ZHCSOF7B september 2022 – june 2023 TPS25990
PRODUCTION DATA
Power Good is an active high digital output which is asserted high to indicate when the device is in steady-state and capable of delivering maximum power.
Event or Condition | FET Status | PG Pin Status | PG Delay |
---|---|---|---|
Device disabled ( VEN < VUVLO) | OFF | L | tPGD |
VIN Undervoltage (VIN < VUVP or VIN < VIN_UV_FLT) | OFF | L | |
VDD Undervoltage (VDD < VUVP ) | OFF | L | |
VIN Overvoltage (VIN > VIN_OV_FLT) | OFF | L | tPGD |
Steady-state | ON | H | tPGA |
Inrush | ON | L | tPGA |
Transient overcurrent | ON | H | N/A |
Circuit-breaker (persistent overcurrent followed by OC_TIMER expiry) | OFF | L | tOC_TIMER + tPGD |
Fast-trip | OFF | L (VOUT < VOUT_PGTH) H (VOUT > VOUT_PGTH) | tPGD N/A |
Overtemperature | Shutdown | L | tPGD |
GPIO1 pin is configured as PG output by default. Refer to GPIO_CONFIG_12 register for more details and configuration options.
After power up, PG is pulled low initially. The device initiates an inrush sequence in which the gate driver circuit starts charging the gate capacitance from the internal charge pump. When the FET gate voltage reaches the full overdrive indicating that the inrush sequence is complete and the device is capable of delivering full power, the PG pin is asserted high after a de-glitch time (tPGA). The PG assertion delay can be optionally increased by setting the PG_DVDT_DLY bit in the DEVICE_CONFIG register.
The PG is de-asserted if the output voltage falls below a threshold at any point during normal operation or the device detects a fault (except short-circuit). The PG de-assertion threshold can be digitally programmed through the VOUT_PGTH register. The PG de-assertion de-glitch time is tPGD.
The PG is an open-drain pin and must be pulled up to an external supply.
When there is no supply to the device, the PG pin is expected to stay low. However, there is no active pulldown in this condition to drive this pin all the way down to 0 V. If the PG pin is pulled up to an independent supply which is present even if the device is unpowered, there can be a small voltage seen on this pin depending on the pin sink current, which is a function of the pullup supply voltage and resistor. Minimize the sink current to keep this pin voltage low enough not to be detected as a logic HIGH by associated external circuits in this condition.