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针对输入纹波因数较大的LED驱动电路,提出了一种新型的过流保护阈值调整电路。该电路应用于峰值电流检测模式的反激式LED驱动电路,可适应不同输入电压下过流点偏差。使用新型结构,电路可自动调节过流保护电路阈值,而无需采样输入电压大小,过流阈值调节范围为0.78~0.88V。电路结构简洁,有效预防了功率管因过流而可能造成的损坏,同时获得更高的电源效率。该电路适用于大多数输入电压纹波较大的AC-DC电源芯片。
Aiming at the LED driver circuit with large input ripple factor, a novel overcurrent protection threshold adjustment circuit is proposed. The circuit used in peak current detection mode flyback LED driver circuit can be adapted to different input voltage over-current point deviation. With the new structure, the circuit can automatically adjust the over-current protection circuit threshold, without the need to sample the input voltage size, over-current threshold adjustment range of 0.78 ~ 0.88V. The circuit structure is concise and effective, which can effectively prevent the power tube from being damaged due to over-current, and at the same time obtaining higher power efficiency. This circuit is suitable for most AC-DC power chips with large input voltage ripple.