US 12,149,094 B2
Adaptive boosting of rectified voltage in a wireless charging system
Chee Weng Cheong, Singapore (SG); and Kien Beng Tan, Singapore (SG)
Assigned to STMicroelectronics Asia Pacific Pte Ltd, Singapore (SG)
Filed by STMicroelectronics Asia Pacific Pte Ltd, Singapore (SG)
Filed on Sep. 30, 2021, as Appl. No. 17/490,437.
Prior Publication US 2023/0099911 A1, Mar. 30, 2023
Int. Cl. H02J 3/32 (2006.01); G01R 19/165 (2006.01); H02J 7/04 (2006.01); H02J 50/10 (2016.01); H02J 50/90 (2016.01); H02M 1/00 (2006.01); H02M 3/156 (2006.01); H02M 7/217 (2006.01); H02M 7/219 (2006.01); H03K 17/687 (2006.01)
CPC H02J 50/10 (2016.02) [G01R 19/16538 (2013.01); H02J 7/04 (2013.01); H02J 50/90 (2016.02); H02M 1/0003 (2021.05); H02M 3/156 (2013.01); H02M 7/219 (2013.01); H03K 17/687 (2013.01)] 17 Claims
OG exemplary drawing
 
1. A wireless power receiver, comprising:
a receiver coil having first and second terminals;
a bridge rectifier having first and second inputs coupled to the first and second terminals of the receiver coil, the bridge rectifier having a first output coupled to ground and a second output coupled to a rectified voltage node at which a rectified voltage is produced;
a first transistor having a conduction path coupled between the second input of the bridge rectifier and ground, the first transistor controlled by a first gate voltage generated at a first node;
a switch control circuit having an input coupled to the rectified voltage node and an output coupled to the first node, the switch control circuit generating the first gate voltage at the first node as a function of the rectified voltage;
a second transistor having a conduction path coupled between the first node and ground, the second transistor controlled by a second gate voltage; and
a rectified voltage detection circuit having an input coupled to the rectified voltage node and an output at which the second gate voltage is generated, the rectified voltage detection circuit generating the second gate voltage as a function of the rectified voltage;
wherein the switch control circuit is configured to generate the first gate voltage such that it turns on the first transistor to thereby boost the rectified voltage, in response to the rectified voltage becoming greater than a turn-on voltage; and
wherein the rectified voltage detection circuit is configured to, in response to the rectified voltage exceeding a lower threshold voltage greater than the turn-on voltage, generate the second gate voltage such that it increases conductivity of the second transistor as the rectified voltage increases, the increase in the conductivity of the second transistor serving to lower the first gate voltage to thereby decrease conductivity of the first transistor and prevent the rectified voltage from exceeding an upper threshold voltage.