MM1412

MITSUMI MITSUMI Protection of Lithium-Ion Batteries MM1412 Protection of Lithium-Ion Batteries Monolithic IC MM1412 Outline This IC is used to protect lithium-ion batteries consisting of two cells. It adopts a compact package and has the functions of previous models, with functions for overcharge detection, overdischarge detection and overcurrent detection. A dead time can be set externally. Features 1. Overcharge detection voltage accuracy (0°C to 50°C) 2. Consumption current (Vcell=4.5V) 3. Consumption current (Vcell=3.5V) 4. Consumption current (Vcell=1.9V) 5. Overcharge sensing dead time ±25mV/cell 150µA typ. 15.0µA typ. 0.5µA typ. can be set externally. Package VSOP-8A Applications IC for protection of lithium-ion batteries consisting of two cells. Pin Assignment 1 2 8 7 6 5 3 4 1 2 3 4 5 6 VSOP-8A 7 8 OC GD CS GND TD VL VCC VH MITSUMI MITSUMI Protection of Lithium-Ion Batteries MM1412 Block Diagram MITSUMI Protection of Lithium-Ion Batteries MM1412 Pin Description Pin No. Pin name Overcharge detection output pin 1 OC PNPTR open collector output Overcharge mode: ON Normal mode, overdischarge mode, overcurrent mode: OFF Discharge control FET (N-ch) control output pin 2 GD Normal mod, overcharge mode: H Overdischarge mode, overcurrent mode: L Overcurrent detection input pin 3 CS Monitors discharge current equivalently by the voltage drop between discharge control FET source and drain. Stops discharge when voltage between CS pin and GND pin goes above overcurrent detection threshold value, and holds until load is released. 4 5 GND TD VL VCC VH Ground pin, or lower cell load negative pole input pin. Overcharge detection dead time setting pin Dead time can be set by adding a capacitor between TD and GND pins. Battery intermediate potential input pin Connection pin for lower cell positive electrode side and upper cell negative electrode side. Power supply input pin Upper cell positive electrode input pin Functions 6 7 8 Note: Mode Descriptions (1) Overcharge mode Either H cell or L cell battery voltage exceeds overcharge detection voltage. Overcharge detection operation delay can be set by the dead time setting pin. (2) Normal mode Both H and L cell battery voltages exceed overdischarge detection voltage and are less than overcharge detection voltage. (3) Overdischarge mode Either H or L cell battery voltage is less than overdischarge detection voltage. Overdischarge detection dead time is set internally. Overdischarge mode is released when charging causes voltage to rise above overdischarge detection voltage. Also, when battery voltage goes above overdischarge release voltage, it resets without charging, but the value is set high. (This function is included in case charging can not be detected. Also, this release voltage has a temperature coefficient of -6mV/°C.) (4) Overcurrent mode Voltage between CS and GND exceeds overcurrent detection voltage during discharge. MITSUMI Protection of Lithium-Ion Batteries MM1412 Absolute Maximum Ratings (Ta=25°C) Symbol TSTG TOPR VCC max. VOC max. VCS max. Pd Ratings -40~+125 -20~+70 -0.3~+18 -0.6~VCC -0.6~VCC 300 Unit °C °C V V V mW Item Storage temperature Operating temperature Power supply voltage OC pin impressed voltage CS pin impressed voltage Allowable loss Recommended Operating Conditions Item Operating temperature Operating power supply voltage Symbol TOPR VOP Ratings -20~+70 +0.9~+18 Unit °C V Electrical Characteristics (Except where noted otherwise, Ta=25°C) Item Symbol Measurement conditions Min. Typ. Max. Unit Overcharge detection voltage VOC Ta=0°C~50°C 4.325 4.350 4.375 V Overcharge detection hysteresis voltage VOC 170 220 270 mV Overdischarge detection voltage VOD 2.20 2.30 2.40 V Consumption current 1 IVH1 VH=VL=1.0V VCS=1.4V 0.1 µA Consumption current 2 IVH2 VH=VL=1.9V VCS=3.2V 0.5 0.8 µA Consumption current 3 IVH3 VH=VL=3.5V 15.0 20.0 µA Consumption current 4 IVH4 VH=VL=4.5V, ROC=270kΩ 150 µA VH=VL=3.5V -0.3 0 0.3 µA VL pin input current IVL Overdischarge release voltage VDF Discharge resume by voltage rise 3.30 3.50 3.70 V GD pin H output voltage VGDH VH=VL=3.5V, IL=-10µA VH-0.3 VH-0.2 V GD pin L output voltage VGDL VH=VL=3.5V, IL=10µA 0.2 0.3 V OC pin output current IOCH VH=VL=4.5V 30 150 µA Overcurrent detection threshold value VCS1 135 150 165 mV Overcurrent short threshold value VCS2 When both battery pack pins are shorted 0.35 0.45 0.55 V Overcurrent release Load release: Load of 5MEGΩ or more between both battery pack pins Overcurrent detection delay time 1 tOC1 7 12 18 mS Overcurrent detection delay time 2 tOC2 30 100 uS *1 Overdischarge detection delay time tOD 8 13 20 mS Overcharge detection dead time tOCH CTC=0.18µF 0.5 1.0 1.5 S Start-up voltage VST VH=VL=2.5V -0.24 -0.12 -0.04 V Note 1: Overcurrent short mode delay time (overcurrent delay time 2) is IC response speed. In actual use, the time for discharging the discharge control FET gate capacity is added. Also, when voltage change is large due to excess current, the IC internal bias current may turn off temporarily, causing response time to lengthen. Select the time constant for the capacitor connected to the power supply pin so that power supply fluctuation is more than 100µS/1V. Note 2: Calculate overcharge dead time according to the following formula: Overcharge detection dead time: tALM - 5.55 CTD[S] [CTD: external capacitor, Unit:µF] MITSUMI MITSUMI Protection of Lithium-Ion Batteries MM1412 Measuring Circuit Measuring Circuit 1 (VOC, VOC, VOD, VDF, VST, VCS, IDCH, VGDH, VGDL) Measuring Circuit 2 (tOC, tOD, tOCH) Note : 0.2V 1V/100µS 2.5V 0V 1V/100µS 4.5V CS VL 2.0V VOD VL 4.0V VOC GD t OC GD OC t OC t OCH MITSUMI MITSUMI Protection of Lithium-Ion Batteries MM1412 Timing Chart Short load Overcharge Open load Over load Overcharge Keep overcharge Overdischarge detection Overdischarge Charge sensing VH Overdischarge Overcharge VH Overdischarge Dischage control Gate off dead time Keep cirquit setting Power down dead time Overdischarge dead time Power down Overdischarge dead time GD Over current dead time TD HI-impedance OC Application Circuit MITSUMI Protection of Lithium-Ion Batteries MM1412 Characteristics Overcharge Detection Time (Dead Time) Overcharge detection time (S) 1 0.1 0.01 0.001 0.001 0.01 0.1 External capacitance (CTD) Note: Dead time can be calculated according to the following formula: tOC=5.55 CTD [S] tOC=Overcharge Detection Time CTD=External Capacitor···Unit : µF