Patent ID: 11942940
Assignee: RENESAS ELECTRONICS AMERICA INC.
Field: Electrical machinery, apparatus, energy (Electrical engineering)
Classification: CPC H  Y | IPC H

Claim 12:
13. A system comprising:
a first device;
a second device connected to the first device, the second device comprises a high side switching element and a low side switching element;
the first device is configured to send an enable signal to the second device;
the second device is configured to:
receive the enable signal from the first device; and
enable a low power state of the second device;

in response to the low power state of the second device being enabled:
the first device is configured to send a three-level pulse width modulation (PWM) control signal to the second device to drive the high side switching element and the low side switching element, wherein the three-level PWM control signal varies among a low level, a middle level, and a high level;
the second device is further configured to:
receive the three-level PWM control signal from the first device;
detect a lapse of a hand off time, wherein the hand off time is a duration in which the middle level of the three-level PWM control signal is sustained during the low power state of the device; and
in response to the detection of the lapse of the hand off time during the low power state of the device, and in response to the three-level PWM control signal transitioning to the low level during the low power state of the device, use the three-level PWM signal to activate the low side switching element of the second device to charge a bootstrap capacitor of the second device during the low power state of the device.