ZHCSI22E October 2017 – August 2019 TPS2662
The TPS2662x family incorporate circuitry to protect the system during overvoltage conditions. The TPS26620, TPS26621, TPS26624 and TPS26625 feature overvoltage cut off functionality. A voltage more than V(OVPR) on OVP pin turns off the internal FET and protects the downstream load. To program the OVP threshold externally, connect a resistor divider from IN supply to OVP terminal to RTN as shown in Figure 31. If the over voltage feature is not to be used then connect OVP terminal to RTN directly and ensure VIN is not exceeded beyond OVPMAX.
The TPS26622 and TPS26623 features an internally fixed 38 V overvoltage clamp (VOVC) functionality. The OVP terminal of these devices must be connected to the RTN terminal directly. These devices clamp the output voltage to VOVC, when the input voltage exceeds 38 V. During the output voltage clamp operation, the power dissipation in the internal MOSFET is PD = (VIN – VOVC) × IOUT. Excess power dissipation for prolonged period can make the device to enter into thermal shutdown. Figure 25 illustrates the overvoltage clamp functionality.