CN102740538A - Led drive circuit - Google Patents
Led drive circuit Download PDFInfo
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- CN102740538A CN102740538A CN2011100926177A CN201110092617A CN102740538A CN 102740538 A CN102740538 A CN 102740538A CN 2011100926177 A CN2011100926177 A CN 2011100926177A CN 201110092617 A CN201110092617 A CN 201110092617A CN 102740538 A CN102740538 A CN 102740538A
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B47/00—Circuit arrangements for operating light sources in general, i.e. where the type of light source is not relevant
- H05B47/20—Responsive to malfunctions or to light source life; for protection
- H05B47/24—Circuit arrangements for protecting against overvoltage
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B45/00—Circuit arrangements for operating light-emitting diodes [LED]
- H05B45/50—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits
- H05B45/56—Circuit arrangements for operating light-emitting diodes [LED] responsive to malfunctions or undesirable behaviour of LEDs; responsive to LED life; Protective circuits involving measures to prevent abnormal temperature of the LEDs
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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
- Y02B20/30—Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
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- Circuit Arrangement For Electric Light Sources In General (AREA)
- Led Devices (AREA)
Abstract
The present invention relates to an LED drive circuit which includes a micro-control unit, a voltage protection unit and an LED light source. The voltage protection unit includes an under-voltage protection module, an overvoltage protection module and a reference voltage module. The under-voltage protection module includes a detection voltage input terminal and a reference minimum voltage input terminal. The overvoltage protection module comprises a detection voltage input and a reference maximum voltage input terminal. The reference voltage module provides reference minimum voltage to the under-voltage protection module and provides reference maximum voltage to the overvoltage protection module. The under-voltage protection module and a reference voltage regulation module are set, thus when input voltage is lower than rated minimum voltage, detection voltage is lower than the reference minimum voltage, and the LED light source is turned off. The overvoltage protection module and the reference voltage regulation module, thus when the input voltage is higher than rated maximum voltage, the detection voltage is higher than the reference maximum voltage, and the LED light source is turned off. The LED drive circuit can maintain a constant current characteristic and has the protection of under-voltage, overvoltage and overheating.
Description
Technical field
The present invention relates to a kind of lighting field, relate in particular to a kind of led drive circuit.
Background technology
Along with the continuous development of science and technology, characteristic such as LED possesses the light efficiency height as new type light source, and energy-efficient, the life-span is long, and low pressure is controlled is widely used in the indoor and outdoor lighting in each field, various led drive circuits also occurred thereupon.All be to adopt the DC-DC wave chopping technology to come driving LED at present in the place of low-voltage; It has that power consumption is little, efficient is high, reliable and stable, advantage such as the unit power volume is little, in light weight; But its cost height, complicated circuit, fragile, stronger shortcomings such as High-frequency Interference are arranged, brought inconvenience to the user.In application, led drive circuit need keep constant-current characteristics as far as possible, promptly when the supply voltage change, still can keep the electric current of led drive circuit in small range, to change.Under the prerequisite that keeps constant-current characteristics, defencive function is also very important, such as the defencive function of voltage and the defencive function of temperature.
Summary of the invention
The object of the present invention is to provide a kind of led drive circuit, its input voltage is when specified minimum voltage is extremely between the specified ceiling voltage, and under the adjustment of led drive circuit, the operating current of said led light source can keep constant-current characteristics; When specified minimum voltage was extremely between the specified ceiling voltage, led light source was not closed in led drive circuit control to the input voltage of led drive circuit, avoids when input voltage is too small or excessive, damages driving LED drive circuit and led light source; When ambient temperature changed, led drive circuit can reduce the operating current of led light source or close led light source, avoided the too high light decay that causes of temperature of led light source to quicken or burn out.
Above-mentioned purpose realizes through following technical proposals:
A kind of led drive circuit comprises micro-control unit, voltage protection unit and led light source; The input voltage of said led drive circuit when specified minimum voltage is between the specified ceiling voltage, said led light source operate as normal;
Said voltage protection unit comprises the under-voltage protection module, overvoltage protective module and reference voltage Voltage stabilizing module; Said under-voltage protection module comprises detection voltage input end and benchmark minimum voltage input; Said overvoltage protective module comprises detection voltage input end and reference maximum voltage input; Said reference voltage module provides the benchmark minimum voltage and reference maximum voltage is provided for overvoltage protective module for the under-voltage protection module;
Under-voltage protection module and reference voltage Voltage stabilizing module are set, and when making input voltage be lower than specified minimum voltage, the detection voltage of under-voltage protection module is lower than the benchmark minimum voltage, and under-voltage protection module controls micro-control unit makes it close led light source;
Overvoltage protective module and reference voltage Voltage stabilizing module are set, and when making input voltage be higher than specified ceiling voltage, the detection voltage of overvoltage protective module is higher than reference maximum voltage, and overvoltage protective module control micro-control unit makes it close led light source.
Above-mentioned purpose can also be further perfect through following technical proposals.
Said under-voltage protection module comprises first operational amplifier, first pull-up resistor and first pull down resistor; First pull-up resistor, one end is connected to high level, first pull-up resistor and the series connection of first pull down resistor, and first pull down resistor, one end ground connection, the node of first pull-up resistor and first pull down resistor is connected to the inverting input of first operational amplifier;
Said overvoltage protective module comprises second operational amplifier, second pull-up resistor and second pull down resistor; Second pull-up resistor, one end is connected to high level, second pull-up resistor and the series connection of second pull down resistor, and second pull down resistor, one end ground connection, the node of second pull-up resistor and second pull down resistor is connected to the in-phase input end of second operational amplifier;
Said reference voltage Voltage stabilizing module comprises first current-limiting resistance and reference voltage voltage stabilizing chip; First current-limiting resistance, one end is connected to high level, first current-limiting resistance and the series connection of reference voltage voltage stabilizing chip, reference voltage voltage stabilizing chip one end ground connection; The node of first current-limiting resistance and reference voltage voltage stabilizing chip is connected to the in-phase input end of first operational amplifier and the inverting input of second operational amplifier;
The output of the output of said first operational amplifier and second operational amplifier is connected to the voltage protection input port of micro-control unit; The positive power source terminal of the positive power source terminal of said first operational amplifier and second operational amplifier is connected respectively to high level, and the negative power end of the negative power end of said first operational amplifier and second operational amplifier is ground connection respectively.
Beneficial effect of the present invention:
The input voltage of led drive circuit of the present invention is when specified minimum voltage is extremely between the specified ceiling voltage, and under the adjustment of led drive circuit, the operating current of said led light source can keep constant-current characteristics; When specified minimum voltage was extremely between the specified ceiling voltage, led light source was not closed in led drive circuit control to the input voltage of led drive circuit, avoids when input voltage is too small or excessive, damages driving LED drive circuit and led light source; When ambient temperature changed, led drive circuit can reduce the operating current of led light source or close led light source, avoided the too high light decay that causes of temperature of led light source to quicken or burn out.
Description of drawings
Fig. 1 is the structural representation of led drive circuit of the present invention;
Fig. 2 is the circuit theory diagrams of led drive circuit of the present invention;
Wherein:
101 first operational amplifiers (symbol U2A), 102 first pull-up resistors (symbol R2), 103 first pull down resistors (symbol R3);
201 second operational amplifiers (symbol U2B), 202 second pull-up resistors (symbol R4), 203 second pull down resistors (symbol R5), 204 second filter capacitors (symbol C2), 205 first counnter attack diodes (symbol D1), 206 second counnter attack diodes (symbol D2);
301 first current-limiting resistances (symbol R1), 302 reference voltage voltage stabilizing chips (symbol U3);
401 negative tempperature coefficient thermistors (symbol RT1), 402 divider resistances (symbol R6);
501 drive triode (symbol Q2), 502 second current-limiting resistances (symbol R11), 503 the 3rd pull down resistors (symbol R12); 504 the 3rd current-limiting resistances (symbol R10), 505 switch triodes (symbol Q1), 506 the 3rd pull-up resistors (symbol R9); 507 fly-wheel diodes (symbol D3); 508 afterflow inductance (symbol L1), 509 first filter capacitors (symbol C3), 510 current sampling resistors (symbol R13);
601 the 4th pull-up resistors (symbol R8), 602 switches (symbol K1);
701 single-chip microcomputers (symbol U1);
Filtering and storage source electric capacity (symbol C1); Rectifier bridge heap (symbol D4); LED1, LED2, LED3 led light source.
Embodiment
In order to make the object of the invention, technical scheme and advantage clearer,, led drive circuit of the present invention is further elaborated below in conjunction with accompanying drawing and embodiment.Should be appreciated that specific embodiment described herein only in order to explanation the present invention, and be not used in qualification the present invention.
Led drive circuit of the present invention, as shown in Figure 1, comprise micro-control unit (Micro Control Unit is called for short MCU), voltage protection unit and led light source; The input voltage of said led drive circuit when specified minimum voltage is between the specified ceiling voltage, said led light source operate as normal; Like specified minimum voltage is 11 volts, and specified ceiling voltage is 30 volts;
Said voltage protection unit comprises the under-voltage protection module, overvoltage protective module and reference voltage Voltage stabilizing module; Said under-voltage protection module comprises detection voltage input end and benchmark minimum voltage input; Said overvoltage protective module comprises detection voltage input end and reference maximum voltage input; Said reference voltage module provides the benchmark minimum voltage and reference maximum voltage is provided for overvoltage protective module for the under-voltage protection module;
Under-voltage protection module and reference voltage Voltage stabilizing module are set, and when making input voltage be lower than specified minimum voltage, the detection voltage of under-voltage protection module is lower than the benchmark minimum voltage, and under-voltage protection module controls micro-control unit makes it close led light source;
Overvoltage protective module and reference voltage Voltage stabilizing module are set, and when making input voltage be higher than specified ceiling voltage, the detection voltage of overvoltage protective module is higher than reference maximum voltage, and overvoltage protective module control micro-control unit makes it close led light source.
Wherein, Pulse width modulation (Pulse Width Modulation; Be called for short PWM) ripple, be to utilize the numeral of micro-control unit to export a kind of very effective technology that analog circuit is controlled, be widely used in from many fields of measurement, the power of communicating by letter control and conversion.
As shown in Figure 2, said under-voltage protection module comprises first operational amplifier 101 (symbol U2A), first pull-up resistor 102 (symbol R2) and first pull down resistor 103 (symbol R3); First pull-up resistor 102 (symbol R2) end is connected to high level; First pull-up resistor 102 (symbol R2) and first pull down resistor 103 (symbol R3) series connection; First pull down resistor 103 (symbol R3) end ground connection, the node of first pull-up resistor 102 (symbol R2) and first pull down resistor 103 (symbol R3) is connected to the inverting input (symbol pin 2) of first operational amplifier 101 (symbol U2A);
Said overvoltage protective module comprises second operational amplifier 201 (symbol U2B), second pull-up resistor 202 (symbol R4) and second pull down resistor 203 (symbol R5); Second pull-up resistor 202 (symbol R4) end is connected to high level; Second pull-up resistor 202 (symbol R4) and second pull down resistor 203 (symbol R5) series connection; Second pull down resistor 203 (symbol R5) end ground connection, the node of second pull-up resistor 202 (symbol R4) and second pull down resistor 203 (symbol R5) is connected to the in-phase input end (symbol pin 5) of second operational amplifier 201 (symbol U2B);
Said reference voltage Voltage stabilizing module comprises first current-limiting resistance 301 (symbol R1) and reference voltage voltage stabilizing chip 302 (symbol U3); First current-limiting resistance 301 (symbol R1) end is connected to high level, first current-limiting resistance 301 (symbol R1) and reference voltage voltage stabilizing chip 302 (symbol U3) series connection, reference voltage voltage stabilizing chip 302 (symbol U3) end ground connection; The node of first current-limiting resistance 301 (symbol R1) and reference voltage voltage stabilizing chip 302 (symbol U3) is connected to the in-phase input end (symbol pin 3) of first current-limiting resistance 301 (symbol R1) and the inverting input (symbol pin 6) of second operational amplifier 201 (symbol U2B);
The output (symbol pin 1) of said first operational amplifier 101 (symbol U2A) and the output (symbol pin 7) of second operational amplifier 201 (symbol U2B) are connected to the voltage protection input port (symbol PB2) of micro-control unit; The positive power source terminal (symbol pin 8) of said first operational amplifier 101 (symbol U2A) and the positive power source terminal (symbol pin 8) of second operational amplifier 201 (symbol U2B) are connected respectively to high level, and the negative power end (symbol pin 4) of said first operational amplifier 101 (symbol U2A) and the negative power end (symbol pin 4) of second operational amplifier 201 (symbol U2B) be ground connection respectively.
Under-voltage protection module and reference voltage Voltage stabilizing module are set; When making input voltage be lower than specified minimum voltage (when input voltage is lower than 11 volts), the voltage of the inverting input (symbol pin 2) of said first operational amplifier 101 (symbol U2A) (being the detection voltage of under-voltage protection module) is lower than the voltage (being the benchmark minimum voltage) of its in-phase input end (symbol pin 3); Output (symbol pin 1) the output high level of said first operational amplifier 101 (symbol U2A), micro-control unit is closed to constant current driving unit output pulse width modulating wave and then is closed led light source (being that micro-control unit is closed led light source);
Overvoltage protective module and reference voltage Voltage stabilizing module are set; When making input voltage be higher than specified ceiling voltage (when input voltage is higher than 30 volts), the voltage of the in-phase input end (symbol pin 5) of said second operational amplifier 201 (symbol U2B) (being the detection voltage of overvoltage protective module) is higher than the voltage (being reference maximum voltage) of its inverting input (symbol pin 6); Output (symbol pin 7) the output high level of said second operational amplifier 201 (symbol U2B), micro-control unit is closed to constant current driving unit output pulse width modulating wave and then is closed led light source (being that micro-control unit is closed led light source).
As shown in Figure 2, led drive circuit also comprises the overtemperature protection unit, and said overtemperature protection unit comprises negative tempperature coefficient thermistor 401 (symbol RT1) and divider resistance 402 (symbol R6); Negative tempperature coefficient thermistor 401 (symbol RT1) is connected to high level, negative tempperature coefficient thermistor 401 (symbol RT1) and divider resistance 402 (symbol R6) series connection, divider resistance 402 (symbol R6) ground connection; Node between negative tempperature coefficient thermistor 401 (symbol RT1) and the divider resistance 402 (symbol R6) is connected to the overtemperature protection input port (symbol PB1) of micro-control unit.
Wherein, negative tempperature coefficient thermistor 401 (symbol RT1) is along with temperature rising resistance reduces.
Electric current when said micro-control unit is worked according to led light source is provided with the upper limit and the maximum operating currenbt of the running current of led light source;
The operating current of said overtemperature protection unit is gone up in limited time greater than running current, and micro-control unit controls is to the pulse width modulation ripple of constant current driving unit output and then turn the electric current of led light source down;
The operating current of said overtemperature protection unit is during greater than maximum operating currenbt, and micro-control unit is closed to constant current driving unit output pulse width modulating wave and then closed led light source.
Wherein, the electric current during the led light source operate as normal is a scope, and this scope is set to the running current of led light source; The maximum current that led light source can bear is set to the maximum operating currenbt of led light source.
As shown in Figure 2, said constant current driving unit comprises driving triode 501 (symbol Q2), second current-limiting resistance 502 (symbol R11); The 3rd pull down resistor 503 (symbol R12), the 3rd current-limiting resistance 504 (symbol R10), switch triode 505 (symbol Q1); The 3rd pull-up resistor 506 (symbol R9); Fly-wheel diode 507 (symbol D3), afterflow inductance 508 (symbol L1), first filter capacitor 509 (symbol C3) and current sampling resistor 510 (symbol R13);
The base stage of said driving triode 501 (symbol Q2) is connected with the pulse width modulation ripple delivery outlet (symbol PB3) of micro-control unit through second current-limiting resistance 502 (symbol R11);
Connect the 3rd pull down resistor 503 (symbol R12) between the grounded emitter of said driving triode 501 (symbol Q2), its emitter and base stage;
The collector electrode of said driving triode 501 (symbol Q2) is connected with the base stage of switch triode 505 (symbol Q1) through the 3rd current-limiting resistance 504 (symbol R10);
The emitter of said switch triode 501 (symbol Q2) is connected to high level, series connection the 3rd pull-up resistor 506 (symbol R9) between the base stage of said switch triode 505 (symbol Q1) and the emitter;
The collector electrode of said switch triode 505 (symbol Q1) is through fly-wheel diode 507 (symbol D3) ground connection, and the collector electrode of said switch triode 505 (symbol Q1) is through afterflow inductance 508 (symbol L1) and first filter capacitor 509 (symbol C3) ground connection; The node of afterflow inductance 508 (symbol L1) and first filter capacitor 509 (symbol C3) is through led light source and current sampling resistor 510 (symbol R13) ground connection;
The node of said led light source and current sampling resistor 510 (symbol R13) is connected to the sample rate current input port (symbol PB4) of micro-control unit.
Preferably, led drive circuit also comprises control unit, and said control unit comprises the 4th pull-up resistor 601 (symbol R8) and switch 602 (symbol K1); The 4th pull-up resistor 601 (symbol R8) is connected to high level, the 4th pull-up resistor 601 (symbol R8) and switch 602 (symbol K1) series connection, switch 602 (symbol K1) ground connection; The node of the 4th pull-up resistor 601 (symbol R8) and switch is connected to the power supply signal input port (symbol PB0) of micro-control unit; The switching signal that said micro-control unit produces according to switch 602 (symbol K1), through said constant current driving unit, voltage protection unit and overtemperature protection unit controls led light source.
Preferably, said micro-control unit is single-chip microcomputer 701 (symbol U1); Said single-chip microcomputer 701 (symbol U1) to constant current driving unit output pulse width modulating wave, makes led light source work through pulse width modulation ripple delivery outlet (symbol PB3) according to the switching signal of power supply signal input port (symbol PB0); Again to sample rate current input port (symbol PB4) operating current sampling to led light source; Single-chip microcomputer 701 (symbol U1) compares the running current of the led light source that the operating current of led light source and single-chip microcomputer U1 are provided with; Output pulse width modulating wave according to comparative result adjustment pulse width modulation ripple delivery outlet (symbol PB3); And then the operating current of adjustment led light source, thereby reach the purpose of constant current.
Preferably, the node of said second pull-up resistor 202 (symbol R4) and second pull down resistor 203 (symbol R5) is through second filter capacitor 204 (symbol C2) ground connection.
Preferably, the output (symbol pin 1) of said first operational amplifier 101 (symbol U2A) is connected to the voltage protection input port (symbol PB2) of micro-control unit through the first counnter attack diode 205 (symbol D1).
The output (symbol pin 7) of said second operational amplifier 201 (symbol U2B) is connected to the voltage protection input port (symbol PB2) of micro-control unit through the second counnter attack diode 206 (symbol D2).
Preferably, input voltage is through two input utmost points (symbol 1 and 3) input of rectifier bridge heap (symbol D4), and rectifier bridge is piled positive pole (symbol 2) the output high level of (symbol D4), negative pole (symbol 4) ground connection of rectifier bridge heap (symbol D4).
The input voltage of led drive circuit of the present invention is when specified minimum voltage is extremely between the specified ceiling voltage, and under the adjustment of led drive circuit, the operating current of said led light source can keep constant-current characteristics; When specified minimum voltage was extremely between the specified ceiling voltage, led light source was not closed in led drive circuit control to the input voltage of led drive circuit, avoids when input voltage is too small or excessive, damages driving LED drive circuit and led light source; When ambient temperature changed, led drive circuit can reduce the operating current of led light source or close led light source, avoided the too high light decay that causes of temperature of led light source to quicken or burn out.
Should be noted that at last that obviously those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these revise and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification.
Claims (10)
1. led drive circuit is characterized in that:
Comprise micro-control unit, voltage protection unit and led light source; The input voltage of said led drive circuit when specified minimum voltage is between the specified ceiling voltage, said led light source operate as normal;
Said voltage protection unit comprises the under-voltage protection module, overvoltage protective module and reference voltage Voltage stabilizing module; Said under-voltage protection module comprises detection voltage input end and benchmark minimum voltage input; Said overvoltage protective module comprises detection voltage input end and reference maximum voltage input; Said reference voltage module provides the benchmark minimum voltage and reference maximum voltage is provided for overvoltage protective module for the under-voltage protection module;
Under-voltage protection module and reference voltage Voltage stabilizing module are set, and when making input voltage be lower than specified minimum voltage, the detection voltage of under-voltage protection module is lower than the benchmark minimum voltage, and under-voltage protection module controls micro-control unit makes it close led light source;
Overvoltage protective module and reference voltage Voltage stabilizing module are set, and when making input voltage be higher than specified ceiling voltage, the detection voltage of overvoltage protective module is higher than reference maximum voltage, and overvoltage protective module control micro-control unit makes it close led light source.
2. led drive circuit according to claim 1 is characterized in that:
Said under-voltage protection module comprises first operational amplifier (101), first pull-up resistor (102) and first pull down resistor (103); First pull-up resistor (102) one ends are connected to high level; First pull-up resistor (102) and first pull down resistor (103) series connection; First pull down resistor (103) one end ground connection, the node of first pull-up resistor (102) and first pull down resistor (103) is connected to the inverting input of first operational amplifier (101);
Said overvoltage protective module comprises second operational amplifier (201), second pull-up resistor (202) and second pull down resistor (203); Second pull-up resistor (202) one ends are connected to high level; Second pull-up resistor (202) and second pull down resistor (203) series connection; Second pull down resistor (203) one end ground connection, the node of second pull-up resistor (202) and second pull down resistor (203) is connected to the in-phase input end of second operational amplifier (201);
Said reference voltage Voltage stabilizing module comprises first current-limiting resistance (301) and reference voltage voltage stabilizing chip (302); First current-limiting resistance (301) one ends are connected to high level, first current-limiting resistance (301) and reference voltage voltage stabilizing chip (302) series connection, reference voltage voltage stabilizing chip (302) one end ground connection; The node of first current-limiting resistance (301) and reference voltage voltage stabilizing chip (302) is connected to the in-phase input end of first operational amplifier (101) and the inverting input of second operational amplifier (201);
The output of the output of said first operational amplifier (101) and second operational amplifier (201) is connected to the voltage protection input port of micro-control unit; The positive power source terminal of the positive power source terminal of said first operational amplifier (101) and second operational amplifier (201) is connected respectively to high level, and the negative power end of the negative power end of said first operational amplifier (101) and second operational amplifier (201) is ground connection respectively.
3. led drive circuit according to claim 1 is characterized in that:
Also comprise the overtemperature protection unit, said overtemperature protection unit comprises negative tempperature coefficient thermistor (401) and divider resistance (402); Negative tempperature coefficient thermistor (401) is connected to high level, negative tempperature coefficient thermistor (401) and divider resistance (402) series connection, divider resistance (402) ground connection; Node between negative tempperature coefficient thermistor (401) and the divider resistance (402) is connected to the overtemperature protection input port of micro-control unit.
4. led drive circuit according to claim 1 is characterized in that:
Said constant current driving unit comprises driving triode (501), second current-limiting resistance (502), the 3rd pull down resistor (503); The 3rd current-limiting resistance (504); Switch triode (505), the 3rd pull-up resistor (506), fly-wheel diode (507); Afterflow inductance (508), first filter capacitor (509) and current sampling resistor (510);
The base stage of said driving triode (501) is connected with the pulse width modulation ripple delivery outlet of micro-control unit through second current-limiting resistance (502);
The 3rd pull down resistor (503) of connecting between the grounded emitter of said driving triode (501), its emitter and base stage;
The collector electrode of said driving triode (501) is connected with the base stage of switch triode (505) through the 3rd current-limiting resistance (504);
The emitter of said switch triode (505) is connected to high level, series connection the 3rd pull-up resistor (506) between the base stage of said switch triode (505) and the emitter;
The collector electrode of said switch triode (505) is through fly-wheel diode (507) ground connection, and the collector electrode of said switch triode (505) is through afterflow inductance (508) and first filter capacitor (509) ground connection; The node of said afterflow inductance (508) and first filter capacitor (509) is through led light source and current sampling resistor (510) ground connection;
The node of said led light source and current sampling resistor (510) is connected to the sample rate current input port of micro-control unit.
5. led drive circuit according to claim 4 is characterized in that:
Also comprise control unit, said control unit comprises the 4th pull-up resistor (601) and switch (602); The 4th pull-up resistor (601) is connected to high level, the 4th pull-up resistor (601) and switch (602) series connection, switch (602) ground connection; The node of the 4th pull-up resistor (601) and switch (602) is connected to the power supply signal input port of micro-control unit; The switching signal that said micro-control unit produces according to switch (602), through said constant current driving unit, voltage protection unit and overtemperature protection unit controls led light source.
6. led drive circuit according to claim 2 is characterized in that:
Under-voltage protection module and reference voltage Voltage stabilizing module are set, and when making input voltage be lower than specified minimum voltage, the voltage of the inverting input of said first operational amplifier (101) is lower than the voltage of its in-phase input end; The output output high level of said first operational amplifier (101), micro-control unit is closed led light source;
Overvoltage protective module and reference voltage Voltage stabilizing module are set, and when making input voltage be higher than specified ceiling voltage, the voltage of the in-phase input end of said second operational amplifier (201) is higher than the voltage of its inverting input; The output output high level of said second operational amplifier (201), micro-control unit is closed led light source.
7. led drive circuit according to claim 3 is characterized in that:
The electric current of said micro-control unit during according to the led light source operate as normal, the upper limit of the running current of setting and maximum operating currenbt;
The operating current of said overtemperature protection unit is gone up in limited time greater than running current, and micro-control unit controls is to the pulse width modulation ripple of constant current driving unit output and then turn the electric current of led light source down;
The operating current of said overtemperature protection unit is during greater than maximum operating currenbt, and micro-control unit is closed to constant current driving unit output pulse width modulating wave and then closed led light source.
8. led drive circuit according to claim 5 is characterized in that:
Said micro-control unit is single-chip microcomputer (701); Said single-chip microcomputer (701) to constant current driving unit output pulse width modulating wave, makes led light source work through pulse width modulation ripple delivery outlet according to the switching signal of power supply signal input port; Again to of the operating current sampling of sample rate current input port to led light source; Single-chip microcomputer (701) compares the running current of the led light source that the operating current of led light source and single-chip microcomputer (701) are provided with; According to the output pulse width modulating wave of comparative result adjustment pulse width modulation ripple delivery outlet, and then the operating current of adjustment led light source.
9. led drive circuit according to claim 2 is characterized in that:
The node of said second pull-up resistor (202) and second pull down resistor (203) is through second filter capacitor (204) ground connection.
10. led drive circuit according to claim 2 is characterized in that:
The output of said first operational amplifier (101) is connected to the voltage protection input port of micro-control unit through the first counnter attack diode (205);
The output of said second operational amplifier (201) is connected to the voltage protection input port of micro-control unit through the second counnter attack diode (206).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110092617.7A CN102740538B (en) | 2011-04-13 | 2011-04-13 | Led drive circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201110092617.7A CN102740538B (en) | 2011-04-13 | 2011-04-13 | Led drive circuit |
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| CN102740538A true CN102740538A (en) | 2012-10-17 |
| CN102740538B CN102740538B (en) | 2015-03-11 |
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| CN201110092617.7A Active CN102740538B (en) | 2011-04-13 | 2011-04-13 | Led drive circuit |
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Cited By (15)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN103295537A (en) * | 2013-05-08 | 2013-09-11 | 深圳市华星光电技术有限公司 | LED backlight driving circuit, backlight module and liquid crystal display device |
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| CN112985585A (en) * | 2021-02-02 | 2021-06-18 | 上海医勒希科技有限公司 | Calibration method and calibration system for standard light source and photometer |
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| CN103813564A (en) * | 2012-11-05 | 2014-05-21 | 海洋王（东莞）照明科技有限公司 | Lamp and protection circuit thereof |
| CN103857101B (en) * | 2012-11-29 | 2016-08-03 | 深圳市海洋王照明工程有限公司 | A kind of drive circuit and light fixture |
| CN103857101A (en) * | 2012-11-29 | 2014-06-11 | 深圳市海洋王照明工程有限公司 | Drive circuit and lamp fixture |
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| WO2014117606A1 (en) * | 2013-01-31 | 2014-08-07 | 四川新力光源股份有限公司 | Alternating current rectifying circuit and alternating current rectifying method for driving led module |
| US9485829B2 (en) | 2013-01-31 | 2016-11-01 | Sichuan Sunfor Light Co., Ltd. | Alternating current rectifying circuit and alternating current rectifying method for driving LED module |
| WO2014180057A1 (en) * | 2013-05-08 | 2014-11-13 | 深圳市华星光电技术有限公司 | Led backlight drive circuit, backlight module, and liquid crystal display apparatus |
| US9257078B2 (en) | 2013-05-08 | 2016-02-09 | Shenzhen China Star Optoelectronics Technology Co., Ltd | LED backlight driving circuit having divider units and method for driving the LED backlight driving circuit |
| CN103295537A (en) * | 2013-05-08 | 2013-09-11 | 深圳市华星光电技术有限公司 | LED backlight driving circuit, backlight module and liquid crystal display device |
| CN104717774A (en) * | 2013-12-16 | 2015-06-17 | 深圳市海洋王照明工程有限公司 | Lamp over-voltage protection circuit and lighting equipment |
| CN105846400B (en) * | 2015-01-16 | 2019-06-14 | 海洋王照明科技股份有限公司 | Single-stage open loop emergency supply circuit |
| CN105846400A (en) * | 2015-01-16 | 2016-08-10 | 海洋王照明科技股份有限公司 | Single-stage open-loop emergency power supply circuit |
| CN104912976A (en) * | 2015-06-30 | 2015-09-16 | 浙江玛拓驱动设备有限公司 | Safety type controller of electromagnetic brake |
| CN104912976B (en) * | 2015-06-30 | 2017-08-29 | 浙江玛拓驱动设备有限公司 | A kind of safety controller of electromagnetic brake |
| CN105517235A (en) * | 2015-12-23 | 2016-04-20 | 成都雷纳斯科技有限公司 | Constant-current driving circuit-based multifunctional control system for LED lamp |
| CN105451401A (en) * | 2016-01-31 | 2016-03-30 | 芜湖锐芯电子科技有限公司 | LED open-circuit voltage protection method and circuit and drive circuit using same |
| CN107947121A (en) * | 2017-12-12 | 2018-04-20 | 成都爱特联科技有限公司 | A kind of Switching Power Supply with over-and under-voltage defencive function |
| CN110418471A (en) * | 2019-09-02 | 2019-11-05 | 惠州市创舰实业有限公司 | Adjust protection circuit, lamps and lanterns and power supply |
| CN112630512A (en) * | 2020-12-07 | 2021-04-09 | 浙江中控技术股份有限公司 | FF bus under-voltage indicating circuit |
| CN112630512B (en) * | 2020-12-07 | 2024-05-03 | 浙江中控技术股份有限公司 | FF bus undervoltage indicating circuit |
| CN112985585A (en) * | 2021-02-02 | 2021-06-18 | 上海医勒希科技有限公司 | Calibration method and calibration system for standard light source and photometer |
| CN112985585B (en) * | 2021-02-02 | 2023-02-03 | 上海医勒希科技有限公司 | Calibration method and calibration system for standard light source and photometer |
| CN115268544A (en) * | 2022-07-20 | 2022-11-01 | 武汉海微科技有限公司 | Bias power supply circuit of OLED display screen for automobile |
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