Detection and protection circuit for LED (light-emitting diode) short circuit of LED driving chip and method of detection and protection circuit

Abstract

The invention relates to a detection and protection circuit for an LED (light-emitting diode) short circuit of an LED driving chip and a method of the detection and protection circuit. The circuit comprises an output short circuit detection module, a continuous counter connected with the output short circuit detection module, a logic trigger connected with the continuous counter and a low-power-consumption short circuit protection module connected with the logic trigger. According to the detection and protection circuit for the LED (light emitting diode) short circuit of the LED driving chip, the power consumption of the LED short circuit can be reduced; therefore, under the LED output short circuit, the working frequency of the chip is not the low starting frequency, and the chip works at extremely low frequency; furthermore, the phenomenon of misjudgment of the LED short circuit because the output of the chip is nearly zero during starting of the chip can be avoided; meanwhile, harsh noise produced by the low frequency can be still eliminated.

Description

technical field [0001] The invention relates to short-circuit protection technology, in particular to a detection and protection circuit and a method thereof for LED short-circuit of an LED drive chip. Background technique [0002] With the accelerated development of the LED lighting industry, the advantages of energy saving, environmental protection, reliability and stability, and low cost have become the mainstream development direction of LED and LED driver ICs on the market. The energy saving of LED is not only reflected in normal working conditions, but also should conform to the development trend of low power consumption when the circuit fails. [0003] Conventional LED lighting driver ICs in the current technology usually operate at a low frequency of several kilohertz when the output is short-circuited, that is, the low frequency at system startup. figure 1 It is a functional block diagram of a common LED short-circuit protection circuit in the prior art, and the ci...

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Problems solved by technology

[0004] The reason why the LED circuit enters this low-frequency working state of several thousand Hz is that there is no distinction between system start-up and LED output short circuit. This is because the existing LED circuit itself does not design special protection functions for LED output short circuit, so , when the LED is short-circuited, the output voltage is zero, and the LED system cannot identify whether it is a power-on start-up or a LED short-circuit failure, so that the LED enters a low-frequency working state of several thousand Hz, which is the same as the low frequency of the system startup after short-circuiting

However, since the output voltage is always zero when the LED is short-circuited, the circuit will always work at a low frequency of several thousand Hz. Although working at a low frequency of several thousand Hz can reduce power consumption, the traditional LED short-circuit protection circuit with a working frequency of several thousand Hz still produces Large power consumption, so there is more room for optimization, and the human ear can hear this low-frequency buzzing sound, and the noise pollution generated will affect people's life and work

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