CN214381486U

CN214381486U - Driving power supply

Info

Publication number: CN214381486U
Application number: CN202023011928.XU
Authority: CN
Inventors: 刘新明
Original assignee: Guangdong NRE Technology Co Ltd
Current assignee: Guangdong NRE Technology Co Ltd
Priority date: 2020-12-15
Filing date: 2020-12-15
Publication date: 2021-10-08
Anticipated expiration: 2030-12-15

Abstract

The utility model relates to a driving power supply, including voltage detection circuit, temperature detection circuit, electric current gear selection circuit, electric current error amplifier, voltage detection circuit obtains the single-phase alternating current peak value of driving power supply input department and comes to compare with reference voltage Vu3+, and when single-phase alternating current peak value is less than reference voltage Vu3+, control electric current gear selection circuit pulled high electric current error amplifier's input side resistance value in order to reduce current; the temperature detection circuit obtains the temperature of the driving power supply to compare with a reference temperature, and controls the current gear selection circuit to increase the input side resistance value of the current error amplifier to reduce the current when the temperature of the driving power supply exceeds the reference temperature, wherein the reference temperature is not lower than 5 ℃. The utility model is used for promote the reliability of drive power supply under the unusual environment such as high temperature state or input voltage fluctuation are big.

Description

Driving power supply

Technical Field

The utility model belongs to the technical field of the LED drive and specifically relates to a drive power supply.

Background

The service life of the driving power supply is reduced under the condition that the driving power supply is in a high-temperature state or the input voltage fluctuates greatly (is too low), generally, in order to guarantee the service life of the power supply, the power supply is generally turned off and stopped to work under one of the two conditions, but sometimes, a user does not want to turn off the power supply (for example, the application of an LED street lamp in a remote area), therefore, a design circuit reduces the output power of the power supply by half, reduces the heat generation to solve the problem caused by the over-temperature, or reduces the stress of components to solve the problem caused by the voltage fluctuation, and the design is used for improving the reliability of the power supply.

SUMMERY OF THE UTILITY MODEL

The utility model aims at promoting the reliability of drive power supply under the unusual environment such as high temperature state or input voltage fluctuation are big.

The utility model discloses a following technical scheme realizes:

the driving power supply comprises a voltage detection circuit, a temperature detection circuit, a current gear selection circuit and a current error amplifier, wherein the voltage detection circuit acquires the peak value of single-phase alternating current at the input of the driving power supply to compare with a reference voltage Vu3+, and controls the current gear selection circuit to pull up the input side resistance value of the current error amplifier to reduce the current when the peak value of the single-phase alternating current is lower than the reference voltage Vu3 +; the temperature detection circuit obtains the temperature of the driving power supply to compare with a reference temperature, and controls the current gear selection circuit to increase the input side resistance value of the current error amplifier to reduce the current when the temperature of the driving power supply exceeds the reference temperature, wherein the reference temperature is not lower than 5 ℃.

Furthermore, the voltage detection circuit also comprises a rectification filter circuit, and the rectification filter circuit acquires the peak value of the single-phase alternating current from the input position of the driving power supply and sends the peak value to the voltage detection circuit.

Further, the rectifying and filtering circuit supplies the peak value of the single-phase alternating current to the input voltage detection circuit through a diode D2.

Further, the output end of the voltage detection circuit and the output end of the temperature detection circuit are connected together through a diode respectively.

Further, the voltage detection circuit performs comparison through a comparison circuit Vu3, and outputs high and low levels to perform control; and/or the temperature detection circuit compares the temperature with the temperature through a comparison circuit Vu5 and a thermistor RT1, and outputs high and low levels to control.

Further, the comparison circuit is a hysteresis comparator.

Further, when the temperature of the driving power supply exceeds the reference temperature or when the temperature of the driving power supply exceeds the reference temperature, the current gear selection circuit is controlled to reduce the current of the current error amplifier to half of the original current.

Furthermore, the current gear selection circuit comprises a MOS transistor Q1, a resistor R9 and a resistor R12, the resistances of the resistor R9 and the resistor R12 are equal, a branch formed by the MOS transistor Q1 connected with the resistor R12 in series is connected with the resistor R9 in parallel, one end of a circuit formed by the parallel connection is grounded, the other end of the circuit is connected to the reverse input end of the current error amplifier, and the voltage detection circuit and the temperature detection circuit output to the gate of the MOS transistor Q1 for control.

Further, the voltage detection circuit and the temperature detection circuit are optically coupled to output to the gate of the MOS transistor Q1.

Furthermore, the voltage detection circuit is provided with a hysteresis comparator Vu3, a resistor R5 and a resistor R8, the peak value of the single-phase alternating current is divided and attenuated by the resistor R5 and the resistor R8 and then is sent to the reverse input end of the hysteresis comparator Vu3 as a voltage Vu3-, the forward input end of the hysteresis comparator Vu3 is connected to a reference voltage Vu3+, and the output end of the hysteresis comparator Vu3 is grounded through a light emitting diode of a diode D3 and an optical coupler U4 in sequence; the temperature detection circuit comprises a resistor R11, an NTC thermistor RT1, a hysteresis comparator Vu5 and a diode D4, wherein a power supply VCC is sequentially connected with the resistor R11 and the thermistor RT1 in series to the ground for voltage division, the divided voltage is used as voltage Vu 5-and is sent to the reverse input end of the hysteresis comparator Vu5, the forward input end of the hysteresis comparator Vu5 is connected with reference voltage Vu5+, and the output end of the hysteresis comparator Vu5 is sequentially grounded through a light emitting diode of the diode D4 and an optical coupler U4.

The utility model discloses an acquire the single-phase alternating current peak value and the power temperature of drive power supply input department and feed back power output to reduce current error amplifier's output current through electric current gear selection circuit, reduce to generate heat and solve the problem that the excess temperature produced, perhaps reduce the stress of components and parts and improve the drive power supply reliability with the problem of solving the voltage fluctuation production.

The above description is only an overview of the technical solutions of the present invention, and in order to make the technical means of the present invention more clearly understood, the present invention can be implemented according to the content of the description, and in order to make the said and other objects, features and advantages of the present invention more obvious and understandable, the following detailed description of the present invention is given.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like elements throughout the drawings.

In the drawings:

fig. 1 is a schematic circuit diagram of the present invention for improving reliability of the driving power supply.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

As shown in FIG. 1, the input of the driving power supply is single-phase alternating current, the input voltage peak value of the single-phase alternating current is obtained by a rectifying and filtering circuit, the input voltage peak value is transmitted to an input voltage detection circuit 1 through a diode D2 for detection, and the high and low levels output by the voltage detection circuit 1 control the operation of a current gear selection circuit 3 connected to the input side of a current error amplifier 4 in the driving power supply.

Specifically, the voltage detection circuit 1 includes a hysteretic comparator Vu3, a resistor R5, a resistor R8, and a diode D3, the peak value of the input voltage is sent to a voltage divider circuit formed by serially connecting a resistor R5 and a resistor R8, the peak value of the input voltage is divided and attenuated by the resistor R5 and the resistor R8, and then sent to the reverse input terminal of the hysteretic comparator Vu3 as a voltage Vu3-, the forward input terminal of the hysteretic comparator Vu3 is connected to a reference voltage Vu3+, and the output terminal of the hysteretic comparator Vu3 is grounded through light emitting diodes of a diode D3 and an optical coupler U4 in sequence. And all nodes except the ground in the voltage division circuit are grounded through capacitors, so that input filtering is realized.

The current gear selection circuit 3 is composed of a MOS transistor Q1, a resistor R9 and a resistor R12, the resistances of the resistor R9 and the resistor R12 are equal, when the current gear selection circuit is connected, a branch formed by the MOS transistor Q1 connected with the resistor R12 in series is connected with the resistor R9 in parallel, one end of a circuit formed by the parallel connection is grounded, the other end of the circuit is connected to the reverse input end of the current error amplifier 4, a power supply VGG is connected to the ground through a resistor R6 and a photosensitive semiconductor of an optical coupler U4 in sequence, and a joint between the resistor R6 and the photosensitive semiconductor is connected with the grid of the MOS transistor Q1.

The peak value of the input voltage is divided and attenuated by a diode D2, and then the attenuated input voltage is added into a hysteresis comparator Vu3 to be compared with a reference voltage Vu3+, if the input voltage is reduced to a certain value (the value can be set by the ratio of R5 to R8), namely Vu 3-is lower than Vu3+, the output is high level to turn on a light emitting diode of an optical coupler U4 and feed back to the secondary side, the grid voltage of Q1 is pulled down to cause Q1 not to be turned on, current detection only flows through R9, R9 is R12 (neglecting Q1 on resistance Rq1: R9 ═ R12> > Rq1), at the moment, the input side resistance value of the current error amplifier 4 is doubled, the current is half of the original current, and the reduction of the input voltage to a certain value and the power is realized.

In order to improve the reliability of the driving power supply in a high-temperature state, a temperature detection circuit 2 is further required to be arranged, the temperature detection circuit 2 comprises a resistor R11, an NTC thermistor RT1, a hysteretic comparator Vu5 and a diode D4, the power supply VCC is sequentially connected with the resistor R11 and the thermistor RT1 in series to the ground for voltage division, the divided voltage is used as voltage Vu 5-and is sent to the reverse input end of the hysteretic comparator Vu5, the forward input end of the hysteretic comparator Vu5 is connected with reference voltage Vu5+, and the output end of the hysteretic comparator Vu5 is sequentially grounded through a light emitting diode of the diode D4 and the optocoupler U4.

Normally, temperature detection is not effective, only when the temperature of a driving power supply rises, the resistance value of RT1 (negative temperature coefficient thermistor) is reduced to cause Vu 5-voltage reduction, Vu 5-is compared with Vu5+, when the temperature of the driving power supply exceeds a reference temperature, Vu5- < Vu5+ outputs high level, a U4 light emitting diode is conducted and fed back to a secondary side, the grid voltage of Q1 is pulled down to cause Q1 not to be conducted, current detection only flows through R9, and the power is reduced by half when the current is half of the original current, and the temperature rises to a certain value.

This embodiment utilizes temperature sensor to acquire power supply temperature, adopts bleeder circuit to acquire power input voltage at power input end, feeds back power output end through the hysteresis comparator, reduces half output current through processing circuit, reduces to generate heat and solves the problem that the excess temperature produced, perhaps reduces the stress of components and parts and produces in order to solve the problem that voltage fluctuation produced, improves the drive power reliability.

In this embodiment, the function of "or" is achieved by using D3 and D4, that is, if any one of the inputs is true, the output is true, the input voltage is lower than the threshold value to turn on D3, D4 is not turned on, and half of the output power can be achieved, and the temperature rise turns on D4 and turns off D3, and half of the output power can be achieved.

In this embodiment, Vu3 and Vu5 are hysteresis comparators, and first analyze Vu3, when Vin is normal (for example, commercial power 220VAC), Vu3- > Vu3+, the comparator outputs a low level, the optical coupler is not turned on, and the output is normal, which can be known from the characteristics of the operational amplifier circuit: the Vu3+ (Vref × R10/(R10+ R7) + Vu3(out) × R7/(R10+ R7), the Vin voltage starts to drop at a certain time, so the output is a low-level saturation voltage, the term Vu3(out) × R7/(R10+ R7) can be ignored to be approximately equal to 0, Vin drops to Vu3 ═ Vref × R10/(R10+ R7) at a certain time, the operational amplifier flip condition is performed at this time, the output is a high level below this value, the output is a high level at this time, and the function of halving the output current is realized. The inversion condition at this time is Vu3- > Vu3+ ═ Vref R10/(R10+ R7) + Vu3(out) × R7/(R10+ R7), and Vu3(out) × R7/(R10+ R7) is not zero because Vu3(out) is at a high level (approximately VCC), which is called a hysteresis voltage, i.e., the input voltage required to recover the normal operation is higher than the half-time of the input current at the time of falling. The frequent switching of the two modes is avoided, and the stability is improved. The same applies to Vu 5.

It should be noted that the output of the hysteretic comparator needs to be controlled to make U4 reach the saturation current of the optical coupler, so that the gate voltage of Q1 can be pulled down stably. The output power is not necessarily halved, and the power reduction can be realized by adjusting the resistance values of R9 and R12.

It should be finally noted that the above embodiments are only intended to illustrate the technical solutions of the present invention, and not to limit the scope of the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solutions of the present invention can be modified or replaced with equivalents without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A drive power supply characterized by:

comprises a voltage detection circuit, a temperature detection circuit, a current gear selection circuit and a current error amplifier,

the voltage detection circuit acquires a peak value of the single-phase alternating current at the input position of the driving power supply to compare with a reference voltage Vu3+, and controls the current gear selection circuit to pull up the input side resistance value of the current error amplifier to reduce the current when the peak value of the single-phase alternating current is lower than the reference voltage Vu3 +;

the temperature detection circuit obtains the temperature of the driving power supply to compare with a reference temperature, and controls the current gear selection circuit to increase the input side resistance value of the current error amplifier to reduce the current when the temperature of the driving power supply exceeds the reference temperature, wherein the reference temperature is not lower than 5 ℃.

2. The drive power supply according to claim 1, characterized in that: the single-phase alternating current power supply device further comprises a rectification filter circuit, wherein the rectification filter circuit obtains a single-phase alternating current peak value from the input position of the driving power supply and sends the single-phase alternating current peak value to the voltage detection circuit.

3. The drive power supply according to claim 2, characterized in that: the rectifying and filtering circuit transmits the single-phase alternating current peak value to the input voltage detection circuit through a diode D2.

4. The drive power supply according to claim 1, characterized in that: the output end of the voltage detection circuit and the output end of the temperature detection circuit are connected together through a diode respectively.

5. The drive power supply according to claim 4, characterized in that: the voltage detection circuit compares the voltage with the comparison circuit Vu3 and outputs high and low levels to control the comparison circuit; and/or the temperature detection circuit compares the temperature with the temperature through a comparison circuit Vu5 and a thermistor RT1, and outputs high and low levels to control.

6. The drive power supply according to claim 5, characterized in that: the comparison circuit is a hysteresis comparator.

7. The drive power supply according to claim 5, characterized in that: when the temperature of the driving power supply exceeds the reference temperature or when the temperature of the driving power supply exceeds the reference temperature, the current gear selection circuit is controlled to reduce the current of the current error amplifier to half of the original current.

8. The drive power supply according to claim 7, characterized in that: the current gear selection circuit comprises an MOS tube Q1, a resistor R9 and a resistor R12, the resistances of the resistor R9 and the resistor R12 are equal, a branch formed by the MOS tube Q1 connected with the resistor R12 in series is connected with the resistor R9 in parallel, one end of a circuit formed by the parallel connection is grounded, the other end of the circuit is connected to the reverse input end of the current error amplifier, and the voltage detection circuit and the temperature detection circuit are output to the grid electrode of the MOS tube Q1 to be controlled.

9. The drive power supply according to claim 8, characterized in that: the voltage detection circuit and the temperature detection circuit are optically coupled to output to the gate of the MOS transistor Q1.

10. The drive power supply according to claim 8, characterized in that: the voltage detection circuit is provided with a hysteresis comparator Vu3, a resistor R5 and a resistor R8, the peak value of single-phase alternating current is divided and attenuated by the resistor R5 and the resistor R8 and then is sent to the reverse input end of the hysteresis comparator Vu3 as voltage Vu3-, the forward input end of the hysteresis comparator Vu3 is connected to reference voltage Vu3+, and the output end of the hysteresis comparator Vu3 is grounded through a light emitting diode of a diode D3 and an optical coupler U4 in sequence; the temperature detection circuit comprises a resistor R11, an NTC thermistor RT1, a hysteresis comparator Vu5 and a diode D4, wherein a power supply VCC is sequentially connected with the resistor R11 and the thermistor RT1 in series to the ground for voltage division, the divided voltage is used as voltage Vu 5-and is sent to the reverse input end of the hysteresis comparator Vu5, the forward input end of the hysteresis comparator Vu5 is connected with reference voltage Vu5+, and the output end of the hysteresis comparator Vu5 is sequentially grounded through a light emitting diode of the diode D4 and an optical coupler U4.