I'm looking for a cost efficient way to create +/- 5.5v and 25.6v from a 12VDC wall wart supply. The product I'm working on will probably use a DC wall wart so I need a solution that will work with that.

I need these voltages to drive the GWTS80MNFG1E by Solomon goldentek display. The 5.5v is supplied for the display driver chip while the 25.6v is used to drive the backlight. There is also 3.3v and gnd to be connected but I already have those on the dev kit I'm using along with 12v and 5v.

According to the datasheet max current draw should be 80mA for the 5.5v supply and the backlight current should be around 75mA at 25.6v. Max current draw for the 3.3v supply is listed as 50mA.

Ideally I'd like to breadboard the solution so I can test the display before designing a board.

Thanks for helping! B

EDIT: I decided on the TPS65132 by TI which I'll power using the 5V on my board. For the LED driver I'm going to try using FAN5333 (not sure yet if I will be able to drive the 3 strings of 8 LEDs each with each string wired in parallel to the other one...)

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    \$\begingroup\$ What have you looked at so far? There are rather a lot of switching power supply solutions floating about. Thousands, in fact. \$\endgroup\$ – Spehro Pefhany Oct 4 '16 at 20:37
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    \$\begingroup\$ To get 26V from 12V a boost switcher will be needed. Regarding breadboarding of this kind of electronics, you better digest this post, electronics.stackexchange.com/questions/259558/… \$\endgroup\$ – Ale..chenski Oct 4 '16 at 20:47
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    \$\begingroup\$ Are you going to make many of these? Otherwise the most cost efficient will be a bunch of switch regulator PCBs from eBay. \$\endgroup\$ – pipe Oct 4 '16 at 21:01
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    \$\begingroup\$ And what is the -5.5 V for? It's in the question title but not in the body. \$\endgroup\$ – Transistor Oct 4 '16 at 21:11
  • \$\begingroup\$ both +5.5 and -5.5 are used to drive the driver chip of the display (see datasheet) \$\endgroup\$ – b20000 Oct 5 '16 at 18:22

As other stated, there are thousands of solutions out there. You also do not mention how much current you require, so making the assumption here that yours is a relatively low current (circa 2A) requirement.

One such possibility is to use the LT1941 from Linear Technology. This is a triple monolithic switching regulator. To quote the data sheet:

"Two of the regulators are step-down converters with 3A and 2A power switches. The third regulator can be configured as a boost, inverter or SEPIC converter and has a 1.5A power switch"

Here's the link for more info: LT1941 Triple Monolithic Switching Regulator. On the down side, you really do need to prototype on PCB given the nature of the application and the relatively high switching frequency (1.1MHz).

Another possibility is the ti LM5001 regulator. Here's a good design resource for using the LM5001 in different topologies. You can use the LM5001 in a fly-back configuration to obtain your three desired. More design resources can be found on both Linear Technologies and Texas Instruments sites. As far as cost goes, the LM5001 is also slightly cheaper than the LT1941, but do consider that the LT1941 packs a lot more features on-chip.

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    \$\begingroup\$ Unless I'm missing something, the LT1941 won't do (without a separate inverter chip) because the OP needs both boost (25.5V) and inversion (-5V) and those features are only provided on just the same regulator. The other two are buck only with no inversion option. \$\endgroup\$ – tcrosley Oct 4 '16 at 23:29
  • \$\begingroup\$ @tcrosley you are correct, the LT1941 won't work for this scenario \$\endgroup\$ – b20000 Oct 5 '16 at 18:17
  • \$\begingroup\$ @tcrosley you are missing the fact that the third regulator in there can be configured as a boost, inverting or SEPIC regulator so no extra chip is needed to achieve the inversion. Refer to Fig. 1 of Page 1 of the data sheet, where a typical circuit is presented outputting 1.8V, 3.3V and -12V outputs from 4.7V - 14V. Using LM5001, you can get inverted and/or stepped down and/or up in a flyback topology. Here is a specific reference link. That said, the LT1941 is a better fit IMHO if you want no flyback transformer and low component count. \$\endgroup\$ – prof.hell Oct 5 '16 at 23:41
  • \$\begingroup\$ @b20000 No he is not. Please see the comment above and try to read the references provided. \$\endgroup\$ – prof.hell Oct 5 '16 at 23:41
  • \$\begingroup\$ I agree, I was wrong, I read boost/inverter and wasn't paying attention that SEPIC can either be higher or lower than the input. Nice part. \$\endgroup\$ – tcrosley Oct 5 '16 at 23:45

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