ZHCSMO2A June 2022 – November 2022 LMR51430
PRODUCTION DATA
The integrated soft-start circuit prevents input inrush current impacting the LMR51430 and the input power supply. Soft start is achieved by slowly ramping up the internal reference voltage when the device is first enabled or powered up. The typical soft-start time is 4.0 ms.
The LMR51430 also employs overcurrent 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 cause a false start as the device enters into hiccup mode. This action results in a continuous recycling of soft start without raising up to the programmed output voltage. The LMR51430 is able to charge the output capacitor to the programmed VOUT by controlling the average inductor current during the start-up sequence in the blanking time, tOCP_BLK.