US 12,143,004 B2
Charging circuit for bootstrap capacitors
Gary Chunshien Wu, San Diego, CA (US); and Gregory Szczeszynski, Nashua, NH (US)
Assigned to Murata Manufacturing Co., Ltd., Kyoto (JP)
Filed by Murata Manufacturing Co., Ltd., Kyoto (JP)
Filed on May 24, 2022, as Appl. No. 17/752,492.
Prior Publication US 2023/0387796 A1, Nov. 30, 2023
Int. Cl. H02M 1/088 (2006.01); H02M 3/07 (2006.01); H02M 3/158 (2006.01)
CPC H02M 1/088 (2013.01) [H02M 3/07 (2013.01); H02M 3/158 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A charging circuit configured to provide charge transfer among a plurality of bootstrap capacitors of a power converter having a plurality of power switches, each bootstrap capacitor having a top plate and a bottom plate, wherein the top plates of each adjacent pair of bootstrap capacitors are coupled by a respective diode within a diode stack, the charging circuit including two or more trigger-bypass circuits each coupled to a respective diode within the diode stack and configured to initiate a bypass function with respect to the respective diode in response to receipt of an associated trigger signal, and to provide a trigger signal after an associated one of the plurality of power switches is switched to a conductive state and thereby connects the bottom plates of an adjacent pair of bootstrap capacitors, wherein each trigger-bypass circuit includes:
(a) a first PFET having a conduction channel coupled between the cathode and the anode of the respective diode and a gate coupled to the associated trigger signal; and
(b) a second PFET having a conduction channel coupled between the cathode of the respective diode and a gate of the first PFET and a gate coupled to the anode of the respective diode.