8.3.3 Power Good (PG)

The TPS22971 has a power good (PG) output signal to indicate the gate of the pass FET is driven high and the switch is fully on (full load ready). The signal is an active high and open drain output which can be connected to a voltage source through an external pull up resistor, R_PU. This voltage source can be V_OUT from the TPS22971 or another external voltage. Equation 4 and Equation 5 show the approximate equation for the relationship between CT setting, V_IN and PG Turn-On time (t_PG,ON):

Equation 4.

Equation 5.

where

• t_PG,ON is the PG Turn-On time (in µs)
• V_IN is the input voltage (in V)
• C_T is the capacitance value on the CT pin (in pF)