant-current circuit A4 is placed in off-state.
NTC resistance R N4 is being arranged under the base stage and the situation between the emitter of NPN transistor Q4; Through setting its resistance value for suitable value; For NTC resistance R N4, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
And resistance R 4_2 presents base current to NPN transistor Q4, and the electric current that flows through resistance R 4_2 equals the 1/h of the output current of constant-current circuit A4 FE(h here FEBe the h parameter of NPN transistor Q4).The overtemperature protection operation that will cause NPN transistor Q4 to be in off-state is taken into account; Become suitable value through the current settings that will flow through resistance Q4_2; For resistance R 4_2, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
< the 5th embodiment >
According to a fifth embodiment of the invention the configuration of led drive circuit shown in Fig. 5.The led drive circuit of present embodiment shown in Figure 5 is provided with: bridge diode 2; Constant-current circuit A5 and B5; Switching circuit C5; Resistance R 5_1 and R5_2; NPN transistor Q5; And negative temperature coefficient resister (below be called " NTC resistance ") RN5.Switching circuit C5 is formed; Make if the bias current of presenting to its control terminal T6 is equal to or greater than predetermined value; Then the path between its contact terminal T4 and the contact terminal T5 becomes and conducts; And if the bias current of presenting to its control terminal T6 less than predetermined value, then the path between its contact terminal T4 and the contact terminal T5 becomes not conducting.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A5 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A5 is connected to the contact terminal T4 of switching circuit C5.The contact terminal T5 of switching circuit C5 is connected to another output of bridge diode 2.And the end of resistance R 5_1 is connected to the negative electrode of led module 3, and the other end of resistance R 5_1 is connected to the bias current terminal T3 of constant-current circuit A5 and the end of resistance R 5_2.The other end of resistance R 5_2 is connected to the collector electrode of NPN transistor Q5, and the emitter of NPNQ5 is connected to the control terminal T6 of switching circuit C5.And constant-current circuit B5 is arranged between the base stage of negative electrode and NPN transistor Q5 of led module 3, and NTC resistance R N5 is arranged between another output of base stage and bridge diode 2 of NPN transistor Q5.
NPN transistor Q5 is driven by constant-current circuit B5, and presents bias current to the control terminal T6 of switching circuit C5.In the led drive circuit of present embodiment shown in Figure 5, through the bias current of limit switch circuit C5, thus the output of restriction constant-current circuit A5, thus this constant-current circuit A5 presents constant current driving LED module 3 to led module 3.Utilize this design, the load of NPN transistor Q5 reduces, thereby smaller transistor is used for NPN transistor Q5 becomes possibility, to limit the output of constant-current circuit A5.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A5) set to constant-current circuit A5.
In the led drive circuit of present embodiment shown in Figure 5, along with ambient temperature rises, the resistance value of NTC resistance R N5 reduces, and causes the base stage of NPN transistor Q5 and the voltage between the emitter to reduce.Therefore, the bias current of presenting to the control terminal T6 of switching circuit C5 reduces, and consequently the constant current value of constant-current circuit A5 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 5 reaches predefined specified level or when higher, NPN transistor Q5 is placed in off-state, does not consequently present bias current to the control terminal T6 of switching circuit C5.Therefore, constant-current circuit A5 is placed in off-state.
Under the situation of the base stage that NTC resistance R N5 is connected to NPN transistor Q5,,, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong for NTC resistance R N5 through setting its resistance value for suitable value.
And constant-current circuit B5 presents base current to NPN transistor Q5, and the 1/h of its constant current value bias current of equaling to present to the control terminal T6 of switching circuit C5 FE(h here FEBe the h parameter of NPN transistor Q5).The overtemperature protection operation that will cause NPN transistor Q5 to be in off-state is taken into account; Through setting its constant current value for suitable value; For constant-current circuit B5, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
< the 6th embodiment >
According to a sixth embodiment of the invention the configuration of led drive circuit shown in Fig. 6.The led drive circuit of present embodiment shown in Figure 6 is provided with: bridge diode 2; Constant-current circuit A6 and B6; Switching circuit C6; Resistance R 6_1 and R6_2; NPN transistor Q6; And such as the positive temperature coefficient resistor RP6 of PTC thermistor (below be called " PTC resistance R P6 ").Switching circuit C6 is formed; Make if the bias current of presenting to its control terminal T6 is equal to or greater than predetermined value; Then the path between its contact terminal T4 and the contact terminal T5 becomes and conducts; Less than predetermined value, then the path between its contact terminal T4 and the contact terminal T5 becomes not conducting as if the bias current of presenting to its control terminal T6.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A6 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A6 is connected to the contact terminal T4 of switching circuit C6.The contact terminal T5 of switching circuit C6 is connected to another output of bridge diode 2.And the end of resistance R 6_1 is connected to the negative electrode of led module 3, and the other end of resistance R 6_1 is connected to the bias current terminal T3 of constant-current circuit A6 and the end of resistance R 6_2.The other end of resistance R 6_2 is connected to the collector electrode of control terminal T6 and the NPN transistor Q6 of switching circuit C6, and the emitter of NPN transistor Q6 is connected to another output of bridge diode 2.And constant-current circuit B6 is arranged between the base stage of negative electrode and NPN transistor Q6 of led module 3, and PTC resistance R P6 is arranged between the base stage and emitter of NPN transistor Q6.
To PTC resistance R P6 circulation electric current is arranged from constant-current circuit B6, and set the resistance value of the constant current value of constant-current circuit B6 and PTC resistance R P6 for feasible NPN transistor Q6 at normal temperatures and remain on off-state.And, bias current is fed to the control terminal T6 of switching circuit C6 through R6_1 and R6_2 from the negative electrode of led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A6) set to constant-current circuit A6.
In the led drive circuit of present embodiment shown in Figure 6, along with ambient temperature rises, the resistance value of PTC resistance R P6 increases, and causes the base stage of NPN transistor Q6 and the voltage between the emitter to increase.Therefore, NPN transistor Q6 makes the bias current of presenting to the control terminal T6 of switching circuit C6 reduce, and consequently the constant current value of constant-current circuit A6 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 6 reaches predefined specified level or when higher; All bias currents that NPN transistor Q6 will present to the control terminal T6 of switching circuit C6 are pulled out, and consequently do not present bias current to the control terminal T6 of switching circuit C6.Therefore, constant-current circuit A6 is placed in off-state.
In the led drive circuit of present embodiment shown in Figure 6, the bias current of presenting to switching circuit C6 through restriction, thereby the output of restriction constant-current circuit A6, thus this constant-current circuit A6 presents constant current driving LED module 3 to led module 3.Utilize this design, the load of NPN transistor Q6 reduces, thereby smaller transistor is used for NPN transistor Q6 becomes possibility, to limit the output of constant-current circuit A6.
PTC resistance R P6 is being arranged under the base stage and the situation between the emitter of NPN transistor Q6; Through setting its resistance value for suitable value; For PTC resistance R P6, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
And; Constant-current circuit B6 presents base current to NPN transistor Q6; Make NPN transistor Q6 when being placed in conducting state because of the overtemperature protection operation; All bias currents that to present to the control terminal T6 of switching circuit C6 are pulled out, as long as constant-current circuit B6 can present the 1/h that is equal to or greater than the bias current of presenting to the control terminal T6 of switching circuit Q6 FE(h here FEBe the h parameter of NPN transistor Q6) electric current get final product.Thereby, through setting its constant current value for suitable value,, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong for constant-current circuit B6.
< the 7th embodiment >
According to a seventh embodiment of the invention the example of configuration of led drive circuit shown in Fig. 7 A.The led drive circuit of present embodiment shown in Figure 7 is provided with: bridge diode 2; Constant-current circuit A7A; Switching circuit C7A; Resistance R 7_1A to R7_3A; NPN transistor Q7A; And positive temperature coefficient resistor (below be called " PTC resistance ") RP7A.Switching circuit C7A is formed; Make if the bias current of presenting to its control terminal T6 is equal to or greater than predetermined value; Then the path between its contact terminal T4 and the contact terminal T5 becomes and conducts; Less than predetermined value, then the path between its contact terminal T4 and the contact terminal T5 becomes not conducting as if the bias current of presenting to its control terminal T6.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A7A is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A7A is connected to the contact terminal T4 of switching circuit C7A.The contact terminal T5 of switching circuit C7A is connected to another output of bridge diode 2.And the end of resistance R 7_1A is connected to the negative electrode of led module 3, and the other end of resistance R 7_1A is connected to the bias current terminal T3 of constant-current circuit A7A and the end of resistance R 7_2A.The other end of resistance R 7_2A is connected to the collector electrode of control terminal T6 and the NPN transistor Q7A of switching circuit C7A, and the emitter of NPN transistor Q7A is connected to another output of bridge diode 2.And resistance R 7_3A is arranged between the base stage of negative electrode and NPN transistor Q7A of led module 3, and PTC resistance R P7A is arranged between the base stage and emitter of NPN transistor Q7A.
To PTC resistance R P7A circulation electric current is arranged from resistance R 7_3A, and set the resistance value of resistance R 7_3A and PTC resistance R P7A for feasible NPN transistor Q7A at normal temperatures and remain on off-state.And, bias current is fed to the control terminal T6 of switching circuit C7A through R7_1A and R7_2A from the negative electrode of led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A7A) set to constant-current circuit A7A.
In the led drive circuit of the present embodiment shown in Fig. 7 A, along with ambient temperature rises, the resistance value of PTC resistance R P7A increases, and causes the base stage of NPN transistor Q7A and the voltage between the emitter to increase.Therefore, NPN transistor Q7A makes the bias current of presenting to the control terminal T6 of switching circuit C7A reduce, and consequently the constant current value of constant-current circuit A7A is restricted.When the ambient temperature of the led drive circuit of the present embodiment shown in Fig. 7 A reaches predefined specified level or when higher; All bias currents that NPN transistor Q7A will present to the control terminal T6 of switching circuit C7A are pulled out, and consequently do not present bias current to the control terminal T6 of switching circuit C7A.Therefore, constant-current circuit A7A is placed in off-state.
In the led drive circuit of present embodiment shown in Figure 7, through the bias current of limit switch circuit C7A, thus the output of restriction constant-current circuit A7A, thus this constant-current circuit A7A presents constant current driving LED module 3 to led module 3.Utilize this design, the load of NPN transistor Q7A reduces, thereby smaller transistor is used for NPN transistor Q7A becomes possibility, to limit the output of constant-current circuit A7A.
PTC resistance R P7A is being arranged under the base stage and the situation between the emitter of NPN transistor Q7A; Through setting its resistance value for suitable value; For PTC resistance R P7A, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
And; Resistance R 7_3A presents base current to NPN transistor Q7A; Make NPN transistor Q7A when being placed in conducting state because of the overtemperature protection operation; All bias currents that to present to the control terminal T6 of switching circuit C7A are pulled out, as long as resistance R 73 can be presented the 1/h that is equal to or greater than the bias current of presenting to the control terminal T6 of switching circuit Q7A FE(h here FEBe the h parameter of NPN transistor Q7A) electric current get final product.Thereby, set suitable value for through the current value that will flow through resistance R 7_3A, for resistance R 7_3, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
According to a seventh embodiment of the invention another example of configuration of led drive circuit shown in Fig. 7 B.Through with configuration shown in Figure 5 is made amendment from the modification that Fig. 6 to Fig. 7 carried out identically, that is, replace constant-current circuit B5 through using resistance R 7_3B, thereby obtain the configuration shown in Fig. 7 B.Resistance R 7_3B presents base current to NPN transistor Q7B, and the 1/h of the electric current that the flows through resistance R 7_3B bias current that equals to present to the control terminal T6 of switching circuit C7B FE(h here FEBe the h parameter of NPN transistor Q7B).The overtemperature protection operation that will cause NPN transistor Q7B to be in off-state is taken into account; Set suitable value for through the current value that will flow through resistance R 7_3B; For resistance R 7_3B, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
< the 8th embodiment >
Shown in Fig. 8 according to the configuration of the led drive circuit of the eighth embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 8 is provided with: bridge diode 2; Constant-current circuit A8 and B8; Resistance R 8; NPN transistor Q8; And positive temperature coefficient resistor (below be called " PTC resistance ") RP8.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A8 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A8 is connected to another output of bridge diode 2.And an end of resistance R 8 is connected to the negative electrode of led module 3, and the other end of resistance R 8 is connected to the collector electrode of bias current terminal T3 and the NPN transistor Q8 of constant-current circuit A8.The emitter of NPN transistor Q8 is connected to another output of bridge diode 2.And constant-current circuit B8 is arranged between the base stage of negative electrode and NPN transistor Q8 of led module 3, and PTC resistance R P8 is arranged between the base stage and emitter of NPN transistor Q8.
To PTC resistance R P8 circulation electric current is arranged from constant-current circuit B8, and set the resistance value of the constant current value of constant-current circuit B8 and PTC resistance R P8 for feasible NPN transistor Q8 at normal temperatures and remain on off-state.And, bias current is fed to the bias current terminal T3 of constant-current circuit A8 through resistance R 8 from the negative electrode of led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A8) set to constant-current circuit A8.
In the led drive circuit of present embodiment shown in Figure 8, along with ambient temperature rises, the resistance value of PTC resistance R P8 increases, and causes the base stage of NPN transistor Q8 and the voltage between the emitter to increase.Therefore, NPN transistor Q8 makes the bias current of presenting to the bias current terminal T3 of constant-current circuit A8 reduce, and consequently the constant current value of constant-current circuit A8 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 8 reaches predefined specified level or when higher; All bias currents that NPN transistor Q8 will present to the bias current terminal T3 of constant-current circuit A8 are pulled out, and consequently do not present bias current to the bias current terminal T3 of constant-current circuit A8.Therefore, constant-current circuit A8 is placed in off-state.
In the led drive circuit of present embodiment shown in Figure 8, directly limit the output of constant-current circuit A8, thereby this constant-current circuit A8 presents constant current driving LED module 3 to led module 3 through NPN transistor Q8.Though some is heavy for the load on the NPN transistor Q8, it can reduce the size of resulting circuit.
PTC resistance R P8 is being arranged under the base stage and the situation between the emitter of NPN transistor Q8; Through setting its resistance value for suitable value; For PTC resistance R P8, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
And; Constant-current circuit B8 presents base current to NPN transistor Q8; Make NPN transistor Q8 when being placed in conducting state because of the overtemperature protection operation; All bias currents that to present to the bias current terminal T3 of constant-current circuit A8 are pulled out, as long as constant-current circuit Q8 can present the 1/h that is equal to or greater than the bias current of presenting to the bias current terminal T3 of constant-current circuit A8 FE(h here FEBe the h parameter of NPN transistor Q8) electric current get final product.Thereby, through setting its constant current value for suitable value,, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong for constant-current circuit B8.
< the 9th embodiment >
Shown in Fig. 9 according to the configuration of the led drive circuit of the nineth embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 9 is provided with: bridge diode 2; Constant-current circuit A9 and B9; Resistance R 9; NPN transistor Q9; And positive temperature coefficient resistor (below be called " PTC resistance ") RP9_1 and RP9_2.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of anode led module 3.The constant current terminal T1 of constant-current circuit A9 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A9 is connected to another output of bridge diode 2.And an end of resistance R 9 is connected to the negative electrode of led module 3, and the other end of resistance R 9 is connected to the collector electrode of bias current terminal T3 and the NPN transistor Q9 of constant-current circuit A9 through PTC resistance R P9_2.The emitter of NPN transistor Q9 is connected to another output of bridge diode 2.And constant-current circuit B9 is arranged between the base stage of negative electrode and NPN transistor Q9 of led module 3, and PTC resistance R P91 is arranged between the base stage and emitter of NPN transistor Q9.
To PTC resistance R P9_1 circulation electric current is arranged from constant-current circuit B9, and set the resistance value of the constant current value of constant-current circuit B9 and PTC resistance R P9_1 for feasible NPN transistor Q9 at normal temperatures and remain on off-state.And, bias current is fed to the bias current terminal T3 of constant-current circuit A9 through resistance R 9 and PTC resistance R 9_2 from the negative electrode of led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A9) set to constant-current circuit A9.
In the led drive circuit of present embodiment shown in Figure 9, along with ambient temperature rises, the resistance value of PTC resistance R P9_1 and PTC resistance R P9_2 increases, and causes the base stage of NPN transistor Q9 and the voltage between the emitter to increase.Therefore, NPN transistor Q9 makes the bias current of presenting to the bias current terminal T3 of constant-current circuit A9 reduce, and consequently the constant current value of constant-current circuit A9 is restricted.And, thereby also limit the bias current of presenting to the bias current terminal T3 of constant-current circuit A9 through the resistance value of using PTC resistance R 9_2.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 9 reaches predefined specified level or when higher; All bias currents that NPN transistor Q9 will present to the bias current terminal T3 of constant-current circuit A9 are pulled out, and consequently do not present bias current to the bias current terminal T3 of constant current A9.Therefore, constant-current circuit A9 is placed in off-state.
In the led drive circuit of present embodiment shown in Figure 9; The bias current that PTC resistance R 9_2 restriction is presented to the bias current terminal T3 of constant-current circuit A9; So and NPN transistor Q9 directly pulls out this bias current, drives this led module 3 thereby said constant-current circuit A9 presents constant current to led module 3.Thereby, more promptly limit the output of constant-current circuit A9.
PTC resistance R P9_1 is being arranged under the base stage and the situation between the emitter of NPN transistor Q9; Through setting its resistance value for suitable value; For PTC resistance R P9_1, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
And; Constant-current circuit B9 presents base current to NPN transistor Q9; Make NPN transistor Q9 when being placed in conducting state because of the overtemperature protection operation; All bias currents that to present to the bias current terminal T3 of constant-current circuit A9 are pulled out, as long as constant-current circuit B9 can present the 1/h that is equal to or greater than the bias current of presenting to the bias current terminal T3 of constant-current circuit A9 FE(h here FEBe the h parameter of NPN transistor Q9) electric current get final product.Thereby, through setting its constant current value for suitable value,, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong for constant-current circuit B9.
PTC resistance R P9_2 is applied in by resulting pulsating voltage after PTC resistance R P9_2 and resistance R 9 dividing potential drops.Therefore, thus PTC resistance R P9_2 need be configured to drop on the resistance value that rated power and rated voltage obtain with interior value through use.
Also can make amendment to configuration shown in Figure 8 and configuration shown in Figure 9 with the modification of being carried out from Fig. 6 to Fig. 7 A identically.That is, constant-current circuit B8 and B9 can be replaced by the resistance with suitable resistance value.
< example of the configuration of constant-current circuit >
Then, thus at constant-current circuit from Figure 10 to led module that present constant current driving LED module shown in---be the example of the configuration of constant-current circuit A1 to A6, A7A, A7B, A8, A9 among above-mentioned first to the 9th embodiment.Constant-current circuit shown in Figure 10 is provided with: NPN transistor Q10; Resistance R 10; Zener diode ZD10; Constant current terminal T1 and T2; And bias current terminal T3.
The base stage of NPN transistor Q10 is connected to negative electrode and the bias current terminal T3 of Zener diode ZD10; The collector electrode of NPN transistor Q10 is connected to constant current terminal T1, and the emitter of NPN transistor Q10 is connected to anode and the constant current terminal T2 of Zener diode ZD10 through resistance R 10.
In addition, thus at constant-current circuit from Figure 11 to led module that present constant current driving LED module shown in---be constant-current circuit A1 to A6, A7A, A7B, A8, and the example of the configuration of A9 among above-mentioned first to the 9th embodiment.Constant-current circuit shown in Figure 11 is provided with: PNP transistor Q11; Resistance R 11; Zener diode ZD11; Constant current terminal T1 and T2; And bias current terminal T3.
The base stage of PNP transistor Q11 is connected to anode and the bias current terminal T3 of Zener diode ZD11; The emitter of PNP transistor Q11 is connected to negative electrode and the constant current terminal T1 of Zener diode ZD11 through resistance R 11, and the collector electrode of PNP transistor Q11 is connected to constant current terminal T2.
Two constant current value of the constant-current circuit shown in Figure 10 and 11 all are expressed as (V Z-V BE)/R, V here ZThe Zener voltage of expression Zener diode ZD10 or ZD11, V BEExpression NPN transistor Q10 or the base stage of PNP transistor Q11 and the voltage between the emitter, and R representes the resistance value of resistance R 10 or R11.
Constant-current circuit shown in Figure 10 and constant-current circuit shown in Figure 11 also can be used to after among the tenth to the 13 embodiment that describes.
Then, make electric current flow into the constant-current circuit of negative temperature coefficient resister (below be called " NTC resistance ") or positive temperature coefficient resistor (below be called " PTC resistance ") shown in Figure 12---be above-mentioned first, second, the example of the configuration of constant-current circuit B1, B2, B5, B6, B8 and B9 among the 5th, the 6th, the 8th and the 9th embodiment.Constant-current circuit shown in Figure 12 is provided with: NPN transistor Q12_1 and Q12_2; And resistance R 12_1 and R12_2.
The base stage of NPN transistor Q12_1 is connected to the emitter of NPN transistor Q12_2 and the end of resistance R 12_2, and the collector electrode of NPN transistor Q12_1 is connected to the base stage of NPN transistor Q12_2 and the end of resistance R 12_1.The collector electrode of the other end of resistance R 12_1 and NPN transistor Q12_2 is connected to the constant current terminal on the side of constant-current circuit.The other end of the emitter of NPN transistor Q12_1 and resistance R 12_2 is connected to the constant current terminal on the opposite side of constant-current circuit.
In addition, make electric current flow into the constant-current circuit of negative temperature coefficient resister (below be called " NTC resistance ") or positive temperature coefficient resistor (below be called " PTC resistance ") shown in Figure 13---be above-mentioned first, second, another example of the configuration of constant-current circuit B1, B2, B5, B6, B8 and B9 among the 5th, the 6th, the 8th and the 9th embodiment.Constant-current circuit shown in Figure 13 is provided with: PNP transistor Q13_1 and Q13_2; And resistance R 13_1 and R13_2.
The base stage of the transistorized Q13_1 of PNP is connected to the emitter of PNP transistor Q13_2 and the end of resistance R 13_2, and the collector electrode of the transistorized Q13_1 of PNP is connected to the base stage of PNP transistor Q13_2 and the end of resistance R 13_1.The other end of the emitter of the transistorized Q13_1 of PNP and resistance R 13_2 is connected to the constant current terminal on the side of constant-current circuit, and the collector electrode of the other end of resistance R 13_1 and PNP transistor Q13_2 is connected to the constant current terminal on the opposite side of constant-current circuit.
Two constant current value of the constant-current circuit shown in Figure 12 and 13 all are expressed as V BE/ R, V here BERepresent the voltage between each transistorized base stage and the emitter, and R representes the resistance value of each resistance.
As long as the arbitrary terminal among bias current terminal T3 and constant current terminal T1 or the T2 links together through the resistance with suitable value, then the constant-current circuit shown in Figure 10 or 11 can be used as the constant-current circuit that makes electric current flow into negative temperature coefficient resister or positive temperature coefficient resistor---be above-mentioned first, second, each constant-current circuit among constant-current circuit B1, B2, B5, B6, B8 and the B9 among the 5th, the 6th, the 8th and the 9th embodiment.
As long as the bias current terminal is arranged to be connected to the base stage of NPN transistor Q12_2 or PNP transistor Q13_2, thereby then Figure 12 or constant-current circuit shown in Figure 13 just can be used as constant-current circuit from constant current driving LED module to led module that present---be among above-mentioned first to the 9th embodiment constant-current circuit A1 to A6, A7A, A7B, A8, reach each constant-current circuit among the A9.And, these constant-current circuits also can be used to after among the tenth to the 13 embodiment that describes.
< example of the configuration of switching circuit >
Then, at switching circuit shown in Figure 14---be the example of the configuration of switching circuit C5, C6, C7A and C7B among above-mentioned the 5th to the 7th embodiment.Switching circuit shown in Figure 14 is provided with: thyristor TTY14; Resistance R 14; Contact terminal T4 and T5; And control terminal T6.The gate pole of thyristor TTY14 is connected to an end of control terminal T6 and resistance R 14, and the anode of thyristor TTY14 is connected to contact terminal T4, and the other end of the negative electrode of thyristor TTY14 and resistance R 14 is connected to contact terminal T5.
At switching circuit shown in Figure 15---be another example of the configuration of switching circuit C5, C6, C7A and C7B among above-mentioned the 5th to the 7th embodiment.Switching circuit shown in Figure 15 is provided with: bidirectional triode thyristor TRI15; Resistance R 15; Contact terminal T4 and T5; And control terminal T6.The gate pole of bidirectional triode thyristor TRI15 is connected to an end of control terminal T6 and resistance R 15, and the anode of bidirectional triode thyristor TRI15 is connected to contact terminal T4, and the other end of the negative electrode of TRI15 and resistance R 15 is connected to contact terminal T5.
< the tenth embodiment >
Then, shown in Figure 16 according to the configuration of the led drive circuit of the tenth embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 16 is provided with: bridge diode 2; Constant-current circuit A16; Switching circuit C16; Resistance R 16_1 to R16_3; And positive temperature coefficient (below be called " PTC resistance ") RP16.Notice that switching circuit C16 is configured to Figure 14 or that kind shown in Figure 15.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A16 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A16 is connected to the contact terminal T4 of switching circuit C16.The contact terminal T5 of switching circuit C16 is connected to another output of bridge diode 2.And the end of resistance R 16_1 is connected to the negative electrode of led module 3, and the other end of resistance R 16_1 is connected to the bias current terminal T3 of constant-current circuit A16 and the end of resistance R 16_2.The other end of resistance R 16_2 is connected to the control terminal T6 of switching circuit C16 and the end of resistance R 16_3 through PTC resistance R P16.The other end of resistance R 16_3 is connected to another output of bridge diode 2.
Bias current is fed to the control terminal T6 of switching circuit C16 through resistance R 16_1 and R16_2 and PTC resistance R P16 from the negative electrode of led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A16) set to constant-current circuit A16.
In the led drive circuit of present embodiment shown in Figure 16; Along with ambient temperature rises; The resistance value of PTC resistance R P16 increases, so the delay of the phase angle of thyristor among the switching circuit C16 or bidirectional triode thyristor, and consequently the constant current value of constant-current circuit A16 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 16 reaches predefined specified level or when higher; The thyristor among the switching circuit C16 or the gate current of bidirectional triode thyristor are not enough; Therefore; Switching circuit C16 is placed in off-state, and constant-current circuit A16 is placed in off-state.
< the 11 embodiment >
Shown in Figure 17 according to the configuration of the led drive circuit of the 11st embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 17 is provided with: bridge diode 2; Constant-current circuit A17; Switching circuit C17; Resistance R 17_1 to R17_3; Positive temperature coefficient resistor (below be called " PTC resistance ") RP17; And capacitor C AP17.Notice that switching circuit C17 is configured to that kind shown in Figure 14 or 15.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A17 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A17 is connected to the contact terminal T4 of switching circuit C17.The contact terminal T5 of switching circuit C17 is connected to another output of bridge diode 2.And an end of resistance R 171 is connected to the negative electrode of led module 3, and the other end of resistance R 17_1 is connected to the bias current terminal T3 of constant-current circuit A17 and the end of resistance R 17_2.The other end of resistance R 17_2 is connected to the control terminal T6 of switching circuit C17, the end of resistance R 17_3 and the end of capacitor C AP17 through PTC resistance R P17.The other end of the other end of resistance R 17_3 and capacitor C AP17 is connected to another output of bridge diode 2.
Bias current is fed to the control terminal T6 of switching circuit C17 through resistance R 17_1 and R17_2 and PTC resistance R P17 from the negative electrode of led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A17) set to constant-current circuit A17.
In the led drive circuit of present embodiment shown in Figure 17; Along with ambient temperature rises; The resistance value of PTC resistance R P17 increases; Therefore the thyristor among the switching circuit C17 or the phase angle of bidirectional triode thyristor postpone according to the resistance value of PTC resistance R P17 and the capacitance of capacitor C AP17, and consequently the constant current value of constant-current circuit A17 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 17 reaches predefined specified level or when higher; The phase place Rotate 180 of thyristor among the switching circuit C17 or bidirectional triode thyristor °; Therefore; Switching circuit C17 is placed in off-state, and constant-current circuit A17 is placed in off-state.
< the 12 embodiment >
Shown in Figure 18 according to the configuration of the led drive circuit of the 12nd embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 180 is provided with: bridge diode 2; Constant-current circuit A18; Switching circuit C18; Resistance R 18_1 to R18_3; And positive temperature coefficient resistor (below be called " PTC resistance ") RP18.Notice that switching circuit C18 is configured to that kind shown in Figure 14 or 15.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A18 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A18 is connected to the contact terminal T4 of switching circuit C18.The contact terminal T5 of switching circuit C18 is connected to another output of bridge diode 2.And the end of resistance R 18_1 is connected to the negative electrode of led module 3, and the other end of resistance R 18_1 is connected to the bias current terminal T3 of constant-current circuit A18 and the end of resistance R 18_2.The other end of resistance R 18_2 is connected to the end of PTC resistance R P18 and the end of resistance R P18_3.The other end of PTC resistance R P18 is connected to the control terminal T6 of switching circuit C18.The other end of resistance R 18_3 is connected to another output of bridge diode 2.
Bias current is fed to the control terminal T6 of switching circuit C18 through resistance R 18_1 and R18_2 and PTC resistance R P18 from the negative electrode of led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A18) set to constant-current circuit A18.
In the led drive circuit of present embodiment shown in Figure 180; Along with ambient temperature rises; The resistance value of PTC resistance R P18 increases, so the phase delay of thyristor among the switching circuit C18 or bidirectional triode thyristor, and consequently the constant current value of constant-current circuit A18 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 180 reaches predefined specified level or when higher; The thyristor among the switching circuit C18 or the gate current of bidirectional triode thyristor are not enough; Therefore; Switching circuit C18 is placed in off-state, and constant-current circuit A18 is placed in off-state.
< the 13 embodiment >
Shown in Figure 19 according to the configuration of the led drive circuit of the 13rd embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 19 is provided with: bridge diode 2; Constant-current circuit A19; Switching circuit C19; Resistance R 19_1 to R19_3; Positive temperature coefficient resistor (below be called " PTC resistance ") RP19_1 and RP19_2.Notice that switching circuit C19 is configured to that kind shown in Figure 14 or 15.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A19 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A19 is connected to the contact terminal T4 of switching circuit C19.The contact terminal T5 of switching circuit C19 is connected to another output of bridge diode 2.And the end of resistance R 19_1 is connected to the negative electrode of led module 3, and the other end of resistance R 19_1 is connected to the bias current terminal T3 of constant-current circuit A19 and the end of resistance R 19_2.The other end of resistance R 19_2 is connected to the end of PTC resistance R P19_2 and the end of resistance R 19_3 through PTC resistance R P19_1.The other end of PTC resistance R P19_2 is connected to the control terminal T6 of switching circuit C19.The other end of resistance R 19_3 is connected to another output of bridge diode 2.
Can bias current be fed to the control terminal T6 of switching circuit C19 through resistance R 19_1 and R19_2 and then through PTC resistance R P19_1 and RP19_2 from the negative electrode of led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value; Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A19) set to constant-current circuit A19.
In the led drive circuit of present embodiment shown in Figure 19; Along with ambient temperature rises; The resistance value of PTC resistance R P19_1 and RP19_2 increases; Therefore the phase angle of thyristor among the switching circuit C19 or bidirectional triode thyristor postpones, and consequently the constant current value of constant-current circuit A19 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 19 reaches predefined specified level or when higher; The thyristor among the switching circuit C19 or the gate current of bidirectional triode thyristor are not enough; Therefore; Switching circuit C19 is placed in off-state, and constant-current circuit A19 is placed in off-state.
< the 14 embodiment >
The configuration of the led drive circuit shown in Figure 21 in the 14th embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 21 is provided with: bridge diode 2; Constant-current circuit A21, B21_1 and B21_2; NPN transistor Q21_1 and Q21_2; Resistance R 21; And positive temperature coefficient resistor (below be called " PTC resistance ") RP21.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A21 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A21 is connected to another output of bridge diode 2.The collector electrode of NPN transistor Q21_1 is connected to the negative electrode of led module 3, and the emitter of NPN transistor Q21_1 is connected to the bias current terminal T3 of constant-current circuit A21 through resistance R 21.And constant-current circuit B21_1 is connected between the negative electrode of base stage and led module 3 of NPN transistor Q21_1.The collector electrode of NPN transistor Q21_2 is connected to the base stage of NPN transistor Q21_1, and the emitter of NPN transistor Q21_2 is identical with constant-current circuit T2, is connected to another output of bridge diode 2.And constant-current circuit B21_2 is arranged between the base stage of negative electrode and NPN transistor Q21_2 of led module 3, and PTC resistance R P21 is arranged between the base stage and emitter of NPN transistor Q21_2.
NPN transistor Q21_1 is controlled by constant-current circuit B21_1 and NPN transistor Q21_2, thereby presents bias current to the bias current terminal T3 of constant-current circuit A21.In the led drive circuit of present embodiment shown in Figure 21; Thereby the bias current that the base current restriction of NPN transistor Q21_2 control NPN transistor Q21_1 is presented to the bias current terminal T3 of constant-current circuit A21; So that the output of restriction constant-current circuit A21, thereby this constant-current circuit A21 presents constant current driving LED module 3 to led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and be applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A21) set to constant-current circuit A21.
In the led drive circuit of present embodiment shown in Figure 21, along with ambient temperature rises, then the resistance value of PTC resistance R P21 increases, and causes the base stage of NPN transistor Q21_2 and the voltage between the emitter to increase.Thereby the base current of NPN transistor Q21_1 reduces, and the bias current of presenting to bias current terminal T3 reduces, and therefore, the constant current of constant-current circuit A21 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 21 reaches predefined specified level or when higher, NPN transistor Q21_1 is placed in off-state, does not consequently present bias current to the bias current terminal T3 of constant-current circuit A21.Therefore, constant-current circuit A21 is placed in off-state.
PTC resistance R P21 is being arranged under the base stage and the situation between the emitter of NPN transistor Q21_2; Through setting its resistance value for suitable value; For PTC resistance R P21, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
< the 15 embodiment >
Shown in Figure 22 according to the configuration of the led drive circuit of the 15th embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 22 is provided with: bridge diode 2; Constant-current circuit A22 and B22; NPN transistor Q22_1 and Q22_2; Resistance R 22_1 and R22_2; And positive temperature coefficient resistor (below be called " PTC resistance ") RP22.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A22 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A22 is connected to another output of bridge diode 2.The collector electrode of NPN transistor Q22_1 is connected to the negative electrode of led module 3, and the emitter of NPN transistor Q22_1 is connected to the bias current terminal T3 of constant-current circuit A22 through resistance R 22_1.And resistance R 22_2 is connected between the negative electrode of base stage and led module 3 of NPN transistor Q22_1.The collector electrode of NPN transistor Q22_2 is connected to the base stage of NPN transistor Q22_1, and the emitter of NPN transistor Q22_2 is identical with constant current terminal T2, is connected to another output of bridge diode 2.And constant-current circuit B22 is arranged between the base stage of negative electrode and NPN transistor Q22_2 of led module 3, and PTC resistance R P22 is arranged between the base stage and emitter of NPN transistor Q22_2.
NPN transistor Q22_1 is controlled by resistance R 22_2 and NPN transistor Q22_2, thereby presents bias current to the bias current terminal T3 of constant-current circuit A22.In the led drive circuit of present embodiment shown in Figure 22; Thereby the bias current that the base current restriction of NPN transistor Q22_2 control NPN transistor Q22_1 is presented to the bias current terminal T3 of constant-current circuit A22; So that the output of restriction constant-current circuit A22, thereby this constant-current circuit A22 presents constant current driving LED module 3 to led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A22) set to constant-current circuit A22.
In the led drive circuit of present embodiment shown in Figure 22, along with ambient temperature rises, the resistance value of PTC resistance R P22 increases, and causes the base stage of NPN transistor Q22_2 and the voltage between the emitter to increase.Thereby the base current of NPN transistor Q22_1 reduces, and the bias current of therefore presenting to bias current terminal T3 reduces, and consequently the constant current value of constant-current circuit A22 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 22 reaches predefined specified level or when higher, NPN transistor Q22_1 is placed in off-state, does not consequently present bias current to the bias current terminal T3 of constant-current circuit A22.Therefore, constant-current circuit A22 is placed in off-state.
PTC resistance R P22 is being arranged under the base stage and the situation between the emitter of NPN transistor Q22_2; Through setting its resistance value for suitable value; For PTC resistance R P22, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
< the 16 embodiment >
Shown in Figure 23 according to the configuration of the led drive circuit of the 16th embodiment of the present invention.The led drive circuit of present embodiment shown in Figure 23 is provided with: bridge diode 2; Constant-current circuit A23; NPN transistor Q23_1 and Q23_2; Resistance R 23_1 to R23_3; And positive temperature coefficient resistor (below be called " PTC resistance ") RP23.
The input of bridge diode 2 is connected to commercial AC 100V power supply 1, and an output of bridge diode 2 is connected to the anode of led module 3.The constant current terminal T1 of constant-current circuit A23 is connected to the negative electrode of led module 3, and the constant current terminal T2 of constant-current circuit A23 is connected to another output of bridge diode 2.The collector electrode of NPN transistor Q23_1 is connected to the negative electrode of led module 3, and the emitter of NPN transistor 23_1 is connected to the bias current terminal T3 of constant-current circuit A23 through resistance R 23_1.And resistance R 23_2 is connected between the negative electrode of base stage and led module 3 of NPN transistor Q23_1.The collector electrode of NPN transistor Q23_2 is connected to the base stage of NPN transistor Q23_1, and the emitter of NPN transistor R23_2 is identical with constant current terminal T2, is connected to another output of bridge diode 2.And resistance 23_3 is arranged between the base stage of negative electrode and NPN transistor Q23_2 of led module 3, and PTC resistance R P23 is arranged between the base stage and emitter of NPN transistor Q23_2.
NPN transistor Q23_1 is controlled by resistance R 23_2 and NPN transistor Q23_2, thereby presents bias current to the bias current terminal T3 of constant-current circuit A23.In the led drive circuit of present embodiment shown in Figure 23; Thereby the bias current that the base current restriction of NPN transistor Q23_2 control NPN transistor Q23_1 is presented to the bias current terminal T3 of constant-current circuit A23; So that the output of restriction constant-current circuit A23, thereby this constant-current circuit A23 presents constant current driving LED module 3 to led module 3.
Carry out full-wave rectification from the AC voltage of commercial AC100V power supply 1 output by bridge diode 2, be about the pulsating voltage of 141V and it is applied to led module 3 thereby obtain its peak value.Therefore, the electric current that flows through led module 3 also becomes pulsation, and its peak value equals the value (constant current value of constant-current circuit A23) set to constant-current circuit A23.
In the led drive circuit of present embodiment shown in Figure 23, along with ambient temperature rises, the resistance value of PTC resistance R P23 increases, and causes the base stage of NPN transistor Q23_2 and the voltage between the emitter to increase.Thereby the base current of NPN transistor Q23_1 reduces, and the bias current of presenting to bias current terminal T3 reduces, and therefore, the constant current value of constant-current circuit A23 is restricted.When the ambient temperature of the led drive circuit of present embodiment shown in Figure 23 reaches predefined specified level or when higher, NPN transistor Q23_1 is placed in off-state, does not consequently present bias current to the bias current terminal T3 of constant-current circuit A23.Therefore, constant-current circuit A23 is placed in off-state.
PTC resistance R P23 is being arranged under the base stage and the situation between the emitter of NPN transistor Q23_2; Through setting its resistance value for suitable value; For PTC resistance R P23, can use the lower device of its rated power or its withstand voltage not high device, and can not go wrong.
And resistance R 23_3 presents base current to NPN transistor Q23_2, and the electric current that flows through resistance 23_2 is used to control NPN transistor Q23_1, and this NPN transistor Q23_1 presents bias current to the bias current terminal T3 of constant-current circuit A23.As long as set the resistance value of resistance R 23_3 for suitable value; Even do not reach temperature to the overtemperature protection operating and setting; When led module 3 grades become unusually (short circuit or near short circuit) cause applying under the voltage condition beyond the regular event scope to constant-current circuit A23; The base stage of NPN transistor Q23_2 and the voltage between the emitter rise; The base stage of NPN transistor Q23_1 and the voltage between the emitter reduce, and the bias current of presenting to bias current terminal T3 reduces, so the constant current value of constant-current circuit A23 is restricted.Thereby, the overheating protection circuit that can resistance R 23_3 be limited with the constant current value of doing constant-current circuit A23.
< other >
In switching circuit shown in Figure 14, thyristor TTY14 can replace with photosensitive thyristor, and in switching circuit shown in Figure 15, bidirectional triode thyristor TRI15 can replace with photosensitive bidirectional triode thyristor.For this reason, the cathode leg on the input side needs ground connection.
The input voltage of led drive circuit of the present invention is not limited to the commercial 100V voltage that provides in Japan.Through setting the circuit constant of led drive circuit of the present invention for suitable value, thus can be with other country at the commercial voltage that provides or the alternating voltage after the step-down input voltage as led drive circuit of the present invention.
And, through led drive circuit of the present invention is added the protection device such as current fuse, safer LED drive unit can be provided.
And; In each figure of the Fig. 1 to 19 Figure 10 to Figure 15 and Figure 21 to 23; Not only can an end of constant-current circuit from electric current to the corresponding resistance with plus or minus temperature coefficient that present or resistance be connected to the negative electrode of led module, thus but also can be through setting current value or resistance value for anode that suitable value is connected to led module.
For example, in the situation of Fig. 1, the end of NTC resistance R N1 is connected to the negative electrode of led module 3, and in the situation of Fig. 5, the end of constant-current circuit B5 is connected to the negative electrode of led module 3.Each end also can be connected to the anode of led module 3.
Thus, guaranteed before constant-current circuit A1 to A19 starts, make constant-current circuit A1 to A19 and switching circuit C5 to C19 conducting and disconnection reliably or limit it.
And; Through from the switching circuit shown in the constant-current circuit shown in Figure 10 to 13 and Figure 14 and 15, suitably selecting constant-current circuit and switching circuit respectively; And they are suitably connected, thereby can the led drive circuit that be equipped with overheat protective function be connected between the anode of bridge diode and led module.
Overtemperature protection portion is the part that is formed by thermistor etc., and the resistance value of this thermistor has bigger variation with temperature, and when superheating phenomenon takes place when the restriction electric current.Thermistors etc. are arranged near heating region or its, and it is overheated to detect.And that light adjusting circuit is set is identical with the incandescent lamp of control light etc. with some back level at the AV power supply, light adjusting circuit also can be set with control light in a circuit according to the invention.

Claims (29)

1. led drive circuit, this led drive circuit driving LED is characterized in that, comprising:
Rectification circuit, said rectification circuit converts alternating voltage to pulsating voltage;
Constant-current circuit; And
Overtemperature protection portion, said overtemperature protection portion limits the output of said constant-current circuit,
Wherein said LED and said constant-current circuit are connected in series on the outlet side of said rectification circuit,
Said constant-current circuit and the not shared identical components and parts of said overtemperature protection portion.
2. led drive circuit as claimed in claim 1 is characterized in that,
Said overtemperature protection portion comprises:
The PNP transistor; And
Resistance, said resistance has negative temperature coefficient, and is arranged between transistorized base stage of said PNP and the emitter.
3. led drive circuit as claimed in claim 2 is characterized in that,
The transistorized said emitter and collector of said PNP is connected to the path of circulate among from the constant current of said constant-current circuit output.
4. led drive circuit as claimed in claim 2 is characterized in that,
Said overtemperature protection portion also comprises:
Constant-current source, said constant-current source is connected in series with the said resistance with said negative temperature coefficient,
Magnitude of voltage between transistorized said base stage of wherein said PNP and the said emitter is the product that multiplies each other and obtain through with the constant current value of said constant-current source and the resistance value with said resistance of said negative temperature coefficient.
5. led drive circuit as claimed in claim 2 is characterized in that,
Said overtemperature protection portion also comprises:
Resistive element, said resistive element is connected in series with the said resistance with said negative temperature coefficient,
Magnitude of voltage between transistorized said base stage of wherein said PNP and the emitter is the product that current value and the resistance value with said resistance of said negative temperature coefficient through the electric current that will flow through said resistance with said negative temperature coefficient and said resistive element multiplies each other and obtain.
6. led drive circuit as claimed in claim 1 is characterized in that,
Said overtemperature protection portion comprises:
NPN transistor; And
Resistance, said resistance has negative temperature coefficient, and is arranged between the base stage and emitter of said NPN transistor,
The said emitter and collector of said NPN transistor is connected to the path of circulate among from the constant current of said constant-current circuit output.
7. led drive circuit as claimed in claim 1 is characterized in that, also comprises:
Switching circuit, said switching circuit switch the conducting and the disconnection of said constant-current circuit,
Wherein said LED, said constant-current circuit and said switching circuit are connected in series on the outlet side of said rectification circuit, and
Said overtemperature protection portion controls said switching circuit.
8. led drive circuit as claimed in claim 7 is characterized in that,
Said overtemperature protection portion comprises:
Bipolar transistor, said bipolar transistor is presented bias current to the control terminal of said switching circuit; And
Resistance, said resistance has negative temperature coefficient, and the one of which end is connected to the base stage of said bipolar transistor,
The said base stage of wherein said bipolar transistor and the voltage between the emitter change according to the resistance value with said resistance of said negative temperature coefficient.
9. led drive circuit as claimed in claim 7 is characterized in that,
Said overtemperature protection portion comprises:
NPN transistor, said NPN transistor will be pulled out to the bias current that the control terminal of said switching circuit is presented; And
Resistance, said resistance has positive temperature coefficient, and the one of which end is connected to the base stage of said NPN transistor,
The said base stage of wherein said NPN transistor and the voltage between the emitter change according to the resistance value with said resistance of said positive temperature coefficient.
10. led drive circuit as claimed in claim 8 is characterized in that,
Said overtemperature protection portion also comprises:
Constant-current source, said constant-current source is connected in series with the said resistance with said negative temperature coefficient,
The said base stage of wherein said bipolar transistor and the magnitude of voltage between the emitter are the products that multiplies each other and obtain through with the constant current value of said constant-current source and the resistance value with said resistance of said negative temperature coefficient.
11. led drive circuit as claimed in claim 9 is characterized in that,
Said overtemperature protection portion also comprises:
Constant-current source, said constant-current source is connected in series with the said resistance with said positive temperature coefficient,
The said base stage of wherein said NPN transistor and the magnitude of voltage between the emitter are the products that multiplies each other and obtain through with the constant current value of said constant-current source and the resistance value with said resistance of said positive temperature coefficient.
12. led drive circuit as claimed in claim 8 is characterized in that,
Said overtemperature protection portion also comprises:
Resistive element, said resistive element is connected in series with the said resistance with said negative temperature coefficient,
The said base stage of wherein said bipolar transistor and the magnitude of voltage between the emitter are the products that value and the resistance value with said resistance of said negative temperature coefficient through the electric current that will flow through said resistance with said negative temperature coefficient and said resistive element multiplies each other and obtain.
13. led drive circuit as claimed in claim 9 is characterized in that,
Said overtemperature protection portion also comprises:
Resistive element, said resistive element is connected in series with the said resistance with said positive temperature coefficient,
The said base stage of wherein said NPN transistor and the magnitude of voltage between the emitter are the products that value and the resistance value with said resistance of said positive temperature coefficient through the electric current that will flow through said resistance with said positive temperature coefficient and said resistive element multiplies each other and obtain.
14. led drive circuit as claimed in claim 1 is characterized in that,
Said overtemperature protection portion comprises:
NPN transistor, said NPN transistor will be pulled out to the bias current that said constant-current circuit is presented; And
Resistance, said resistance has positive temperature coefficient, and is arranged between the base stage and emitter of said NPN transistor.
15. led drive circuit as claimed in claim 14 is characterized in that,
Said overtemperature protection portion comprises:
Constant-current source, said constant-current source is connected in series with the said resistance with said positive temperature coefficient,
The said base stage of wherein said NPN transistor and the magnitude of voltage between the emitter are the products that multiplies each other and obtain through with the constant current value of said constant-current source and the resistance value with said resistance of said positive temperature coefficient.
16. led drive circuit as claimed in claim 14 is characterized in that,
Said overtemperature protection portion also comprises:
Resistive element, said resistive element is connected in series with the said resistance with said positive temperature coefficient,
The said base stage of wherein said NPN transistor and the magnitude of voltage between the emitter are the products that value and the resistance value with said resistance of said positive temperature coefficient through the electric current that will flow through said resistance with said positive temperature coefficient and said resistive element multiplies each other and obtain.
17. led drive circuit as claimed in claim 14 is characterized in that,
Said overtemperature protection portion also comprises:
Another resistance, said another resistance has positive temperature coefficient, and is arranged with the said resistance branch with said positive temperature coefficient,
Said another resistance that wherein has said positive temperature coefficient is set to said constant-current circuit to be presented on the path of said bias current.
18. led drive circuit as claimed in claim 1 is characterized in that,
Said overtemperature protection portion comprises:
Npn bipolar transistor, said npn bipolar transistor is presented bias current to the bias current terminal of said constant-current circuit;
Control is with the npn bipolar transistor and first constant-current source, and said control is connected to the base stage of said npn bipolar transistor respectively with the npn bipolar transistor and first constant-current source, and is used to control said bias current;
Resistance, said resistance has positive temperature coefficient, and the one of which end is connected to the base stage of said control with npn bipolar transistor; And
Second constant-current source, said second constant-current source is connected in series with the said resistance with said positive temperature coefficient,
Wherein said control is the product that multiplies each other and obtain through with the constant current value of said second constant-current source and the resistance value with said resistance of said positive temperature coefficient with the said base stage of NPN transistor and the magnitude of voltage between the emitter.
19. led drive circuit as claimed in claim 1 is characterized in that,
Said overtemperature protection portion comprises:
Npn bipolar transistor, said npn bipolar transistor is presented bias current to the bias current terminal of said constant-current circuit;
Control is with npn bipolar transistor and resistive element, and said control is connected to the base stage of said npn bipolar transistor respectively with npn bipolar transistor and resistive element, and is used to control said bias current;
Resistance, said resistance has positive temperature coefficient, and the one of which end is connected to the base stage of said control with NPN transistor; And
Constant-current source, said constant-current source is connected in series with the said resistance with said positive temperature coefficient,
Wherein said control is the product that multiplies each other and obtain through with the constant current value of said constant-current source and the resistance value with said resistance of said positive temperature coefficient with the said base stage of npn bipolar transistor and the magnitude of voltage between the emitter.
20. led drive circuit as claimed in claim 1 is characterized in that,
Said overtemperature protection portion comprises:
Npn bipolar transistor, said npn bipolar transistor is presented bias current to the bias current terminal of said constant-current circuit;
Control is with the npn bipolar transistor and first resistive element, and said control is connected to the base stage of said npn bipolar transistor respectively with the npn bipolar transistor and first resistive element, and is used to control said bias current;
Resistance, said resistance has positive temperature coefficient, and the one of which end is connected to the base stage of said control with NPN transistor; And
Second resistive element, said second resistive element is connected in series with the said resistance with said positive temperature coefficient,
Wherein said control is the product that value and the resistance value with said resistance of said positive temperature coefficient of the electric current through will flowing through said resistance with said positive temperature coefficient and said second resistive element multiplies each other and obtain with the said base stage of NPN transistor and the magnitude of voltage between the emitter.
21. led drive circuit as claimed in claim 1 is characterized in that,
Said constant-current circuit comprises:
First resistance;
Zener diode; And
First bipolar transistor, the emitter of said first bipolar transistor are connected to an end of said first resistance, and the base stage of said first bipolar transistor is connected to an end of said Zener diode.
22. led drive circuit as claimed in claim 1 is characterized in that,
Said constant-current circuit comprises:
First bipolar transistor;
Second bipolar transistor;
First resistance, an end of said first resistance is connected to the base stage of said second bipolar transistor; And
Second resistance, said second resistance are arranged between the base stage and emitter of said first bipolar transistor,
The said base stage of the collector electrode of wherein said first bipolar transistor and said second bipolar transistor links together, and the emitter of the said base stage of said first bipolar transistor and said second bipolar transistor links together.
23. led drive circuit as claimed in claim 7 is characterized in that,
Said switching circuit comprises:
Thyristor or bidirectional triode thyristor; And
First resistance, said first resistance is arranged between the gate pole and negative electrode of said thyristor or said bidirectional triode thyristor.
24. led drive circuit as claimed in claim 7 is characterized in that,
Said switching circuit comprises:
Thyristor or bidirectional triode thyristor; And
First resistance, said first resistance are arranged between the gate pole and negative electrode of said thyristor or said bidirectional triode thyristor,
And
Said overtemperature protection portion comprises:
Resistance, said resistance has positive temperature coefficient, and is arranged on to the said gate pole of said thyristor or said bidirectional triode thyristor and presents on the path of bias current; And
Resistive element, said resistive element are arranged between the cathode output end of said gate pole and said rectification circuit of said thyristor or said bidirectional triode thyristor.
25. led drive circuit as claimed in claim 24 is characterized in that,
Said overtemperature protection portion comprises:
Electric capacity, said electric capacity and said resistive element are connected in parallel.
26. led drive circuit as claimed in claim 7 is characterized in that,
Said switching circuit comprises:
Thyristor or bidirectional triode thyristor; And
First resistance, said first resistance has positive temperature coefficient, and is arranged between the gate pole and negative electrode of said thyristor or said bidirectional triode thyristor,
And
Said overtemperature protection portion comprises:
Resistance, said resistance has positive temperature coefficient, and the one of which end is connected to the said gate pole of said thyristor or said bidirectional triode thyristor; And
Resistive element, said resistive element are arranged between the cathode output end of the other end and said rectification circuit of the said resistance with said positive temperature coefficient.
27. led drive circuit as claimed in claim 26 is characterized in that,
Said overtemperature protection portion also comprises:
Another resistance, said another resistance has positive temperature coefficient, and is arranged with the said resistance branch with said positive temperature coefficient,
Said another resistance that wherein has positive temperature coefficient is arranged on to the said gate pole of said thyristor or said bidirectional triode thyristor to be presented on the path of bias current.
28. led drive circuit as claimed in claim 1 is characterized in that,
When said constant-current circuit reaches predetermined temperature or when higher, said overtemperature protection portion limits the said output of said constant-current circuit.
29. led drive circuit as claimed in claim 1 is characterized in that,
When said led module reaches predetermined temperature or when higher, said overtemperature protection portion limits the said output of said constant-current circuit.
CN2009101592886A 2008-08-06 2009-08-06 Led drive circuit Expired - Fee Related CN101646290B (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015000221A1 (en) * 2013-07-04 2015-01-08 京东方科技集团股份有限公司 Driving circuit and light-emitting device

Families Citing this family (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102261583A (en) * 2010-05-24 2011-11-30 台达电子工业股份有限公司 Light source module
US8680790B2 (en) * 2011-03-10 2014-03-25 Tyco Electronics Corporation Electrical connector for connecting a light emitting diode (LED) to a driver
CN102685967A (en) * 2011-03-11 2012-09-19 亿广科技(上海)有限公司 Light-emitting diode (LED) driving circuit
JP5887524B2 (en) * 2011-04-19 2016-03-16 パナソニックＩｐマネジメント株式会社 Power supply
CN102223748A (en) * 2011-06-17 2011-10-19 苏州半导体总厂有限公司 Drive method and drive power source of light-emitting diode (LED) lamp with alternating current power supply
DE102011088407A1 (en) * 2011-12-13 2013-06-13 Osram Gmbh Circuit arrangement and method for operating an LED chain and lighting device with such a circuit arrangement and an LED chain
CN103200729B (en) * 2012-01-10 2015-02-04 四川新力光源股份有限公司 Light emitting diode (LED) luminous device directly driven in constant current by alternating current
CN103200728B (en) * 2012-01-10 2015-02-04 四川新力光源股份有限公司 White-light light emitting diode (LED) luminous device directly driven in constant current by alternating current
KR102028170B1 (en) * 2012-08-13 2019-10-02 삼성에스디아이 주식회사 cell balancing circuit and battery pack having the same
TW201413684A (en) * 2012-09-17 2014-04-01 Luxul Technology Inc Full voltage serial and parallel LED lamp
US9456484B2 (en) * 2012-10-19 2016-09-27 Epistar Corporation Light-emitting device circuit and method of operating thereof
JP2013080717A (en) * 2012-12-26 2013-05-02 T-Net Japan Co Ltd Led lighting fixture
CN104093238B (en) * 2014-06-24 2016-05-11 苏州达方电子有限公司 In the time of high temperature, can reduce the power supply changeover device of light emitting diode drive current
CN105704855A (en) * 2016-01-04 2016-06-22 京东方光科技有限公司 Induction lamp and driving method thereof
CN208107667U (en) * 2016-01-22 2018-11-16 嘉兴山蒲照明电器有限公司 A kind of LED straight lamp, ballast bypass type LED straight lamp and straight tube lamp system
CN106877287B (en) * 2017-04-05 2019-03-26 京东方科技集团股份有限公司 A kind of thermal-shutdown circuit and driving method
CN109936887A (en) * 2017-12-15 2019-06-25 松下知识产权经营株式会社 HF switch driving power, excess temperature protection method and the lighting device using the high frequency switch power
CN108968826A (en) * 2018-08-22 2018-12-11 深圳市云鼠科技开发有限公司 A kind of small-power constant-current circuit applied to sweeping robot control circuit board
DE112020002722B4 (en) 2019-05-28 2023-03-02 Murata Manufacturing Co., Ltd. LED DRIVER CIRCUIT

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4528492A (en) * 1983-04-05 1985-07-09 Hitachi Koki Company, Limited Battery charger
CN1035392A (en) * 1988-01-25 1989-09-06 西屋电气公司 Have overtemperature protection and low error I 2The circuit breaker of t calculation element
CN101032188A (en) * 2004-08-04 2007-09-05 詹姆斯·K·吴 Led lighting system

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS585085U (en) * 1981-06-30 1983-01-13 トヨタ自動車株式会社 Vehicle light emitting diode display circuit
JPS6315078U (en) * 1986-07-15 1988-02-01
JP3265849B2 (en) * 1994-09-16 2002-03-18 富士電機株式会社 Self-extinguishing element with overheat protection device
JP2000022263A (en) * 1998-06-29 2000-01-21 Murata Mfg Co Ltd Semiconductor laser driving circuit and semiconductor laser
JP2001025151A (en) * 1999-07-05 2001-01-26 Crown Denso:Kk Control power guarantee type of protective current against overcurrent
JP4034199B2 (en) * 2003-02-04 2008-01-16 松下電器産業株式会社 Optical beacon LED drive circuit
JP2006040584A (en) * 2004-07-22 2006-02-09 Matsushita Electric Works Ltd Led lighting device and illumination device incorporating the same
JP2008125339A (en) * 2006-10-17 2008-05-29 Kanazawa Inst Of Technology Inrush current prevention circuit, load drive circuit, and light-emitting device using them
JP2008166192A (en) * 2006-12-28 2008-07-17 Atex Co Ltd Power supply circuit for driving led

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4528492A (en) * 1983-04-05 1985-07-09 Hitachi Koki Company, Limited Battery charger
CN1035392A (en) * 1988-01-25 1989-09-06 西屋电气公司 Have overtemperature protection and low error I 2The circuit breaker of t calculation element
CN101032188A (en) * 2004-08-04 2007-09-05 詹姆斯·K·吴 Led lighting system

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2015000221A1 (en) * 2013-07-04 2015-01-08 京东方科技集团股份有限公司 Driving circuit and light-emitting device

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