GNSS Module Series
L76&L76-L_Hardware_Design 24 / 59
If V_BCKP is powered by a rechargeable battery, it is necessary to implement an external charging circuit
for the battery. A reference charging circuit is illustrated below.
Figure 6: Reference Charging Circuit for a Rechargeable Battery
3.3. Power Mode
3.3.1. Continuous Mode
If VCC is powered on, the modules automatically enter Continuous mode. Continuous mode comprises
acquisition mode and tracking mode. In acquisition mode, the modules start to search satellites, and to
determine visible satellites, coarse frequency, as well as the code phase of satellite signals. When the
acquisition is completed, the modules automatically switch to tracking mode. In tracking mode, the
modules track satellites and demodulate the navigation data from specific satellites.
3.3.2. Standby Mode
Standby mode is a low-power consumption mode. In Standby mode, the internal core and I/O power
domain are still active, but RF and TCXO are powered off, and the modules stop satellites search and
navigation. The UART interface still receives commands or any other data in Standby mode, but NMEA
messages can’t be output via the interface.
The following describes how to enter or exit from Standby mode:
⚫ Pulling STANDBY pin low will make the GNSS module enter Standby mode and releasing STANDBY
pin which has been pulled high internally will make the modules back to Continuous mode. Note that
pulling down STANDBY pin to ground will cause the extra current consumption which makes the
typical Standby current reach to about 600 μA @ VCC=3.3 V.
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