Datasheet

126
8024A–AVR–04/08
ATmega8HVA/16HVA
When the Discharge High-current Protection is activated, the external D-FET and C-FET are dis-
abled and a Current Protection Timer is started. This timer ensures that the FETs are disabled
for at least one second. The application software must then set the DFE and CFE bits in the FET
Control and Status Register to re-enable normal operation. If the D-FET is re-enabled while the
loading of the battery still is too large, the Discharge High-current Protection will be activated
again.
23.7 Charge High-current Protection
If the voltage at the PI/NI pins is above the Charge High-current Detection level for a time longer
than High-current Protection Reaction Time, the chip activates Charge High-current Protection.
When the Charge High-current Protection is activated, the external D-FET and C-FET are dis-
abled and a Current Protection Timer is started. This timer ensures that the FETs are disabled
for at least one second. The application software must then set the DFE and CFE bits in the FET
Control and Status Register to re-enable normal operation. If the C-FET is re-enabled and the
charger continues to supply too high currents, the Charge High-current Protection will be acti-
vated again.
The Short-circuit, Over-current and High-current Protection parameters are programmable to
adapt to different types of batteries. The parameters are set by writing to I/O Registers. The
Parameter Registers can be locked after the initial configuration, prohibiting any further updates
until the next Hardware Reset.
Refer to ”Register Description for Battery Protection” on page 125 for register descriptions.
23.8 Battery Protection CPU Interface
The Battery Protection CPU Interface is illustrated in Figure 22-1.
Figure 23-1. Battery Protection CPU Interface
Each protection has an Interrupt Flag. Each Flag can be read and cleared by the CPU, and each
flag has an individual interrupt enable. All enabled flags are combined into a single battery pro-
5
/
5
/
10
/
Interrupt
Request
Interrupt
Acknowledge
FET
Control
Current
Battery
Protection
Battery Protection
Control Register
Battery Protection
Timing Register
Battery Protection
Level Register
Battery Protection
Parameter Lock
Register
PI
NI
LOCK?
LOCK? LOCK?
8-BIT DATA BUS
Power-off
Battery
Protection
Interrupt
Register
Current
Protection