CN104427721B - Led drive circuit - Google Patents
Led drive circuit Download PDFInfo
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- CN104427721B CN104427721B CN201410411953.7A CN201410411953A CN104427721B CN 104427721 B CN104427721 B CN 104427721B CN 201410411953 A CN201410411953 A CN 201410411953A CN 104427721 B CN104427721 B CN 104427721B
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- 238000001514 detection method Methods 0.000 claims description 19
- 239000003990 capacitor Substances 0.000 description 31
- 230000005611 electricity Effects 0.000 description 11
- 239000004065 semiconductor Substances 0.000 description 10
- 230000008878 coupling Effects 0.000 description 6
- 238000010168 coupling process Methods 0.000 description 6
- 238000005859 coupling reaction Methods 0.000 description 6
- 230000008929 regeneration Effects 0.000 description 6
- 238000011069 regeneration method Methods 0.000 description 6
- 238000004804 winding Methods 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 229910001218 Gallium arsenide Inorganic materials 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000001172 regenerating effect Effects 0.000 description 2
- 229910010271 silicon carbide Inorganic materials 0.000 description 2
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000000994 depressogenic effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005538 encapsulation Methods 0.000 description 1
- 229910052733 gallium Inorganic materials 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
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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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- Circuit Arrangement For Electric Light Sources In General (AREA)
- Continuous-Control Power Sources That Use Transistors (AREA)
Abstract
The present invention provides LED drive circuit, its can when not lighting LED standby the power supply of supply microcomputer.LED drive circuit has: constant-current control signal output circuit (current sense resistor Rs), the constant-current control signal that its output is corresponding with the reactor current flowing through reactor (L)；Isobarically Control signal output apparatus (CV), the Isobarically Control signal that its output is corresponding with output voltage (Vout)；And control circuit (Ta), it is when the usual action not being transfused to standby signal, by constant-current control signal, LED current is carried out current constant control, when the standby action being transfused to standby signal, make the output voltage (Vout) lower than the ignition voltage of LED array (LD) by Isobarically Control signal constant is voltage-controlled.
Description
Technical field
The present invention relates to the LED drive circuit using the switch element of normal open type to light LED with constant current.
Background technology
In recent years it has been proposed that following technology: semiconductor substrate will employ GaAs (GaAs), GaN (nitridation
Gallium), low-loss wide bandgap semiconductor element of SiC (carborundum) etc. be used as the switch element (example of switching power circuit
As with reference to patent document 1).By using wide bandgap semiconductor element as switch element, it is possible to do not reducing power supply
Operating frequency is improved, it is possible to realize the miniaturization of device, it is possible to constitute switch element and inductor in the case of efficiency
It is sealing into the subminiature nonisulated copped wave modular power source of same encapsulation.
[patent document 1] Japanese Unexamined Patent Publication 2011-199024
But, in the lighting apparatus such as pendent lamp, employ microcomputer for light modulation and these actions of mixing colours, because of
This is in addition to as the subminiature nonisulated copped wave modular power source of LED drive circuit, in addition it is also necessary to microcomputer
Power source special (about 5V10mA).Particularly, the lighting apparatus more than 25W tackles higher hamonic wave at needs,
And also use in the case of power factor correction circuit, by power factor correction circuit, LED drive circuit, miniature
The power source special of computer and 3 converters are constituted, and become complicated circuit structure, thus cause cost increase.
Summary of the invention
It is an object of the invention in view of the above problems, solve problem of the prior art, it is provided that one can not lighted
The LED drive circuit of the power supply of supply microcomputer during LED standby.
The LED drive circuit of the present invention, it is exported by direct current and lights LED with constant current, and wherein, this direct current exports
Being to utilize the discharge and recharge of reactor to generate, the discharge and recharge of this reactor is the connection of switch element based on normal open type
Disconnection action and perform, described LED drive circuit is characterised by, has: constant-current control signal output circuit,
The constant-current control signal that its output is corresponding with the reactor current flowing through described reactor；Isobarically Control signal output electricity
Road, the Isobarically Control signal that its output is corresponding with output voltage；And control circuit, it be not transfused to standby letter at it
Number usual action time, the LED current flowing through described LED is entered by this control circuit by described constant-current control signal
Row current constant control, when the standby action being transfused to standby signal, this control circuit passes through described Isobarically Control signal
Isobarically Control becomes the output voltage that the ignition voltage than described LED is low.
In accordance with the invention it is possible to when not lighting LED standby the power supply of supply microcomputer.
Accompanying drawing explanation
Fig. 1 is the circuit structure diagram of the 1st embodiment structure of the LED drive circuit illustrating the present invention.
Fig. 2 is the circuit structure diagram of the structure example illustrating the Isobarically Control signal output apparatus CV shown in Fig. 1.
Fig. 3 is the oscillogram of the 1st embodiment action of the LED drive circuit for the present invention is described.
Fig. 4 is the circuit structure diagram of the 2nd embodiment structure of the LED drive circuit illustrating the present invention.
Fig. 5 is the circuit structure diagram of the 3rd embodiment structure of the LED drive circuit illustrating the present invention.
Label declaration
10a:LED drive circuit (the 1st embodiment)；10b:LED drive circuit (the 2nd embodiment)；
10c:LED drive circuit (the 3rd embodiment)；BF: buffer circuit；C1: feed-through capacitor；C2: output
Capacitor；C3, C4: coupling capacitor；Ccomp, C5: capacitor；MCU: microcomputer；CV: permanent
Voltage-controlled signal output apparatus processed；D1: regeneration diode；D2, D3, D4: diode；L: reactor；LD:
LED array；OTA: trsanscondutance amplifier；OSC: triangular wave oscillator；Q1: switch element (the 1st switch unit
Part)；Q2: switch element (the 2nd switch element)；Q3: bipolar transistor；Q4: switch element；R1、R2、
R3, R10, R11, R12: resistance；Reg: constant voltage regulator circuit；Rs: current sense resistor；Ta: control
Circuit (the 1st embodiment)；Tb: control circuit (the 2nd, the 3rd embodiment)；Ton: comparator；Vref1:
Reference voltage；ZD1, ZD2: Zener diode.
Detailed description of the invention
Then, embodiments of the present invention are specifically described referring to the drawings.It addition, in the various figures, to identical structure mark
Note identical label clipped explanation.
(the 1st embodiment)
It is the use of the wide bandgap semiconductor of normal open type with reference to Fig. 1, the LED drive circuit 10a of the 1st embodiment
The auto-excitation type buck circuit of element.LED drive circuit 10a has rectification circuit DB, width as normal open type
The switch element Q1 of bandgap semiconductor element, Q2, switch element Q2 is carried out current constant control control circuit Ta,
Feed-through capacitor C1, reactor L, winding AW, regeneration diode D1, output capacitor C2, Zener diode
ZD1, resistance R1, R2, R3, diode D2, current sense resistor Rs, capacitor Ccomp, Isobarically Control
Signal output apparatus CV and constant voltage regulator circuit Reg.Further, LED drive circuit 10a using constant current drive as
LED array LD of load circuit, and power to the microcomputer MCU carrying out brightness adjustment control and toning control.
Hereinafter, in order to distinguish switch element Q1 and switch element Q2, switch element Q1 is referred to as the 1st switch element Q1,
Switch element Q2 is referred to as the 2nd switch element Q2.
The input terminal V+ and input terminal V0 of LED drive circuit 10a are connected to by diode bridge
The rectification output cathode terminal of rectification circuit DB of formula composition, the rectification output negative pole terminal of ground connection.At rectification circuit
The upper connection of AC input terminal ACin1, ACin2 of DB has commercial ac power source AC1, from commercial ac power source
The ac input voltage of AC1 exports from rectification circuit DB after full-wave rectification.
Rectification output cathode terminal and input terminal V0, i.e. rectification at input terminal V+, i.e. rectification circuit DB
Between the rectification output negative pole terminal of circuit DB, it is connected in parallel to following series circuit and feed-through capacitor C1,
This series circuit is by the 1st switch element Q1, the 2nd switch element Q2, reactor L, output capacitor C2, electricity
Stream detection resistance Rs is constituted.Input terminal V+ connects and has the drain terminal of the 1st switch element Q1, the 1st
Connect on the source terminal of switch element Q1 and have the drain terminal of the 2nd switch element Q2, and in the 2nd switch unit
Connect on the source terminal of part Q2 and have a terminal of reactor L.Another terminal of reactor L connects and has
The positive electrode of output capacitor C2, the negative electrode of output capacitor C2 connects with a terminal of current sense resistor Rs
Connect.
The two ends of output capacitor C2 are the output of LED drive circuit 10a, and the positive electricity of output capacitor C2 is extremely
Output terminal Vout+, the negative electricity of output capacitor C2 extremely output terminal Vout-.In this output terminal Vout
+, on Vout-, in the way of being in output terminal Vout+side using anode, connect LED array LD having as load.
Additionally, between output terminal Vout+and input terminal V0, connect and have Isobarically Control signal output apparatus CV,
And connect via constant voltage regulator circuit Reg and have microcomputer MCU.It addition, constant voltage regulator circuit Reg
Be by output terminal Vout+voltage be converted to the operating voltage of microcomputer MCU and be supplied to microcomputer
The circuit of MCU.
At the source terminal of the 2nd switch element Q2 and the tie point of a terminal of reactor L and input terminal
Between V0, connect and have regeneration diode D1.At source terminal and the reactor L of the 2nd switch element Q2 one
Connecting on the tie point of terminal and have the negative electrode of regeneration diode D1, connecting on input terminal V0 has regeneration diode
The anode of D1.Thus, when the 1st switch element Q1 and the 2nd switch element Q2 two side connect, to reactor L
Apply voltage with LED array LD, thus in reactor L, accumulate electric power.Further, at the 1st switch element Q1
Even if disconnect with any one party in the 2nd switch element Q2, become reactor L in parallel with output capacitor C2
The state connected, the power supply accumulated by reactor L is to LED array LD.
1st switch element Q1 of high side uses the negative voltage induced in winding AW magnetic-coupled with reactor L
Turn off control.One end of winding AW magnetic-coupled with reactor L and reactor L and the 2nd switch element Q2
The tie point of source terminal connect, the other end is via coupling capacitor C3 and the gate terminal of the 1st switch element Q1
Son connects.Thus, when the polarity of voltage of reactor L inverts, induce in winding AW so that the 1st switch
The gate terminal of element Q1 becomes the voltage of negative potential, thus the 1st switch element Q1 is maintained off-state.
Diode D2 is had additionally, be connected between the gate terminal and input terminal V0 of the 1st switch element Q1.The 1st
Connecting on the gate terminal of switch element Q1 and have the negative electrode of diode D2, connecting on input terminal V0 has two poles
The anode of pipe D2.Thus, by the forward voltage VF of the diode D2 gate terminal to the 1st switch element Q1
Carry out voltage clamping.
Between gate terminal and the source terminal of the 2nd switch element Q2 of downside, it is connected in parallel to Zener diode
ZD1 and resistance R1.The anode of Zener diode ZD1 and the gate terminal of the 2nd switch element Q2 connect, negative electrode
It is connected with the source terminal of the 2nd switch element Q2.
Control circuit Ta is the IC circuit for the 2nd switch element Q2 carries out current constant control, has mutual conductance and amplifies
Device (Voltage-current conversion amplifier) OTA, buffer BF, reference voltage V ref1, bipolar transistor Q3, two
Pole pipe D3, public terminal COM, current feedback terminal Isense, external phase compensate terminal COMP, drive letter
Number lead-out terminal OUT, starting current input terminal ST and standby terminal Stby.
The public terminal COM of control circuit Ta is connected with the input terminal V0 of ground connection, current feedback terminal Isense
With output terminal Vout-, i.e. the tie point of LED array LD and current sense resistor Rs be connected, external phase mend
Repay terminal COMP to be connected with ground terminal via capacitor Ccomp, drive signal output terminal OUT via electricity
The gate terminal of resistance R2 and the 2nd switch element Q2 of downside is connected, and starting current input terminal ST is via resistance
R3 is connected with input terminal V+.
In control circuit Ta, the 1st inversing input terminal of current feedback terminal Isense and trsanscondutance amplifier OTA
Connecting, the 2nd inversing input terminal of standby terminal Stby and trsanscondutance amplifier OTA is connected, trsanscondutance amplifier OTA
Non-inverting input terminal be connected with the positive terminal of reference voltage V ref1, the negative terminal of reference voltage V ref1 with
Public terminal COM connects.Additionally, the lead-out terminal of trsanscondutance amplifier OTA compensates terminal COMP with external phase
Connect.Trsanscondutance amplifier OTA will be separately input to the 1st inversing input terminal and the voltage of the 2nd inversing input terminal
In the voltage of higher side and the potential difference of reference voltage V ref1 that is input to non-inverting input terminal be converted to electricity
Flow and export.Therefore, using the two ends of detected detection resistance Rs as the reactor current flowing through reactor L
Between voltage (voltage of the 1st inversing input terminal) and be input to standby terminal Stby voltage (the 2nd reversion input
The voltage of terminal) in the voltage of higher side compare with reference voltage V ref1, its potential difference is converted to electricity
Stream also exports from trsanscondutance amplifier OTA.
Further, the lead-out terminal of trsanscondutance amplifier OTA is connected via the base stage of buffer BF with bipolar transistor Q3,
The colelctor electrode of bipolar transistor Q3 is connected with driving signal output terminal OUT via diode D3, bipolar transistor
The emitter stage of Q3 is connected with public terminal COM.It addition, the negative electrode of diode D3 and the collection of bipolar transistor Q3
Electrode connects, and anode is connected with driving signal output terminal OUT.
Thus, voltage between the two ends as the reactor current and detected detection resistance Rs that flow through reactor L
(voltage of the 1st inversing input terminal) than be input to standby terminal Stby voltage (the 2nd inversing input terminal
Voltage) in the case of height, the collector current of bipolar transistor Q3 becomes and external phase compensates terminal COMP
The charge volume of capacitor Ccomp connected, value that i.e. mean value of reactor current is corresponding.Therefore, as often
In the case of switch element Q1, Q2 of the wide bandgap semiconductor element of flow-through is on-state, by opening with the 2nd
Close the voltage drop of the resistance R1 connected between gate terminal and the source terminal of element Q2, determine as the 2nd switch
The Vgs of voltage between the gate/source of element Q2, compensates terminal therefore, it is possible to controlled into by Vgs with external phase
The negative potential that the charge volume of capacitor Ccomp that COMP connects is corresponding.By the Vgs so controlled is set to
Make wide bandgap semiconductor element carry out in the range of action as constant flow element, the 2nd switch element Q2 as with reactance
The constant flow element of the constant current value that the mean value of device electric current is corresponding plays a role.
With reference to Fig. 2, Isobarically Control signal output apparatus CV output terminal Vout+and input terminal V0 (ground connection
Terminal) between be connected in series with resistance R10, resistance R11, resistance R12, the connection of resistance R10 and resistance R11
The standby terminal Stby of some A and control circuit Ta connects.Additionally, there is switch element in parallel with resistance R12
Q4, it is by carrying out on-off from outside standby signal.
Then, the action of the LED drive circuit 10a of the 1st embodiment is described in detail with reference to Fig. 3.Hereinafter, as
Shown in bracket, the resistance value of each resistance R10, R11, R12 in Isobarically Control signal output apparatus CV is set
Be set to 239r:1r:5r, and will when generally exporting (NOM) from the voltage of output terminal Vout+output
Vout is set to substantially 60V, is set to reference voltage V ref1=0.3V.
When connecting dc source, switch element Q1, Q2 connect, and therefore reactor current flows out and linearly increasing.
Thus, reactor L accumulates electric power, and compensates, to external phase, the capacitor that terminal COMP is connected
Ccomp is charged.Not being transfused to when generally exporting of standby signal (NOM), switch element Q4 is for connecting
State, when being set to output voltage Vout=60V, corresponding to being input to control from Isobarically Control signal output apparatus CV
The voltage of the standby terminal Stby of circuit Ta processed, input is less than the 0.25V of reference voltage V ref1=0.3V.Thus,
Using voltage (the 1st reversion between the two ends of detected detection resistance Rs as the reactor current flowing through reactor L
The voltage of input terminal) compare with reference voltage V ref1=0.3V, its potential difference is converted to electric current and from across
Leading amplifier OTA output, the collector current of bipolar transistor Q3 becomes and external phase compensation terminal COMP
The charge volume of capacitor Ccomp connected, value that i.e. mean value of reactor current is corresponding.Further, even if to increase
The reactor current added reached to compensate with external phase the capacitor Ccomp that is connected of terminal COMP charge volume,
During the constant current value of i.e. the 2nd switch element Q2 that the mean value of reactor current is corresponding, owing to reactor current to enter one
Step increases, and therefore the drain terminal of switch element Q1, the i.e. voltage of the source terminal of switch element Q1 steeply rise.
Thus, the Vgs of switch element Q1 becomes the negative potential less than threshold value Vth (negative voltage), and switch element Q1 breaks
Open.
When switch element Q1 disconnects, the reversion of the polarity of voltage of reactor L, induce in winding AW so that the
The gate terminal of 1 switch element Q1 becomes the voltage of negative potential, thus the 1st switch element Q1 is maintained disconnection
State, during becoming the regeneration that the electric power that reactor L accumulated is released.Further, by releasing in during regenerating
Electric power and when not having reactor current to flow through reactor L, do not induce in the gate terminal of switch element Q1 and become
The voltage of negative potential, is again switched on switch element Q1, Q2, repeatedly the most identical with above-mentioned action action, thus
As it is shown on figure 3, during becoming the current constant control that with such as 100mA LED current carried out current constant control.
When being transfused to standby signal standby (Stby), switch element Q4 goes off state.In the case of Gai, defeated
Go out voltage Vout=12.25V, and be input to the standby end of control circuit Ta from Isobarically Control signal output apparatus CV
The voltage of sub-Stby becomes reference voltage V ref1=0.3V.Output voltage Vout=12.25V and LED array LD
Lighting start voltage to compare be of a sufficiently low value, based on the voltage being input to standby terminal Stby, (the 2nd reversion is defeated
Enter the voltage of terminal), as it is shown on figure 3, become the Isobarically Control phase that with 12.25V, output voltage is carried out Isobarically Control
Between.Additionally, output voltage Vout=12.25V is set as the electricity that the operating voltage than microcomputer MCU is high
Pressure, is converted to operating voltage by constant voltage regulator circuit Reg and is supplied to microcomputer MCU.
Additionally, Isobarically Control signal output apparatus CV plays a role as secondary side excess voltage protection.That is, when
When becoming output voltage Vout=72V, it is input to treating of control circuit Ta from Isobarically Control signal output apparatus CV
The voltage of machine terminal Stby rises to the voltage consistent with reference voltage V ref1=0.3V.Thereby, it is possible to prevent output
Voltage Vout rises to more than 72V.
As described above, according to the 1st embodiment, have: constant-current control signal output circuit (examine by electric current
Measuring resistance Rs), the constant-current control signal that its output is corresponding with the reactor current flowing through reactor L；Isobarically Control is believed
Number output circuit CV, the Isobarically Control signal that its output is corresponding with output voltage Vout；And control circuit Ta,
LED current, when the usual action not being transfused to standby signal (NOM), is carried out by it by constant-current control signal
Current constant control, when the standby action being transfused to standby signal (Stby), by Isobarically Control signal Isobarically Control
Become the output voltage Vout that the ignition voltage than LED array LD is low.
Utilize this structure, it is possible to supply miniature calculating when not lighting LED array LD standby by Isobarically Control
The power supply of machine, thereby serves to following effect: need not arrange the power source special of microcomputer, it is possible to simplify electricity
Line structure, it is possible to realize cost and reduce.Additionally, in the case of employing multiple modular power source in pendent lamp etc., moreover it is possible to
Enough multiple modular power source is made to carry out redundancy operating side by side by the output voltage Vout of (Stby) during standby action.
Further, according to the 1st embodiment, control circuit Ta be configured to have utilize constant-current control signal (electric current examine
Voltage between the two ends of measuring resistance Rs: the voltage of the 1st inversing input terminal) and reference voltage V ref1 between difference electricity
Press average detection circuit (trsanscondutance amplifier OTA and and mutual conductance that the mean value to reactor current detects
Capacitor Ccomp that the lead-out terminal of amplifier OTA connects), and according to being detected by average detection circuit
The mean value of reactor current carries out current constant control to LED current.
Utilize this structure, when usual action (NOM), use wide bandgap semiconductor as switch element and to carry out
In the buck circuit of high frequency, it is possible to the mean value equally carrying out LED current controls, even if there is input
Variation in voltage also is able to maintain constant-current characteristics, therefore, it is possible to provide the microminiature LED drive device of corresponding whole world input.
Further, according to the 1st embodiment, Isobarically Control signal output apparatus CV is configured to be transfused to standby letter
Number standby action time (Stby), with the output that the ignition voltage than LED array LD that carries out Isobarically Control is low
Voltage, exports the Isobarically Control signal consistent with reference voltage V ref1 of average detection circuit, control circuit Ta
By the way of average detection circuit is consistent with reference voltage with Isobarically Control signal, output voltage Vout is carried out perseverance
Voltage-controlled system.
Utilize this structure, it is possible in the case of the switching circuit being not provided with complexity, with the point than LED array LD
The output voltage that bright voltage is low carries out Isobarically Control.
Further, according to the 1st embodiment, Isobarically Control signal output apparatus CV is configured at output voltage Vout
When reaching overvoltage set in advance, export the voltage conduct consistent with reference voltage V ref1 of average detection circuit
Isobarically Control signal, control circuit Ta passes through average detection circuit with Isobarically Control signal and reference voltage V ref1
Consistent mode carries out Isobarically Control to output voltage Vout.
Utilize this structure, it is possible to Isobarically Control signal output apparatus CV is used as secondary side excess voltage protection.
(the 2nd embodiment)
It is the use of the wide bandgap semiconductor of normal open type with reference to Fig. 4, the LED drive circuit 10b of the 2nd embodiment
The separated exciting buck circuit of element.In the LED drive circuit 10 of the 1st embodiment, by the 2nd of downside the
Switch element Q2 is used as constant flow element, and in the LED drive circuit 10b of the 2nd embodiment, by controlling
Circuit Tb carries out on-off control to the 2nd switch element Q2 of downside.
Between gate terminal and the source terminal of the 2nd switch element Q2 of downside, connect and have Zener diode ZD2.
The anode of Zener diode ZD2 and the gate terminal of the 2nd switch element Q2 connect, negative electrode and the 2nd switch element
The source terminal of Q2 connects.Additionally, between the gate terminal and input terminal V0 of the 2nd switch element Q2, even
It is connected to the most high-resistance resistance R2.Zener diode ZD2 and resistance R2 is before control circuit Tb carries out action
Period in, as the current potential of the source terminal according to the 2nd switch element Q2, make the 2nd switch element Q2 carry out
The autobias circuit of disconnection action plays a role.That is, the 1st switch element Q1 being connected in series and the 2nd switch element
Q2 disconnects the normal open type of this characteristic when being and have connection, Vgs=negative potential when Vgs=0V, therefore to electricity
Source connect time etc. control circuit Tb carry out in the period before action, the 1st switch element Q1 and the 2nd switch element
When the grid voltage of Q2 becomes the current potential identical with source potential, it is turned on, flows super-high-current.Therefore,
High-resistance resistance R2 is connected between gate terminal and input terminal V0 (ground terminal) so that the 2nd opens
Close the grid voltage of element Q2 to be depressed into by abundant self-bias by negative voltage and be connected between gate terminal and source terminal
Till Zener voltage Vz of Zener diode ZD2, thus the 2nd switch element Q2 is disconnected.Thus, even if controlling
Circuit Tb processed does not carry out action, it is also possible to make the 2nd switch element Q2 turn off action when power on, because of
This is before control circuit Tb carries out action, and the 2nd switch element Q2 can be stably used as the semiconductor of nomal closed type
Element processes.
Control circuit Tb is the IC circuit for the 2nd switch element Q2 carries out on-off control, has mutual conductance
Amplifier (Voltage-current conversion amplifier) OTA, reference voltage V ref1, triangular wave oscillator OSC, comparator
Ton, buffer BF, public terminal COM, current feedback terminal Isense, external phase compensation terminal COMP,
Drive signal output terminal OUT, starting current input terminal ST, control portion power supply terminal Vcc and standby terminal
Stby。
In the LED drive circuit 10b of the 2nd embodiment, current sense resistor Rs and the 2nd switch element Q2
Source terminal and the tie point of reactor L between connect, the public terminal COM of control circuit Tb and electric current are examined
The tie point of measuring resistance Rs and reactor L connects, current feedback terminal Isense and the source of the 2nd switch element Q2
The tie point of extreme son and current sense resistor Rs connects.Further, external phase compensates terminal COMP via electric capacity
Device Ccomp is connected with the tie point of current sense resistor Rs and reactor L, drives signal output terminal OUT warp
It is connected by the gate terminal of coupling capacitor C4 and the 2nd switch element Q2 of downside, starting current input terminal ST
It is connected with input terminal V+ via resistance R3.
In control circuit Tb, the 1st inversing input terminal of current feedback terminal Isense and trsanscondutance amplifier OTA
Connecting, the 2nd inversing input terminal of standby terminal Stby and trsanscondutance amplifier OTA is connected, trsanscondutance amplifier OTA
Non-inverting input terminal be connected with the positive terminal of reference voltage V ref1, the negative terminal of reference voltage V ref1 with
Public terminal COM connects.Additionally, the lead-out terminal of trsanscondutance amplifier OTA compensates terminal COMP with external phase
Connect.Trsanscondutance amplifier OTA will be separately input to the 1st inversing input terminal and the voltage of the 2nd inversing input terminal
In higher side voltage and reference voltage V ref1 being input to non-inverting input terminal between potential difference conversion
For electric current and export.Therefore, using the detected detection resistance Rs as the reactor current flowing through reactor L
Between two ends voltage (voltage of the 1st inversing input terminal) and be input to standby terminal Stby voltage (the 2nd reversion
The voltage of input terminal) in the voltage of higher side compare with reference voltage V ref1, its potential difference is changed
Export for electric current and from trsanscondutance amplifier OTA.
Additionally, the lead-out terminal of trsanscondutance amplifier OTA is connected with the non-inverting input terminal of comparator Ton, compare
The inversing input terminal of device Ton is connected with the lead-out terminal of triangular wave oscillator OSC.Further, comparator Ton
Lead-out terminal is connected with driving signal output terminal OUT via buffer BF.It addition, triangular wave oscillator OSC
Become the knot being transfused to critical actuating signal from the anode-side of LED array LD via the diode D5 that adverse current prevents
Structure, after during regenerating, middle reactor current L has become 0, triangular wave rises.
Thus, voltage between the two ends as the reactor current and detected detection resistance Rs that flow through reactor L
(voltage of the 1st inversing input terminal) than be input to standby terminal Stby voltage (the 2nd inversing input terminal
Voltage) in the case of height, when the triangular wave exported from triangular wave oscillator OSC exceedes and external phase compensates terminal
When the charge volume of capacitor Ccomp that COMP connects, voltage that i.e. mean value of reactor current is corresponding, compare
The output of device Ton is reversed to low level.Thus, it is output into rectangular wave from buffer circuit BF, passes through coupling
When conjunction capacitor C4 carries out capacitor coupling to the output from buffer circuit BF, it is converted into original waveform
Area split up and down after positive voltage and negative voltage.Therefore, when off to the grid of the 2nd switch element Q2
Terminal applies negative voltage drastically, therefore, it is possible to make the 2nd switch element Q2 disconnect rapidly, and is maintained disconnection
State.That is, coupling capacitor C4 plays a role as pulse signal change-over circuit, and it will be defeated from buffer circuit BF
The pulse signal gone out is converted to the waveform born from common potential, and by the output of pulse signal after conversion to the 2nd switch unit
The gate terminal of part Q2.It addition, the grid that positive voltage is more than the 2nd switch element Q2 is pressure, but by Zener two
The forward voltage VF of pole pipe ZD2 carries out voltage clamping, therefore, it is possible in the damage being not resulted in the 2nd switch element Q2
In the case of make the 2nd switch element Q2 connect.
It addition, in LED drive circuit 10b, the 1st switch element Q1 and the 2nd switch element Q2 is total to
Source common gate connection, therefore by the 1st switch element Q1 is set to high pressure element, the 2nd switch element Q2 is set to
Low pressure element, is controlled by the on-off of the 2nd switch element Q2 and utilizes the 1st switch element Q1 to have resistance to
Pressure.Therefore, in action, additionally it is possible to the 1st switch element Q1 is replaced into low pressure SiMOSFET etc..
Additionally, between control portion power supply terminal Vcc and public terminal COM, connect and have capacitor C5, and
It is connected between output terminal Vout+and the control portion power supply terminal Vcc of control circuit Tb and has diode D2.Two
The anode of pole pipe D2 and output terminal Vout+be connected, negative electrode is connected with control portion power supply terminal Vcc.Utilize this knot
Structure, after the starting of control circuit Tb, utilizes bootstrap configuration to electric capacity from LED array LD as load circuit
Device C5 supplies electric power, and capacitor C5 supplies power for operation to control circuit Tb.
Further, Isobarically Control signal output apparatus CV and the control portion power supply terminal Vcc of control circuit Tb and public
Connecting between terminal COM, the detection of output voltage Vout is carried out by boostrap circuit.Thereby, it is possible in high side
Configuration Isobarically Control signal output apparatus CV carries out Isobarically Control, it is not necessary to the level shift etc. of high pressure.
As described above, according to the 2nd embodiment, it is configured to that there is the anode-side from LED array LD
Utilize the power supply circuit (diode D4) of the power supply of bootstrap configuration supply control circuit Tb, Isobarically Control signal
The Isobarically Control signal that output circuit CV output is corresponding with the supply voltage of control circuit Tb.
Utilize this structure, it is possible to carry out Isobarically Control at high side configuration Isobarically Control signal output apparatus CV, be not required to
Want the level shift etc. of high pressure.
(the 3rd embodiment)
With reference to Fig. 5, the LED drive circuit 10c of the 3rd embodiment is from the LED drive circuit of the 2nd embodiment
10b eliminates the 1st switch element Q1, winding AW and the capacitor C3 of high side, the most right by control circuit Tb
2nd switch element Q2 carries out on-off control, thus generates direct current output.So, controlled by separated exciting
Make the 2nd switch element Q2, it is not necessary to make other switch element and constant-current circuit and the 2nd switch element Q2 series connection even
Connect, therefore, it is possible to simplify circuit structure.
It addition, the present invention is not limited to the respective embodiments described above, it is known that in the range of the technological thought of the present invention, energy
Enough each embodiment is suitably changed.It addition, the quantity of said structure parts, position, shape etc. are not limited to
Above-mentioned embodiment, can become and be suitable for carrying out the quantity of the present invention, position, shape etc..It addition, in the various figures,
Identical structural element is marked identical label.
Claims (5)
1. a LED drive circuit, it is exported by direct current and lights LED with constant current, and wherein, this direct current exports
Being to utilize the discharge and recharge of reactor to generate, the discharge and recharge of this reactor is the connection of switch element based on normal open type
Disconnection action and perform, described LED drive circuit is characterised by, has:
Constant-current control signal output circuit, the current constant control that its output is corresponding with the reactor current flowing through described reactor
Signal；
Isobarically Control signal output apparatus, the Isobarically Control signal that its output is corresponding with output voltage；And
Control circuit, when the usual action not being transfused to standby signal, this control circuit is believed by described current constant control
Number the LED current flowing through described LED is carried out current constant control, when the standby action being transfused to standby signal,
This control circuit is electric by the output that the described voltage-controlled ignition voltage made than described LED of Isobarically Control signal constant is low
Pressure.
LED drive circuit the most according to claim 1, it is characterised in that
Described control circuit has average detection circuit, this average detection circuit by described constant-current control signal with
The mean value of described reactor current is detected by the potential difference between reference voltage, and described control circuit is according to by institute
The mean value stating the described reactor current that average detection circuit detects carries out constant current control to described LED current
System.
LED drive circuit the most according to claim 2, it is characterised in that
Described Isobarically Control signal output apparatus
When being transfused to the standby action of described standby signal, to have carried out the point of LED described in the ratio of Isobarically Control
The output voltage that bright voltage is low, exports the described constant voltage control consistent with the described reference voltage of described average detection circuit
Signal processed,
Described control circuit by described average detection circuit so that described Isobarically Control signal and described reference voltage
Consistent mode carries out Isobarically Control to output voltage.
4. according to the LED drive circuit described in Claims 2 or 3, it is characterised in that
When output voltage reaches overvoltage set in advance, the output of described Isobarically Control signal output apparatus is flat with described
The voltage that the described reference voltage of mean value detecting circuit is consistent, as described Isobarically Control signal,
Described control circuit by described average detection circuit so that described Isobarically Control signal and described reference voltage
Consistent mode carries out Isobarically Control to output voltage.
LED drive circuit the most according to claim 1, it is characterised in that
Described LED drive circuit has power supply circuit, and this power supply circuit is from the anode-side profit of described LED
The power supply of described control circuit is supplied with bootstrap configuration,
The described Isobarically Control letter that the output of Isobarically Control signal output apparatus is corresponding with the supply voltage of described control circuit
Number.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2013186383A JP2015053225A (en) | 2013-09-09 | 2013-09-09 | Led drive circuit |
| JP2013-186383 | 2013-09-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN104427721A CN104427721A (en) | 2015-03-18 |
| CN104427721B true CN104427721B (en) | 2016-08-24 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410411953.7A Expired - Fee Related CN104427721B (en) | 2013-09-09 | 2014-08-20 | Led drive circuit |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JP2015053225A (en) |
| CN (1) | CN104427721B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11778709B2 (en) | 2018-10-18 | 2023-10-03 | Signify Holding, B.V. | Driving circuit and associated lamp |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6771870B2 (en) * | 2015-08-31 | 2020-10-21 | 三菱電機株式会社 | Lighting device and lighting device |
| JP6593694B2 (en) * | 2015-09-10 | 2019-10-23 | パナソニックＩｐマネジメント株式会社 | Visible light communication device and method for manufacturing visible light communication device |
| CN111770613B (en) * | 2020-06-06 | 2021-02-23 | 深圳市零奔洋光电股份有限公司 | Adaptive control circuit and method for LED lamp strip |
| CN113873714B (en) * | 2020-06-30 | 2024-03-29 | 深圳市帝迈生物技术有限公司 | Light source driver and sample analyzer |
| CN114499121B (en) * | 2022-04-14 | 2022-07-15 | 深圳市芯茂微电子有限公司 | Controller of switching power supply and switching power supply |
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| CN201718084U (en) * | 2010-05-12 | 2011-01-19 | 深圳桑达国际电子器件有限公司 | Circuit for driving LED to emit light and LED light-emitting device |
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| JP5206000B2 (en) * | 2008-02-07 | 2013-06-05 | 東芝ライテック株式会社 | Power supply device and lighting fixture |
| JP5516955B2 (en) * | 2010-02-10 | 2014-06-11 | 東芝ライテック株式会社 | Lighting device and lighting device |
| JP5501134B2 (en) * | 2010-07-23 | 2014-05-21 | 三菱電機株式会社 | LED lighting device |
| JP5220235B2 (en) * | 2012-12-27 | 2013-06-26 | 三菱電機株式会社 | Power supply device and lighting fixture |
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| CN101626647A (en) * | 2008-07-11 | 2010-01-13 | 立景光电股份有限公司 | Driving system and method of light emitting diode with high efficacy of power consumption |
| CN201541197U (en) * | 2008-09-29 | 2010-08-04 | 技领半导体(上海)有限公司 | Power supply converter of adjusting output current of switch-type adjuster |
| CN201718084U (en) * | 2010-05-12 | 2011-01-19 | 深圳桑达国际电子器件有限公司 | Circuit for driving LED to emit light and LED light-emitting device |
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| US11778709B2 (en) | 2018-10-18 | 2023-10-03 | Signify Holding, B.V. | Driving circuit and associated lamp |
Also Published As
| Publication number | Publication date |
|---|---|
| CN104427721A (en) | 2015-03-18 |
| JP2015053225A (en) | 2015-03-19 |
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