LED driving power supply anti-surge voltage spike suppression circuit with OVP function

Abstract

The utility model belongs to the technical field of circuit structures, and relates to an LED driving power supply anti-surge voltage spike suppression circuit with an OVP function, which is provided with a main chip IC, and the main chip IC comprises a sixth pin, a seventh pin and an eighth pin. The sixth pin is a power supply pin; the eighth pin is an overvoltage protection pin (OVP pin), and the seventh pin is an under-voltage protection pin (UVP pin); the eighth pin is connected with the ground end, at least one resistor is connected in series between the eighth pin and the ground end and is a fifth resistor, and the seventh resistor is an OTP resistor; the seventh pin is outwards connected with a sixth resistor; a first node is arranged between the fifth resistor and the seventh resistor, and a second node is arranged between the seventh resistor and the ground end; according to the circuit provided by the utility model, the filter capacitor is designed at the pull-down detection signal of the OVP pin, so that the overall anti-interference capability of the circuit is improved, the cost is extremely low, and the circuit is very practical.

Description

Technical Field

[0001] This utility model belongs to the field of circuit structure technology and relates to an LED driver power supply anti-surge voltage spike suppression circuit with OVP function. Background Technology

[0002] Currently, many LED driver circuits encounter unstable grid voltage in practical applications, especially in areas with unstable voltage and various voltage spikes in the grid. The main reasons for grid instability are that when lightning strikes transmission lines, substations, or power distribution equipment, it instantly generates extremely high voltage. Even if lightning does not directly strike the grid, its electromagnetic field will induce transient high voltage on the transmission line, which will also form voltage spikes. These spikes are conducted to the power supply end through the grid, causing damage to the LED power supply or causing the LED to flicker. Secondly, when a high-power inductive load starts, it generates an inrush current several times the rated current, causing a sudden drop in local voltage. When the load stops, the disconnection of the inductive load may trigger an operational overvoltage spike, which can also cause abnormal operation of the LED driver power supply. Therefore, LED driver circuits are generally designed with overvoltage and undervoltage protection functions. However, many current overvoltage protection circuits cannot identify and suppress the spike voltage interference generated by this transient overvoltage, which will trigger the OVP protection circuit to malfunction. The control chip will abnormally cut off or turn on the switching transistor under non-overvoltage conditions, causing the LED power supply to flash. Therefore, this type of switching power supply chip with OVP control function urgently needs improvement in both the peripheral circuit and the internal structure of the chip. Utility Model Content

[0003] The purpose of this invention is to provide a circuit with an ingenious structural design that increases the overall anti-interference capability of the circuit by designing a filter capacitor at the signal detection terminal of the chip's OVP pin, which is very practical.

[0004] The above objective is achieved through the following technical solution: an LED driver power supply surge voltage spike suppression circuit with OVP function, wherein the circuit is provided with a main chip IC, the main chip IC including a sixth pin, a seventh pin and an eighth pin; the sixth pin is a power supply pin;

[0005] The eighth pin is an overvoltage protection pin (OVP pin), and the seventh pin is an undervoltage protection pin (UVP pin).

[0006] The eighth pin is connected to ground, and at least one resistor, the fifth resistor, is connected in series between the eighth pin and ground; the seventh pin is connected to a sixth resistor.

[0007] A first node is provided between the fifth resistor and the seventh resistor, and a second node is provided between the seventh resistor and the ground terminal;

[0008] The sixth resistor is connected to the first node, and a third node is provided between the sixth resistor and the first node;

[0009] A filter capacitor is provided between the third node and the second node, that is, the filter capacitor is connected in parallel with the seventh resistor.

[0010] Furthermore, the filter capacitor is 100-1000pF.

[0011] Furthermore, the filter capacitor is 220pF.

[0012] Furthermore, the filter capacitor is a small-capacity ceramic capacitor.

[0013] In this invention, the eighth pin is an overvoltage protection pin. By setting a resistor and a voltage withstand voltage, it provides the detection voltage required for the overvoltage protection point of the circuit. At the same time, the detection voltage is filtered by grounding through capacitor C, filtering out various pulse interference signals or transient surge voltage peaks in the power grid and filtering them to ground, thereby stabilizing and smoothing the OVP detection level. Therefore, the OVP overvoltage protection circuit will not be falsely triggered, increasing the overall anti-interference capability of the power supply. Moreover, only a filter capacitor needs to be added, which is very low cost and achieves a very good anti-interference effect. Attached Figure Description

[0014] Figure 1 The circuit structure diagram of the surge voltage spike suppression circuit of the LED driver power supply with OVP function of this utility model is shown. Detailed Implementation

[0015] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0016] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0017] like Figure 1The diagram shown is a schematic diagram of the surge voltage spike suppression circuit of the LED driver power supply with OVP function of this utility model. The surge voltage spike suppression circuit of the LED driver power supply with OVP function of this utility model is provided with a main chip IC, which includes a sixth pin 6, a seventh pin 7 and an eighth pin 8. The sixth pin 6 is a power supply pin.

[0018] In this invention, the eighth pin 8 is an overvoltage protection pin (OVP pin), and the seventh pin 7 is an undervoltage protection pin (UVP pin); the eighth pin 8 is connected to ground, and at least one resistor is connected in series between the eighth pin 8 and ground; for example, the fifth resistor R5 and the seventh resistor R7 are OTP detection resistors; the seventh pin 7 is connected to a sixth resistor R6.

[0019] A first node S1 is provided between the fifth resistor R5 and the seventh resistor R7, and a second node S2 is provided between the seventh resistor R7 and the ground terminal; the sixth resistor R6 is connected to the first node S1, and a third node S3 is also provided between the sixth resistor and the first node S1; a filter capacitor C1 is provided between the third node S3 and the second node S2, that is, the filter capacitor C1 is connected in parallel with the seventh resistor R7.

[0020] The mains voltage is often unstable, fluctuating wildly. Therefore, a resistor is connected in series in the eighth pin of the circuit. This resistor is a voltage divider, and changing its resistance value can adjust the overvoltage protection level. However, due to various interference signals in the mains or other reasons causing momentary surge spikes, the overvoltage protection circuit may still be falsely triggered. Therefore, in this invention, the OVP detection voltage is filtered by capacitor C to filter various pulse interference signals or transient surge spike voltages in the mains and filter them to ground, thereby stabilizing and smoothing the OVP detection level. As a result, the OVP overvoltage protection circuit will not be falsely triggered, increasing the overall anti-interference capability of the power supply, so that the switching power supply can work normally under harsh conditions.

[0021] In this invention, preferably, the filter capacitor C1 is 100-1000pF, more preferably, it is 220pF; the filter capacitor C1 is a small-capacity ceramic capacitor.

[0022] In this invention, as another approach, the aforementioned filter capacitor can also be added to the middle of the OVP unit circuit inside the chip.

[0023] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An LED driving power supply surge voltage spike suppression circuit with OVP function, characterized in that, The circuit is provided with a main chip (IC), the sixth pin (6), the seventh pin (7) and the eighth pin (8) are included on the main chip (IC); the sixth pin (6) is a power supply pin; The eighth pin (8) is an overvoltage protection pin, and the seventh pin (7) is an undervoltage protection pin; The eighth pin (8) is connected with the ground end, and at least one resistance, which is a fifth resistance (R5), is connected in series between the eighth pin (8) and the ground end, and a seventh resistance (R7) is an OTP resistance; the seventh pin (7) is connected with a sixth resistance (R6) outwardly; The first node (S1) is arranged between the fifth resistance (R5) and the seventh resistance (R7), and the second node (S2) is arranged between the seventh resistance (R7) and the ground end; The sixth resistance (R6) is connected with the first node (S1), and the third node (S3) is further arranged between the sixth resistance (R6) and the first node (S1); The filter capacitor (C1) is connected in parallel with the seventh resistance (R7) between the third node (S3) and the second node (S2).

2. The LED driving power surge voltage spike suppression circuit with OVP function according to claim 1, characterized in that, The filter capacitor (C1) is 100-1000PF.

3. The LED driving power surge voltage spike suppression circuit with OVP function according to claim 1, characterized in that, The filter capacitor (C1) is 220PF.

4. The LED driving power surge voltage spike suppression circuit with OVP function according to claim 1, characterized in that, The filter capacitor (C1) is a small-capacity ceramic capacitor.

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