LED driving power supply input overvoltage protection control circuit

Abstract

The utility model relates to an input overvoltage protection control circuit of an LED driving power supply. A voltage input end; the overvoltage detection circuit is connected with the voltage input end and is used for detecting the voltage of the voltage input end; the relay control circuit is connected with the overvoltage detection circuit and is used for receiving a detection signal of the overvoltage detection circuit and sending a control signal; the auxiliary power supply is connected with the relay control circuit; the coil end of the relay is connected with the relay control circuit and used for receiving a control signal, one end of the conduction end of the relay is connected with the voltage input end, and the other end of the relay is used for outputting the control signal to a main circuit. According to the invention, the driving power supply is protected. The driving power supply is prevented from being damaged, and the safety risk problem of fire disasters is avoided.

Description

Technical Field

[0001] The utility model relates to the field of LED power supplies, and in particular to an LED driving power supply input overvoltage protection control circuit. Background Art

[0002] As technology continues to develop and mature, LED lighting applications are becoming more and more extensive. The power of the driver power supply used is also increasing, and the application environment is becoming more and more complex. When used in areas with unstable power grids, the input overvoltage problem will occur due to voltage fluctuations in the power grid. The driver power supply will explode and be damaged due to input overvoltage, and in severe cases, it may even cause a fire.

[0003] At present, the general practice of input overvoltage protection in the industry is to pull down the VCC of the main control circuit IC through the control circuit when the input voltage is too high, so that the entire circuit does not work. In this way, although the circuit does not work, the excessive voltage is still applied to the components of the drive power supply. MOS tubes, electrolytic capacitors and other devices are still subjected to excessive voltage. Therefore, the drive power supply is still at risk of damage. Utility Model Content

[0004] In order to solve the above problems, the present technical solution provides an LED drive power input overvoltage protection control circuit.

[0005] To achieve the above purpose, the technical solution is as follows:

[0006] An LED driving power input overvoltage protection control circuit, comprising:

[0007] Voltage input terminal;

[0008] An overvoltage detection circuit, connected to the voltage input terminal, and used to detect the voltage level of the voltage input terminal;

[0009] A relay control circuit, connected to the overvoltage detection circuit, for receiving a detection signal from the overvoltage detection circuit and sending a control signal;

[0010] an auxiliary power supply connected to the relay control circuit;

[0011] The relay has a coil end connected to the relay control circuit for receiving a control signal, one end of the conduction end is connected to the voltage input end, and the other end is used to output to the main circuit.

[0012] In some embodiments, the overvoltage detection circuit includes a resistor R1, a resistor R2, a resistor R3 and a resistor R4 connected to the voltage input end in sequence, the resistor R4 is grounded, the common end of the resistor R3 and the resistor R4 is connected to the base of the transistor Q1, the collector of the transistor Q1 receives the control signal VB and the control signal G, and its emitter is grounded.

[0013] In some embodiments, the relay control circuit includes a MOS tube Q3, a gate of the MOS tube Q3 is connected to the control signal VB, and the gate is also connected to the voltage input end through resistors R15, R14, and R16 in sequence, a drain of the MOS tube Q3 is connected to the auxiliary power supply through resistors R18 and R17 in sequence, and a source of the MOS tube Q3 is connected to the coil end of the relay.

[0014] In some embodiments, a transistor Q2 is further included, wherein the base of the transistor Q2 receives a signal from the auxiliary power supply, the collector of the transistor Q2 is connected to the resistor R15, and the emitter of the transistor Q2 is grounded.

[0015] In some embodiments, a transistor Q4 is further included, wherein the base of the transistor Q4 is connected to the control signal VB, the emitter thereof is connected to the coil end of the relay, the collector thereof is connected to the voltage VCC1 via a diode D9, and the collector is also connected to the auxiliary power supply via a resistor R20.

[0016] The beneficial effects of this application are:

[0017] This application mainly solves the problem that the input voltage fluctuates too high when the power grid is unstable, causing the driver to explode and be damaged. This application protects the driver power supply, avoiding damage to the driver power supply and the safety risk of fire. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following briefly introduces the drawings required for describing the embodiments.

[0019] Figure 1 It is a schematic diagram of the block structure of an embodiment of the utility model;

[0020] Figure 2 It is a schematic diagram of the circuit structure of an embodiment of the utility model. DETAILED DESCRIPTION

[0021] In order to make the technical problems, technical solutions and beneficial effects solved by the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and are not used to limit the utility model.

[0022] Please refer to Figure 1-2 As shown, an LED driving power input overvoltage protection control circuit includes:

[0023] Voltage input terminal;

[0024] An overvoltage detection circuit, connected to the voltage input terminal, and used to detect the voltage level of the voltage input terminal;

[0025] A relay control circuit, connected to the overvoltage detection circuit, for receiving a detection signal from the overvoltage detection circuit and sending a control signal;

[0026] an auxiliary power supply connected to the relay control circuit;

[0027] The relay has a coil end connected to the relay control circuit for receiving a control signal, one end of the conduction end is connected to the voltage input end, and the other end is used to output to the main circuit.

[0028] In this embodiment, the overvoltage detection circuit includes a resistor R1, a resistor R2, a resistor R3 and a resistor R4 which are sequentially connected to the voltage input end, the resistor R4 is grounded, the common end of the resistor R3 and the resistor R4 is connected to the base of the transistor Q1, the collector of the transistor Q1 receives the control signal VB and the control signal G, and its emitter is grounded. When the input voltage is input, it is collected through the resistor R1-3 and reaches the base of the transistor Q1. If the voltage is overvoltage, the transistor Q1 is turned on and the control signal is grounded, thereby disconnecting subsequent work. If the voltage is in a normal state, the transistor Q1 will not be turned on, and the control signal will power the next module to enable the circuit to work normally.

[0029] In this embodiment, the relay control circuit includes a MOS tube Q3, a gate of the MOS tube Q3 is connected to the control signal VB, and the gate is also connected to the voltage input end through resistors R15, R14, and R16 in sequence, a drain of the MOS tube Q3 is connected to the auxiliary power supply through resistors R18 and R17 in sequence, and a source of the MOS tube Q3 is connected to the coil end of the relay. When the circuit works normally, the control signals VB and G turn on the MOS tube Q3, so that the voltage at the input end or the voltage of the auxiliary power supply supplies power to the coils of relays K1 and K2, and relays K1 and K2 are closed, one is responsible for connecting the L phase of the power supply, and the other is responsible for the N phase, so that the neutral and live wires of the power supply work normally.

[0030] In this embodiment, a transistor Q2 is also included, the base of which receives a signal from the auxiliary power supply, the collector of which is connected to the resistor R15, and the emitter of which is grounded. The auxiliary power supply sends a signal AA to turn on the transistor Q2, so that the voltage at point G drops to a low level, and Q3 is not turned on, thereby preventing the resistors R17 and 18 from losing too much power.

[0031] In this embodiment, a transistor Q4 is further included, wherein the base of the transistor Q4 is connected to the control signal VB, the emitter thereof is connected to the coil end of the relay, the collector thereof is connected to the voltage VCC1 via a diode D9, and the collector is also connected to the auxiliary power supply via a resistor R20.

[0032] How this application works:

[0033] When the power supply is powered on, the circuit supplies power to the relay through R17, R18, and Q3, and the relay is closed. At this time, the input end of the power supply is connected to the main circuit of the power supply through the relay, and the main circuit of the power supply can work and output voltage and current. At the same time, after the main circuit of the power supply works, VCC1 has a voltage output, and the relay is continuously powered through the auxiliary source. In order to avoid excessive loss of R17 and R18 in the circuit, the auxiliary power supply supplies power to Q2 through the AA point, pulling down the gate voltage of Q3. Thus, Q3 is turned off. At this time, the relay is completely powered by the auxiliary source VCC1.

[0034] When the input voltage is too high, the voltage is detected through the voltage-dividing resistor (R1, R2, R3, R4) on the overvoltage detection circuit. The voltage on resistor R4 will increase with the increase of the input voltage. When the voltage rises to the set overvoltage protection point voltage, the base voltage of Q1 in the relay control circuit reaches the threshold that can make Q1 conduct, and Q1 conducts. As a result, the voltage at point VB and point G is pulled down, thus disconnecting the power supply circuit of the relay. When the relay is disconnected, the power input terminal is disconnected from the main circuit of the power supply, and the main circuit of the power supply does not work. And because the relay is physically disconnected, it can be achieved that the main circuit of the power supply is completely free of any voltage. Thus, the protection effect is achieved.

[0035] When the input voltage returns to a value within the normal range, the voltage on R4 will also decrease, Q1 will not conduct, the power supply to the relay will be restored, and the relay will close. The entire circuit will resume normal operation.

[0036] The key point of this application is that when the input voltage is too high, the relay in the circuit is disconnected to completely disconnect the product from the input voltage. This protects the safety of the entire product. When the voltage returns to normal, the circuit can automatically resume normal operation. In addition, this application uses a simple circuit to achieve a safe and reliable input overvoltage protection function, avoiding damage to the power supply and lamps due to excessive voltage. This protects the property safety of customers very well.

[0037] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application. Other principles and basic structures that are the same or similar to those of the present application are within the protection scope of the present application.

Claims

1. An LED drive power input overvoltage protection control circuit, characterized in that: include; Voltage input terminal; An overvoltage detection circuit, connected to the voltage input terminal, and used to detect the voltage level of the voltage input terminal; A relay control circuit, connected to the overvoltage detection circuit, for receiving a detection signal from the overvoltage detection circuit and sending a control signal; an auxiliary power supply connected to the relay control circuit; The relay has a coil end connected to the relay control circuit for receiving a control signal, one end of the conduction end is connected to the voltage input end, and the other end is used to output to the main circuit.

2. The LED driving power input overvoltage protection control circuit according to claim 1, characterized in that: The overvoltage detection circuit includes a resistor R1, a resistor R2, a resistor R3 and a resistor R4 connected to the voltage input end in sequence, the resistor R4 is grounded, the common end of the resistor R3 and the resistor R4 is connected to the base of the transistor Q1, the collector of the transistor Q1 receives the control signal VB and the control signal G, and the emitter thereof is grounded.

3. The LED driving power input overvoltage protection control circuit according to claim 2, characterized in that: The relay control circuit includes a MOS tube Q3, a gate of the MOS tube Q3 is connected to the control signal VB, and the gate is also connected to the voltage input end through resistors R15, R14 and R16 in sequence, a drain of the MOS tube Q3 is connected to the auxiliary power supply through resistors R18 and R17 in sequence, and a source of the MOS tube Q3 is connected to the coil end of the relay.

4. The LED driving power input overvoltage protection control circuit according to claim 3, characterized in that: It also includes a transistor Q2, the base of which receives a signal from the auxiliary power supply, the collector of which is connected to the resistor R15, and the emitter of which is grounded.

5. The LED driving power input overvoltage protection control circuit according to claim 4, characterized in that: It also includes a transistor Q4, the base of which is connected to the control signal VB, the emitter of which is connected to the coil end of the relay, the collector of which is connected to the voltage VCC1 through a diode D9, and the collector is also connected to the auxiliary power supply through a resistor R20.

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