Joulwatt Technology (Hangzhou) Co., Ltd.

Xunjin Dou

Xunwei Zhou

Aimin Xu

Yongji He

A control method and a control circuit for a switching power supply circuit and the switching power supply circuit. The switching power supply circuit includes a main switching transistor, a synchronous rectifier and an inductive element. When a switching signal indicates that the synchronous rectifier is turned from on to off, and the main switching transistor is turned from off to on, a gate voltage of the synchronous rectifier is pulled down to be lower than a threshold voltage of the synchronous rectifier and higher than a zero voltage by using a resistor-capacitor delay effect and timing is started. When a gate voltage of the main switching transistor is detected to rise to a first voltage or the timing reaches a first time, the gate voltage of the synchronous rectifier is pulled down to the zero voltage.

Control method and control circuit for switching power supply circuit, and switching power supply circuit

This invention provides a switching power supply controlling circuit, the switching power supply comprises an upper transistor and a lower transistor, the switching power supply controlling circuit comprises a boost circuit, an input terminal of the boost circuit is connected to an input terminal of the switching power supply, the boost circuit output a first voltage to control a working state of the boost circuit, driving the upper transistor to be in an on state. The switching power supply controlling circuit adopts a boost circuit to provide a driving power for the upper transistor, and there is no need to set a bootstrap pin or a bootstrap capacitor.

Switching power supply controlling circuit and controlling method thereof

A power device driving method and a driving circuit for a switching circuit having a main switching transistor, a synchronous rectifier, and an inductive element. When a switching signal indicates that the synchronous rectifier is turned from on to off and the main switching transistor is turned from off to on, a gate voltage of the synchronous rectifier is pulled down to be lower than a threshold voltage of the synchronous rectifier and higher than zero voltage by a body effect of a MOS transistor, and timing is started. When detecting that a gate voltage of the main switching transistor rises to a first voltage or the timing reaches a first time, the gate voltage of the synchronous rectifier is pulled down to the zero voltage.

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Hangzhou, China

Xunjin Dou