ZHCSI48B September 2017 – June 2018 TPS560430
UNLESS OTHERWISE NOTED, this document contains PRODUCTION DATA.
The integrated soft-start circuit prevents input inrush current impacting the TPS560430 and the input power supply. Soft-start is achieved by slowly ramping up the target regulation voltage when the device is first enabled or powered up. The typical soft-start time is 1.8 ms.
The TPS560430 also employs over-current protection blanking time TOCP_BLK (33 ms typical) at the beginning of power-up. Without this feature, in applications with a large amount of output capacitors and high VOUT, the inrush current is large enough to trigger the current-limit protection, which may make the device entering into hiccup mode. The device tries to restart after the hiccup period, then hit current-limit and enter into hiccup mode again, so VOUT cannot ramp up to the setting voltage ever. By introducing OCP blanking feature, the hiccup protection function is disabled during TOCP_BLK, and TPS560430 charges the VOUT with its maximum limited current, which maximizes the output current capacity during this period. Kindly note that, the peak current limit (IHS_LIMIT) and valley current limit (ILS_LIMIT) protection function are still available during TOCP_BLK, so there is no concern of inductor current running away.