Voltage drop on half load using TOP267EG

Posted by: oki on 04/11/2025

Hello there,

We have been working on TOP267 and designed a 24V/5A SMPS using ETD Core, at load it is tuned to 24VDC at half load it goes down to 22V, and at full load further decreases to 21V. Is there any way we can reduce this difference a drop of 1 volt works best for us

Please suggest ways to overcome this issue

Files

Schematic 24V_5A_0.pdf (138.53 KB)

Transformer_24V_5A (1)_0.pdf (74.8 KB)

Comments

Hi Oki,

We may reconfigure the value of R13 and consider introducing an RC across R13 with values as suggested from the device design guide on page 17 as RB and CB.

Also, we can consider adding pre-load in the output.

I hope this works for you. Please let us know if you need further support.

Hey thanks for the reply

need to know how can I decide on the cross-frequency ??

Hi oki,

Thank you for your prompt reply.

You may consider a frequency within 100Hz to 7KHz as suggested on figure 17 on page 15 of the design guide.

Voltage drops under half-load can point to inefficiencies in your topology or component mismatch. I had similar issues until I consulted the INN3678C-H606 datasheet, which offered excellent insight into power density and thermal behavior. Ovaga Technologies stocks this part, and using it helped me reduce voltage fluctuations in a compact power supply I used in a casino LED system.