LM25019 ISOLATED OUTPUTLM25019 MIN VIN

WhiteHorse

Other Parts Discussed in Thread: LM25019

e2e,

We have a customer that needs an isolated output buck regulator capabile of Vin = 10V to 36V minimum and ouput current of 50mA. Figure 17 in the LM25019 data sheet provides an example schematic with Vin = 20V to 48V and isolated output. Since the Vin min for the LM25019 is 7.5V could the circuit in figure 17 work with Vin = 10V to 48V?

Thanks for your help.

Regards

John Wiemeyer

over 10 years ago

0 Vijay86929 over 10 years ago

TI__Genius 11490 points

Hi John,

What is your isolated output voltage?

0 Vijay86929 over 10 years ago in reply to Vijay86929

TI__Genius 11490 points

The IC can work down to 7.5 V min, but for Fly-Buck topology to regulate the secondary properly, we recommend keeping the non-isolated output (VOUT1) <=1/2*VIN(min)

So for the VIN(min)=10V, the non-isolated output should be 5V or so. Then you can step up to VOUT2=10V (if that is the target) on the isolated output using a 1:2 transformer.

Regards,

0 WhiteHorse over 10 years ago in reply to Vijay86929

Genius 4430 points

Thanks for those details. That answers my question.

Regards,

John WIemeyer

Power management

Power management forum

LM25019 ISOLATED OUTPUTLM25019 MIN VIN