L6924D datasheet(25/38 Pages) STMICROELECTRONICS

No de pièce	L6924D

Description	Battery charger system with integrated power switch for Li-ION/Li-POLYMER

PDF	38 Pages

Scroll/Zoom	100%

Fabricant	STMICROELECTRONICS [STMicroelectronics]

Site Internet	http://www.st.com

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25 / 38 page

L6924D

Application information: monitoring and protection

25/38

8.1

NTC thermistor

The device allows designers to monitor the battery temperature by measuring the voltage

across an NTC or PTC resistor. Li-Ion batteries have a narrow range of operating temperature,

usually from 0°C to 50°C. This window is programmable by an external divider which is

comprised of an NTC thermistor connected to GND and a resistor connected to VREF. When

the voltage on the TH pin exceeds the minimum or maximum voltage threshold (internal

window comparator), the device stops the charge process, and indicates a fault condition

through the status pin.

When the voltage (and thus, the temperature), returns to the window range, the device re-starts

the charging process. Moreover, there is a hysteresis for both the upper and lower thresholds,

as shown in Figure 20

Note:

TBAT = OK when the Battery temperature between 0°C and 50°C

Figure 19. Battery temperature control flow chart

L6924D Fiches technique(PDF) 25 Page - STMicroelectronics