CFAH2004A-YMC-JP current problem


New member
I am currently working on a project using the CFAH2004A-YMC-JP
negative contrast character display. I am using an ATMEL Atmega163 micro to control the display. After reviewing the data sheet I found that pin 1 is ground, pin 2 is +5V, and pin 3 is a variable voltage. For that I am using a 10k pot hooked to +5 and ground and it is currently set at about .5-.6 volts. My problem is with pins 15 and 16. I am assuming that pin 15 gets connected to +5V and pin 16 gets connected to ground. Is that right? To get my +5V i am using a 7805 regulator but the current draw is so great that it is causing the regulator to fail. When I measured the current i found that at power up it is at 730mA and steadily climbs to 850mA. After that I usally turn it off.

To counteract this problem i tried using a LM317 regulator set to +9V, then connected that to the 7805 regulator but found the result of that to be even more strange. When the LCD is hooked up using this configuration the output of the 317 drops from +9V to +5V and the output of the 7805 drops from +5V to 3.7V. This gets rid of my current problem but unfortunatly I cannot read what is on the screen.

What is the current draw supposed to be for this display? Am I doing something wrong that would cause such a large current draw? Any insight would be much appreciated.
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