Patent ID: 7952339
Filing Date: 2011-05-31
Classification: H02M,H03K,Y02B

Abstract:
1. A semiconductor circuit including power switching elements for performing switching control, comprising: means for detecting voltages between the drains and sources of the power switching elements; means for defining a specific voltage developed immediately before or immediately after the detected voltages assume reverse polarity, as a voltage of the synchronous rectifying drive performed due to the first control signals; means for changing the first control signals from “off” signals to “on” signals if voltages between the drains and sources of the switching elements satisfy a condition for the synchronous rectifying drive performed due to the first control signals; means for holding the power switching elements in the “on” states by causing the first control signals to continue to be the “on” control signals for an ensuing constant period of time, irrespective of whether or not the voltages between the drains and sources of the power switching elements satisfy the condition for the synchronous rectifying drive due to the first control signals, and control means operated by second control signals for controlling the power switching elements, wherein the power switching elements are configured to turn on when the first control signals and/or the second control signals are the “on” drive signals, and wherein a first period during which the first control signals are the “on” drive signals, and wherein a first period during which the first control signals continue to be the “on” control signals is set longer than a second period during which the power switching elements can remain driven in the “on” states after the second control signals change from the “off” control signals to the “on” control signals.