Reverse current stopping circuit of synchronous rectification type DC-DC converter

摘要

A reverse current stopping circuit includes a synchronous rectification device, a comparator for detecting a reverse current of an inductor, the synchronous rectification device being turned off when the reverse current is detected by the comparator, a reverse current detector circuit for detecting a switching terminal voltage after the synchronous rectification device is turned off, thereby determining a value of the inductor current to decide whether the inductor current is flowing in a reverse direction or a forward direction, and a memory unit for receiving a predetermined output signal from the reverse current detector circuit in accordance with a result of the reverse current detector circuit, and outputting a control signal for an offset voltage in accordance with the predetermined output signal. The offset voltage is changed in accordance with the control signal so as to adjust the inductor current to zero when the synchronous rectification device is turned off.