Other Parts Discussed in Thread: TPS7H4001-SP
Tool/software:
Hello E2E,
These questions apply to a critical long duration space-flight mission:
- As compared to running the TPS50601A-SP in continuous forward conduction mode are there any detrimental impacts to running it in reverse current/discontinuous mode on: Ripple/Noise voltage, Transient response, regulation, etc.
- Does the PSPICE transient model include accurate behavior of the TPS50601A-SP when operating in reverse/discontinuous mode.
- Is it advisable to keep TPS50601A-SP designs operating in continuous forward conduction mode or is the part designed for comparable performance in reverse-current/discontinuous mode as compared to continuous-forward-conduction mode?
- Is there an efficiency versus switching frequency curve available, couldn’t find it in the datasheet? Typically more efficient to run at lower frequency but that can exacerbate reverse current.
For context:
We’ve analyzed our VRM’s for maximum current loads and are now double-checking designs at minimum current loads. Not unexpectedly at very low load currents it’s possible the inductor ripple current can reverse, e.g. (Inductor Ripple Current)/2 > (Load Current). Doing some extreme what-ifs to help understand how the part is behaving we see inductor current reverse, go to zero, and the PH Node go up to Vin+0.5V, indicating the reverse current might be flowing back thru the high-side FET. Occurred to us we need to ask you folks if there’s any detrimental impacts of operating the part in reverse/discontinuous current mode, and if yes what those impacts are.
Thank you,
-John