CN101169918A - Light source drive circuit - Google Patents

Light source drive circuit Download PDF

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Publication number
CN101169918A
CN101169918A CNA2006101425273A CN200610142527A CN101169918A CN 101169918 A CN101169918 A CN 101169918A CN A2006101425273 A CNA2006101425273 A CN A2006101425273A CN 200610142527 A CN200610142527 A CN 200610142527A CN 101169918 A CN101169918 A CN 101169918A
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China
Prior art keywords
circuit
pulse width
width signal
light
light adjusting
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CNA2006101425273A
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CN101169918B (en
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陈弼先
赵翰楀
林信彰
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CPT DISPLAY TECHNOLOGY (SHENZHEN)CO., LTD.
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Chunghwa Picture Tubes Ltd
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B20/00—Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
    • Y02B20/40—Control techniques providing energy savings, e.g. smart controller or presence detection

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Abstract

A light source driving circuit for driving a light emitting element comprises a power supply circuit, a light adjusting circuit, and a feedback circuit/control circuit, wherein the power supply circuit is coupled with one end of a light emitting element; the light adjusting circuit is coupled with the other end of the light emitting element; and the feedback circuit/control circuit is coupled between the power supply circuit and the light adjusting circuit. When the light source drive circuit turns off the power supply circuit to stop supplying power to the light emitting element, the feedback circuit/control circuit delays the time point for switching off the light adjusting circuit so as to prevent the light adjusting circuit from being broken down by over-high voltage.

Description

Light source driving circuit
Technical field
The invention relates to a kind of driving circuit, and particularly relevant for a kind of light source driving circuit of driven light-emitting element.
Background technology
Light source driving circuit is widely used in the various display device, the light emitting diode of for example backlight liquid crystal display driving circuit, or hand held device (LED) driving circuit.Because display device is seen in day by day in the electronic product of various kinds, so light source driving circuit just has the development potentiality of height.Wherein there are many advantages to be enhanced constantly and to promote, comprise that energy conversion efficiency increases, stability promotes or the like.
Known framework in order to the light source driving circuit that drives a light emitting diode string 101 as shown in Figure 1, wherein light emitting diode string 101 is made up of the light emitting diode 102 of a plurality of serial connections.This known light source driving circuit comprises DC-DC power supply converter 103, electric capacity 104, output voltage feedback loop 105, sequential control circuit 106 and light adjusting circuit 107.Wherein light adjusting circuit 107 is coupled between the negative electrode and common electric potential GND of light emitting diode string 101, and receives the pulse width signal PWM that sequential control circuit 106 is exported.In addition, output voltage feedback loop 105 utilizes the resistance of two series connection, is respectively 108 and 109 and implements.
DC-DC power supply converter 103 supplying DC power source voltages are given light emitting diode string 101, and feedback control and output DC source voltage stably according to the feedback signal FB that output voltage feedback loop 105 received.Sequential control circuit 106 determines the width of the pulse width signal PWM that it is exported according to the brightness that the user sets.Conducting when light adjusting circuit 107 is in noble potential at pulse width signal PWM, and when pulse width signal PWM is in electronegative potential, close.See through the width of adjusting pulse width signal PWM, just can control the conducting state of light adjusting circuit 107, whether flow through electric current to control light emitting diode string 101 further.
So, when setting brightness when brighter, it is longer that pulse width signal PWM presents time of noble potential, make the ON time of light adjusting circuit 107 longer, thereby the brightness of light emitting diode string 101 is also brighter.Otherwise when setting brightness was dark, it is shorter that pulse width signal PWM presents the time of noble potential, make the ON time of light adjusting circuit 107 shorter, thereby the brightness of light emitting diode string 101 is also darker.
Yet, when pulse width signal PWM is in electronegative potential, light adjusting circuit 107 is closed (being the negative electrode of light emitting diode string 101 and the not conducting of electrical path between the common electric potential GND), and this moment, the pressure drop of the direct supply voltage that DC-DC power supply converter 103 is supplied all dropped on the light adjusting circuit 107.When a lot of light emitting diode 102 of light emitting diode string 101 series connection, the magnitude of voltage of the direct supply voltage that DC-DC power supply converter 103 is supplied will be very high.
In the case, if light adjusting circuit 107 is withstand voltage not enough, the direct supply voltage that will cause light adjusting circuit 107 to be supplied by DC-DC power supply converter 103 punctures, and causes light adjusting circuit 107 damages.In addition, also may therefore need to use withstand voltage higher light adjusting circuit 107, yet, withstand voltage higher light adjusting circuit 107 certainly will need bigger volume and higher price, except the volume that may increase integrated circuit, more increase the cost of circuit, also therefore reduced the competitive power of product on market.
Summary of the invention
Purpose of the present invention is providing a kind of light source driving circuit exactly, in order to adaptive adjustment output voltage, and when light source driving circuit stops output supply voltage to light-emitting component, postpone the time point that light adjusting circuit is closed, to prevent that the light source driving circuit inner member from damaging, and prolongs the serviceable life of light source driving circuit.
A further object of the present invention provides a kind of light source driving circuit, in order to lower the cost of light source driving circuit inner member, to reach the increase product competitiveness.
According to above-mentioned and other purpose, the present invention proposes a kind of light source driving circuit, and in order to drive first light-emitting component, this light source driving circuit comprises power supply circuit, first light adjusting circuit and feedback loop.Wherein power supply circuit has output terminal and feedbacks end, its output terminal couples a wherein end of first light-emitting component, give first light-emitting component in order to power supply voltage, and power supply circuit is held the value of the feedback signal decision supply voltage that is received according to its back coupling.
First light adjusting circuit has first end, second end and pulse width signal input end, and its first end couples the other end of first light-emitting component, and its second end couples common electric potential.Feedback loop is coupled between the back coupling end of the pulse width signal input end of first light adjusting circuit and power supply circuit, in order to receive and to transmit the pulse width signal input end of pulse width signal to the first light adjusting circuit, so that first light adjusting circuit determines the conducting state between its first end and its second end according to the logic state of pulse width signal.And feedback loop makes power supply circuit stop supplies supply voltage according to one of pulse width signal particular logic state, and postpones the time point that first light adjusting circuit is closed.
According to above-mentioned and other purpose, the present invention proposes a kind of light source driving circuit, and in order to drive first light-emitting component, this light source driving circuit comprises power supply circuit, first light adjusting circuit and control circuit.Wherein power supply circuit has output terminal and control end, and its output terminal couples a wherein end of first light-emitting component, gives first light-emitting component in order to power supply voltage.First light adjusting circuit has first end, second end and pulse width signal input end, and its first end couples the other end of first light-emitting component, and its second end couples common electric potential.
Control circuit is coupled between the control end of the pulse width signal input end of first light adjusting circuit and power supply circuit, in order to receive and to transmit the pulse width signal input end of pulse width signal to the first light adjusting circuit and the control end of power supply circuit, so that first light adjusting circuit determines the conducting state between its first end and its second end according to the logic state of pulse width signal, and make power supply circuit whether determine output supply voltage according to the pulse width signal that its control end received.And control circuit postpones the time point of power supply circuit output supply voltage according to first logic state of pulse width signal, and make power supply circuit stop supplies supply voltage, and postpone the time point that first light adjusting circuit is closed according to second logic state of pulse width signal.
Described according to one embodiment of the invention, above-mentioned feedback loop comprises first diode, delay circuit and output voltage feedback loop.Wherein the anode of first diode couples the back coupling end of power supply circuit, and the negative electrode of first diode receives pulse width signal.Delay circuit is coupled between the pulse width signal input end of the negative electrode of first diode and first light adjusting circuit, in order to the pulse width signal input end of reception and transmission pulse width signal to the first light adjusting circuit, and when presenting particular logic state, pulse width signal postpones the time point that first light adjusting circuit is closed.The output voltage feedback loop is coupled between the back coupling end of the output terminal of power supply circuit and power supply circuit, the supply voltage of exporting in order to the foundation power supply circuit and determine the value of feedback signal.
Delay circuit comprises second diode, first impedor and second impedor.Wherein the anode of second diode couples the negative electrode of first diode, and the negative electrode of second diode couples the pulse width signal input end of first light adjusting circuit.A first impedor wherein end couples the anode of second diode, and the first impedor other end couples the negative electrode of second diode.Second impedor is coupled between the negative electrode and common electric potential of second diode.The output voltage feedback loop comprises the 3rd impedor and the 4th impedor.Wherein the 3rd an impedor wherein end couples the output terminal of power supply circuit, and the 3rd impedor other end couples the back coupling end of power supply circuit.The 4th impedor is coupled between the 3rd impedor other end and the common electric potential.
Each comprises a resistance respectively first impedor of this embodiment, the 3rd impedor and the 4th impedor, and second impedor comprises an electric capacity.
Described according to another embodiment of the present invention, also in order to drive second light-emitting component, a wherein end of second light-emitting component couples the output terminal of power supply circuit to above-mentioned light source driving circuit, and light source driving circuit also comprises second light adjusting circuit.Second light adjusting circuit has first end, second end and pulse width signal input end, and its first end couples the other end of second light-emitting component, and its second end couples common electric potential.
The feedback loop of this embodiment comprises first diode, delay circuit and output voltage feedback loop.Wherein the anode of first diode couples the back coupling end of power supply circuit, and the negative electrode of first diode receives pulse width signal.Delay circuit is coupled between the pulse width signal input end three of the pulse width signal input end of negative electrode, first light adjusting circuit of first diode and second light adjusting circuit, in order to receive and to transmit the pulse width signal input end of pulse width signal to the first light adjusting circuit and second light adjusting circuit.And delay circuit postpones the time point that first light adjusting circuit and second light adjusting circuit are closed when pulse width signal presents particular logic state.The output voltage feedback loop is coupled between the back coupling end of the output terminal of power supply circuit and power supply circuit, the supply voltage of exporting in order to the foundation power supply circuit and determine the value of feedback signal.
Delay circuit comprises second diode, first impedor and second impedor.Wherein the anode of second diode couples the negative electrode of first diode, and the negative electrode of second diode couples the pulse width signal input end of first light adjusting circuit and second light adjusting circuit.A first impedor wherein end couples the anode of second diode, and the first impedor other end couples the negative electrode of second diode.Second impedor is coupled between the negative electrode and common electric potential of second diode.The output voltage feedback loop comprises the 3rd impedor and the 4th impedor.Wherein the 3rd an impedor wherein end couples the output terminal of power supply circuit, and the 3rd impedor other end couples the back coupling end of power supply circuit.
The 4th impedor is coupled between the 3rd impedor other end and the common electric potential.
Each comprises a resistance respectively first impedor of this embodiment, the 3rd impedor and the 4th impedor, and second impedor comprises an electric capacity.
Described according to another embodiment of the present invention, above-mentioned light source driving circuit is also in order to drive second light-emitting component, the 3rd light-emitting component and the 4th light-emitting component.A wherein end of second light-emitting component, the 3rd light-emitting component and the 4th light-emitting component all couples the output terminal of power supply circuit, and first light adjusting circuit also comprises the 3rd end, in order to coupling the other end of the 3rd light-emitting component, and light source driving circuit also comprises second light adjusting circuit.Second light adjusting circuit has first end, second end, the 3rd end and pulse width signal input end, and its first end couples the other end of second light-emitting component, and its second end couples common electric potential, and its 3rd end is in order to couple the other end of the 4th light-emitting component.First light adjusting circuit and second light adjusting circuit determine the conducting state between its first end and its second end all according to the logic state of pulse width signal, and the conducting state between the 3rd end and its second end.
The feedback loop of this embodiment comprises first diode, first delay circuit, second delay circuit and output voltage feedback loop.Wherein the anode of first diode couples the back coupling end of power supply circuit, and the negative electrode of first diode receives pulse width signal.First delay circuit is coupled between the pulse width signal input end of the negative electrode of first diode and first light adjusting circuit, in order to receive and to transmit the pulse width signal input end of pulse width signal to the first light adjusting circuit.And first delay circuit postpones the time point that first light adjusting circuit is closed when pulse width signal presents particular logic state.
Second delay circuit is coupled between the pulse width signal input end of the negative electrode of first diode and second light adjusting circuit, in order to receive and to transmit the pulse width signal input end of pulse width signal to the second light adjusting circuit.And second delay circuit postpones the time point that second light adjusting circuit is closed when pulse width signal presents particular logic state.The output voltage feedback loop is coupled between the back coupling end of the output terminal of power supply circuit and power supply circuit, the supply voltage of exporting in order to the foundation power supply circuit and determine the value of feedback signal.
First delay circuit comprises second diode, first impedor, second impedor and the 3rd impedor.Wherein the anode of second diode couples the negative electrode of first diode, and the negative electrode of second diode couples the pulse width signal input end of first light adjusting circuit.A first impedor wherein end couples the anode of second diode, and the first impedor other end couples the negative electrode of second diode.Second impedor is coupled between the negative electrode and common electric potential of second diode.The 3rd impedor is coupled between the pulse width signal input end of the negative electrode of second diode and first light adjusting circuit.
Second delay circuit comprises the 3rd diode, the 4th impedor, the 5th impedor and the 6th impedor.Wherein the anode of the 3rd diode couples the negative electrode of first diode, and the negative electrode of the 3rd diode couples the pulse width signal input end of second light adjusting circuit.The 4th an impedor wherein end couples the anode of the 3rd diode, and the 4th impedor other end couples the negative electrode of the 3rd diode.The 5th impedor is coupled between the negative electrode and common electric potential of the 3rd diode.The 6th impedor is coupled between the pulse width signal input end of the negative electrode of the 3rd diode and second light adjusting circuit.The output voltage feedback loop comprises the 7th impedor and the 8th impedor.Wherein the 7th an impedor wherein end couples the output terminal of power supply circuit, and the 7th impedor other end couples the back coupling end of power supply circuit.The 8th impedor is coupled between the 7th impedor other end and the common electric potential.
Each comprises a resistance respectively first impedor of this embodiment, the 3rd impedor, the 4th impedor, the 6th impedor, the 7th impedor and the 8th impedor, and each comprises an electric capacity respectively second impedor and the 5th impedor.
Described according to one embodiment of the invention, above-mentioned control circuit comprises first delay circuit and second delay circuit.Wherein first delay circuit is coupled between the control end and pulse width signal of power supply circuit, in order to receive and to transmit the control end of pulse width signal to power supply circuit, and when pulse width signal presents first logic state, postpone the time point of power supply circuit output supply voltage, and when presenting second logic state, pulse width signal makes power supply circuit stop supplies supply voltage.Second delay circuit is coupled between the pulse width signal input end and pulse width signal of first light adjusting circuit, in order to the pulse width signal input end of reception and transmission pulse width signal to the first light adjusting circuit, and when presenting second logic state, pulse width signal postpones the time point that first light adjusting circuit is closed.
First delay circuit comprises first diode, first impedor and second impedor.Wherein the anode of first diode couples the control end of power supply circuit, and the negative electrode of first diode couples pulse width signal.A first impedor wherein end couples the anode of first diode, and the first impedor other end couples the negative electrode of first diode.Second impedor is coupled between the anode and common electric potential of first diode.Second delay circuit comprises second diode, the 3rd impedor and the 4th impedor.Wherein the anode of second diode couples pulse width signal, and the negative electrode of second diode couples the pulse width signal input end of first light adjusting circuit.The 3rd an impedor wherein end couples the anode of second diode, and the 3rd impedor other end couples the negative electrode of second diode.The 4th impedor is coupled between the negative electrode and common electric potential of second diode.
First impedor and the 3rd impedor of this embodiment respectively comprise a resistance, and second impedor and the 4th impedor respectively comprise an electric capacity.
Described according to another embodiment of the present invention, also in order to drive second light-emitting component, a wherein end of second light-emitting component couples the output terminal of power supply circuit to above-mentioned light source driving circuit, and light source driving circuit also comprises second light adjusting circuit.Second light adjusting circuit has first end, second end and pulse width signal input end, and its first end couples the other end of second light-emitting component, and its second end couples common electric potential.
The control circuit of this embodiment comprises first delay circuit and second delay circuit.Wherein first delay circuit is coupled between the control end and pulse width signal of power supply circuit, in order to receive and to transmit the control end of pulse width signal to power supply circuit, and when pulse width signal presents first logic state, postpone the time point of power supply circuit output supply voltage, and when presenting second logic state, pulse width signal makes power supply circuit stop supplies supply voltage.
Second delay circuit is coupled between the pulse width signal input end and pulse width signal three of pulse width signal input end, second light adjusting circuit of first light adjusting circuit, in order to receiving and to transmit the pulse width signal input end of pulse width signal to the first light adjusting circuit and second light adjusting circuit, and when presenting second logic state, pulse width signal postpones the time point that first light adjusting circuit and second light adjusting circuit are closed.
First delay circuit comprises first diode, first impedor and second impedor.Wherein the anode of first diode couples the control end of power supply circuit, and the negative electrode of first diode couples this pulse width signal.A first impedor wherein end couples the anode of first diode, and the first impedor other end couples the negative electrode of first diode.Second impedor is coupled between the anode and common electric potential of first diode.
Second delay circuit comprises second diode, the 3rd impedor and the 4th impedor.The anode of second diode couples pulse width signal, and the negative electrode of second diode couples the pulse width signal input end of first light adjusting circuit and second light adjusting circuit.The 3rd an impedor wherein end couples the anode of second diode, and the 3rd impedor other end couples the negative electrode of second diode.The 4th impedor is coupled between the negative electrode and common electric potential of second diode.
First impedor and the 3rd impedor of this embodiment respectively comprise a resistance, and second impedor and the 4th impedor respectively comprise an electric capacity.
Described according to another embodiment of the present invention, above-mentioned light source driving circuit is also in order to drive second light-emitting component, the 3rd light-emitting component and the 4th light-emitting component.A wherein end of second light-emitting component, the 3rd light-emitting component and the 4th light-emitting component all couples the output terminal of power supply circuit, and first light adjusting circuit also comprises the 3rd end, in order to coupling the other end of the 3rd light-emitting component, and light source driving circuit also comprises second light adjusting circuit.Second light adjusting circuit has first end, second end, the 3rd end and pulse width signal input end, and its first end couples the other end of second light-emitting component, and its second end couples common electric potential, and its 3rd end is in order to couple the other end of the 4th light-emitting component.First light adjusting circuit and second light adjusting circuit determine the conducting state between its first end and its second end all according to the logic state of pulse width signal, and the conducting state between the 3rd end and its second end.
The control circuit of this embodiment comprises first delay circuit, second delay circuit and the 3rd delay circuit.Wherein first delay circuit is coupled between the control end and pulse width signal of power supply circuit, in order to receive and to transmit the control end of pulse width signal to power supply circuit, and when pulse width signal presents first logic state, postpone the time point of power supply circuit output supply voltage, and when presenting second logic state, pulse width signal makes power supply circuit stop supplies supply voltage.
Second delay circuit is coupled between the pulse width signal input end and pulse width signal of first light adjusting circuit, in order to the pulse width signal input end of reception and transmission pulse width signal to the first light adjusting circuit, and when presenting second logic state, pulse width signal postpones the time point that first light adjusting circuit is closed.The 3rd delay circuit is coupled between the pulse width signal input end and pulse width signal of second light adjusting circuit, in order to the pulse width signal input end of reception and transmission pulse width signal to the second light adjusting circuit, and when presenting second logic state, pulse width signal postpones the time point that second light adjusting circuit is closed.
First delay circuit comprises first diode, first impedor and second impedor.Wherein the anode of first diode couples the control end of power supply circuit, and the negative electrode of first diode couples pulse width signal.A first impedor wherein end couples the anode of first diode, and the first impedor other end couples the negative electrode of first diode.Second impedor is coupled between the anode and common electric potential of first diode.
Second delay circuit comprises second diode, the 3rd impedor, the 4th impedor and the 5th impedor.Wherein the anode of second diode couples pulse width signal, and the negative electrode of second diode couples the pulse width signal input end of first light adjusting circuit.The 3rd an impedor wherein end couples the anode of second diode, and the 3rd impedor other end couples the negative electrode of second diode.The 4th impedor is coupled between the negative electrode and common electric potential of second diode.The 5th impedor is coupled between the pulse width signal input end of the negative electrode of second diode and first light adjusting circuit.
The 3rd delay circuit comprises the 3rd diode, the 6th impedor, the 7th impedor and the 8th impedor.Wherein the anode of the 3rd diode couples pulse width signal, and the negative electrode of the 3rd diode couples the pulse width signal input end of second light adjusting circuit.The 6th an impedor wherein end couples the anode of the 3rd diode, and the 6th impedor other end couples the negative electrode of the 3rd diode.The 7th impedor is coupled between the negative electrode and common electric potential of the 3rd diode.The 8th impedor is coupled between the pulse width signal input end of the negative electrode of the 3rd diode and second light adjusting circuit.
First impedor of this embodiment, the 3rd impedor, the 5th impedor, the 6th impedor, the 8th impedor respectively comprise a resistance, and second impedor, the 4th impedor, the 7th impedor respectively comprise an electric capacity.
The present invention is at the powered-down supply circuit, so that power supply circuit stops output supply voltage when giving light-emitting component, postpone the time point that light adjusting circuit is closed, make light adjusting circuit avoid being punctured by too high voltage, therefore can prevent that the light source driving circuit inner member from damaging, prolong the serviceable life of light source driving circuit, and also make light source driving circuit needn't adopt high withstand voltage light adjusting circuit, lower the cost of light source driving circuit inner member, reached the increase product competitiveness.
For above-mentioned and other purposes, feature and advantage of the present invention can be become apparent, preferred embodiment cited below particularly, and conjunction with figs. are described in detail below
Description of drawings
Fig. 1 is the framework of known light source driving circuit.
Fig. 2 is the circuit diagram according to the light source driving circuit of one embodiment of the invention.
Fig. 3, Fig. 4, Fig. 5, Fig. 6, Fig. 7 are the circuit diagram according to the light source driving circuit of another embodiment of the present invention.
[main element symbol description]
101,201,301,401,402,403,501,601,701,702,703: light-emitting component
102,202,502: light emitting diode
103: DC-DC power supply converter
203,503: power supply circuit
107,204,302,404,407,504,602,704,707: light adjusting circuit
104,205,207,213,411,505,511,514,711: electric capacity
206,211,409,509,512,709: diode
208,406,408,507,508,706,708: delay circuit
105,209: the output voltage feedback loop
106,210,506: sequential control circuit
108,109,212,214,215,405,410,412,510,513,705,710,712: resistance
FB: feedback signal
GND: common electric potential
PWM: pulse width signal
Vo: supply voltage
Embodiment
Fig. 2 is the circuit diagram according to the light source driving circuit of one embodiment of the invention.Please refer to Fig. 2, this light source driving circuit is in order to drive first light-emitting component 201.First light-emitting component 201 can be a light emitting diode, as Fig. 2 202 shown in, also can be the light emitting diode string that forms by a plurality of light emitting diodes 202 serial connections, or the light-emitting component of other patterns/light-emitting component string.This light source driving circuit comprises power supply circuit 203, first light adjusting circuit 204, electric capacity 205 and feedback loop.
Power supply circuit 203 has output terminal and feedbacks end, its output terminal couples a wherein end of first light-emitting component 201, give first light-emitting component 201 in order to power supply voltage Vo, and power supply circuit 203 is held the value of the feedback signal FB decision supply voltage Vo that is received according to its back coupling.When feedback signal FB is high logic state (during noble potential), power supply circuit 203 output supply voltage Vo, when feedback signal FB is low logic state (during electronegative potential), 203 of power supply circuits stop output supply voltage Vo.Right user can change the manner of execution of power supply circuit 203 according to actual demand.
In this embodiment, first light adjusting circuit 204 has first end, second end and pulse width signal input end, its first end couples the other end of first light-emitting component 201, its second end couples common electric potential GND, and first light adjusting circuit 204 determines the conducting state between its first end and its second end according to the logic state of pulse width signal, with this embodiment, when pulse width signal is high logic state, first end and the electrical path between second end of first light adjusting circuit 204 are conducting, on the contrary then not conducting.
And above-mentioned feedback loop comprises first diode 206, electric capacity 207, delay circuit 208 and output voltage feedback loop 209.Wherein delay circuit 208 is in order to receiving pulse width signal PWM, and transmits the pulse width signal input end of pulse width signal PWM to the first light adjusting circuit 204, and postpones the time point that first light adjusting circuit is closed when pulse width signal presents particular logic state.The supply voltage Vo that output voltage feedback loop 209 is exported in order to foundation power supply circuit 203 and determine the value of feedback signal FB.Yet electric capacity 205 is rectification with the function of electric capacity 207, be not to be the necessary member of circuit, so the user can do increase and decrease according to the needs of reality.
Above-mentioned pulse width signal PWM is provided by sequential control circuit 210, and sequential control circuit 210 is converted to pulse width signal PWM in order to the brightness settings that the user imported.When setting brightness when brighter, it is longer that pulse width signal PWM presents time of high logic state (being noble potential), make the ON time of first light adjusting circuit 204 longer, thereby the brightness of first light-emitting component 201 is also brighter.Otherwise when setting brightness was dark, it is shorter that pulse width signal PWM presents the time of high logic state, make the ON time of first light adjusting circuit 204 shorter, thereby the brightness of first light-emitting component 201 is also darker.
Delay circuit 208 comprises second diode 211, first impedor and second impedor.A first impedor wherein end couples the anode of second diode 211, and the first impedor other end couples the negative electrode of second diode 211.Second impedor is coupled between the negative electrode and common electric potential GND of second diode 211.Wherein first impedor and second impedor are realized with resistance 212 and electric capacity 213 respectively.Output voltage feedback loop 209 comprises the 3rd impedor and the 4th impedor.The 3rd an impedor wherein end couples the output terminal of power supply circuit 203, and the 3rd impedor other end couples the back coupling end of power supply circuit 203.The 4th impedor is coupled between the 3rd impedor other end and the common electric potential GND.Wherein the 3rd impedor and the 4th impedor are realized with resistance 214 and 215 respectively.
When pulse width signal PWM presented high logic state, first diode 206 ended, and 211 conductings of second diode.Therefore feedback signal FB presents resistance 215 resulting dividing potential drops, makes power supply circuit 203 normal output supply voltage Vo, and makes 203 pairs of electric capacity of power supply circuit 205 charge.Because this moment second, diode 211 was conducting, so pulse width signal PWM seen through the pulse width signal input end that second diode 211 is sent to first light adjusting circuit 204, and electric capacity 213 is charged.And the pulse width signal PWM that first light adjusting circuit 204 is just received according to its pulse width signal input end comes the electrical path between its first end of conducting and second end, beginning to draw (Sink Current) electric current, and then make light-emitting component 201 conductings and shinny of winning.
When pulse width signal PWM presents low logic state (be above-mentioned particular logic state, that is electronegative potential), 206 conductings of first diode, and second diode 211 ends.Therefore the voltage level of feedback signal FB is pulled low to electronegative potential, makes power supply circuit 203 stop output supply voltage Vo, and makes electric capacity 205 begin discharge.And stopping moment of output supply voltage at power supply circuit 203, the supply voltage Vo that does not disappear just can discharge through resistance 214 with electric capacity 205 as yet.
Because when pulse width signal PWM presents low logic state, second diode 211 is for ending, therefore the electric capacity 213 pulse width signal input end and the resistance 212 that begin to see through first light adjusting circuit 204 discharges, and makes the light adjusting circuit 204 of winning can utilize electric capacity 213 stored electric power and postpones a period of time and just close.And power supply circuit 203 stops output supply voltage Vo and first light adjusting circuit 204 to be closed the two mistiming that presents is resistance 212 and the two the product (being the RC time constant) of value of electric capacity 213.Thus, just can avoid first light adjusting circuit 204 when pulse width signal PWM presents low logic state, by too high supply voltage Vo or electric capacity 205 stored electric power puncture.
According to the embodiment institute teaching of Fig. 2, the present invention also can adopt a plurality of light adjusting circuits in light source driving circuit, to drive a plurality of light-emitting components.Below will be that example illustrates the present invention with the light source driving circuit that drives two light-emitting components, as shown in Figure 3.
Fig. 3 is the circuit diagram according to the light source driving circuit of another embodiment of the present invention.Please refer to Fig. 3.The circuit that Fig. 3 illustrated is added second light-emitting component 301 and second light adjusting circuit 302 for the circuit that Fig. 2 illustrated, and forms one in order to drive the light source driving circuit of two light-emitting components.Wherein second light-emitting component 301 can be identical with first light-emitting component 201.
And second light adjusting circuit 302 has first end, second end and pulse width signal input end equally, and its first end couples the other end of second light-emitting component 301, its second end couples common electric potential GND, and its pulse width signal input end couples the pulse width signal input end of first light adjusting circuit 204.And second light adjusting circuit 302 also determines the conducting state between its first end and its second end according to the logic state of pulse width signal, with this embodiment, when pulse width signal is high logic state, first end and the electrical path between second end of second light adjusting circuit 302 are conducting, on the contrary then not conducting.Below will outline the manner of execution of circuit shown in Figure 3, and just repeat no more about the circuit relation that couples partly of former Fig. 2.
When pulse width signal PWM presented high logic state, first diode 206 ended, and 211 conductings of second diode.Therefore feedback signal FB presents resistance 215 resulting dividing potential drops, makes power supply circuit 203 normal output supply voltage Vo, and makes 203 pairs of electric capacity of power supply circuit 205 charge.Because this moment second, diode 211 was conducting, so pulse width signal PWM seen through the pulse width signal input end that second diode 211 is sent to first light adjusting circuit 204 and second light adjusting circuit 302, and electric capacity 213 is charged.And the pulse width signal PWM that first light adjusting circuit 204 and second light adjusting circuit 302 are just received according to its pulse width signal input end begins current drawn, to make win light-emitting component 201 and second light-emitting component, 301 conductings and shinny respectively.
When pulse width signal PWM presents low logic state, 206 conductings of first diode, and second diode 211 ends.Therefore the voltage level of feedback signal FB is pulled low to electronegative potential, makes power supply circuit 203 stop output supply voltage Vo, and makes electric capacity 205 begin discharge.And stopping moment of output supply voltage at power supply circuit 203, the supply voltage Vo that does not disappear just can discharge through resistance 214 with electric capacity 205 as yet.
Because when pulse width signal PWM presents low logic state, second diode 211 is for ending, therefore the electric capacity 213 pulse width signal input end and the resistance 212 that begin to see through first light adjusting circuit 204 and second light adjusting circuit 302 discharges, and makes win light adjusting circuit 204 and second light adjusting circuit 302 can utilize electric capacity 213 stored electric power and postpones a period of time and just close.And power supply circuit 203 stops output supply voltage Vo and first light adjusting circuit 204 to be closed the two mistiming that presents is resistance 212 and the two the product of value of electric capacity 213.Similarly, power supply circuit 203 stops output supply voltage Vo and second light adjusting circuit 302 and is closed the two mistiming that presents and also is the two the product of value of resistance 212 and electric capacity 213.Thus, just can avoid first light adjusting circuit 204 and second light adjusting circuit 302 when pulse width signal PWM presents low logic state, by too high supply voltage Vo or electric capacity 205 stored electric power puncture.
According to the teaching of the described embodiment of Fig. 3, this area has knows that usually the knowledgeable should know by inference, if use a plurality of light-emitting components and a plurality of light adjusting circuit to implement.
Though Fig. 3 has described a kenel in order to the light source driving circuit that drives a plurality of light-emitting components, yet based on teaching embodiment illustrated in fig. 2, the present invention can also have another kenel in order to the light source driving circuit that drives a plurality of light-emitting components, below will be that example illustrates the present invention with the light source driving circuit that drives four light-emitting components, as shown in Figure 4.
Fig. 4 is the circuit diagram according to the light source driving circuit of another embodiment of the present invention.Please refer to Fig. 4.The circuit that Fig. 4 illustrated is added second light-emitting component 401, the 3rd light-emitting component 402 and the 4th light-emitting component 403 for the circuit that Fig. 2 illustrated, and wherein second light-emitting component 401, the 3rd light-emitting component 402 and the 4th light-emitting component 403 can be identical with first light-emitting component 201.And light source driving circuit shown in Figure 4 adopts first light adjusting circuit 404 with first end, second end, the 3rd end and pulse width signal input end for first light adjusting circuit 204 of Fig. 2 is changed, and is connected in series a resistance 405 between the pulse width signal input end with the negative electrode of second diode 211 of delay circuit 208 and first light adjusting circuit 404 more and forms first delay circuit 406.
In addition, in embodiment shown in Figure 4, more than adopt second light adjusting circuit 407 and second delay circuit 408, wherein second light adjusting circuit 407 has first end, second end, the 3rd end and pulse width signal input end equally.First light adjusting circuit 404 and second light adjusting circuit 407 all determine the conducting state between its first end and its second end according to the logic state of pulse width signal, and determine the conducting state between its 3rd end and its second end.With this embodiment, when pulse width signal is high logic state, first end of first light adjusting circuit 404 and the electrical path between second end, and the 3rd electrical path between end and second end be conducting, and first end of second light adjusting circuit 407 and the electrical path between second end, and the 3rd electrical path between end and second end also be conducting, otherwise then neither conducting.In addition, the internal circuit design of second delay circuit 408 is identical with first delay circuit 406.Second delay circuit 408 comprises the 3rd diode 409, resistance 410, electric capacity 411 and resistance 412.
First end of first light adjusting circuit 404 is in order to couple first light-emitting component 201, second end of first light adjusting circuit 404 is in order to couple common electric potential GND, the 3rd end of first light adjusting circuit 404 is in order to coupling the 3rd light-emitting component 402, and the pulse width signal input end of first light adjusting circuit 404 is in order to couple resistance 405.First end of second light adjusting circuit 407 is in order to couple second light-emitting component 401, second end of second light adjusting circuit 407 is in order to couple common electric potential GND, the 3rd end of second light adjusting circuit 407 is in order to coupling the 4th light-emitting component 403, and the pulse width signal input end of second light adjusting circuit 407 is in order to couple resistance 412.
According to the coupling mode of above-mentioned each element, light source driving circuit shown in Figure 4 is driven four light-emitting components.Yet above-mentioned first light adjusting circuit 404 and second light adjusting circuit 407 are not limited to have only first end, second end, the 3rd end and pulse width signal input end, it can also be to have first end, second end, the 3rd end, the 4th end and pulse width signal input end, or have first end, second end, the 3rd end, the 4th end, five terminal and pulse width signal input end, or even more input ends as first end, second end, the 3rd end and so on, to couple more light-emitting component simultaneously.Yet must be noted that light adjusting circuit of every increase, just must increase a delay circuit accordingly.Below will outline the manner of execution of circuit shown in Figure 4, and just repeat no more about the circuit relation that couples partly of former Fig. 2.
When pulse width signal PWM presented high logic state, first diode 206 ended, and second diode 211 and 409 conductings of the 3rd diode.Therefore feedback signal FB presents resistance 215 resulting dividing potential drops, makes power supply circuit 203 normal output supply voltage Vo, and makes 203 pairs of electric capacity of power supply circuit 205 charge.And first light adjusting circuit 404 of this moment and the pulse width signal input end of second light adjusting circuit 407 are received pulse width signal PWM, and electric capacity 213 also is recharged with electric capacity 411.And the pulse width signal PWM that first light adjusting circuit 404 and second light adjusting circuit 407 are just received according to its pulse width signal input end begins to draw electric current, so the just conducting and shinny of first light-emitting component 201 and the 3rd light-emitting component 402, and the just conducting and shinny of second light-emitting component 401 and the 4th light-emitting component 403 because second light adjusting circuit 407 begins to draw electric current because first light adjusting circuit 404 begins to draw electric current.
When pulse width signal PWM presents low logic state, 206 conductings of first diode, and second diode 211 and the 3rd diode 409 end.Therefore the voltage level of feedback signal FB is pulled low to electronegative potential, makes power supply circuit 203 stop output supply voltage Vo, and makes electric capacity 205 begin discharge.And stopping moment of output supply voltage at power supply circuit 203, the supply voltage Vo that does not disappear just can discharge through resistance 214 with electric capacity 205 as yet.
Because when pulse width signal PWM presents low logic state, second diode 211 and the 3rd diode 409 are for ending, therefore the electric capacity 213 pulse width signal input end and the resistance 212 that begin to see through first light adjusting circuit 404 discharges, and makes the light adjusting circuit 404 of winning can utilize electric capacity 213 stored electric power and postpones a period of time and just close.Simultaneously, pulse width signal input end and resistance 410 that electric capacity 411 also begins to see through the secondth light adjusting circuit 407 discharge, and make second light adjusting circuit 407 can also utilize electric capacity 411 stored electric power and postpone a period of time and just close.
Power supply circuit 203 stops output supply voltage Vo and to close 404 the two mistiming that presented of first light adjusting circuit be resistance 212 and the two the product of value of electric capacity 213.Similarly, power supply circuit 203 stops output supply voltage Vo and to close 407 the two mistiming that presented of second light adjusting circuit be resistance 410 and the two the product of value of electric capacity 411.Thus, just can avoid first light adjusting circuit 404 and second light adjusting circuit 407 when pulse width signal PWM presents low logic state, by too high supply voltage Vo or electric capacity 205 stored electric power puncture.
What deserves to be mentioned is, the user can see through the resistance that changes resistance 405 and the ON time that changes first light-emitting component 201 and the 3rd light-emitting component 402, also can see through the resistance that changes resistance 412 and the ON time that changes second light-emitting component 401 and the 4th light-emitting component 403.When ON time not simultaneously, the value of the electric current of surging that output terminal took place (Inrush Current) of supply circuit 203 just capable of reducing power source.Yet resistance 405 is not the necessary member of this circuit with resistance 412, so the user can do increase and decrease according to the needs of reality.
According to the teaching of the described embodiment of Fig. 4, this area has knows that usually the knowledgeable should know by inference, if use a plurality of light-emitting components and a plurality of light adjusting circuit to implement.
Except the circuit kenel of the light source driving circuit of the various embodiments described above institute teaching, teaching according to Fig. 2 embodiment, the user can also also implement to postpone to the time point of power supply circuit output supply voltage, wherein three of embodiment that below will be in the above described manner enumerate other kenels of light source driving circuit again, so that having, this field knows the knowledgeable usually, other that can the present invention more than you know may have are implemented kenels, the enforcement kenel of these three demonstrations such as Fig. 5, Fig. 6 and shown in Figure 7.
Fig. 5 is the circuit diagram according to the light source driving circuit of another embodiment of the present invention.Please refer to Fig. 5, this light source driving circuit is in order to drive first light-emitting component 501.First light-emitting component 501 can be a light emitting diode, as Fig. 5 502 shown in, also can be the light emitting diode string that forms by a plurality of light emitting diodes 502 serial connections, or the light-emitting component of other patterns/light-emitting component string.
This light source driving circuit comprises power supply circuit 503, first light adjusting circuit 504, electric capacity 505 and control circuit.Wherein power supply circuit 503 has output terminal and control end, its output terminal couples a wherein end of first light-emitting component 501, give first light-emitting component 501 in order to power supply voltage Vo, and power supply circuit 503 determines the value of supply voltage Vo according to the received signal of its control end.When the received signal of the control end of power supply circuit 503 is high logic state (during noble potential), power supply circuit 503 output supply voltage Vo, when the received signal of the control end of power supply circuit 503 is low logic state (during electronegative potential), 503 of power supply circuits stop output supply voltage Vo.Right user can change the manner of execution of power supply circuit 503 according to actual demand.In addition, the function of above-mentioned electric capacity 505 is rectification, be not to be the necessary member of circuit, so the user can do increase and decrease according to the needs of reality.
In this embodiment, first light adjusting circuit 504 has first end, second end and pulse width signal input end, and its first end couples the other end of first light-emitting component, and its second end couples common electric potential GND.And first light adjusting circuit 504 determines the conducting state between its first end and its second end according to the logic state of pulse width signal, with this embodiment, when pulse width signal is high logic state, first end and the electrical path between second end of first light adjusting circuit 504 are conducting, on the contrary then not conducting.
Above-mentioned pulse width signal PWM is provided by sequential control circuit 506, and sequential control circuit 506 is converted to pulse width signal PWM in order to the brightness settings that the user imported.When setting brightness when brighter, it is longer that pulse width signal PWM presents time of high logic state (being noble potential), make the ON time of first light adjusting circuit 504 longer, thereby the brightness of first light-emitting component 501 is also brighter.Otherwise when setting brightness was dark, it is shorter that pulse width signal PWM presents the time of high logic state, make the ON time of first light adjusting circuit 504 shorter, thereby the brightness of first light-emitting component 501 is also darker.
Above-mentioned control circuit comprises first delay circuit 507 and second delay circuit 508.Wherein first delay circuit 507 is in order to receive pulse width signal PWM, and transmission pulse width signal PWM is to the control end of power supply circuit 503, and first delay circuit 507 presents high logic state (i.e. first logic state in pulse width signal PWM, that is noble potential) time point that postpones power supply circuit 503 output supply voltage Vo the time, and present low logic state (i.e. second logic state in pulse width signal PWM, that is electronegative potential) time, makes power supply circuit 503 stop supplies supply voltage Vo.Second delay circuit 508 is in order to reception pulse width signal PWM, and the pulse width signal input end of transmission pulse width signal PWM to the first light adjusting circuit 504, and postpones the time point that first light adjusting circuit 504 is closed when pulse width signal PWM presents second logic state.
First delay circuit 507 comprises first diode 509, first impedor and second impedor.A first impedor wherein end couples the anode of first diode 509, and the first impedor other end couples the negative electrode of first diode 509.Second impedor is coupled between the anode and common electric potential GND of first diode 509.Wherein first impedor and second impedor are realized with resistance 510 and electric capacity 511 respectively.Second delay circuit 508 comprises second diode 512, the 3rd impedor and the 4th impedor.The 3rd an impedor wherein end couples the anode of second diode 512, and the 3rd impedor other end couples the negative electrode of second diode 512.The 4th impedor is coupled between the negative electrode and common electric potential GND of second diode 512.Wherein the 3rd impedor and the 4th impedor are realized with resistance 513 and electric capacity 514 respectively.
When pulse width signal PWM presented high logic state, first diode 509 ended, and 512 conductings of second diode.Therefore pulse width signal PWM is seen through resistance 510 and electric capacity 511 is charged, be enough to impel power supply circuit 503 output supply voltage Vo up to electric capacity 511 stored electric power, so ability output supply voltage Vo after making power supply circuit 503 be postponed a period of time.And when pulse width signal PWM presented high logic state, pulse width signal PWM was also seen through the pulse width signal input end that second diode 512 is sent to first light adjusting circuit 504, and to electric capacity 514 chargings.And first light adjusting circuit 504 makes light-emitting component 501 conductings and shinny of winning just according to pulse width signal PWM that its pulse width signal input end received and begin to draw electric current.According to above-mentioned, it is the two the product of value of resistance 510 and electric capacity 511 that power supply circuit 503 output supply voltage Vo and first light adjusting circuit 204 begin to draw mistiming that current both presents.
When pulse width signal PWM presents low logic state, 509 conductings of first diode, and second diode 512 ends.Electric capacity 505, electric capacity 511 all begin discharge with electric capacity 514 at this moment.And this moment, the control end of power supply circuit 503 directly coupled electronegative potential through first diode 509, so power supply circuit 503 stops output supply voltage immediately.Yet because electric capacity 514 discharges for seeing through resistance 513, therefore discharge is carried out slowlyer, postpones a period of time just to close so first light adjusting circuit 504 just can utilize electric capacity 514 stored electric power.And power supply circuit 503 stops output supply voltage Vo and first light adjusting circuit 504 to be closed the two mistiming that presents is resistance 513 and the two the product of value of electric capacity 514.By aforesaid way, just can avoid first light adjusting circuit 504 when pulse width signal PWM presents low logic state, by too high supply voltage Vo or electric capacity 505 stored electric power puncture.
According to the embodiment institute teaching of Fig. 5, the present invention also can adopt a plurality of light adjusting circuits in light source driving circuit, to drive a plurality of light-emitting components.Below will be that example illustrates the present invention with the light source driving circuit that drives two light-emitting components, as shown in Figure 6.
Fig. 6 is the circuit diagram according to the light source driving circuit of another embodiment of the present invention.Please refer to Fig. 6.The circuit that Fig. 6 illustrated is added second light-emitting component 601 and second light adjusting circuit 602 for the circuit that Fig. 5 illustrated, and forms one in order to drive the light source driving circuit of two light-emitting components.Wherein second light-emitting component 601 can be identical with first light-emitting component 501.
Second light adjusting circuit 602 has first end, second end and pulse width signal input end equally, and its first end couples the other end of second light-emitting component 601, its second end couples common electric potential GND, and its pulse width signal input end couples the pulse width signal input end of first light adjusting circuit 504.Second light adjusting circuit 602 also determines the conducting state between its first end and its second end according to the logic state of pulse width signal.With this embodiment, when pulse width signal was high logic state, first end and the electrical path between second end of second light adjusting circuit 602 were conducting, on the contrary then not conducting.Below will outline the manner of execution of circuit shown in Figure 6, and just repeat no more about the circuit relation that couples partly of former Fig. 5.
When pulse width signal PWM presented high logic state, first diode 509 ended, and 512 conductings of second diode.Therefore pulse width signal PWM is seen through resistance 510 and electric capacity 511 is charged, be enough to impel power supply circuit 503 output supply voltage Vo up to electric capacity 511 stored electric power, so ability output supply voltage Vo after making power supply circuit 503 be postponed a period of time.
And when pulse width signal PWM presented high logic state, pulse width signal PWM was also seen through the pulse width signal input end that second diode 512 is sent to first light adjusting circuit 504 and second light adjusting circuit 602, and to electric capacity 514 chargings.And the pulse width signal PWM that first light adjusting circuit 504 and second light adjusting circuit 602 are just received according to its pulse width signal input end respectively begins to draw electric current, to make first light-emitting component 501 and second light-emitting component, 601 conductings and shinny respectively.According to above-mentioned, the power supply circuit 503 output supply voltage Vo and first light adjusting circuit 504 begin to draw the mistiming that current both presents, and power supply circuit 503 output supply voltage Vo and second light adjusting circuit 601 begin to draw the mistiming that current both presents, and is all the two the product of value of resistance 510 and electric capacity 511.
When pulse width signal PWM presents low logic state, 509 conductings of first diode, and second diode 512 ends.Electric capacity 505, electric capacity 511 all begin discharge with electric capacity 514 at this moment.And this moment, the control end of power supply circuit 503 directly coupled electronegative potential through first diode 509, so power supply circuit 503 stops output supply voltage immediately.Yet because electric capacity 514 discharges for seeing through resistance 513, therefore discharge is carried out slowlyer, postpones a period of time just to close so first light adjusting circuit 504 and second light adjusting circuit 602 just can utilize electric capacity 514 stored electric power.
Power supply circuit 503 stops output supply voltage Vo and closes 504 the two mistiming that presented of first light adjusting circuit, and power supply circuit 503 stops output supply voltage Vo and closes 602 the two mistiming that presented of second light adjusting circuit, is all the two the product of value of resistance 513 and electric capacity 514.By aforesaid way, just can avoid first light adjusting circuit 504 and second light adjusting circuit 602 when pulse width signal PWM presents low logic state, by too high supply voltage Vo or electric capacity 505 stored electric power puncture.
According to the teaching of the described embodiment of Fig. 6, this area has knows that usually the knowledgeable should know by inference, if use a plurality of light-emitting components and a plurality of light adjusting circuit to implement.
Though Fig. 6 has described a kenel in order to the light source driving circuit that drives a plurality of light-emitting components, yet based on teaching embodiment illustrated in fig. 5, the present invention can also have another kenel in order to the light source driving circuit that drives a plurality of light-emitting components, below will be that example illustrates the present invention with the light source driving circuit that drives four light-emitting components, as shown in Figure 7.
Fig. 7 is the circuit diagram according to the light source driving circuit of another embodiment of the present invention.Please refer to Fig. 7.The circuit that Fig. 7 illustrated is added second light-emitting component 701, the 3rd light-emitting component 702 and the 4th light-emitting component 703 for the circuit that Fig. 5 illustrated, and wherein second light-emitting component 701, the 3rd light-emitting component 702 and the 4th light-emitting component 703 can be identical with first light-emitting component 501.And light source driving circuit shown in Figure 7 adopts first light adjusting circuit 704 with first end, second end, the 3rd end and pulse width signal input end for first light adjusting circuit 504 of Fig. 5 is changed, and is connected in series a resistance 705 between the pulse width signal input end with the negative electrode of second diode 512 of second delay circuit 508 and first light adjusting circuit 704 more and forms first delay circuit 706.
In addition, in the embodiment of Fig. 7, more than adopt second light adjusting circuit 707 and the 3rd delay circuit 708, the second light adjusting circuits 707 to have first end, second end, the 3rd end and pulse width signal input end equally.First light adjusting circuit 704 and second light adjusting circuit 707 all determine the conducting state between its first end and its second end according to the logic state of pulse width signal, and determine the conducting state between its 3rd end and its second end.With this embodiment, when pulse width signal is high logic state, first end of first light adjusting circuit 704 and the electrical path between second end, and the 3rd electrical path between end and second end be conducting, and first end of second light adjusting circuit 707 and the electrical path between second end, and the 3rd electrical path between end and second end be conducting, otherwise then neither conducting.In addition, the internal circuit design of the 3rd delay circuit 708 is identical with second delay circuit 706.The 3rd delay circuit 708 comprises the 3rd diode 709, resistance 710, electric capacity 711 and resistance 412.
First end of first light adjusting circuit 704 is in order to couple first light-emitting component 501, second end of first light adjusting circuit 704 is in order to couple common electric potential GND, the 3rd end of first light adjusting circuit 704 is in order to coupling the 3rd light-emitting component 702, and the pulse width signal input end of first light adjusting circuit 704 is in order to couple resistance 705.First end of second light adjusting circuit 707 is in order to couple second light-emitting component 701, second end of second light adjusting circuit 707 is in order to couple common electric potential GND, the 3rd end of second light adjusting circuit 707 is in order to coupling the 4th light-emitting component 703, and the pulse width signal input end of second light adjusting circuit 707 is in order to couple resistance 712.
According to the coupling mode of above-mentioned each element, light source driving circuit shown in Figure 7 is driven four light-emitting components.Yet above-mentioned first light adjusting circuit 704 and second light adjusting circuit 707 are not limited to have only first end, second end, the 3rd end and pulse width signal input end, it can also be to have first end, second end, the 3rd end, the 4th end and pulse width signal input end, or have first end, second end, the 3rd end, the 4th end, five terminal and pulse width signal input end, or even more input ends as first end, second end, the 3rd end and so on, to couple more light-emitting component simultaneously.Yet must be noted that light adjusting circuit of every increase, just must increase a delay circuit accordingly.Below will outline the manner of execution of circuit shown in Figure 7, and just repeat no more about the circuit relation that couples partly of former Fig. 5.
When pulse width signal PWM presented high logic state, first diode 509 ended, and second diode 512 and 709 conductings of the 3rd diode.Therefore pulse width signal PWM is seen through resistance 510 and electric capacity 511 is charged, be enough to impel power supply circuit 503 output supply voltage Vo up to electric capacity 511 stored electric power, therefore ability output supply voltage Vo after making power supply circuit 503 be postponed a period of time, then when power supply circuit 203 output supply voltage Vo, electric capacity 205 is recharged.
And when pulse width signal PWM presented high logic state, the pulse width signal input end of first light adjusting circuit 704 and second light adjusting circuit 707 was received pulse width signal PWM, and electric capacity 514 also is recharged with electric capacity 711.And the pulse width signal PWM that first light adjusting circuit 704 and second light adjusting circuit 707 are just received according to its pulse width signal input end begins to draw electric current, so the just conducting and shinny of first light-emitting component 501 and the 3rd light-emitting component 702, and the just conducting and shinny of second light-emitting component 701 and the 4th light-emitting component 703 because second light adjusting circuit 707 begins to draw electric current because first light adjusting circuit 704 begins to draw electric current.
According to above-mentioned, the power supply circuit 503 output supply voltage Vo and first light adjusting circuit 704 begin to draw the mistiming that current both presents, and power supply circuit 503 output supply voltage Vo and second light adjusting circuit 707 begin to draw the mistiming that current both presents, and is all the two the product of value of resistance 510 and electric capacity 511.
When pulse width signal PWM presents low logic state, 509 conductings of first diode, and second diode 512 and the 3rd diode 709 end.Electric capacity 505, electric capacity 511, electric capacity 514 and electric capacity 711 all begin discharge at this moment.And this moment, the control end of power supply circuit 503 directly coupled electronegative potential through first diode 509, so power supply circuit 503 stops output supply voltage immediately.Yet, because electric capacity 514 discharges for seeing through resistance 513, and electric capacity 711 discharges for seeing through resistance 710, therefore electric capacity 514 carries out slowlyer with electric capacity 711 discharges, postpone a period of time just closes so first light adjusting circuit 704 just can utilize electric capacity 514 stored electric power, and second light adjusting circuit 707 also can utilize electric capacity 711 stored electric power and postpone a period of time and just close.
Power supply circuit 503 stops output supply voltage Vo and first light adjusting circuit 704 is closed the mistiming that the two presents, and is the two the product of value of resistance 513 and electric capacity 514.And power supply circuit 503 stops output supply voltage Vo and second light adjusting circuit 707 is closed the mistiming that the two presents, and is the two the product of value of resistance 710 and electric capacity 711.By aforesaid way, just can avoid first light adjusting circuit 704 and second light adjusting circuit 707 when pulse width signal PWM presents low logic state, by too high supply voltage Vo or electric capacity 505 stored electric power puncture.
What deserves to be mentioned is, the user can see through the resistance that changes resistance 705 and the ON time that changes first light-emitting component 501 and the 3rd light-emitting component 702, also can see through the resistance that changes resistance 712 and the ON time that changes second light-emitting component 701 and the 4th light-emitting component 703.When ON time not simultaneously, the value of the electric current of surging that output terminal took place (Inrush Current) of supply circuit 503 just capable of reducing power source.Yet resistance 705 is not the necessary member of this circuit with resistance 712, so the user can do increase and decrease according to the needs of reality.
Though the various embodiments described above provide multiple possible enforcement kenel to feedback loop and control circuit, yet having, this field knows that usually the knowledgeable should know, each manufacturer is neither the same with the design of control circuit for feedback loop, therefore so long as when power supply circuit stops output supply voltage, designed feedback loop or control circuit can postpone the time point that light adjusting circuit is closed, make light adjusting circuit avoid being punctured, just met spiritual place of the present invention by too high voltage.
In addition, the power supply circuit of the various embodiments described above is not limited to specific certain power supply circuit, such as the various servants of opening up that derive of voltage-dropping type (Buck), booster type (Boost), buck-boost type (Buck-Boost) power supply circuit and above-mentioned power supply circuit for example forward (Forward), return speed (Flyback), half-bridge, full-bridge or the like, also or linear voltage regulator all can be in order to implement embodiments of the invention.
In addition, the power supply circuit 503 of Fig. 5, Fig. 6 and the described embodiment of Fig. 7 can also be the switching type power supply supply circuit with input end, its input end is in order to couple external power source, and power supply circuit 503 determines the output terminal whether external power source that its input end is received directly is coupled to power supply circuit 503 according to the logic state of the signal that its control end received, and uses to be used as supply voltage Vo.
In sum, the present invention is at the powered-down supply circuit, so that power supply circuit stops output supply voltage when giving light-emitting component, postpone the time point that light adjusting circuit is closed, make light adjusting circuit avoid being punctured by too high voltage, therefore can prevent that the light source driving circuit inner member from damaging, prolong the serviceable life of light source driving circuit, and also make light source driving circuit needn't adopt high withstand voltage light adjusting circuit, lower the cost of light source driving circuit inner member, reached the increase product competitiveness.
Though the present invention discloses as above with preferred embodiment; right its is not in order to limit the present invention; have in the technical field under any and know the knowledgeable usually; without departing from the spirit and scope of the present invention; when can doing a little change and retouching, so protection scope of the present invention is as the criterion when looking accompanying the claim person of defining.

Claims (18)

1. light source driving circuit, in order to drive first light-emitting component, this light source driving circuit comprises:
One power supply circuit, have output terminal and feedback end, its output terminal couples a wherein end of this first light-emitting component, gives this first light-emitting component in order to supply a supply voltage, and this power supply circuit holds a feedback signal that is received to determine the value of this supply voltage according to its back coupling;
First light adjusting circuit has first end, second end and pulse width signal input end, and its first end couples the other end of this first light-emitting component, and its second end couples a common electric potential; And
One feedback loop, be coupled between the back coupling end of the pulse width signal input end of this first light adjusting circuit and this power supply circuit, in order to receive and to transmit the pulse width signal input end of a pulse width signal to this first light adjusting circuit, so that this first light adjusting circuit determines the conducting state between its first end and its second end according to the logic state of this pulse width signal, and this feedback loop makes this this supply voltage of power supply circuit stop supplies according to a particular logic state of this pulse width signal, and postpones the time point that this first light adjusting circuit is closed.
2. light source driving circuit as claimed in claim 1 is characterized in that this feedback loop also comprises the output terminal that is coupled to this power supply circuit, in order to determine the value of this feedback signal according to this supply voltage.
3. light source driving circuit as claimed in claim 1 is characterized in that, this feedback loop comprises:
First diode, its anode couple the back coupling end of this power supply circuit, and its negative electrode receives this pulse width signal; And
One delay circuit, be coupled between the pulse width signal input end of the negative electrode of this first diode and this first light adjusting circuit, in order to receiving and to transmit the pulse width signal input end of this pulse width signal, and when presenting this particular logic state, this pulse width signal postpones the time point that this first light adjusting circuit is closed to this first light adjusting circuit.
4. light source driving circuit as claimed in claim 3 is characterized in that, this delay circuit comprises:
Second diode, its anode couples the negative electrode of this first diode, and its negative electrode couples the pulse width signal input end of this first light adjusting circuit;
First impedor, the one end couples the anode of this second diode, and its other end couples the negative electrode of this second diode; And
Second impedor is coupled between the negative electrode and this common electric potential of this second diode.
5. light source driving circuit as claimed in claim 3 is characterized in that, this feedback loop also comprises:
One output voltage feedback loop is coupled between the back coupling end of the output terminal of this power supply circuit and this power supply circuit, determines the value of this feedback signal in order to this supply voltage of exporting according to this power supply circuit.
6. light source driving circuit as claimed in claim 1 is characterized in that, also comprises:
One sequential control circuit couples this feedback loop, in order to the brightness settings that the user imported, is converted to this pulse width signal.
7. light source driving circuit as claimed in claim 1 is characterized in that, also in order to drive second light-emitting component, a wherein end of this second light-emitting component couples the output terminal of this power supply circuit to this light source driving circuit, and this light source driving circuit also comprises:
Second light adjusting circuit, this second light adjusting circuit has first end, second end and pulse width signal input end, and its first end couples the other end of this second light-emitting component, and its second end couples this common electric potential.
8. light source driving circuit as claimed in claim 7 is characterized in that, this feedback loop comprises:
First diode, its anode couple the back coupling end of this power supply circuit, and its negative electrode receives this pulse width signal; And
One delay circuit, be coupled between the pulse width signal input end three of the pulse width signal input end of negative electrode, this first light adjusting circuit of this first diode and this second light adjusting circuit, in order to receiving and to transmit the pulse width signal input end of this pulse width signal, and when presenting this particular logic state, this pulse width signal postpones the time point that this first light adjusting circuit and this second light adjusting circuit are closed to this first light adjusting circuit and this second light adjusting circuit.
9. light source driving circuit as claimed in claim 7, it is characterized in that, this light source driving circuit is also in order to drive one the 3rd light-emitting component and one the 4th light-emitting component, a wherein end of the 3rd light-emitting component and a wherein end of the 4th light-emitting component all couple the output terminal of this power supply circuit, and this first light adjusting circuit and this second light adjusting circuit also comprise the 3rd end respectively, the 3rd end of this first light adjusting circuit is in order to couple the other end of the 3rd light-emitting component, the 3rd end of this second light adjusting circuit is in order to couple the other end of the 4th light-emitting component, and this first light adjusting circuit and this second light adjusting circuit determine the conducting state between its 3rd end and its second end all according to the logic state of this pulse width signal.
10. light source driving circuit as claimed in claim 9 is characterized in that, this feedback loop comprises:
First diode, its anode couple the back coupling end of this power supply circuit, and its negative electrode receives this pulse width signal;
First delay circuit, be coupled between the pulse width signal input end of the negative electrode of this first diode and this first light adjusting circuit, in order to receiving and to transmit the pulse width signal input end of this pulse width signal, and when presenting this particular logic state, this pulse width signal postpones the time point that this first light adjusting circuit is closed to this first light adjusting circuit; And
Second delay circuit, be coupled between the pulse width signal input end of the negative electrode of this first diode and this second light adjusting circuit, in order to receiving and to transmit the pulse width signal input end of this pulse width signal, and when presenting this particular logic state, this pulse width signal postpones the time point that this second light adjusting circuit is closed to this second light adjusting circuit.
11. a light source driving circuit, in order to drive first light-emitting component, this light source driving circuit comprises:
One power supply circuit has output terminal and control end, and its output terminal couples a wherein end of this first light-emitting component, gives this first light-emitting component in order to supply a supply voltage;
First light adjusting circuit has first end, second end and pulse width signal input end, and its first end couples the other end of this first light-emitting component, and its second end couples a common electric potential; And
One control circuit, be coupled between the control end of the pulse width signal input end of this first light adjusting circuit and this power supply circuit, in order to receive and to transmit a pulse width signal to the pulse width signal input end of this first light adjusting circuit and the control end of this power supply circuit, so that this first light adjusting circuit determines the conducting state between its first end and its second end according to the logic state of this pulse width signal, and make this power supply circuit whether export this supply voltage according to this pulse width signal decision that its control end received, and this control circuit postpones the time point that this power supply circuit is exported this supply voltage according to first logic state of this pulse width signal, and make this this supply voltage of power supply circuit stop supplies, and postpone the time point that this first light adjusting circuit is closed according to second logic state of this pulse width signal.
12. light source driving circuit as claimed in claim 11 is characterized in that, this control circuit comprises:
First delay circuit, be coupled between the control end and this pulse width signal of this power supply circuit, in order to receive and to transmit the control end of this pulse width signal to this power supply circuit, and when this pulse width signal presents this first logic state, postpone the time point that this power supply circuit is exported this supply voltage, and when presenting this second logic state, this pulse width signal makes this this supply voltage of power supply circuit stop supplies; And
Second delay circuit, be coupled between the pulse width signal input end and this pulse width signal of this first light adjusting circuit, in order to receiving and to transmit the pulse width signal input end of this pulse width signal, and when presenting this second logic state, this pulse width signal postpones the time point that this first light adjusting circuit is closed to this first light adjusting circuit.
13. light source driving circuit as claimed in claim 12 is characterized in that, this first delay circuit comprises:
First diode, its anode couples the control end of this power supply circuit, and its negative electrode couples this pulse width signal;
First impedor, the one end couples the anode of this first diode, and its other end couples the negative electrode of this first diode; And
Second impedor is coupled between the anode and this common electric potential of this first diode.
14. light source driving circuit as claimed in claim 12 is characterized in that, this second delay circuit comprises:
Second diode, its anode couples this pulse width signal, and its negative electrode couples the pulse width signal input end of this first light adjusting circuit;
The 3rd impedor, the one end couples the anode of this second diode, and its other end couples the negative electrode of this second diode; And
The 4th impedor is coupled between the negative electrode and this common electric potential of this second diode.
15. light source driving circuit as claimed in claim 11 is characterized in that, also in order to drive second light-emitting component, a wherein end of this second light-emitting component couples the output terminal of this power supply circuit to this light source driving circuit, and this light source driving circuit also comprises:
Second light adjusting circuit, this second light adjusting circuit has first end, second end and pulse width signal input end, and its first end couples the other end of this second light-emitting component, and its second end couples this common electric potential.
16. light source driving circuit as claimed in claim 15 is characterized in that, this control circuit comprises:
First delay circuit, be coupled to the control end of this power supply circuit and this pulse width signal between, in order to receive and to transmit the control end of this pulse width signal to this power supply circuit, and when this pulse width signal presents this first logic state, postpone the time point that this power supply circuit is exported this supply voltage, and when presenting this second logic state, this pulse width signal makes this this supply voltage of power supply circuit stop supplies; And
Second delay circuit, be coupled between the pulse width signal input end and this pulse width signal three of pulse width signal input end, this second light adjusting circuit of this first light adjusting circuit, in order to receiving and to transmit the pulse width signal input end of this pulse width signal, and when presenting this second logic state, this pulse width signal postpones the time point that this first light adjusting circuit and this second light adjusting circuit are closed to this first light adjusting circuit and this second light adjusting circuit.
17. light source driving circuit as claimed in claim 15, it is characterized in that, this light source driving circuit is also in order to drive the 3rd light-emitting component and the 4th light-emitting component, a wherein end of the 3rd light-emitting component and a wherein end of the 4th light-emitting component all couple the output terminal of this power supply circuit, and this first light adjusting circuit and this second light adjusting circuit also comprise the 3rd end respectively, the 3rd end of this first light adjusting circuit is in order to couple the other end of the 3rd light-emitting component, the 3rd end of this second light adjusting circuit is in order to couple the other end of the 4th light-emitting component, and this first light adjusting circuit and this second light adjusting circuit determine the conducting state between its 3rd end and its second end all according to the logic state of this pulse width signal.
18. light source driving circuit as claimed in claim 17 is characterized in that, this control circuit comprises:
First delay circuit, be coupled between the control end and this pulse width signal of this power supply circuit, in order to receive and to transmit the control end of this pulse width signal to this power supply circuit, and when this pulse width signal presents this first logic state, postpone the time point that this power supply circuit is exported this supply voltage, and when presenting this second logic state, this pulse width signal makes this this supply voltage of power supply circuit stop supplies;
Second delay circuit, be coupled between the pulse width signal input end and this pulse width signal of this first light adjusting circuit, in order to receiving and to transmit the pulse width signal input end of this pulse width signal, and when presenting this second logic state, this pulse width signal postpones the time point that this first light adjusting circuit is closed to this first light adjusting circuit; And
The 3rd delay circuit, be coupled between the pulse width signal input end and this pulse width signal of this second light adjusting circuit, in order to receiving and to transmit the pulse width signal input end of this pulse width signal, and when presenting this second logic state, this pulse width signal postpones the time point that this second light adjusting circuit is closed to this second light adjusting circuit.
CN200610142527A 2006-10-23 2006-10-23 Drive circuit for driving LED and LED string Expired - Fee Related CN101169918B (en)

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CN102237045A (en) * 2011-07-25 2011-11-09 深圳Tcl新技术有限公司 Converter for multi-phase regional controlled light driving
CN102237045B (en) * 2011-07-25 2014-07-23 深圳Tcl新技术有限公司 Converter for multi-phase regional controlled light driving
CN102966881A (en) * 2011-08-31 2013-03-13 株式会社东芝 Light source device, driving device, and electronic device
CN102354484A (en) * 2011-09-20 2012-02-15 深圳市华星光电技术有限公司 Light emitting diode (LED) dimming driving device, method and liquid crystal display
CN103280189A (en) * 2013-05-17 2013-09-04 深圳市华星光电技术有限公司 LED (Light-Emitting Diode) dimming circuit
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