NJW4100

- 10 -

Ver.2005-01-20

3. Charge Control Output Block (CNT pin)

A PNP transistor connected to the CNT pin controls the voltage and current required to charge the battery.

When the CHG-SW pin and battery-connected detection are both ON the system moves to charge control mode. If battery

voltage and temperature conditions are appropriate, charging will begin. During 2mA charging the PNP transistor will go to

OFF status.

4. Temperature Detection Block, Battery Connected Detection Block (TDET pin, TH pin, TL pin)

The charge temperature range is set with the TL pin (high temperature) and the TH pin (low temperature).

you can select any type of thermistor (NTC) and any charge temperature range (Figure 4).

The TL pin and the TH pin are set to go to the potential states shown below for fluctuations in TDET voltage.

Pin voltages are obtained from the

following formulae.

TDET pin (thermistor setting)

)

V

24

.

1

(

REF

T

TDET

T

TDET

V

R

R

R

V

×

+

=

TH pin (low temperature setting)

)

V

24

.

1

(

REF

TL

TH

THL

TL

TH

TH

V

R

R

R

R

R

V

×

+

+

+

=

TL pin (high temperature setting)

)

V

24

.

1

(

REF

TL

TH

THL

TL

TL

V

R

R

R

R

V

×

+

+

=

Figure 4 Temperature Detection Block

When the detected temperature goes out of the range of the set values, charging stops, and LED-R and LED-G turn off.

After temperature is restored, charging recommences in line with battery voltage status.

The TDET pin is also used for the battery-connected detection feature.

The battery-connected detection feature determines that a battery is connected if TDET pin voltage is no greater than

1.15V(typ.), and commences charging.

Battery Connected

Detection

Low Temperature

Detection

High Temperature

Detection

Charge

-ON

TDET

TH

TL

Lithium Ion Battery

To CHG-SW

To UVLO