UB6054

Preliminary

CMOS IC

UNISONICTECHNOLOGIESCO.,LTD

7 of 13

www.unisonic.com.tw

QW-R52-867.a

OPERATION(Cont.)

4. Charge Status Indicator (CHRG)

The charge status output has three different states: strong pull-down (~10mA), weak pull-down (~20μA) and high

impedance. The strong pull-down state indicates that the UTC UB6054 is in a charge cycle. Once the charge cycle

meets the UVLO conditions and the UTC UB6054 is ready to charge. High impedance indicates that the UTC

UB6054

5. Thermal Limiting

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

above a preset value of approximately 120°С. This feature protects the UTC UB6054 from excessive temperature

and allows the user to push the limits of the power handling capability of a given circuit board without risk of

damaging the UTC UB6054. 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.

6. Undervoltage Lockout (UVLO)

An internal undervoltage lockout circuit monitors the input voltage and keeps the charger in shutdown mode until

Furthermore, to protect against reverse current in the power MOSFET, the UVLO circuit keeps the charger in