ZHCSJB5B September 2019 – December 2019 DRV8904-Q1 , DRV8906-Q1 , DRV8908-Q1 , DRV8910-Q1 , DRV8912-Q1
UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.
The synchronous rectification of the half bridges operating in PWM mode (OUT4, OUT5 and OUT6) are enabled by setting the corresponding HBX_FW bits in free-wheeling control register (FW_CTRL_1 and FW_CTRL_2). By default, the synchronous rectification mode is disabled.
Figure 38 shows the parallel operation of half-bridges in PWM mode with synchronous rectification disabled. As shown in this figure, during the PWM off time, the high-side diode of the OUT4, OUT5 and OUT6 conducts to close the current path required for motor.
When synchronous rectification mode is enabled, the high-side FETs of OUT4, OUT5 and OUT6 starts conducting during the PWM OFF time to close the motor current path as shown in Figure 39.