M62244FP
3. Detecting battery temperature
The voltage produced by division by the externally connected pull-up resistor (for Vcvref) and external thermistor
is input to the Tdet pin. This voltage indicates the battery’s temperature. How the temperature limits affect
operation is described below.
(1) When charging is to start
Charging starts as long as the temperature is within the range from –3.5°C to 43°C.
(2) While charging
Charging stops and the IC enters the corresponding standby mode (battery-temperature standby mode) if the
temperature departs from the –5°C to 55°C range.
4. Precharge 1 (3-mA constant-current charge)
Precharge 1 starts when a connected battery is detected and one of the conditions below are satisfied. The 3-mA
current value for precharge 1 is an internal setting.
(1) Vcc ≥ 5.2 V
(2) Battery temperature is greater than or equal to –3°C and less than 43°C
Transitions from pre-charge 1 to other modes occur under the following conditions.
(1) When the battery voltage is 2.0 V or more, the 60-min. timer is masked and the IC makes the transition to
precharge 2.
(2) The IC enters the abnormal mode when the battery voltage is 1.0 V or less 10 minutes after the start of a period
in precharge 1.
(3) The IC enters the abnormal mode when the battery-voltage is 2.0 V or less 60 minutes after the start of a period
in precharge 2.
5. Precharge 2 (100-mA constant-current charge)
When the battery-voltage is 2.0 V or more but less than 2.9 V during precharge-1 operation, the IC enters precharge
2. The current value of precharge 2 is controlled so that the voltage between pins Idet1 and Idet2 is 20 mV, which
is an internal setting. When RS = 0.2 Ω, constant-current control obtains 20 mV/0.2 Ω = 100 mA.
Transitions from precharge 2 to other modes occur under one of the following conditions.
(1) When the battery voltage is 2.9 V or more, the 60-min. timer is masked and the IC makes the transition to fast-
charge mode.
(2) The IC enters the abnormal mode when the battery-voltage is 2.9 V or less 60 minutes after the start of a period
in precharge2.
(3) The IC enters the abnormal mode when the battery voltage is below 1.95 V.
6. Fast charge (1.0-A constant-current charge/4.2-V constant voltage charge)
When the IC is in either precharge mode and the battery-voltage is 2.9 V or more, the IC starts fast charging, during
which the battery is charged at constant current and then constant voltage.
Constant-current control is applied while the battery-voltage is 2.9 V or more but less than 4.2 V. During constant-
current charging, the voltage between pins Idet1 and Idet2 is 200 mV. This is an internal setting. Accordingly,
when RS = 0.2 Ω, the constant-current value is 200 mV/0.2 Ω = 1.0 A.
Constant-voltage control is applied while the battery voltage is 4.2 V. In charging at constant voltage, the charge
current is controlled to keep the battery voltage at 4.2 V.
The following conditions govern transitions from fast charging to other modes.
(1) When the charging current is less than the charging-completed current, the IC makes the transition to the
charging-completed judgement mode. An internally set voltage of 25 mV is the default measure for charging-
completed current, so when RS = 0.2 Ω, the current threshold is 25 mV/0.2 Ω = 125 mA. When the Ifull pin is
open-circuit, the above default value is selected; ground connection of Ifull selects a value of 15 mV.
(2) When the charge-current does not fall below the charging-completed current within 240 minutes of the start of
fast charging, the IC makes the transition to the charging-completed judgement mode. Note, however, that the
judgement being made in the completion-judgement mode differs from that for the transition of item (1).
(3) The IC enters the abnormal mode when the battery voltage is 2.6 V or less.
Rev.1.0, Sep.19.2003, page 12 of 17
RENESAS [ RENESAS TECHNOLOGY CORP ]
