SLLSFH8A August 2021 – December 2021 MCT8316A
Two modes are available for configuring the way the MCT8316A stops driving the motor when the current threshold is reached. The recirculate (or brake) mode is selected if IPD_RLS_MODE = 0b. In this configuration, the low-side (LSC) MOSFET remains ON to allow the current to recirculate between the MOSFET (LSC) and body diode (LSA) (see Figure 8-22). Hi-Z mode is selected if IPD_RLS_MODE = 1b. In Hi-Z mode, both the high-side (HSA) and low-side (LSC) MOSFETs are turned OFF and the current recirculates through the body diodes back to the power supply (see Figure 8-23).
In the Hi-Z mode, the phase current has a faster settle-down time, but that can result in a voltage increase on VM. The user must manage this with an appropriate selection of either a clamp circuit or by providing sufficient capacitance between VM and GND to absorb the energy. If the voltage surge cannot be contained or if it is unacceptable for the application, recirculate mode must be used. When using the recirculate mode, select the IPD_CLK_FREQ appropriately to give the current in the motor windings enough time to decay to to 0-A before the next IPD phase pattern is applied.