JAJSLZ0A May 2023 – February 2024 TPS543A22
PRODUCTION DATA
During start-up, the device softly increases the reference voltage from zero to the final value, thereby reducing converter inrush current. There are four options for the soft-start time, which is the time it takes for the reference to ramp to 0.5 V:
The soft-start time is selected with a resistor to AGND on the MSEL pin. See Section 6.3.9.
If a prebiased output condition exists prior to start-up, the device prevents current from being discharged from the output. During monotonic prebiased start-up, the low-side MOSFET is not allowed to sink current until the SS pin voltage is higher than the FB pin voltage and the high-side MOSFET begins to switch. The one exception is if the BOOT-SW voltage is below the UVLO threshold. While in BOOT-SW UVLO, the low-side MOSFET is allowed to turn on to charge the BOOT capacitor. The low-side MOSFET reverse current protection provides another layer of protection for the device after the high-side MOSFET begins to switch.