JAJSQL9C may 2018 – august 2023 LV3842
ADVANCE INFORMATION
The integrated soft-start circuit prevents input inrush current impacting the LV3842 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 LV3842 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 can 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 LV3842 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 is still available during TOCP_BLK, so there is no concern of inductor current running away.