UB2011

Preliminary

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

5 of 7

www.unisonic.com.tw

QW-R121-028 .a

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OPERATION

The UTC UB2011 is a lithium-ion battery charge controller using a constant-current/constant-voltage algorithm

enters constant-current mode, where the programmed charge current is supplied to the battery. When the BAT pin

approaches the final float voltage (2.7V), the UTC UB2011 enters constant-voltage mode and the charge current

begins to decrease. The pin LED will turn high when the charge current drops to terminal value, but the charging do

not stop.

An internal thermal feedback loop reduces the programmed charge current if the die temperature attempts to rise

more than 1%VDD. This feature protects the UTC UB2011 from excessive temperature. The charge current can be

set according to typical (not worst-case) ambient temperature with the assurance that the charger will automatically

reduce the current in worst-case conditions.

When the pin VT is used, the value is more than 90%VDD, no battery is tested by the UTC UB2011 and the LED

is off, the value is less than 90%VDD, the UTC UB2011 is normal. When the pin VT is connected to ground, The

LED is green when the battery is full or no battery.

The charge status output has three different states with LED flash: LED red, LED green and red and green

alternately. When the VCC is rising the LED shows red and green alternately (about 1 second).The LED is green

when battery is charging. Once the charge cycle has terminated, The LED turns red. The red is flash when IC was

wrong. No battery, no light. The LED state indicates that the UTC UB2011 is in a charge cycle.