科研之友
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摘要
Based on the analysis of the overshoot during the process of short-circuit recovery, an improved hiccup mode protection technique with effective overshoot suppression is presented in this paper. The hiccup mode is activated by the error amplifier (EA) output rather than the feedback voltage. And when the voltage exceeds the high-clamping voltage, the soft-start voltage will be quickly discharged to zero and a new soft-start cycle will attempt to restart the converter. The proposed control method makes the EA output voltage rapidly decline once short-circuit recovery happens, which is very effective for the suppression of overshoot. In addition, the circuit has combined with a foldback current limiting method to further improve the effect of short-circuit protection and overshoot suppression. The proposed technique has been successfully applied to a peak current mode buck converter with Nuvoton 0.6-mu m 5 V/18 V Low-V-gs CDMOS process. The experimental results show that even in extreme cases, this method can effectively suppress the overshoot and the overshoot is almost zero.
