Simple Switcher - Negative Input & Negative Output?

James VDC

Other Parts Discussed in Thread: LMR16006Can something from the simple switcher line (ex. LMR16006) be utilized to produced a regulated negative output from a negative input? If so, is there documentation addressing this? If not, is there a switching regulator that is recommendable for this function? My project starts with a negative linear power supply and I need to regulate a node with high enough current and drop that makes a linear regulator a poor option. Ultimately, I'd rather not run my rail through an inverter and then invert that again at the switch regulator. Thanks

over 5 years ago

0 Samuel Jaffe over 5 years ago

TI__Mastermind 25590 points

James,

You can use almost any buck converter as an inverting buck boost. Check out these app notes:

Using a buck converter in an inverting buck-boost topology

Working with inverting buck-boost converters

Basic Calculation of an Inverting Buck-Boost Power Stage

You can find more by searching Google.

-Sam

0 James VDC over 5 years ago in reply to Samuel Jaffe

Prodigy 240 points

Hi Sam, Thanks for the response. Unfortunately, as I indicated, I'm not looking to do a double inversion. I'm starting with a negative supply and wish to regulate to a lower voltage. My gooling has led me here. Best James

0 Samuel Jaffe over 5 years ago in reply to James VDC

TI__Mastermind 25590 points

James,

Sorry about that. I must have read your message without actually reading it. I'm on the same page now!

Yes, we have some examples of negative input to negative output. See below:

E2E for -24V to -17V

E2E for -15V to -5V

and more

-Sam

0 James VDC over 5 years ago in reply to Samuel Jaffe

Prodigy 240 points

Hi Sam. Thanks for the follow-up. This might be a little needy; but I'm looking for a datasheet or white paper that explains how to achieve it. To date I've only had experience with the LMR16006YDDCR simple switcher in the buck/boost world and was hoping to find something with more guidance. Best James

0 Samuel Jaffe over 5 years ago in reply to James VDC

TI__Mastermind 25590 points

James,

We do not have a dedicated white paper or other collateral other than similar collateral to what I've sent. Negative input to negative output is very niche so we have not dedicated resources to this content. Sorry for the inconvenience.

-Sam

0 James VDC over 5 years ago in reply to Samuel Jaffe

Prodigy 240 points

Thank you Sam! It may be an inconvenience but it's nobody's fault! I might just go back to the drawing board and start with a positive supply and have two inverted outputs for the negative supply voltages I need.

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Simple Switcher - Negative Input & Negative Output?