CN206490866U - LED Lighting Power Circuit - Google Patents

Abstract

The utility model discloses a LED lighting power supply circuit, including bridge rectifier circuit, power conversion circuit, rectification output circuit, energy storage filter circuit, output circuit, feedback circuit, PWM module and FPC module integration are in a singlechip, bridge rectifier circuit, power conversion circuit, rectification output circuit, energy storage filter circuit, output circuit and feedback circuit connect gradually; the power conversion circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor, a third capacitor, a first triode, a second diode, a third diode, a voltage stabilizing diode and a transformer. Implement the utility model discloses a LED lighting power supply circuit has following beneficial effect: the circuit has a safety protection function and can improve the safety performance of the circuit.

Description

LED Lighting Power Circuit

technical field

The utility model relates to the lighting field, in particular to an LED lighting power supply circuit.

Background technique

The existing LED power supply circuit includes input filter circuit, rectifier circuit, power conversion circuit, rectifier output circuit, energy storage filter circuit, output circuit, feedback circuit, PWM (pulse width modulation) circuit and PFC (power factor correction) circuit, input The filter circuit, the rectification circuit, the power conversion circuit, the rectification output circuit, the energy storage filter circuit, the output circuit, the feedback circuit and the PWM circuit are connected in sequence, one end of the PFC circuit is connected to the PWM circuit, and the other end is connected to the power conversion circuit. The power conversion circuit usually does not have a circuit protection function, resulting in potential safety hazards during use and unsafe use.

Utility model content

The technical problem to be solved by the utility model is to provide an LED lighting power supply circuit which has a safety protection function and can improve the safety performance of the circuit, aiming at the above-mentioned defects of the prior art.

The technical solution adopted by the utility model to solve the technical problem is: to construct a LED lighting power supply circuit, including a bridge rectifier circuit, a power conversion circuit, a rectifier output circuit, an energy storage filter circuit, an output circuit, a feedback circuit, a PWM module and FPC module, one end of the power conversion circuit is connected to one end of the rectification filter circuit, one end of the rectification output circuit is connected to the other end of the power conversion circuit, one end of the energy storage filter circuit is connected to the rectifier The other end of the output circuit is connected, one end of the output circuit is connected to the other end of the energy storage filter circuit, one end of the feedback circuit is connected to the other end of the output circuit, one end of the PWM module is connected to the The other end of the feedback circuit is connected, the other end of the PWM module is connected to one end of the FPC module, and the other end of the FPC module is connected to the power conversion circuit; the PWM module and the FPC module are integrated in a single chip microcomputer ;

The power conversion circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a first capacitor, a second capacitor, a third capacitor, The first triode, the second triode, the second diode, the third diode, the Zener diode and the transformer, the third resistor is a negative temperature coefficient resistor; one end of the seventh resistor is connected to the One output end of the bridge rectifier circuit is connected, one end of the eighth resistor is connected to the other output end of the bridge rectifier circuit, and the other end of the eighth resistor is respectively connected to one end of the first resistor, The negative pole of the third capacitor is connected to one end of the sixth resistor, and the other end of the first resistor is respectively connected to the cathode of the second diode, the collector of the second triode, and the base of the first triode. connected to one end of the first capacitor, the anode of the second diode is grounded, the emitter of the second triode is grounded, and the base of the second triode is respectively connected to one end of the third resistor 1. One end of the fourth resistor is connected to one end of the second capacitor, the other end of the fourth resistor and the other end of the second capacitor are grounded, and the other end of the third resistor is respectively connected to the negative pole of the Zener diode and One end of the second resistor is connected, the anode of the Zener diode is grounded, the other end of the second resistor is respectively connected to one end of the fifth resistor and the same-named end of the primary coil of the transformer, and the other end of the fifth resistor One end is connected to the other end of the first capacitor, the other end of the primary coil of the transformer is grounded, the same-named end of the secondary coil of the transformer is connected to the other end of the eighth resistor, and the secondary coil of the transformer is connected to the other end of the eighth resistor. The other end of the coil is respectively connected to the collector of the first triode and the anode of the third diode, the cathode of the third diode is connected to the anode of the third capacitor, and the first three The emitter of the diode is grounded.

In the LED lighting power supply circuit of the present invention, a ninth resistor is further included, and the collector of the second triode is connected to the other end of the first resistor through the ninth resistor.

In the LED lighting power supply circuit of the present invention, a fourth capacitor is further included, and the base of the first triode is connected to one end of the first capacitor through the fourth capacitor.

In the LED lighting power supply circuit of the present invention, a tenth resistor is further included, and the collector of the first triode is connected to the other end of the secondary coil of the transformer through the tenth resistor.

In the LED lighting power supply circuit of the present invention, an eleventh resistor is further included, and the emitter of the first triode is grounded through the eleventh resistor.

In the LED lighting power supply circuit of the present invention, a twelfth resistor is further included, and the terminal with the same name of the secondary coil of the transformer is connected to the negative pole of the third capacitor through the twelfth resistor.

In the LED lighting power supply circuit described in the utility model, the first triode and the second triode are both NPN type triodes.

Implementing the LED lighting power supply circuit of the present utility model has the following beneficial effects: since the power conversion circuit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor Resistor, first capacitor, second capacitor, third capacitor, first triode, second triode, second diode, third diode, Zener diode and transformer, seventh resistor and eighth The resistors are all current-limiting resistors for over-current protection, so they have a safety protection function and can improve circuit safety performance.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings according to these drawings without any creative effort.

Fig. 1 is a schematic structural view of an embodiment of the LED lighting power supply circuit of the present invention;

Fig. 2 is a schematic circuit diagram of the power conversion circuit in the embodiment.

detailed description

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. example. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

In the embodiment of the LED lighting power supply circuit of the present invention, the structural diagram of the LED lighting power supply circuit is shown in FIG. 1 . In FIG. 1, the LED lighting power supply circuit includes a bridge rectifier circuit D1, a power conversion circuit 2, a rectification output circuit 3, an energy storage filter circuit 4, an output circuit 5, a feedback circuit 6, a PWM module 71 and an FPC module 72, wherein, One end of the power conversion circuit 2 is connected to one end of the rectification filter circuit D1, one end of the rectification output circuit 3 is connected to the other end of the power conversion circuit 2, one end of the energy storage filter circuit 4 is connected to the other end of the rectification output circuit 3, and the output circuit One end of 5 is connected to the other end of the energy storage filter circuit 4, one end of the feedback circuit 6 is connected to the other end of the output circuit 5, one end of the PWM module 71 is connected to the other end of the feedback circuit 6, and the other end of the PWM module 71 is connected to the FPC One end of the module 72 is connected, and the other end of the FPC module 72 is connected with the power conversion circuit 2; the PWM module 71 and the FPC module 72 are integrated in a single-chip microcomputer 7, which not only saves space, but also improves efficiency.

FIG. 2 is a schematic circuit diagram of the power conversion circuit in this embodiment. In FIG. 2, the power conversion circuit 2 includes a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, Sixth resistor R6, seventh resistor R7, eighth resistor R8, first capacitor C1, second capacitor C2, third capacitor C3, first transistor Q1, second transistor Q2, second diode D2 , a third diode D3, a Zener diode Z and a transformer T1, wherein the third resistor R3 is a negative temperature coefficient resistor, the third capacitor C3 is an electrolytic capacitor, the first triode Q1 is a power switch, and the second triode Tube Q2 is a temperature protection switch. It is worth mentioning that, in this embodiment, both the first transistor Q1 and the second transistor Q2 are NPN transistors. Of course, in some cases of this embodiment, both the first triode Q1 and the second triode Q2 may be PNP transistors, but at this time the structure of the circuit should be changed accordingly.

In this embodiment, one end of the seventh resistor R7 is connected to an output end of the bridge rectifier circuit D1, one end of the eighth resistor R8 is connected to the other output end of the bridge rectifier circuit D1, and the other end of the eighth resistor R8 is respectively It is connected with one end of the first resistor R1, the negative pole of the third capacitor C3 and one end of the sixth resistor R6, and the other end of the first resistor R1 is respectively connected with the cathode of the second diode D2 and the collector of the second triode Q2 1. The base of the first transistor Q1 is connected to one end of the first capacitor C1, the anode of the second diode D2 is grounded, and the emitter of the second transistor Q2 is grounded.

The base of the second triode Q2 is respectively connected to one end of the third resistor R3, one end of the fourth resistor R4, and one end of the second capacitor C2, and the other end of the fourth resistor R4 and the other end of the second capacitor C2 are both grounded , the other end of the third resistor R3 is respectively connected to the negative pole of the Zener diode Z and one end of the second resistor R2, the anode of the Zener diode Z is grounded, and the other end of the second resistor R2 is respectively connected to one end of the fifth resistor R5 and the transformer The same-named end of the primary coil L2 of T1 is connected, the other end of the fifth resistor R5 is connected to the other end of the first capacitor C1, the other end of the primary coil L2 of the transformer T1 is grounded, and the same-named end of the secondary coil L1 of the transformer T1 is connected to the first capacitor C1. The other end of the resistor R8 is connected, the other end of the secondary coil L1 of the transformer T1 is respectively connected to the collector of the first triode Q1 and the anode of the third diode Q2, and the cathode of the third diode D3 is connected to the anode of the third diode Q2. The anode of the three capacitors C3 is connected, and the emitter of the first triode Q1 is grounded. The primary coil L2 of the transformer T1 is an auxiliary inductance, and the primary coil L2 of the transformer T1 is an energy storage inductance.

In this embodiment, both the seventh resistor R7 and the eighth resistor R8 are current-limiting resistors, and the seventh resistor R7 is used to connect the branch between an input terminal of the bridge rectifier circuit D1 and the anode of the second diode D2 For overcurrent protection, the eighth resistor R8 is used for overcurrent protection of the branch between the other input end of the bridge rectifier circuit D2 and one end of the first resistor R1, so it has a safety protection function and can improve circuit safety performance.

When the first transistor Q1 is closed, a charging circuit is formed, and the input power flows into the secondary coil L1 of the transformer T1, the first transistor Q1 and returns to the AC input through the bridge rectifier circuit D1. When the power in the secondary coil L1 of the transformer T1 is stored to a certain extent, the first triode Q1 is disconnected, the charging circuit is disconnected, and the current in the secondary coil L1 of the transformer T1 cannot pass through the first triode Q1. To the AC input, the current flows back to the secondary coil L1 of the transformer T1 through the third diode D3, the load terminal +, and the load terminal - to form a freewheeling loop, which supplies power to the load at this time.

A third capacitor C3 and a sixth resistor R6 for smoothing waveforms are connected between the load terminal + and the load terminal −. The process of charging and freewheeling is repeated, so that the AC/DC power is converted into the appropriate power for the load and supplied to the load.

After being powered on, the DC input voltage after passing through the bridge rectifier circuit D1 flows through the first resistor R1 to provide base current for the first triode Q1, and the first triode Q1 is turned on. At this moment, the main power circuit/charging circuit starts to work, and the power of the DC input voltage flows back through the secondary coil L1 of the transformer T1 and the first transistor Q1, and returns. The current flowing through the secondary coil L1 of the transformer T1 will rise linearly. At this time, an induced current is generated on the primary coil L2 of the transformer T1, flows through the fifth resistor R5 and the first capacitor C1, and reaches the base of the first transistor Q1. pole. The current in the secondary coil L1 of the transformer T1 continues to increase, the current exponential coefficients in the first capacitor C1 and the fifth resistor R5 decrease, and the first transistor Q1 gradually enters the linear region until it is turned off.

When the first transistor Q1 is turned off, the current flowing through the secondary coil L1 of the transformer T1 starts to flow to the third diode D3 and the load terminal, forming a freewheeling loop, and at the same time, the current starts to decrease linearly. When the current drops to zero, the secondary coil L1 of the transformer T1 resonates with the distributed capacitance between the collector and emitter of the first triode Q1, so that the current of the secondary coil L1 of the transformer T1 reverses first Circulation, and then forward circulation. When flowing in the forward direction, the positive voltage induced in the primary coil L2 of the transformer T1 passes through the fifth resistor R5 and the first resistor R1 to turn on the first transistor Q1 again. When the first triode Q1 is turned on, the induced voltage of the primary coil L2 of the transformer T1 will be strengthened, thereby accelerating the turn-on of the first triode Q1. At this time, the main power circuit starts to work again, and the cycle repeats.

When the temperature rises, the resistance of the third resistor R3 will decrease, and the divided voltage on the fourth resistor R4 will increase. When the divided voltage exceeds the threshold voltage for the saturation conduction of the second triode Q2, the second triode The saturation conduction of Q2 draws away the base current of the first transistor Q1 and makes it have a low potential, so as to disconnect the first transistor Q1 , thereby reducing the power provided by the power conversion circuit 2 to the load. When the temperature returns to the normal working state, the resistance value of the third resistor R3 is relatively high, and the fourth resistor R4 cannot obtain a divided voltage sufficient to turn on the second transistor Q2, so the second transistor Q2 will not be turned on. And keep the original turn-on and turn-off timing of the first triode Q1 determined by the fifth resistor R5 and the first capacitor C1.

In this embodiment, the LED lighting power supply circuit further includes a ninth resistor R9, and the collector of the second triode Q2 is connected to the other end of the first resistor R1 through the ninth resistor R9. The ninth resistor R9 is a current limiting resistor, which is used for overcurrent protection of the branch where the collector of the second triode Q2 is located, so as to further improve the safety performance of the circuit.

In this embodiment, the LED lighting power supply circuit further includes a fourth capacitor C4, and the base of the first triode Q1 is connected to one end of the first capacitor C1 through the fourth capacitor C4. The fourth capacitor C4 is a coupling capacitor for preventing interference between the first transistor Q1 and the second transistor Q2.

In this embodiment, the LED lighting power supply circuit further includes a tenth resistor R10, and the collector of the first triode Q1 is connected to the other end of the secondary coil L1 of the transformer T1 through the tenth resistor R10. The tenth resistor R10 is a current limiting resistor, used for overcurrent protection of the branch between the collector of the first triode Q1 and the other end of the secondary coil L1 of the transformer T1.

In this embodiment, the LED lighting power supply circuit further includes an eleventh resistor R11, and the emitter of the first triode Q1 is grounded through the eleventh resistor R11. The eleventh resistor R11 is a current limiting resistor and is used for overcurrent protection of the branch where the emitter of the first triode Q1 is located.

In this embodiment, the LED lighting power supply circuit further includes a twelfth resistor R12, and the terminal with the same name of the secondary coil L1 of the transformer T1 is connected to the negative pole of the third capacitor C3 through the twelfth resistor R12. The twelfth resistor R12 is a current-limiting resistor, which is used for over-current protection of the branch between the terminal of the secondary coil L1 of the transformer T1 and the negative pole of the third capacitor.

In short, since the power conversion circuit is provided with a current-limiting resistor, it can perform over-current protection, so it has a safety protection function and can improve the safety performance of the circuit.

The above descriptions are only preferred embodiments of the present utility model, and are not intended to limit the present utility model. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included in the Within the protection scope of the present utility model.

Claims (7)

1. a kind of LED illumination power circuit, it is characterised in that including bridge rectifier, circuit for power conversion, rectification output electricity Road, energy storage filter circuit, output circuit, feedback circuit, PWM module and FPC modules, one end of the circuit for power conversion and institute One end connection of current rectifying and wave filtering circuit is stated, one end of the rectifying output circuit and the other end of the circuit for power conversion connect Connect, one end of the energy storage filter circuit is connected with the other end of the rectifying output circuit, one end of the output circuit with The other end connection of the energy storage filter circuit, one end of the feedback circuit is connected with the other end of the output circuit, institute The one end for stating PWM module is connected with the other end of the feedback circuit, the other end of the PWM module and the FPC modules One end is connected, and the other end of the FPC modules is connected with the circuit for power conversion；The PWM module and FPC modules are integrated in In one single-chip microcomputer；

The circuit for power conversion includes first resistor, second resistance, 3rd resistor, the 4th resistance, the 5th resistance, the 6th electricity Resistance, the 7th resistance, the 8th resistance, the first electric capacity, the second electric capacity, the 3rd electric capacity, the first triode, the second triode, the two or two Pole pipe, the 3rd diode, voltage-regulator diode and transformer, the 3rd resistor are negative temperature coefficient resister；7th resistance One end be connected with an output end of the bridge rectifier, one end of the 8th resistance and the bridge rectifier The connection of another output end, the other end of the 8th resistance one end respectively with the first resistor, the negative pole of the 3rd electric capacity and One end connection of 6th resistance, negative electrode, the second triode of the other end of the first resistor respectively with second diode Colelctor electrode, one end connection of the base stage of the first triode and the first electric capacity, the plus earth of second diode, described the The grounded emitter of two triodes, the base stage of second triode one end respectively with the 3rd resistor, the 4th resistance One end and the connection of one end of the second electric capacity, the other end of the 4th resistance and the other end of the second electric capacity be grounded, and described the The other end of three resistance is connected with the negative pole of the voltage-regulator diode and one end of second resistance respectively, the voltage-regulator diode Plus earth, the other end of the second resistance is of the same name with the primary coil of one end of the 5th resistance and transformer respectively End connection, the other end of the 5th resistance is connected with the other end of first electric capacity, the primary coil of the transformer The other end is grounded, and the Same Name of Ends of the secondary coil of the transformer is connected with the other end of the 8th resistance, the transformer The other end of secondary coil be connected respectively with the colelctor electrode of first triode and the anode of the 3rd diode, the described 3rd The negative electrode of diode is connected with the positive pole of the 3rd electric capacity, the grounded emitter of first triode.

2. LED illumination power circuit according to claim 1, it is characterised in that also including the 9th resistance, the described 2nd 3 The colelctor electrode of pole pipe is connected by the 9th resistance with the other end of the first resistor.

3. LED illumination power circuit according to claim 2, it is characterised in that also including the 4th electric capacity, the described 1st The base stage of pole pipe is connected by the 4th electric capacity with one end of first electric capacity.

4. the LED illumination power circuit according to claims 1 to 3 any one, it is characterised in that also including the tenth electricity Resistance, the colelctor electrode of first triode is connected by the tenth resistance with the other end of the secondary coil of the transformer.

5. LED illumination power circuit according to claim 4, it is characterised in that also including the 11st resistance, described first The emitter stage of triode passes through the 11st resistance eutral grounding.

6. LED illumination power circuit according to claim 5, it is characterised in that also including the 12nd resistance, the transformation The Same Name of Ends of the secondary coil of device is connected by the 12nd resistance with the negative pole of the 3rd electric capacity.

7. the LED illumination power circuit according to claims 1 to 3 any one, it is characterised in that first triode It is NPN type triode with the second triode.