US 12,261,517 B2
H-bridge circuit with bootstrap capacitor gate drive charging circuit
Ponggorn Kulsangcharoen, West Midlands (GB); Rodrigo Fernandez-Mattos, West Midlands (GB); and Jonathan Roadley-Battin, Birmingham (GB)
Assigned to HAMILTON SUNDSTRAND CORPORATION, Charlotte, NC (US)
Filed by Hamilton Sundstrand Corporation, Charlotte, NC (US)
Filed on Sep. 12, 2022, as Appl. No. 17/942,806.
Claims priority of application No. 21196998 (EP), filed on Sep. 15, 2021.
Prior Publication US 2023/0078379 A1, Mar. 16, 2023
Int. Cl. H02M 1/08 (2006.01); H02M 7/5387 (2007.01); H02M 1/00 (2006.01)
CPC H02M 1/08 (2013.01) [H02M 7/5387 (2013.01); H02M 1/0006 (2021.05)] 11 Claims
OG exemplary drawing
 
1. An H-bridge circuit comprising:
a first set of two series connected switches arranged to switch on and off at a first frequency; and
a second set of two series connected switches in parallel with the first set and arranged to switch on and off at a second frequency; and
a first bootstrap gate drive charging circuit, arranged to drive the second set of switches;
wherein the second set of two series connected switches includes an upper switch (QU) and a lower switch (QL) connected in series,
wherein the first bootstrap gate drive charging circuit is configured to provide an AC output voltage by alternatively turning on and off according to a predetermined duty cycle of alternate upper switch turn-on and lower switch turn-on phases, the bootstrap gate driver charging circuit comprising:
an input terminal;
an output terminal;
a bootstrap capacitor;
a charging path; and
an H-bridge inverter with an inverter input and an inverter output, wherein the inverter input is electrically connected to the input terminal, the inverter output is electrically connected to a first end of the bootstrap capacitor, the charging path is electrically connected between a second end of the bootstrap capacitor and a gate driver supply voltage;
wherein in response to the lower switch being turned ON and the bootstrap charging circuit provides a path to ground with respect to the gate driver supply voltage and in response to the lower switch being turned off, the bootstrap gate driver charging circuit provides a sufficient voltage level to maintain the upper switch ON for a duration of the upper switch turn-on phase by toggling the upper and lower switches for a short period of time during the upper switch turn-on phase, so as to maintain a charge of the bootstrap capacitor during the upper switch turn-on phase.