-15v Inverting Switching Regulator

[LearnMore]

HI,

Does anyone has any reference to workable VIN =15v ,VOUT=-15,
1>Amp>2 inverting switching regulator design?

 

[itsmoked]

Go to National.com and use their WEB BENCH.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[LearnMore]

hi Itsmoked,

The WEB BENCH only support for positive range of output.
I have found out ONSEMI has circuit calculation spread sheet for NCP3163 but I wish to find a used design for safe application.

 

[itsmoked]

No!!! Are you serious?

How about?

http://webench.national.com/ss1/ss?...-5&O1I=2.0&op_TA=30&submit.x=198&submit.y=226

Keith Cress
kcress -

http://www.flaminsystems.com

 

[VEBill]

Also, anything with an 'isolated output' can (usually) have the +/- outputs swapped to provide either polarity.

 

[LearnMore]

HI Smoke,

Thanks for your reply.
The web bench able to work for negative range.... I wonder why i can't get that result previously. May be i keyed in some wrong parameter.

HI VE1BLL,

I will look into it. THank you.

 

[cabraham]

Use the TI (formerly Unitrode) UC2572 control IC. It is optimized for inverting buck-boost (flyback) non-isolated operation. If isolation is needed, then a transformer-isolated flyback is recommended. Otherwise, avoid the custom transformer and use a catalog off the shelf simple inductor.

I've been using the UC2572 for 5 years and swear by it. It is offered in 8-pin SOIC and DIP, uses direct duty cycle voltage mode control, features pulse by pulse current limit, and has a built in p-channel MOSFET gate driver. The p-FET gate driver is unclamped, so if the input is less than 20V, all is well. Just be sure to use a p-FET with a gate-source rating of 20V. The p-FET should be rated for at least 40V drain to source, as well as the Schottky diode. BR.

Claude

 

[LearnMore]

Thanks Claude.
I have read through the datasheet and app.note for the U2572 but i can't find a complete component selection guide.
Do you have a better design guide for U2572?

 

[cabraham]

The TI app note SLVA059, "Understanding Buck-Boost Power Stages" by Everett Rogers is a good start. It covers component requirements as well as frequency compensation for the non-isolated inverting buck-boost, as well as its isolated flyback counterpart. In a nutshell, the p-MOSFET and the Schottky diode should be 40 volts. I'd use a 3 to 4 amp Schottky, such as an SL44. I'd recommend continuous conduction mode, but at 1-2 amp output, discontinuous might be feasible. Also, I use both pre- and post-regulation LC filters with R-C dampers. Dr. Ridley on his site "Switching Power Magazine" has many good app notes on these topics. The UC2572 is spec'd to 200 kHz, so that is the switching frequency I use. I hope this helps.

 

[GonzaloEE]

http://www.powerint.com/designsupport.htm

Good luck!

 

[danonboost]

Check here:

http://www.linear.com/pc/productDetail.jsp?navId=LTC3704

I've had good luck with the 3704 in several designs. The examples are enough to go on assuming you have basic ps design knowledge.

dan