Title:
スイッチング電源装置
Document Type and Number:
Japanese Patent JP7177763
Kind Code:
B2
Abstract:
To provide a switching power supply device capable of reliably preventing element destruction by a through-current when a load is short-circuited.SOLUTION: In a switching power supply device, a synchronous rectifying element TR2 is turned on/off with a drive signal DRV from a control IC 10, and synchronously rectifies a voltage generated in a secondary-side main winding Tm2 of a transformer T by switching of a primary-side switching element TR1. An auxiliary power supply unit 16 for generating a power supply voltage VDD of the control IC 10 connects a capacitor C3 in parallel to a series circuit including a secondary-side auxiliary winding Ts and a bidirectional switch element TR3, and turns on/off the bidirectional switch element TR3 at the same timing as the synchronous rectifying element TR2. When a load is short-circuited, the capacitor C3 is discharged during ON period of the bidirectional switch element TR3 to lower the power supply voltage VDD, and the synchronous rectifying element TR2 is fixed to OFF when the operation of the control IC 10 is stopped, thereby preventing a through-current to occur due to overlap between ON periods of the primary-side switching element TR1 and the synchronous rectifying element TR2.SELECTED DRAWING: Figure 1
Inventors:
Shintaro Ohki
Tetsuro Hirata
Tetsuro Hirata
Application Number:
JP2019198302A
Publication Date:
November 24, 2022
Filing Date:
October 31, 2019
Export Citation:
Assignee:
Cosel Co., Ltd.
International Classes:
H02M3/28
Domestic Patent References:
| JP2007020388A | ||||
| JP2017175753A | ||||
| JP2019161968A | ||||
| JP2018046674A | ||||
| JP2009268226A |
Attorney, Agent or Firm:
Takeuchi Susumu