ZHCSDA7G July 2014 – February 2018 DRV10983
Two options are available for stopping the voltage applied to the motor when the current threshold is reached. If IPDRlsMd = 0, the recirculate mode is selected. The low-side (S6) MOSFET remains on to allow the current to recirculate between the MOSFET (S6) and body diode (S2) (see Figure 16). If IPDRlsMd = 1, the high-impedance (Hi-Z) mode is selected. Both the high-side (S1) and low-side (S6) MOSFETs are turned off and the current flies back across the body diodes into the power supply (see Figure 17).
The high-impedance mode has a faster settle-down time, but could result in a surge on VCC. Manage this with appropriate selection of either a clamp circuit or by providing sufficient capacitance between VCC and GND. If the voltage surge cannot be contained and if it is unacceptable for the application, then select the recirculate mode. When selecting the recirculate mode, select the IPDClk[1:0] bits to give the current in the motor windings enough time to decay to 0.