Ricoh R5460x Series Data Sheet User Guide

R5460x SERIES

Li-ION/POLYMER 2-CELL PROTECTOR

NO.EA-165-091221

OUTLINE The R5460xxxxxx Series are high voltage CMOS-based protection ICs for over-charge/discharge of rechargeable two-cell Lithium-ion (Li+) / Lithium polymer, further include a short circuit protection circuit for preventing large external short circuit current and the protection circuits against the excess discharge-current and excess charge current. Each of these ICs is composed of six voltage detectors, a reference unit, a delay circuit, a short circuit protector, an oscillator, a counter, and a logic circuit. When the over-charge voltage threshold or excess-charge current threshold crosses the each detector threshold from a low value to a high value, the output of COUT pin switches to “L” level after internal fixed delay time. To release over-charge detector after detecting over-charge, the detector can be reset and the output of COUT becomes "H" when a kind of load is connected to VDD after a charger is disconnected from the battery pack and the cell voltage becomes lower than over-charge detector threshold. In case that a charger is continuously connected to the battery pack, if the cell voltage becomes lower than the over-charge detector threshold, over-charge state is also released. The output of DOUT pin, the output of the over-discharge detector and the excess discharge-current detector, switches to “L” level after internally fixed delay time, when discharged voltage crosses the detector threshold from a high value to a value lower than VDET2. The conditions to release over-discharge voltage detector after detecting over-discharge voltage are as follows: A/D versions: after connecting a charger, when the cell voltage becomes higher than over-discharge detector threshold or, without connecting charger, when the cell voltage becomes equal or higher than over-discharge released voltage. C version: after connecting a charger, when the cell voltage becomes higher than over-discharge detector threshold voltage. E version: whether connecting a charger, or not, when the cell voltage becomes higher than released voltage from over-discharge. F version: after connecting a charger, when the cell voltage becomes higher than released voltage from over-discharge. In case that connecting a charger, for A/C/D versions, there is no hysteresis for over-discharge detector. For E/F versions, even if a charger is connected to the battery pack, the hysteresis of over-discharge detector exists. To satisfy the release conditions for over-discharge voltage protector, the output voltage of DOUT becomes "H". Even if a battery is discharged to 0V, charge current is acceptable. After detecting excess-discharge current or short current, when the load is disconnected, the excess discharged or short condition is released and DOUT becomes “H”. After detecting over-discharge voltage, supply current will be kept extremely low by halting internal circuits' operation. When the output of COUT is “H”, if V- pin level is set at -1.6V, the delay time of detector can be shortened. Especially, the delay time of the over-charge detector can be reduced into approximately 1/60 and test time for protection circuit PCB can be reduced. The output type of COUT and DOUT is CMOS.