The TPS1663x incorporate circuitry to protect the system during overvoltage conditions. The TPS16630 features an accurate ± 2% adjustable 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 GND as shown in Figure 9-3. The TPS16632 features an internally fixed 39-V maximum overvoltage clamp V_(OVC) functionality. The TPS16632 clamps the output voltage to V_(OVC), when the input voltage exceeds 40 V. During the output voltage clamp operation, the power dissipation in the internal MOSFET is PD = (V_(IN) – V_(OVC)) × I_(OUT). Excess power dissipation for a prolonged period can increase the device temperature. To avoid this, the internal FET is operated in overvoltage clamp for a maximum duration of t_OVC(dly), 162 msec (typical). After this duration, the internal FET is turned OFF and the subsequent operation of the device depends on the MODE configuration (auto-retry or latch off) setting as per the Table 9-1.

Figure 9-4 illustrates the overvoltage cut-off functionality and Figure 9-5 illustrates the overvoltage clamp functionality. FLT is asserted after a delay of 617 µs (typical) after entering in overvoltage clamp mode and remains asserted until the overvoltage fault is removed.

TPS16630	OVP Setting at 33 V

Figure 9-4 Overvoltage Cut-Off Response at 33-V Level

TPS16632

COUT = 10 µF, FLT connected to VOUT

RLOAD = 30 Ω

Figure 9-5 Overvoltage Clamp Response