CN213638293U

CN213638293U - LED drive protection circuit

Info

Publication number: CN213638293U
Application number: CN202022530238.9U
Authority: CN
Inventors: 马二华; 林璐
Original assignee: Shenzhen Kehua Power Supply Technology Co ltd
Current assignee: Shenzhen Kehua Power Supply Technology Co ltd
Priority date: 2020-11-05
Filing date: 2020-11-05
Publication date: 2021-07-06
Anticipated expiration: 2030-11-05

Abstract

The utility model discloses a LED drive protection circuit, including alternating current power supply input, rectifier circuit, tank circuit, rectification filter circuit, sampling bleeder circuit, switch compensating circuit, control circuit, switch circuit and DC power supply output, this LED drive protection circuit mainly used realizes the overvoltage protection or the excess temperature protection to LED when control chip is inside not to export overvoltage protection and excess temperature protect function, practices thrift the cost of manufacture of LED lamps and lanterns. In addition, although some lamp power supplies have overvoltage protection and over-temperature protection functions, the control chip can not set the output overvoltage protection voltage and the protection temperature, and can not meet the actual requirements, the protection can be realized through the external circuit, so that the conditions that the device is damaged by on-load output overvoltage and the internal output overvoltage protection is low in advance to meet the application requirements when no output overvoltage protection exists are avoided, the over-temperature protection function is added, and the reliable work of the circuit is guaranteed.

Description

LED drive protection circuit

Technical Field

The utility model discloses a LED drive protection circuit belongs to LED power field.

Background

The LED needs a stable voltage when operating, and if the operating voltage of the LED rises, the service life of the LED is damaged. The LED working voltage is usually regulated and controlled by an LED power supply, a power supply chip with an overvoltage protection function is embedded in the market at present, and the power supply can cut off power supply to the LED in time when the LED working voltage is too high, so that the overvoltage protection effect on the LED is realized. However, the cost of such LED power supplies is high, and the voltage-limiting value thereof cannot be adjusted at the later stage of once selection, which is not favorable for saving the manufacturing cost of the LED lamp.

SUMMERY OF THE UTILITY MODEL

The utility model provides a LED drive protection circuit practices thrift the cost of manufacture of LED lamps and lanterns.

The utility model relates to a LED drive protection circuit, which comprises an alternating current power supply input end, a rectifying circuit, an energy storage circuit, a rectifying and filtering circuit, a sampling voltage division circuit, a switch compensation circuit, a control circuit, a switch circuit and a direct current power supply output end,

the input end of the alternating current power supply is connected with the input end of the rectifying circuit, the output end of the rectifying circuit is connected with the input end of the energy storage circuit, the output end of the energy storage circuit is respectively connected with the input end of the rectifying filter circuit and the output end of the switch circuit, the output end of the rectifying filter circuit is respectively connected with the output end of the direct current power supply and the input end of the sampling voltage division circuit, the output end of the sampling voltage division circuit is connected with the input end of the switch compensation circuit, the output end of the switch compensation circuit is connected with the input end of the control circuit, the output end of the control circuit is connected with the input end of the switch circuit, and the output end of the direct current,

when the voltage value of the input end of the sampling voltage division circuit reaches or exceeds a set value, the sampling voltage division circuit is conducted, and the switch compensation circuit is opened, so that the control circuit detects a high current value, the switch circuit is controlled to be disconnected, and the energy storage circuit stops supplying power to the output end of the direct current power supply.

Furthermore, the sampling voltage division circuit comprises a voltage stabilizing diode and a first resistor, wherein the input end of the voltage stabilizing diode is connected with the output end of the rectifying and filtering circuit, the output end of the voltage stabilizing diode is connected with the input end of the first resistor, and the output end of the first resistor is connected with the input end of the switch compensation circuit.

Furthermore, the switch compensation circuit comprises a triode, the base of the triode is connected with the output end of the sampling voltage division circuit, the emitting electrode of the triode is connected with a second resistor in series and is connected with the output end of the rectification filter circuit, and the collecting electrode of the triode is connected with the input end of the control circuit.

Furthermore, the control circuit is set as a control chip, a current acquisition pin of the control chip is connected with an output end of the switch compensation circuit, and a voltage output control pin of the control chip is connected with an input end of the switch circuit.

Further, the switch circuit is a MOS transistor switch.

Further, the rectifying circuit comprises a first diode, a second diode, a third diode and a fourth diode, the first diode is connected with the second diode in series, and a first input end of the alternating current power supply is connected between the first diode and the second diode; the third diode is connected in series with the fourth diode, and a second input end of the alternating current power supply input end is connected between the third diode and the fourth diode.

Further, the energy storage circuit comprises an energy storage inductor.

Further, the sampling voltage division circuit further comprises a temperature sensor and a third resistor, the input end of the temperature sensor is connected with the output end of the rectification filter circuit, the output end of the temperature sensor is connected with the input end of the third resistor, and the output end of the third resistor is connected with the input end of the switch compensation circuit.

The utility model has the advantages as follows:

the utility model discloses a LED drive protection circuit mainly used realizes the cost of manufacture of saving LED lamps and lanterns to LED's overvoltage protection (OVP) or excess temperature protection (OTP) when control chip inside does not have output overvoltage protection (OVP) and excess temperature protection (OTP) function.

In addition, although some lamp power supplies have overvoltage protection (OVP) and over-temperature protection (OTP) functions, the output overvoltage protection (OVP) voltage and the protection temperature of the control chip can not be set, and when the actual requirements cannot be met, adjustable output OVP and OTP protection can be realized through the external circuit, so that the conditions that the device is damaged by on-load output overvoltage and the internal early output overvoltage protection (OVP) cannot meet the application requirements when no output overvoltage protection (OVP) exists are avoided, the over-temperature protection function is added, and the reliable work of the circuit is guaranteed.

Drawings

Fig. 1 is a block diagram of an LED driving protection circuit according to the present invention;

fig. 2 is a circuit diagram of a LED driving protection circuit according to the present invention.

Detailed Description

In order to better understand the technical solution, the technical solution will be described in detail with reference to the drawings and the specific embodiments.

Examples

Referring to fig. 1, an embodiment of the present invention discloses a LED driving protection circuit, which includes an ac power input terminal, a rectifier circuit, an energy storage circuit, a rectifier filter circuit, a sampling voltage divider circuit, a switch compensation circuit, a control circuit, a switch circuit, and a dc power output terminal.

The input end of the alternating current power supply is connected with the input end of the rectifying circuit, the output end of the rectifying circuit is connected with the input end of the energy storage circuit, the output end of the energy storage circuit is respectively connected with the input end of the rectifying filter circuit and the output end of the switch circuit, the output end of the rectifying filter circuit is respectively connected with the output end of the direct current power supply and the input end of the sampling voltage division circuit, the output end of the sampling voltage division circuit is connected with the input end of the switch compensation circuit, the output end of the switch compensation circuit is connected with the input end of the control circuit, the output end of the control circuit is connected with the input end of the switch circuit, and the output end of the direct current.

Referring to fig. 2, the rectifier circuit includes a first diode D1, a second diode D2, a third diode D3 and a fourth diode D4, the first diode D1 is connected in series with the second diode D2, and a first input end L of the ac power input end is connected between the first diode D1 and the second diode D2; the third diode D3 is connected in series with the fourth diode D4, and a second input N of the AC power supply input is connected between the third diode D3 and the fourth diode D4. The rectifying circuit is used for rectifying the alternating current power supply and outputting a direct current power supply to the energy storage circuit and the control circuit.

The energy storage circuit comprises an energy storage inductor L1. The energy storage inductor L1 is used for releasing direct current to supply to the direct current power supply output end so as to light the LED lamp bead. When the LED lamp works normally, the switch circuit is closed, and the control circuit outputs a control constant voltage signal to the energy storage inductor through the switch circuit to output a stable voltage to supply the LED lamp bead at the output end of the direct current power supply.

The sampling voltage division circuit comprises a voltage stabilizing diode ZD1 and a first resistor R10, wherein the input end of the voltage stabilizing diode ZD1 is connected with the output end of the rectifying and filtering circuit, the output end of the voltage stabilizing diode ZD1 is connected with the input end of the first resistor, and the output end of the first resistor R10 is connected with the input end of the switch compensation circuit.

The switch compensation circuit comprises a triode Q2, the base (1) of the triode Q2 is connected with the output end of the sampling voltage division circuit, the emitting electrode (3) of the triode Q2 is connected with a second resistor R12 in series and is connected with the output end of the rectification filter circuit, and the collecting electrode (2) of the triode Q2 is connected with the input end of the control circuit. The voltage at the collector (2) end of the triode Q2 reaches the maximum value when the triode Q2 is conducted, and is the minimum value when the triode Q2 is not conducted, so that the process that the voltage gradually rises does not exist, and the situation of detection delay after overvoltage occurs can be effectively avoided.

The control circuit is set as a control chip U1, a current collecting pin FB of the control chip U1 is connected with the output end of the switch compensation circuit, and a voltage output control pin OUT of the control chip U1 is connected with the input end of the switch circuit. The current acquisition pin FB of the control chip U1 acquires the current of the output end of the switch compensation circuit in real time, and when the current rises (the current rises to indicate output overvoltage), the control chip FB controls the switch circuit to be switched off, and the energy storage inductor L1 stops supplying power. In this embodiment, the switching circuit is a MOS transistor switch Q1.

In a more preferred embodiment, the sampling voltage divider circuit further includes a temperature sensor RT1 and a third resistor R18, an input terminal of the temperature sensor RT1 is connected to an output terminal of the rectifying and filtering circuit, an output terminal of the temperature sensor RT1 is connected to an input terminal of the third resistor R18, and an output terminal of the third resistor R18 is connected to an input terminal of the switching compensation circuit. The over-temperature protection function of the power supply is increased by adding the circuit.

Specifically, the overvoltage protection (OVP) principle of the circuit is as follows: the sampling voltage division circuit samples output V + voltage in real time, the V + voltage is conducted when being larger than the voltage stabilization value of a voltage stabilizing diode ZD1, the voltage of a base electrode (1) of a triode Q2 is larger than the conducting voltage and is conducted, the voltage of a collector electrode (2) of the triode Q2 is far larger than the overcurrent protection voltage sampled by a current acquisition pin FB, and the control chip U1 sends out overcurrent protection (OCP); when the output voltage is reduced, the voltage of the base electrode (1) of the triode Q2 is lower than the conducting voltage, and the current collecting pin FB can be subjected to overcurrent protection. Output overvoltage protection (OVP) is realized by repeated triggering actions, and output no-load can be stabilized within a set value.

The over-temperature protection (OTP) principle of the circuit is as follows: when the temperature sensor RT1 detects that the power supply environment temperature exceeds the rated value, the temperature sensor RT1 is in a short-circuit state, the voltage of the base (1) of the triode Q2 is larger than the conduction voltage and is conducted, the voltage of the position of the collector (2) of the triode Q2 is far larger than the overcurrent protection voltage sampled by the current acquisition pin FB, and the control chip U1 sends out overcurrent protection (OCP). When the power supply environment temperature is lower than the rated value of the temperature sensor RT1, the temperature sensor RT1 is in an open circuit state, the voltage of the base electrode (1) of the pole tube Q2 is lower than the breakover voltage, and the current collection pin FB is subjected to overcurrent protection.

While the preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. It is therefore intended that the appended claims be interpreted as including the preferred embodiment and all such alterations and modifications as fall within the scope of the invention. It will be apparent to those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. An LED drive protection circuit is characterized by comprising an alternating current power supply input end, a rectifying circuit, an energy storage circuit, a rectifying and filtering circuit, a sampling voltage division circuit, a switch compensation circuit, a control circuit, a switch circuit and a direct current power supply output end,

2. The LED driving protection circuit of claim 1, wherein the sampling voltage divider circuit comprises a zener diode and a first resistor, an input terminal of the zener diode is connected to an output terminal of the rectifying and filtering circuit, an output terminal of the zener diode is connected to an input terminal of the first resistor, and an output terminal of the first resistor is connected to an input terminal of the switching compensation circuit.

3. The LED driving protection circuit of claim 1, wherein the switching compensation circuit comprises a transistor, a base of the transistor is connected to the output of the sampling voltage divider circuit, an emitter of the transistor is connected in series to a second resistor and connected to the output of the rectifying and filtering circuit, and a collector of the transistor is connected to the input of the control circuit.

4. The LED driving protection circuit of claim 1, wherein the control circuit is configured as a control chip, a current collection pin of the control chip is connected to the output terminal of the switching compensation circuit, and a voltage output control pin of the control chip is connected to the input terminal of the switching circuit.

5. The LED driving protection circuit of claim 1, wherein the switching circuit is configured as a MOS transistor switch.

6. The LED driving protection circuit according to claim 1, wherein the rectification circuit includes a first diode, a second diode, a third diode, and a fourth diode, the first diode being connected in series with the second diode, a first input terminal of the ac power supply input terminals being connected between the first diode and the second diode; the third diode is connected in series with the fourth diode, and a second input end of the alternating current power supply input end is connected between the third diode and the fourth diode.

7. The LED drive protection circuit of claim 1, wherein the energy storage circuit comprises an energy storage inductor.

8. The LED driving protection circuit of claim 2, wherein the sampling voltage divider circuit further comprises a temperature sensor and a third resistor, an input terminal of the temperature sensor is connected to an output terminal of the rectifying and filtering circuit, an output terminal of the temperature sensor is connected to an input terminal of the third resistor, and an output terminal of the third resistor is connected to an input terminal of the switching compensation circuit.