SLUUDM5 March 2026 MSPM0G1507 , MSPM0G1519 , MSPM0G3507 , MSPM0G3519
Coast (Hi-Z) mode is configured by setting mtrStopOption to 0h.
When motor stop command is received, the FOC application will transition into a high impedance (Hi-Z) state by turning off all MOSFETs. When the FOC application transitions from driving the motor into a Hi-Z state, the inductive current in the motor windings continues to flow and the energy returns to the power supply through the body diodes in the MOSFET output stage (see example in).
The following figure shows an example of how the Hi-Z mode works. In this example, current is applied to the motor through the high-side phase-A MOSFET (HSA), high-side phase-B MOSFET(HSB) and returned through the low-side phase-C MOSFET (LSC).
In Coast mode, a reverse current is injected into the DC bus and might result in DC bus voltage overshoot.