powering an LCD controller with a pin?

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My project uses an atmega168p and a standard LCD 16x2.

In power down mode the avr takes less than 1µA but the LCD chipset takes about 1.5mA, always.

So my question is, can I power the LCD chipset with a pin of the AVR? So before going into sleep mode I could drive the pin low to shutdown the LCD controller?

I know it looks strange to power a chipset with an output pin :oops: ...

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Has your LCD chipset an sleep feature? Check it in the datasheet, and try to find maximum current consumption. If this currend doesn't exceed 10 - 15 mA, then powering it from an AVR pin is nothing too strange.

Backlight should be controlled separately, since it will need many more milliamps (this is if you have any BL).

Guillem.
"Common sense is the least common of the senses" Anonymous.

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Some systems require that the power be applied prior to any signals being applied.

You may wish to make all of the data bus and control signals Low prior to turning ON or Off the power, so as to prevent the LCD controller from being partially powered via a signal line, during the start up or shut down interval.

JC

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Thanks!

The LCD chipset (HD44780 compatible) does not have a sleep mode that I can enable... in the LCD datasheet it says typical 1.5mA and max 4.0mA so my mega168 will handle it.

Brightness is controlled by a separate pin and a transistor. I will make sure to put the data/ctrl line to low before power down/up.

I thought it looked strange to power a chip with another chip, seems not :)

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I have done it and it works but you have to be careful not to power it via the signal lines.