MM1433 Просмотр технического описания (PDF) - Mitsumi

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MM1433

Lithium-Ion Battery Charge Control (1 to 2 cells)

Mitsumi 

MITSUMI

Lithium-Ion Battery Charge Control (1 to 2 cells) MM1433

1.5 Recharging Operation

· On detection of a full charge and after the end of charging, the battery voltage starts to drop.

Recharging starts when the voltage has dropped to the recharge detection voltage (There is no re-

charging detection function for rank B.).

2 Other Protective Functions

2.1 Forced Charge Disabling Function

· By setting pin 1 (CHGSW) or pin 2 (RESET) level HIGH (0.6V - 1.2V), charging is disabled. Normally,

ground these pins.

· Pin 1 (CHGSW): Charging ON/OFF only; timer continues to work. Used to temporarily prohibit

charging.

· Pin 2 (RESET): Resets timer simultaneously with charging ON/OFF.

· Disablement using pin 2 takes precedence over pin 1.

· Pin 1 and Pin 2 are connected to Pin 5 (reference power supply output: VREF) via an internal resistor.

This reference power supply does not have sync capability, so high level should not exceed Pin 5

voltage (VREF).

2.2 Temperature Monitoring Function

· A potential created by splitting the voltage at pin 5 (VREF) using external resistor and thermistor is

monitored at pin 12 (TDET). Charging is disabled if, at the start of charging, the temperature is not

within the range of 3°C to 43°C, or between 3°C and 50°C during charging.

· If a thermistor is not used, a resistor can be connected for charging operation, but temperature

protection will not operate. Note: Battery OPEN detection assumes that the battery pack thermistor is

removable. If the thermistor is not used, a battery OPEN detection circuit is required.

· Pin 5 (VREF) is approximately 1.207V ± 2% and output source current is approximately 180mA.

· Confirmation of charging prohibited status

If charging is prohibited during charging due to the timers reaching time up, the open collector NPN

transistor inside Pin 22 (LED R) will repeat ON/OFF. This can be verified by connecting Pin 22 (LED R)

via a resistor (pull-up connection) to an LED, which will blink.

2.3 Hysteresis and Delay Times

· To protect the circuit from malfunction due to noise, etc., hysteresis characteristics are applied to the

ADP detection voltage, low-voltage detection voltage, and preparatory charge detection voltage.

· Also, a constant delay time is applied to full-charge detection, over-voltage detection, and recharge

detection operations.

· The respective delay times are set by the internal timers. See the "OSC CR Settings" on the data sheet

for the timer settings.

3. Checking Charging Operation

· During pre-charging and full charge operations, the open collector NPN transistor inside Pin 22 (LED R) is

constantly ON. Pre-charging and full charge can be verified by connecting Pin 22 (LED R) via a resistor

(pull-up connection) to a red LED, which will be constantly lit.

· During 1mA charging operation, the open collector NPN transistor inside Pin 22 (LED R) repeats ON/OFF.

When operation switches from 1mA charging to pre-charging, the open collector NPN transistor inside Pin

22 (LED R) stays ON constantly. Switching from 1mA charging to pre-charging can be verified by

connecting Pin 22 (LED R) via a resistor (pull-up connection) to a red LED, which will be constantly lit.

· If charging is prohibited during charging due to the timer reaching time up, the open collector NPN

transistor inside Pin 22 (LED R) will repeat ON/OFF. This can be verified by connecting Pin 22 (LED R) via

a resistor (pull-up connection) to an LED, which will blink.

· Pre-charging timer operation can be verified by Pin 3 (TP1) high/low switching.

The TP1 pin signal inverts at the 10th stage of the pre-charge timer binary counter (total 19 stages) and

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