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Forum Index : Microcontroller and PC projects : for MM+ 100 pin 7" TFT SSD1963

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MMAndy
Regular Member

Joined: 16/07/2015
Location: United States
Posts: 91

Posted: 11:22am 10 Oct 2015

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Inexpensive power solution for MM+ 100 pin with 7" TFT SSD1963.

The input supply to the 100 pin MM+ SnadPIC32 board is
7-12 VDC. This supplies both the onboard 5v regulator @ 500 ma.
and the 3.3V regulator @ 1 AMP.

The keyboard needs 100 ma. @ 5VDC, the TFT display electronics needs 100 ma. @ 3.3 VDC and the backlight needs 5VDC @ 620 ma.

Since we are using a 5VDC USB battery pack/bank or a 5 VDC regulated input
from a wall wart, we need only one master supply input of 5 VDC @ 2 Amp.

We chose, from Tindie,
3.3V fixed 1A switch-mode voltage regulator @ 4.5V to 17VDC input
(Used for TFT display electronics)
5V fixed 1A Switch-Mode Voltage Regulator @ 7.2V to 40VDC input
(Used for keyboard, buzzer and TFT display backlight)

We chose, from Ebay
DC-DC Adjustable Step-up Power Converter Module Output 5V-35V MAX 3 Amp current. Input voltage:3.5V-32V and Output voltage:5V-35V

By adjusting the output of the DC-DC step-up power converter to 9 VDC
we were able to supply 9 VDC to the two fixed regulators and also to
the SnadPIC32 board. The input to the DC-DC step-up converter has to
be 5 VDC for portable operation.

Six power supplies/converters/regulators are being used in our solution. This seems to be an extreme overkill?

Any "user" inexpensive solutions or suggestions to reduce the supply count down is very appreciated!

Edit BTW ...
Our power supply cost is ~$25 $USD + USB Power Bank/PackEdited by MMAndy 2015-10-11

Greg Fordyce
Senior Member

Joined: 16/09/2011
Location: United Kingdom
Posts: 153

Posted: 11:25pm 12 Oct 2015

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I am not using this board but have considered it.

There appears to be a manual for this board at the bottom of this page.
http://easypickit.weebly.com/

On page 3 the diagram at the bottom shows a 3.3 and 5 volt headers marked as item number 3.

I would think you should be able to feed the 5 volt header directly from your 5 volt power supply. This would then power the Snadpic32. Then use the 3.3 volt header on the Snadpic32 to feed the ssd1963 with it's required 3.3 volts. You then feed your keyboard and backlight directly from your 5 volt supply.

I am doing something similar with a Explore64 + ssd1963. I feed the E64 with 5 volts and use the 3.3 volts from the E64 for the ssd1963.

Double check everthing before applying power, I haven't tried this myself and you don't want to let out the magic smoke!

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