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Posted - 27 Feb 2002 :  12:04:27  Show Profile  Email Poster
Q: I want to supply backup power to my Graphics Client. How can I do this?

There are several ways to provide backup voltages to the Graphics Client. The way you do it depends on how you plan to use your system. Do you envision that the display of your device will be turned on all the time? Will your device go to sleep when not in use? Is the power supply to your board always going to be available, or do you expect that it can get cut off at any time? Can your software application recover from complete power failures? These are questions that we ask when assisting customers select a backup power source.

If there is a chance that all external power will be disconnected from your device, there are several ways to protect your data:

1. Store all important data in non-volatile (flash) memory (or on an external server in a client/server application). When power is restored, your application can read from non-volatile memory and resume where it left off.

2. Connect a battery to the VPERM power input on J5.6; voltage can be between 5 and 12 volts. When power fails, the board will go to sleep but memory will be retained using the VPERM supply. Within one or two seconds of being awakened, Windows CE will resume operation where it left off.

3. Connect a 3V battery (+/- 0.1V) to J3. Operation when the power fails will be the same as described in case 2.

When the Graphics Client is asleep and main power is not available, the board draws about 4mA of current. You must size your battery accordingly. ADS does not currently have any specifications for batteries or chargers to use with Graphics Client.

ADS Knowledge Base


1519 Posts

Posted - 13 Mar 2002 :  18:04:23  Show Profile  Email Poster
The 3V battery input is not recommended for new designs.

Please refer to this updated information for details.

Drew Kidder
ADS Technology Transfer
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