AN2390 datasheet(13/42 Pages) STMICROELECTRONICS

部品番号	AN2390

部品情報	A flexible universal battery charger

PDF	42 Pages

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メーカー	STMICROELECTRONICS [STMicroelectronics]

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AN2390

Evaluation board implementation

13/42

2.2.4

Temperature sensing

The circuit for the temperature measurement is given in Figure 7.

Figure 7.

Temperature measurement circuit

For Li-ion, there is an inbuilt NTC so there is no need for an external thermistor but for NiMH,

an external NTC is connected to the negative terminal of the battery.

The same measurement technique is used for both cases. Here the ST7 ADC channel AIN8

is used for the Li-ion temperature measurement and ST7 ADC channel AIN14 is used for

NiMH.

For this demo application, we do not need to monitor the temperature very extensively. We

only need to detect extreme hot or cold conditions. For this reason, rather than using a look-

up table to calculate the temperature, certain predefined parameters are used and these

parameters are compared with the temperature reading in terms of NTC resistance which

simplifies the calculation.

VDD

Battery

ST7 analog input

(AIN8 or AIN14)

AN2390 データシート(PDF) 13 Page - STMicroelectronics