Technical information

Chapter 2: Hardware Interface Description
November 15, 2008 G24-L Module Hardware Description 49
The following table describes the battery charger specifications.
Battery Charging Process
The battery charging process is managed automatically by the G24-LC, as described below.
The charging process is enabled when an external 5V DC supply is connected to the G24-LC
interface, at the VBUS and IGN contacts, while a valid battery is used and properly connected.
Depending on the battery capacity conditions, the charging process will commence in one of the
following states.
Under Voltage
Under Voltage state is defined as battery voltage below the module's minimum operating level. At
this stage, the module can't be turned-on. The battery must be charged until it reaches the
minimum operating voltage level.
The charger supplies a constant current of 150 mA into the battery until the module can be
turned-on.
Pre-Charging
Pre-Charge is defined as a low current charging state, when the battery voltage level is over the
minimum operating level, but still considered low. At this stage the module can be turned-on and
operated.
The charger supplies a constant current of 150 mA into the battery, until a stable voltage level of
3.6V is reached.
Charging (Continuos Current)
In this stage the battery capacity is at a sufficient level to allow safe and steady operation of the
module and the charging process. The charging is performed in 3 stages, from maximum current
down to low current, until the battery reaches its maximum capacity. Each stage provides a
different charging current continuously to the battery, based on the battery level.
Table 2-24: Charger Supply Specifications
Parameter Conditions Min Typ Max Unit
Supply Voltage 4.5 5.0 5.25 V
Supply Current Maximum
Pre-Charge
500
150
mA
Operating
Temperature
Battery Thermistor 0 45
°C