mm1491 Mitsumi Electronics, Corp., mm1491 Datasheet - Page 8

• Manufacturer Part Number: mm1491
• Description: Lithium Battery Protection 1-cell Series
• Manufacturer: Mitsumi Electronics, Corp.

Application Description
Outline
The MM1491 Series are protection IC for over-charge, over-discharge and over-current of rechargeable one-
cell Lithium-ion, further include a short circuit protector for preventing large external short circuit current.
1. Overcharge detection
· The overcharge detector monitors V
threshold VALMI (4.2V typ.) from a low value higher than the VALMI, the overcharge detector can sense a
overcharging and an external charge control Nch-MOS-FET tums to "OFF" with the resister (910k typ.)
between the gate (CO pin) and source of FET, then CO pin "OFF".
(This resistor makes the CO pin "L". Current flows the resister on normal condition, therefore it makes the
resistance value larger because to reduce the consumption current. However it makes resistance value
smaller than 2.2M because of relation between leak current of FET and cut-off time of FET by gate-source
capacitance. : It changes the resistance value from 910K to 2.2M , the consumption current can be
reduced about 2µA.)
Parts List
· R1 : 100
· C1 : 1µF
· R2 : 4.7k
· C2 : 0.047µF
CC
pin voltage. When the V
· RCO : 2.2M
· CTD : 0.1µF/Temp. chr. code B
(· CC1 : 0.1µF/25V)
(· CC2 : 0.1µF/25V)
(· CC3 : 0.1µF/25V)
CC
voltage crosses overcharge detector