Wavecom GX64 Application Note - page 7
Gx64 APPLICATION NOTE
Charging Interface
Page: 7/20
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2
Built-in Charge Circuitry
2.1 Overview
The charging algorithm and its support circuitry that is built into the GR/GS64 family
of products require a DC-voltage on the CHG_IN signal. It also requires a Li-Ion
battery connected between VCC and GND of the system connector. The Li-Ion battery
must include a thermistor with one side connected to GND and the other connected to
ADIN1 of the system connector, so that the battery cell temperature can be
monitored. The thermistor temperature curve can be calibrated by the customer,
making the application very flexible.
The CPS for the charger must be a 500mA current limited 4.5V to 6.0V supply with
reversed current protection.
2.1.1 GR/GS64 Charging Block Diagram
All circuitry required to charge a Li-Ion battery is included in the Wireless CPU. Below
is a block diagram that gives a basic view of how it is implemented inside the Wireless
CPU.
Figure 1.
GR/GS64 Charge Circuitry Block Diagram