Rtc Backup - Quectel UC20 Manual

NOTE
Use the RESET_N only when turning off the module by the command AT+QPOWD and the PWRKEY pin
failed.

3.9. RTC Backup

The RTC (Real Time Clock) can be powered by an external power source through the pin VRTC when the
module is powered down and there is no power supply for the VBAT. It is also available to charge the
battery on the VRTC when module is turned on. You can choose rechargeable battery, capacitor or
non-rechargeable battery depending on different applications.
The following figures show the various sample circuits for VRTC backup.
Non-chargeable
Battery
Rechargeable
Battery
UC20_Hardware_Design
Figure 15: RTC Supply from Non-chargeable Battery
Figure 16: RTC Supply from Rechargeable Battery
Confidential / Released
UMTS/HSPA Module Series
R
VRTC
Module
R
VRTC
Module
UC20 Hardware Design
RTC
Core
RTC
Core
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