LED open-circuit voltage protection method and circuit and driving circuit using the circuit

Abstract

The invention provides an LED open-circuit voltage protection method and circuit and a driving circuit using the circuit. When the Vcc terminal of the driving IC reaches the starting threshold voltage, the driving IC starts to work; after the working time reaches the preset working time, the Vcc terminal of the driving IC A large current is injected into the terminal; the charging voltage of the capacitor C2 at the Vcc terminal rises to reach the voltage regulation value of the voltage regulator ZD2 connected in parallel with the Vcc terminal of the drive IC, thereby obtaining the set value of the overvoltage protection; maintaining this set value realizes the overvoltage protection function ; This kind of LED open-circuit voltage protection method and circuit and the drive circuit using the circuit utilize the function of time-division multiplexing of the Vcc end of the drive IC, and use the voltage value set by Vcc in the system without affecting the system work. Set the voltage setting value of overvoltage protection. While the integration of the driver IC is higher, it can effectively control the overvoltage value of the system and realize the overvoltage protection function.

Description

technical field [0001] The invention relates to an LED open-circuit voltage protection method and circuit and a driving circuit using the circuit. Background technique [0002] The development of LED lights is relatively rapid, and special driver ICs are needed to drive LEDs. In a limited space, how to integrate more necessary functions with a small package driver IC can promote the vigorous development of LED lights. Such as figure 1 As shown, the existing overvoltage protection voltage setting method is to connect a high-value resistor between the pin of the IC and the ground to set the protection voltage value, which brings the following problems: [0003] 1. The IC needs to have a pin specially set the overvoltage value; [0004] 2. The resistance value is too high. In wet conditions, the leakage current will affect the accuracy of the overvoltage protection point; [0005] 3. If the system works under no-load conditions, the inaccurate overvoltage protection point wi...

AI Technical Summary

Problems solved by technology

[0003] 1. The IC needs to have a pin specially set the overvoltage value;

[0004] 2. The resistance value is too high. In wet conditions, the leakage current will affect the accuracy of the overvoltage protection point;

[0005] 3. If the system works under no-load conditions, the inaccurate overvoltage protection point will cause the components in the system to fail due to exceeding the withstand voltage of the components.

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