Abstract:

A novel short-circuit protection circuit is proposed with the case in consideration of the shorted load making performance of the DC/DC converter unstable or damaging the converter,effectively avoiding wasting energy of the converter when load is shorted and the output current is very large.The proposed circuit reduces the maximum output current for short circuit by changing the input reference voltage of the current limit comparator.The circuit is designed and applied in a synchronous BUCK DC/DC converter with high voltage based on 0.35 μm BCD process.The simulation results show that the short circuit current of the chip is 30 mA,decreasing output current and conserving energy compared with the traditional protection circuit.

Key words: DC/DC;short protection;maximum inductor current