M62256FP Datasheet, PDF (6/11 Pages) Mitsubishi Electric Semiconductor – Single chip battery charger control IC

M62256FP
Function Description
1. Charging Operation
(1) Detection of battery
When the Batt SW terminal shows "L", it indicates that the battery is installed.
(2) Conditions for quick charge
As soon as the battery is installed, its voltage and temperature are detected. If the battery voltage is below 5 V, the
preliminary charging mode starts. When the battery voltage exceeds 5 V, the quick charge commences.
On the other hand, if the battery voltage exceeds 5 V, the following will take place. If the battery temperature is less
than 55°C, the quick charge will take place. If it is higher than 55°C, the preliminary charge mode will continue
until the temperature falls below 55°C. The charge current used for the quick charge is set by Iset1.
(3) Initialization timer
The initialization timer is set according to table 1. The –∆V is not detected for 3 minutes. Detection of –∆V within
the initialization timer is set to 1 V to prevent erroneous detection of –∆V during the initial charging.
Table 1 Setting up the Initialization Timer
The Initial Battery Voltage
Less than 5 V
More than 5 V but less than 6.5 V
6.5 V or more
20 m
5m
3m
Time of Initialization Timer
(4) Charge control
When the initialization timer completes its function, detection of –∆V is set to 100 mV and the peak voltage of the
battery held inside is compared against the battery voltage detected. After –∆V is detected, the trickle charge starts
at the current set by Iset2.
(5) Safety timer
The safety timer controls the charging time. The quick charging time stops 3 hours and the trickle charging time
ends after 24 hours.
(6) Protective functions
(a) Over-voltage detection:
Charging stops when the battery voltage goes to 9.5 V or higher.
(b) Over-heat detection:
Charging stops when the battery temperature becomes 63°C or higher. When
the temperature goes to 45°C or lower, it recharges once.
(c) Power supply voltage detection: When the power supply voltage goes below 2.8 V, the initial reset takes place.
(d) Unplugged power supply cord: When the unplugged power supply cord is detected, the output SW is turned
off.
(7) Applicable batteries
Ni-Cd battery, Ni-MH (nickel-metal hydrogen) battery (∆T/∆t, V taper can not be detected.)
REJ03F0246-0200 Rev.2.00 Jun 16, 2008
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