Datasheet

PRINCIPLES OF OPERATION
Start/Stop Charging
Charging Status Indication
TPS65563A
SLVS858A – JULY 2008 – REVISED AUGUST 2008 ......................................................................................................................................................... www.ti.com
Figure 4. Charging Sequence Chart
The TPS65563A has an enable/disable pin for charging (CHG). The only way to start charging is to input a
high-level signal into CHG (see A and C in Figure 2 ). This high level is latched by internal D-FF shown in
Figure 2 . The internal enable (ENA) signal goes up with some delay, which is specified as SW ON after CHG ↑ in
Switching Characteristics. This is to avoid incorrect operation with a pulsed noise at CHG.
To stop charging, there are three trigger events:
• Forced stop by inputting a low level at CHG (see B in Figure 4 )
• Automatic stop by detecting a full charge. VOUT reaches the target value (see D in Figure 4 ).
• Protected stop by detecting an overcurrent protection (OCP) on the SW pin
When the host inputs the high-level signal into CHG, the voltage of VCC and VBAT must meet the recommended
range; VBAT is from 1.4 V to 12 V, VCC is from 2.7 V to 5.5 V. It is acceptable to start recharging after a forced
stop controlled by CHG (see C in Figure 4 ).
When the charging operation is complete, the TPS65563A drives the charge completion indicator pin, XFULL, to
a low level. A controller can detect the status of the device as a logic signal when it is connected through a pullup
resistor (R1) (see Figure 1 ). The only way to reset the indication at XFULL is to input a low level into CHG (see
Figure 4 ).
The XFULL output enables the controller to find the device-protected situation. If overcurrent protection (OCP)
occurs, XFULL never goes to a low level when CHG is at a high level. Therefore, the controller detects OCP by
measuring the time from turning CHG to a high level to turning XFULL to a low level. If the duration is longer than
the maximum designed charge time, OCP occurs.
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