BL4056

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V1.4

Page8

Programming charge current

The charge current is programmed using a single resistor from the PROG pin to ground. The program resistor

and the charge current are calculated using the following equations.:

Charge termination

A charge cycle is terminated when the charge current falls to 1/10

voltage is reached. This condition is detected by using an internal filtered comparator to monitor the PROG pin.

charge current is latched off and the BL4056 enters standby mode, where the input supply current drops to 55µA

(Note:C/10 termination is disabled in trickle charging and thermal limiting modes).

When charging, transient loads on the BAT pin can cause the PROG pin to fall below 100mV for short periods

of time before the DC charge current has dropped to 1/10

the termination comparator ensures that transient loads of this nature do not result in premature charge cycle

termination. Once the average charge current drops below 1/10

charge cycle and ceases to provide any current through the BAT pin. In this state all loads on the BAT pin must be

supplied by the battery.

The BL4056 constantly monitors the BAT pin voltage in standby mode. If this voltage drops below the 4.02V

manually restart a charge cycle when in standby mode, the input voltage must be removed and reapplied or the

charger must be shut down and restarted using the PROG pin. Figure 1 shows the state diagram of a typical charge

cycle.

Charge status indicator

BL4056 has two open-drain status indicator output

and

.

is pull-down when the BL4056 in

a charge cycle. In other status

in high impedance.

and

are all in high impedance when the

battery out of the normal temperature.

Represent in failure state, when TEMP pin in typical connecting, or the charger with no battery: red LED and