ZHCSJN5A February 2018 – April 2019 TPS2HB50-Q1
ADVANCE INFORMATION for pre-production products; subject to change without notice.
The TPS2HB50-Q1 device describes two types of voltage clamps which protect the FET against system-level voltage transients. The two different clamps are shown in Figure 5.
The clamp from VBB to GND is primarily used to protect the controller from positive transients on the supply line (for example, ISO7637-2). The clamp from VBB to VOUT is primarily used to limit the voltage across the FET when switching off an inductive load. If the voltage potential from VBB to GND exceeds the VBB clamp level, the clamp will allow current to flow through the device from VBB to GND (Path 2). If the voltage potential from VBB to VOUT exceeds the clamping voltage, the power FET will allow current to flow from VBB to VOUT (Path 3). Additional capacitance from VBB to GND can increase the reliability of the system during ISO 7637 pulse 2A testing.