W83782D Datasheet, PDF (22/73 Pages) Winbond – MONITORING IC

Preliminary W83782D
Where β is 232K/(232K+56K). If the N2VIN is 0.567 then the V5 is approximately equal to -12V.
The another negative voltage input V6 (approximate -5V) also can be evaluated by the similar
method and the serial resistors can be selected with R7=120K ohms and R8=56K ohms by the
Winbond recommended. The expression equation of V6 With -5V voltage is shown as follows.
V₆
=
N 5VIN − VREF
1−γ
×γ
Where the β is set to 120K/(120K+56K). If the monitored ADC value in the N5VIN channel is 0.8635,
VREF=3.6V and the parameter β is 0.6818 then the negative voltage of V6 can be evalated to be -
5V.
6.3.3 Monitor temperature from thermistor:
The W83782D can connect three thermistors to measure three different envirment temperature. The
specification of thermistor should be considered to (1) β value is 3435K, (2) resistor value is 10K
ohms at 25°C. In the Figure 11, the themistor is connected by a serial resistor with 10K Ohms, then
connect to VREF (Pin 37).
6.3.4 Monitor temperature from Pentium II^TM thermal diode or bipolar transistor 2N3904
The W83782D can alternate the thermistor to Pentium II^TM (Deschutes) thermal diode interface or
transistor 2N3904 and the circuit connection is shown as Figure 12. The pin of Pentium II^TM D- is
connected to power supply ground (GND) and the pin D+ is connected to pin PIITDx in the W83782D.
The resistor R=30K ohms should be connected to VREF to supply the diode bias current and the
bypass capacitor C=3300pF should be added to filter the high frequency noise. The transistor 2N3904
should be connected to a form with a diode, that is, the Base (B) and Collector (C) in the 2N3904
should be tied togeter to act as a thermal diode.
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