Technical information

Chapter 2: Hardware Interface Description
November 15, 2008 G24-L Module Hardware Description 47
Battery Charger Interface
General
G24-LC incorporates a charging circuit to support battery operated applications.
The battery charger interface includes all the necessary circuitry and signals to facilitate operation
and charging of a single cell 3.7V Lithium-Ion battery pack, including safety and temperature
controls. The battery charger interface is designed for a direct and seamless connection to the
battery pack and external charger.
The G24-LC battery charger interface is managed and controlled automatically by the internal
G24-LC charging management application. The management application is responsible for
executing the battery charging algorithm and controlling the battery charging process without
external user intervention.
Battery Connectivity
The battery is connected to the G24-LC module through the 70-pin interface connector in the
same manner as when using any external DC regulated supply. The battery positive (+) and
negative (-) supply contacts are connected to the module's VCC and GND contacts, respectively,
and the battery internal thermistor is connected to the module's ADC3 contact. The battery pack
is required to include an internal thermistor for temperature control, Murata PN
NTH5G10P39A103J08TH, or equivalent. The module will not operate in case the ADC3 signal
is not connected to a valid thermistor.
Important: In the G24-LC model, the ADC3 signal is used specifically for the battery
thermistor measurement, and is not used for general purpose. ADC3 provides a
current source for the thermistor load measurement during charging operation.
ADC3 must be used with a battery thermistor for proper operation.
Charger Connectivity
The external charger is connected to the G24-LC module through the 70-pin interface connector.
The charger provides the necessary external current source to charge the battery when required.
The charger must provide a stable DC voltage and current at the specified levels.
The charger positive (+) supply contact is connected to the module's VBUS and IGN contacts.
VBUS and IGN are connected internally in the module charging circuit. The charger negative (-)
contact is connected to the module's GND contacts.
Important: In the G24-LC model, the Ignition (IGN) signal is used for the external charger
supply together with VBUS, and is not used for turning-on the module. Both VBUS
and IGN must be connected to the external charger for proper operation.