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MITSUMI
Protection of Lithium Ion Batteries (two cells in series) MM1292
Protection of Lithium Ion Batteries (two cells in series)
Monolithic IC MM1292
Outline
This IC is for protecting a lithium ion battery from overcharging, excess discharging, and overcurrent. If abnormalities occur during charging and excess voltage is applied, it has a function that turns off the external FET switch when voltage is applied to each battery beyond a specified time (overcharging detection). It also has a function that turns off the external FET switch when the voltage for each battery falls below a set voltage, to prevent excess discharge when discharging the battery (discharging detection). At that time, the IC is switched to low current consumption mode. Also, when there is a large current flow due to shorting or other reasons, there is a function for turning off the external FET switch (overcurrent detection). These functions comprise a protection circuit, with few external parts, for lithium ion batteries.
2-Cell Protection ICs
Model name MM1302A MM1292C MM1292D MM1302E MM1302F MM1302G MM1292H MM1292J MM1292K MM1292L Overcharge protection Detection voltage Hysteresis 4.25±0.05V 10mV 4.25±0.05V 200mV 4.35±0.05V 200mV 4.10±0.05V 10mV 4.35±0.05V 10mV 4.215±35V 10mV 4.30±0.05V 220mV 4.25±0.05V 220mV 4.25±0.05V 220mV 4.25±0.05V 220mV Overdischarge protection Detection voltage Hysteresis 2.3V±0.1V 700mV 2.4V±0.1V 600mV 2.4V±0.1V 600mV 2.4V±0.1V 600mV None 2.3V±0.1V 700mV 2.05V±0.1V 950mV 2.4V±0.1V 600mV 2.4V±0.1V 600mV 2.2V±0.1V 800mV Overcurrent Detection voltage 220±20mV 150±15mV 150±15mV 150±15mV None 220±20mV 170±15mV 150±15mV 150±15mV 100±10mV
Features
1. Current consumption (during overcharging) 2. Current consumption (normal) 3. Current consumption (during excess discharging) 4. Current consumption (during excess discharging) 5. Overcharge detection voltage (Ta=-20°C~+70°C) 6. Hysteresis voltage 7. Excess discharge detection voltage 8. Discharge resumption voltage 9. Overcurrent detection voltage 10.Reset after overcurrent detection 11.Operating limit voltage VCELL=4.5V VCELL=3.5V VCELL=1.9V VCELL=1.0V 80µA typ. 13µA typ. 0.5µA typ. 0.1µA max. 4.25V±50mV (detection for each cell) 200mV±60mV (detection for each cell) 2.4V±0.1V (detection for each cell) 3.0V±0.1V (detection for each cell) 150mV±15mV load release 0.9V max.
Package
SOP-8C, SOP-8D(MM1292 F) The box represents the rank resulting from the combination of protection functions.
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MITSUMI
Protection of Lithium Ion Batteries (two cells in series) MM1292
Applications
1. Cellular phones 2. Movies
Pin Assignment
1 2 8 7 6 5 3 4 5 1 2 3 4 6 7 SOP-8C/SOP-8D 8 OC GD N.C GND TD VL CS VH
Pin Description
Pin No. Pin Output Function Output pin for control of the charging control FET. When voltage detected between VH-VL or VL-GND goes over overcharge detection voltage (VALM), the output PNP1 OC Output TR (open collector output) is switched ON, and charging is prohibited by activating the element (NPN-TR, or N-ch FET) that switches the charging control FET to OFF. This operation continues until the voltage falls below VALM. Output pin for driving the discharge control FET. When voltage detected between VH2 GD Output VL and VL-GND goes over excess discharge voltage (VS), this pin goes H. When voltage detected between VH-VL and VL-GND falls below VS and the voltage between CS-GND is more than the voltage detected for an overcurrent (VCS), it goes L. Input pin for discharge detection. When voltage between DS-GND during charge 3 DS Input detection exceeds discharge detection voltage (VDS), OC output is switched OFF and charge control FET is switched ON. 4 GND Input Negative connection pin for the low side battery. It is also the GND pin for this IC. (The IC's reference power supply pin.) Over charge detection output non-induction time setting pin. The capacitor connected 5 TD Input between TD-GND is charged with constant current (ITC) during over charging. When TC pin voltage exceeds the threshold value (VTC), OC output is switched ON. 6 VL Input Positive connection pin for the low side battery, and negative connection pin for the high side battery. Overcurrent detection pin during discharge, and charging detection pin during power down. It detects discharge current using the source drain voltage (voltage 7 CS Input between CS-GND) of discharge control FET. Also, when the battery is charged with a current whose CS-GND voltage after power down exceeds the start-up voltage (VST), the bias current is drained to the interior circuit and operating status results. 8 VH Input Positive connection pin for the high side battery, and the IC's current input pin.
MITSUMI
Protection of Lithium Ion Batteries (two cells in series) MM1292
Block Diagram
Note 1. 45µA max. (current consumption during operation of overcharge detection section) flows to input protection resistor R1. Note 2. 0.3µA max. (when cells are balanced) flows to input protection resistor R2. When the cells are.