Eurotech Appliances VIPER / VIPER-LITE PXA255 - Manual (Page 80)

VIPER Technical Manual Power and power management
© 2007 Eurotech Ltd Issue E 80
Example 3: VIPER [Windows CE] at 400MHz in power saving mode + LCD with backlight on + 64MB
FlashDio™ USB memory stick
In this case, the power consumed by the respective categories is:
• VIPER current (Windows CE default) while idle = 334mA ±3mA - 9mA
= 325mA ±3mA.
VIPER current (Windows CE default) while active = 334mA + 99mA
±20mA
= 433mA ±20mA.
• Power saving = 0mA.
• External peripheral current (USB memory stick quiescent) = 650mA (LCD) + 75mA
=
725mA.
External peripheral current (USB memory stick read) = 650mA (LCD) +
121mA
=
771mA
Therefore, the estimated VIPER current while idle (min) is:
325mA ±3mA + 725mA
= 1050mA, ±3mA (5250mW, ±15mW).
and the estimated VIPER current while active and reading from USB memory stick
(max) is:
433mA ±20mA + 771mA
= 1204mA, ±20mA (6020mW, ±100mW) .