Possible Output voltage overshoot with Hiper-LCS2?

Posted by: treez on 10/28/2025

Hi
When the following power supply of the following DER suffers sudden full-load-to-no-load transient, to how high does the output voltage then go up to transiently?
Also, Please can you answer this for all the DER reports of Hiper-LCS2?

https://www.power.com/sites/default/files/documents/der-978_720w_dc-dc_llc_resonant_half-bridge_sr_hiperlcs-2_20250327.pdf?language=en

Also, supposing that the amount of output capacitance is so great that the soft start actually times out before the power supply
gets up into regulation, then what (if any) is the amount of startup vout overshoot eventually seen (if any) with Hiper-LCS2?

Comments

Hi treez,

Our DERs have a transient curve that you can check. In DER 978, expected overshoot during 100% to 0% load is around 620mV above regulation point (48.62V). You may see it in page 53 of the published document.

With great output capacitance, you cannot expect much voltage overshoot during startup since the capacitors are being charged. If the output voltage is still below regulation within 64ms during start up, power supply will go to auto restart or turn off.

Gavin