US 11,721,985 B2
Bidirectional battery charging system including capacitor divider circuit
Yen-Mo Chen, Ottawa, NC (US); and Sungkeun Lim, Milpitas, CA (US)
Assigned to Renesas Electronics America Inc., Milpitas, CA (US)
Filed by RENESAS ELECTRONICS AMERICA INC., Milpitas, CA (US)
Filed on Feb. 22, 2021, as Appl. No. 17/181,850.
Claims priority of provisional application 62/981,335, filed on Feb. 25, 2020.
Prior Publication US 2021/0265842 A1, Aug. 26, 2021
Int. Cl. H02J 7/00 (2006.01)
CPC H02J 7/0013 (2013.01) [H02J 7/00711 (2020.01); H02J 7/007182 (2020.01)] 8 Claims
OG exemplary drawing
 
1. A charging device, comprising:
a capacitor divider circuit including a plurality of battery state inputs operably coupleable to a plurality of battery devices, and a pulse width modulation (PWM) generator operable to selectively charge the battery devices;
a plurality of switching transistors each operatively coupled at a gate terminal thereof to a respective PWM control output of a plurality of PWM control outputs; and
a flying capacitor operatively coupled at a first terminal thereof to a first plurality of the switching transistors, operatively coupled at a second terminal thereof to a second plurality of the switching transistors;
a first comparator operatively coupled to the capacitor divider circuit and operable to determine whether a first difference between voltages associated with the battery devices satisfies a first voltage threshold; and
a second comparator operatively coupled to the capacitor divider circuit and operable to determine whether a second difference between voltages associated with the battery devices satisfies a second voltage threshold,
wherein the capacitor divider circuit is further operable to, in response to a determination that the first difference satisfies the voltage threshold, block charging of one or more of the battery devices, and
wherein the second voltage threshold is a minimum device voltage threshold, and the determination that the second difference satisfies the second voltage threshold comprises a determination that the second difference is less than the voltage threshold.