L10 Hardware Design
backed-up memory which contains all the necessary GPS information for quick start-up and a small
amount of user configuration variables.
Table 7: Pin definition of the V_BCKP pin
Name
Pin
Function
V_BCKP
11
Backup voltage supply
Note: The VRTC couldn’t keep open. The VRTC pin should be connected to a battery or a capacitor
for GPS module hot start and AGPS.
Please refer to the following figure for RTC backup:
RTC
LDO
MODULE
V_BCKP
Non-chargeable
battery or
capacitor
Figure
5:
RTC
supply
from
non
‐
chargeable
battery
or
capacitor
The V_BCKP pin does not implement charging for rechargeable battery. It is necessary to add a
charging circuit for rechargeable battery, shown as the following figure:
Charge Circuit
VCC
RTC
LDO
100R
MODULE
V_BCKP
chargeable
Backup Battery
Figure
6:
Reference
charging
circuit
for
chargeable
battery
z
Coin-type Capacitor backup
Coin-type Rechargeable Capacitor such as XH414H-IV01E form Seiko can be used.
L10_HD_V1.01
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