LM2991: Inquiry about DC/DC converter recommendation that supports negative voltage

JH Shin 

I will try to find the right resource to help you with a -15V to -6V Negative-to-Negative converter.

To build a Negative to Negative converter, you'll need a boost controller or converter.  Here is a refeence design based on the TPS40210, which does -18 to -3.3, which could be updated to a -6V output.

Here is an applications note about it - https://www.ti.com/lit/pdf/slvaf68 though, with the input voltage limited to 18.5V, the TPS61086 might not be the right product for your 15V input needs, but the application note will.

I will try to get this over to someone in our boost converter team to help you find the best part for your needs.

Hi JH,

The boost device TPS61170 should work in VIN = -15V, VOUT = -6V, IOUT = about 300mA(typ) and up to 1A.

I'm doing the simulation to verify the solutions now and will get the feedback to you asap.

And you may also check the reference design that Stefan posted in parallel.

Regards

Lei

Hi JH,

I verified that TPS61170 can work in VIN = -15V, VOUT = -6V, IOUT = about 300mA(typ). Well, the max Iout at this condition is around 600mA.

To support the 1A Iout, TPS61175 can be the choice.

Regards

Lei