SM6780AS datasheet(5/11 Pages) NPC

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SM6780AS

NIPPON PRECISION CIRCUITS—5

Battery Voltage and Temperature Detection

The battery voltage detector input is BATT. The

charger treats the input voltage as the equivalent

voltage of a single cell. For multiple cells (connected

in series), a high-resistance (> 100k

Ω) battery

divider can be used to input the voltage equivalent of

a single cell, as shown in ﬁgure 3.

The battery temperature detector input is TEMP. The

input voltage is provided by a negative temperature

coefﬁcient thermistor (NTC thermistor) located in

close proximity to the battery, as shown in ﬁgure 4.

The input voltage range is 0.5V to VDD.

Note that the thermistor temperature characteristics

are non-linear, so a correction resistance Rc should

be used for linearity correction. The temperature rat-

ing of resistances Rc and Rd should be chosen to

match the battery temperature range rating. If the

temperature detection function is not used, the

TEMP input should be ﬁxed at a potential in the

range 0.25VDD to 0.4VDD.

Figure 3. BATT connection example

BATT pin

Battery

= N

− 1

N:Number of cells

Figure 4. TEMP connection example

TEMP pin

Battery

SM6780AS Datasheet(PDF) 5 Page - Nippon Precision Circuits Inc