Specifications

XT55 Hardware Interface Description

Confidential / Preliminary

mo b i l e

XT55_hd_v00.02 Page 71 of 116 17.03.2004

4.3.1 Trickle Power mode

The default mode of XT55 GPS part is continuous mode, but the user can set the XT55 GPS

part into the Trickle Power mode via input command message. The XT55 GPS part enters

the trickle power mode corresponding to Figure 29 (800ms OFF Time and 200ms ON Time)

as soon as valid GPS data are available. As a result the average power consumption is

reduced by approximately 80 % (approximately 150mW). The settings for the trickle power

mode can be modified by using the SiRFstar demo software. For example if the XT55 GPS

part is configured to enter the OnTime mode each 10s for a duration of 200ms the average

power consumption can be reduced up to approx. 95% (approx. 15mW, ca. 4,8mA at

Vcc=3.3V).

Figure 29: Example for current in Trickle Power mode

For more details refer to [2].