ZHCSJY9B June 2019 – November 2021 TPS1HB50-Q1
PRODUCTION DATA
As discussed in the Reverse Battery section, DGND can be used to prevent excessive reverse current from flowing into the device during a reverse battery event. Additionally, RGND is placed in parallel with DGND if the switch is used to drive an inductive load. The ground protection network (DGND and RGND) can be shared amongst multiple high-side switches.
A minimum value for RGND can be calculated by using the absolute maximum rating for IGND. During the reverse battery condition, IGND = VBB / RGND:
RGND ≥ –13.5 V / –50 mA = 270 Ω
In this example, it is found that RGND must be at least 270 Ω. It is also necessary to consider the power dissipation in RGND during the reverse battery event:
PRGND = (13.5 V)2 / 270 Ω = 0.675 W
In practice, RGND can not be rated for such a high power. In this case, a larger resistor value must be selected.