Switching regulator, including dead time adjusting circuit, and control device thereof

摘要

A switching regulator related to aspects of the invention can include an auxiliary winding for monitoring the voltage across the primary winding of a transformer, a differentiation detecting circuit that detects the timing of reversal start or reversal end of the signal detected by the auxiliary winding and a dead time adjusting circuit that receives a signal to trigger turn OFF of a first switch or a second switch and, after passing a predetermined delay time from the detection of the signal, generates a signal to trigger turn ON of the first switch or the second switch. The differentiation detecting circuit can confirm current transfer between body diodes. The dead time adjusting circuit can adjust a dead time to deliver the signal after a predetermined time from the confirmation of the current transfer. In some aspects of the invention, occurrence of hard switching and short-circuit current can be suppressed.

主权项

1. A switching regulator comprising:
series-connected first switch and second switch that are connected to terminals of a DC power supply; a resonant oscillation circuit connected to both terminals of the first switch or the second switch, including a resonance oscillation capacitor, at least one of a resonant oscillation inductance and a leakage inductance of a transformer, and a primary winding in a primary side of the transformer, serially connected; an auxiliary winding that is provided in the primary side of the transformer and detects change of a voltage across the primary winding of the transformer; a differentiation detecting circuit that differentiates a detection voltage detected by the auxiliary winding to detect a timing of start of reversal or a timing of end of reversal of the detection voltage; and a dead time adjusting circuit that generates a second trigger signal at a timing of turning ON the first switch or the second switch after a predetermined delay time from the timing detected by the differentiation detecting circuit for the start of reversal or the end of reversal of the detection voltage detected by the auxiliary winding.