The TPS16412, TPS16413, TPS16416, and TPS16417 devices respond to output overcurrent or overload conditions by actively limiting the current. The devices first provide a blanking time configured by capacitance on the IDLY pin. During this blanking time, the device can provide a current up to I_OCP value. After the end of this blanking time, the devices limit current to ILIM value. ILIM can be set by connecting resistor on ILIM pin. R_ILIM can be calculated by Equation 3.

If the output current exceeds I_OCP, the device goes into current limiting. During current limiting, if the output current goes below ILIM (I_OUT < ILIM), the device resets the IDLY timer and restarts IDLY timer when I_OUT > ILIM. Figure 8-10 illustrates the current limiting behavior for I_OUT < I_OCP and for I_OCP ≤ I_OUT < I_fast-trip. During current limiting, if the output current goes below ILIM (I_OUT < ILIM), the device resets the IDLY timer and restarts the IDLY timer when I_OUT > ILIM.

Figure 8-10 Current Limiting for I_OUT < I_OCP

Figure 8-11 I_OCP ≤ I_OUT < I_fast-trip

During the current limiting, the device dissipates a power of (V_IN – V_OUT) × I_OUT and the device gets heated up. If the junction temperature of device reaches thermal shutdown temperature (T_TSD), the device turns off the internal FET. If the device does not go into thermal shutdown, the internal FET is turned off after a duration of t_ILIM-DUR. After the internal FET is turned off, the TPS16412 and TPS16416 auto-retry while the TPS16413 and TPS16417 latch off. If ILIM pin is connected to GND or left open, the device turns-off the internal FET. If the IDLY pin is left open or connected to GND, device provides t_ILIM-DUR = 155 ms unless the device enters thermal shutdown. Table 8-1 summarizes the device behavior for different output currents.