Specifications

Product Technical Specification & Customer Design Guidelines
Interfaces
3.13 Battery Charging Interface
The Q64 Wireless CPU
®
supports one battery charging circuit, two algorithms and
one hardware charging mode (pre-charging) for 3 battery technologies:
• Ni-Cd (Nickel-Cadmium) with algorithm 0
• Ni-Mh (Nickel-Metal Hydride) with algorithm 0
• Li-Ion (Lithium-Ion) with algorithm 1
The two algorithms control a switch, which connects the CHG_IN signal to the VCC
signal. The algorithms control the frequency and the connected time of the switching.
During the charging procedure, battery charging level is controlled and when the Li-
Ion algorithm is used, battery temperature is monitored via the ADIN1/BAT-TEMP
ADC input.
One more charging procedure is provided by the Q64 Wireless CPU
®
, called “Pre-
charging” mode, but it is a special charging mode as it is only activated when the
Wireless CPU
®
is OFF. Control is thus only performed by the hardware. The purpose
of this charging mode is to avoid battery damage; it prevents the battery from being
below the minimum level.
3.13.1 Implementation
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WA_DEV_Q64_PTS_001-003 January 9, 2009
CHARGER
DC output
Q64 Wireless CPU
®
BATTERY
TEMPERATURE
SENSOR
INTERFACE
CHG_IN
VREF
NTC
ADIN1 / BAT-TEMP
VCC
ALGORITHM
CONTROL
Figure 26: Charging block diagram
The Q64 charging circuit is composed of a transistor switch (between CHG_IN pin 11
and VCC pins 1, 3, 5, 7, 9). Charging is controlled by 2 software algorithms.