SLVSGB5 August 2022 TPS56C231
PRODUCTION DATA
Refer to the PDF data sheet for device specific package drawings
The TPS56C231x has an internal 1.2-ms soft-start time and an external adjustable soft-start time that can be set by connecting a capacitor on the SS pin. When the EN pin becomes high, the soft-start charge current (ISS) begins charging the external capacitor (CSS) connected between SS and AGND. The device tracks the lower of the internal soft-start voltage or the external soft-start voltage as the reference. Equation 3 is the equation for the soft-start time (tSS):
where
If the output capacitor is prebiased at start-up, the device initiates switching and starts ramping up only after the internal reference voltage becomes greater than the feedback voltage, VFB. This scheme ensures that the converters ramp up smoothly into the regulation point.