CN218301701U

CN218301701U - LED driver with high efficiency

Info

Publication number: CN218301701U
Application number: CN202222722696.1U
Authority: CN
Inventors: 林祝亮; 汪静
Original assignee: Zhejiang Kaiyuan Electromechanical Technology Co ltd
Current assignee: Zhejiang Kaiyuan Electromechanical Technology Co ltd
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2023-01-13
Anticipated expiration: 2032-10-14

Abstract

The utility model discloses a LED driver with high efficiency, including front end rectifier circuit, step-down auxiliary power supply circuit and main power source circuit, front end rectifier circuit is connected with step-down auxiliary power supply circuit and main power source circuit electricity respectively, main power source circuit includes half-bridge DC converting circuit, PWM control chip, H bridge drive MOS tubular circuit, voltage regulation circuit and current regulation circuit all are connected with PWM control chip electricity, half-bridge DC converting circuit is connected with H bridge drive MOS tubular circuit electricity, voltage regulation circuit is used for gathering the direct current voltage of output and with information feedback to PWM control chip, the direct current voltage of output is adjusted to PWM control chip, current regulation circuit is used for gathering the direct current of output and with information feedback to PWM control chip, PWM control chip adjusts the direct current of output.

Description

LED driver with high efficiency

Technical Field

The utility model relates to a LED drive circuit especially relates to a LED driver with high efficiency.

Background

With the increasing projection of global energy crisis, energy conservation becomes one of the important issues facing all mankind. As a fourth generation green illumination Light source, a high brightness Light Emitting Diode (LED) is widely used in indoor and outdoor illumination, medical treatment, large-sized liquid crystal backlight, and other occasions due to its advantages of high efficiency, energy saving, environmental protection, and the like. The LED driving circuit is the most important part of the LED light source, and the development is more rapid in recent years.

The LED driving circuit converts input voltage into voltage and current required by the LED lamp beads. With the continuous expansion of the illumination market, the LED lamp tends to develop in the directions of high power, high reliability, low power consumption, and the like, so as to bring new opportunities and challenges to the development of the LED driving circuit.

The existing LED drive circuit is integrated with an auxiliary power balancing circuit and a flyback converter, and the balance of instantaneous input power and output power is realized through two switching tubes, so that electrolytic capacitors are eliminated, low-frequency ripples of output current are suppressed, and a high power factor is realized.

The existing LED drive circuit is generally designed by adopting electrolytic-capacitor-free or single-rod active current equalization, but the voltage and current control of the drive circuit is little, and the voltage and current control in the LED drive circuit cannot be well realized, so that the problems of poor quality, poor stability and low service life of LED luminescence are solved.

SUMMERY OF THE UTILITY MODEL

Based on the aforesaid can not be fine realize voltage and current control in LED drive circuit, reach to solve the luminous quality of LED poor, poor stability, life-span low grade not enough, the utility model provides a have efficient LED driver.

The utility model provides a technical scheme that above-mentioned technical problem adopted does: the LED driver with high efficiency is characterized by comprising a front-end rectifying circuit, a voltage-reducing auxiliary power supply circuit and a main power circuit, wherein the front-end rectifying circuit is respectively electrically connected with the voltage-reducing auxiliary power supply circuit and the main power circuit, the front-end rectifying circuit is used for accessing alternating current and carrying out pre-stage filtering and full-bridge wave rectification on the alternating current, the voltage-reducing auxiliary power supply circuit is used for supplying power to the main power circuit,

the power supply circuit comprises a half-bridge type DC conversion circuit, a PWM control chip, an H-bridge driving MOS tube circuit, a voltage regulating circuit and a current regulating circuit, wherein the H-bridge driving MOS tube circuit, the voltage regulating circuit and the current regulating circuit are electrically connected with the PWM control chip, the half-bridge type DC conversion circuit is electrically connected with the H-bridge driving MOS tube circuit, the half-bridge type DC conversion circuit is used for converting alternating current into direct current and outputting the direct current, the voltage regulating circuit is used for collecting the output direct current voltage and feeding information back to the PWM control chip, the PWM control chip regulates the output direct current voltage, the current regulating circuit is used for collecting the output direct current and feeding information back to the PWM control chip, and the PWM control chip regulates the output direct current.

The utility model discloses further preferred technical scheme does: the front-end rectifying circuit comprises a capacitor X, a capacitor Y and a full bridge.

The utility model discloses further preferred technical scheme does: the LED driver further comprises a transformer isolation bootstrap circuit, and the half-bridge DC conversion circuit is electrically connected with the H-bridge driving MOS tube circuit through the transformer isolation bootstrap circuit.

The utility model discloses further preferred technical scheme does: the half-bridge DC conversion circuit is electrically connected with a transformer T1, and the transformer T1 is electrically connected with an inductor L.

The utility model discloses further preferred technical scheme does: the LED driver also includes an op-amp platelet circuit for controlling the fan and short circuit protection.

The utility model discloses further preferred technical scheme does: the PWM control chip comprises a pin 9 and a pin 10, the pin 9 and the pin 10 are electrically connected with an H-bridge drive MOS tube circuit, the pin 9 is an emitting electrode of a drive triode 1 in the PWM control chip, and the pin 10 is an emitting electrode of a drive triode 2 in the PWM control chip.

The utility model discloses further preferred technical scheme does: the PWM control chip comprises a pin 1 used for collecting output direct-current voltage and a pin 2 used for accessing reference voltage, the pin 1 and the pin 2 are a non-inverting input end and an inverting input end of an error amplifier, the voltage regulating circuit comprises a resistor R32, a resistor R33, a resistor R34, a resistor R25 and a potentiometer VADJ, the pin 1 is electrically connected with one end of the resistor R34 and one end of the resistor R32 respectively, the other end of the resistor R32 is electrically connected with the resistor R33, the other end of the resistor R33 is accessed into the output direct current, the other end of the resistor R34 is grounded, the pin 2 is electrically connected with one end of the resistor R25 and one end of the potentiometer VADJ respectively, the other end of the potentiometer VADJ is grounded, and the other end of the resistor R25 is accessed into internal voltage of the PWM control chip.

The utility model discloses further preferred technical scheme does: the current regulating circuit comprises a current divider Ri, a resistor R16, a resistor R17 and a potentiometer ADJ, the PWM control chip comprises a pin 15 used for accessing a reference voltage and a pin 16 used for collecting output direct current, the pin 15 and the pin 16 are an inverting input end and a non-inverting input end of an error amplifier, the pin 15 is electrically connected with one end of the resistor R16 and one end of the resistor R17 respectively, the other end of the resistor R16 is electrically connected with the potentiometer ADJ, the other end of the potentiometer ADJ is grounded, the other end of the resistor R17 is accessed into internal voltage of the PWM control chip, the pin 16 is electrically connected with one end of the current divider Ri, the other end of the current divider Ri is grounded, and the current divider Ri is accessed into the output direct current.

Compared with the prior art, the utility model has the advantages that the circuit carries out preceding stage filtering and full-bridge integer wave to the alternating current through front end rectifier circuit, rethread step-down auxiliary power supply circuit carries out step-down auxiliary power supply to main power supply circuit, PWM control chip control H bridge drive MOS pipe circuit is half bridge type DC converting circuit output drive signal, control half bridge type DC converting circuit converts the alternating current to the direct current and exports the LED lamp power supply, when the direct current voltage of the output that voltage regulating circuit gathered is on the high side, output PWM duty cycle reduces, adjust output direct current voltage and reduce, when the direct current voltage of the output that voltage regulating circuit gathered is on the low side, output PWM duty cycle increases, adjust output direct current voltage and rise, keep outputting direct current constant voltage, when the direct current of the output that current regulating circuit gathered is on the high side, output PWM duty cycle reduces, adjust output direct current voltage and reduce, keep outputting direct current constant current, realize the control of voltage and electric current in the circuit, make whole circuit safe high-efficient.

Drawings

The present invention will be described in further detail below with reference to the drawings and preferred embodiments, but those skilled in the art will appreciate that the drawings are only drawn for the purpose of illustrating the preferred embodiments and therefore should not be taken as limiting the scope of the present invention. Furthermore, unless specifically stated otherwise, the drawings are merely schematic representations based on the concept of a composition or construction of the object being described and may include exaggerated displays and are not necessarily drawn to scale.

FIG. 1 is a circuit diagram of the present patent;

FIG. 2 is an operational amplifier platelet circuit;

FIG. 3 is a PWM control chip;

FIG. 4 is a functional block diagram of the present patent;

FIG. 5 is a circuit schematic of a voltage regulation circuit;

FIG. 6 is a circuit schematic of a current regulating circuit;

FIG. 7 is an enlarged partial circuit view of the front end rectifier circuit;

FIG. 8 is a circuit partial enlarged view of the buck auxiliary power supply circuit;

FIG. 9 is an enlarged circuit view of a half-bridge DC converter circuit;

FIG. 10 is an enlarged circuit view of a current regulator circuit;

FIG. 11 is an enlarged circuit view of the transformer isolation bootstrap circuit;

FIG. 12 is a circuit diagram of an enlarged view of a portion of an H-bridge drive MOS transistor circuit;

fig. 13 is a circuit partial enlarged view of the voltage regulating circuit.

In the figure: 1. a front-end rectification circuit; 2. a voltage-reducing auxiliary power supply circuit; 3. a half-bridge DC conversion circuit; 4. a current regulating circuit; 5. a transformer isolation bootstrap circuit; 6. a voltage regulation circuit; 7. an H-bridge driving MOS tube circuit; 8. a PWM control chip; 9. a main power supply circuit; 10. and a small operational amplifier board circuit.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Those skilled in the art will appreciate that the description is illustrative only, and is not to be construed as limiting the scope of the invention.

It should be noted that: like reference numerals refer to like items in the following figures, and thus, once an item is defined in one figure, it may not be further defined or explained in subsequent figures.

As shown in fig. 1 to 13, the LED driver with high efficiency includes a front-end rectification circuit 1, a voltage-reducing auxiliary power supply circuit 2 and a main power supply circuit 9, the front-end rectification circuit 1 is electrically connected to the voltage-reducing auxiliary power supply circuit 2 and the main power supply circuit 9, the front-end rectification circuit 1 is used for accessing an alternating current and performing pre-filtering and full-bridge wave shaping on the alternating current, and the voltage-reducing auxiliary power supply circuit 2 is used for supplying power to the main power supply circuit 9 after reducing the alternating current. The alternating current may be 220V alternating current.

As shown in fig. 7, the front-end rectification circuit 1 preferably includes a capacitor X, a capacitor Y and a full bridge, wherein the capacitor X and the capacitor Y are used for filtering the alternating current, and the full bridge is used for full-bridge wave shaping of the alternating current.

As shown in fig. 1, the main power circuit 9 includes a half-bridge DC converter circuit 3, a PWM control chip 8, an H-bridge driving MOS transistor circuit 7, a voltage regulator circuit 6, and a current regulator circuit 4, the H-bridge driving MOS transistor circuit 7, the voltage regulator circuit 6, and the current regulator circuit 4 are electrically connected to the PWM control chip 8, and the half-bridge DC converter circuit 3 is electrically connected to the H-bridge driving MOS transistor circuit 7.

As shown in fig. 3, the PWM control chip 8 is a control chip available on the market, for example, a control chip with a model number of IC 7500. The pins of the PWM control chip 8 include:

pins

1 and 2 are the homodromous input end and the opposite input end of the error amplifier and are used for voltage feedback regulation;

pins

15 and 16 are the inverting input and the non-inverting input of the error amplifier, and are used for current amplification feedback regulation. Pin 4 is the dead time control terminal,

pins

5 and 6 are the access terminals of the oscillator timing capacitor and resistor, pin 7 is the ground terminal of the chip, pin 12 is the Vcc power input terminal, pin 13 is the fixed 5V voltage, pins 8 and 9 are the collector and emitter of the internal drive triode 1,

pins

10 and 11 are the emitter and collector of the internal drive triode 2, and pin 14 is the internal 5V reference voltage output terminal.

As shown in fig. 9, the half-bridge DC converter circuit 3 is used to convert an alternating current into a direct current and output the direct current.

As shown in fig. 11, the LED driver further includes a transformer isolation bootstrap circuit 5, the transformer isolation bootstrap circuit 5 is disposed between the half-bridge DC conversion circuit 3 and the H-bridge driving MOS transistor circuit 7, and the half-bridge DC conversion circuit 3 and the H-bridge driving MOS transistor circuit 7 are electrically connected through the transformer isolation bootstrap circuit 5.

The half-bridge DC conversion circuit 3 is electrically connected to a transformer T1, and the transformer T1 is electrically connected to an inductor L.

The half-bridge DC converter circuit 3 includes a half-bridge Q1 and a half-bridge Q2.

The transformer isolation bootstrap circuit 5 includes a transformer T3.

Pins 9 and 10 of the PWM control chip 8 are electrically connected with the H-bridge drive MOS tube circuit 7.

Specifically, the 220V alternating current is through preceding stage filtering and full-bridge rectification after, by 9 feet and 10 feet control H bridge drive MOS tube circuit 7 output half-bridge Q1 and half-bridge Q2's of PWM control chip 8 drive signal, drive signal realizes the drive signal bootstrapping through transformer T3, after drive signal is through the bootstrapping, control half-bridge Q1 and half-bridge Q2 drive T1 transformer, realize the holistic step-down transform of alternating current, make the alternating current convert the direct current, direct power output after inductance L and rectification filtering later on, be used for to power supply such as LED.

As shown in fig. 13, the voltage regulating circuit 6 is used for collecting the voltage of the output power supply and feeding back the information to the PWM control chip 8, and the PWM control chip 8 regulates the voltage of the output power supply.

As shown in fig. 5, specifically, pin 1 of the PWM control chip 8 is used to collect voltage of an output power supply, pin 2 of the PWM control chip 8 is used to access a reference voltage, the voltage adjusting circuit 6 includes a resistor R32, a resistor R33, a resistor R34, a resistor R25, and a potentiometer VADJ, pin 1 is electrically connected to one end of the resistor R34 and one end of the resistor R32, the other end of the resistor R32 is electrically connected to the resistor R33, the other end of the resistor R33 is connected to the output power supply, the other end of the resistor R34 is grounded, voltage of the output power supply is divided by two resistors and then input to pin 1, pin 2 is electrically connected to one end of the resistor R25 and one end of the potentiometer VADJ, the other end of the potentiometer VADJ is grounded, the other end of the resistor R25 is connected to internal voltage of the PWM control chip 8, and the reference voltage is obtained through R25 and Rvadj. From this calculation:

5V is the voltage provided by the PWM control chip 8, VOUT is the voltage of the output power supply, and Rvadj is the resistance value of the potentiometer.

The PWM control chip 8 includes a PWM comparator for controlling how much of the output supply voltage is.

When the voltage of the output power supply is larger, the 1-pin signal response is reduced, and compared with the reference voltage input by the 2-pin, negative feedback control is formed, the output PWM duty ratio is reduced, and the voltage of the output power supply is controlled to be reduced. Conversely, when the voltage of the output power supply is smaller, the output PWM duty ratio is increased, and the voltage of the output power supply is controlled to be increased. Thereby realizing constant voltage control.

As shown in fig. 10, the current regulating circuit 4 is used for collecting the output dc current and feeding back information to the PWM control chip 8, and the PWM control chip 8 regulates the current of the output power supply.

As shown in fig. 6, specifically, the current regulating circuit 4 includes a current divider Ri, a resistor R16, a resistor R17, and a potentiometer ADJ, the PWM control chip 8 includes a pin 15 for accessing a reference voltage and a pin 16 for acquiring a signal of the current divider Ri, the pin 15 is electrically connected to one end of the resistor R16 and one end of the resistor R17, respectively, the other end of the resistor R16 is electrically connected to the potentiometer ADJ, the other end of the potentiometer ADJ is grounded, the other end of the resistor R17 is accessed to an internal voltage of the PWM control chip 8, the pin 16 is electrically connected to one end of the current divider Ri, the other end of the current divider Ri is grounded, the current divider Ri is accessed to an output power supply, and the reference voltage accessed by the pin 15 is obtained by a 5V fixed voltage generated inside the PWM control chip 8 through the resistor R16 and the resistor R17. From this calculation:

5V is a 5V fixed voltage generated inside the PWM control chip 8, RADJ is a potentiometer resistance, and Ri is a current regulator resistance.

When the current of the output power supply is larger, the voltage on the 16 pin is increased, and is compared with the set reference voltage of the 15 pin to form negative feedback control current, reduce the PWM duty ratio and reduce the output voltage, thereby realizing constant current control. When the output power supply current is small, the adjustment is not carried out.

The overall control process of the driver circuit is as follows: after 220V alternating current is input and is subjected to pre-stage filter circuit and full-bridge rectification, the voltage is about 15V, the main power circuit 9 is supplied with power through the voltage reduction auxiliary power supply circuit 2, then the DC output is directly carried out after the output of the half-bridge DC conversion circuit 3 is filtered, the PWM control chip 8 is subjected to feedback regulation control through voltage feedback and current feedback, and the main power circuit 9 drives the MOS tube circuit 7 through an H bridge to carry out control regulation on the half-bridge DC conversion circuit 3.

Realize step-down auxiliary power supply through front end full-bridge rectification, control H bridge drive MOS pipe circuit 7 and half-bridge type DC converting circuit 3 output filter through main power supply circuit 9, realize the control of voltage and electric current in the circuit for whole circuit safety is high-efficient.

The LED driver further comprises an op-amp platelet circuit 10 for controlling the fan and short-circuit protection.

It is right above the utility model provides a have efficient LED driver introduced, it is right to have used specific individual example herein the utility model discloses a principle and implementation mode have been elucidated, and the description of above embodiment is only used for helping understanding the utility model discloses and core thought. It should be noted that, for those skilled in the art, without departing from the principle of the present invention, the present invention can be further modified and modified, and such modifications and modifications also fall within the scope of the appended claims.

Claims

1. The LED driver with high efficiency is characterized by comprising a front-end rectifying circuit, a voltage-reducing auxiliary power supply circuit and a main power circuit, wherein the front-end rectifying circuit is respectively electrically connected with the voltage-reducing auxiliary power supply circuit and the main power circuit, the front-end rectifying circuit is used for accessing alternating current and carrying out pre-stage filtering and full-bridge wave rectification on the alternating current, the voltage-reducing auxiliary power supply circuit is used for supplying power to the main power circuit,

2. The LED driver with high efficiency of claim 1, wherein the front-end rectification circuit comprises a capacitor X, a capacitor Y and a full bridge.

3. The LED driver with high efficiency as claimed in claim 1, wherein the LED driver further comprises a transformer isolation bootstrap circuit, and the half-bridge DC conversion circuit and the H-bridge driving MOS transistor circuit are electrically connected through the transformer isolation bootstrap circuit.

4. The LED driver with high efficiency as set forth in claim 1, wherein the half-bridge DC conversion circuit is electrically connected to a transformer T1, and the transformer T1 is electrically connected to an inductor L.

5. The LED driver with high efficiency of claim 1, further comprising an op-amp platelet circuit for controlling a fan and short circuit protection.

6. The LED driver with high efficiency as claimed in claim 1, wherein the PWM control chip comprises a pin 9 and a pin 10, the pin 9 and the pin 10 are electrically connected to the H-bridge driving MOS transistor circuit, the pin 9 is an emitter of the driving transistor 1 inside the PWM control chip, and the pin 10 is an emitter of the driving transistor 2 inside the PWM control chip.

7. The LED driver with high efficiency as claimed in claim 1, wherein the PWM control chip includes a pin 1 for collecting the output DC voltage and a pin 2 for receiving a reference voltage, the pin 1 and the pin 2 are the non-inverting input and the inverting input of the error amplifier, the voltage regulating circuit includes a resistor R32, a resistor R33, a resistor R34, a resistor R25, and a potentiometer VADJ, the pin 1 is electrically connected to one end of the resistor R34 and one end of the resistor R32, the other end of the resistor R32 is electrically connected to the resistor R33, the other end of the resistor R33 receives the output DC voltage, the other end of the resistor R34 is grounded, the pin 2 is electrically connected to one end of the resistor R25 and one end of the potentiometer VADJ, the other end of the potentiometer VADJ is grounded, and the other end of the resistor R25 receives the internal voltage of the PWM control chip.

8. The LED driver with high efficiency as claimed in claim 1, wherein the current regulation circuit includes a current divider Ri, a resistor R16, a resistor R17 and a potentiometer ADJ, the PWM control chip includes a pin 15 for receiving a reference voltage and a pin 16 for collecting an output dc current, the pin 15 and the pin 16 are an inverting input terminal and a non-inverting input terminal of an error amplifier, the pin 15 is electrically connected to one end of the resistor R16 and one end of the resistor R17, respectively, the other end of the resistor R16 is electrically connected to the potentiometer ADJ, the other end of the potentiometer ADJ is grounded, the other end of the resistor R17 is received in an internal voltage of the PWM control chip, the pin 16 is electrically connected to one end of the current divider Ri, the other end of the current divider Ri is grounded, and the current divider Ri receives an output dc current.