W83783S Datasheet, PDF (16/57 Pages) Winbond – MONITORING IC

W83783S
Preliminary
R1
V1
Positive Input
Positive Inputs
VCORE
+3.3VIN
VDD(+5V)
12VIN
R2
Pin 21
Pin 20
Pin 24
Pin 19
8-bit ADC
with
16mV LSB
R5
V3
Negative Input
R7
V4
N12VIN
N5VIN
Pin 18
Pin 17
Typical Thermister Connection
R8
R
10K, 1% _VREF
VT1
RTHM
10K, 25 C
**The connections of VT2
is same as VT1
R6
Pin 22
Pin 23
Figure 11.
6.3.1 Monitor over 4.096V voltage:
The input voltage +12VIN can be expressed as following equation.
12VIN
= V₁
×
R₂
R₁ + R₂
The value of R1 and R2 can be selected to 28K Ohms and 10K Ohms, respectively, when the input
voltage V1 is 12V. The node voltage of +12VIN can be subject to less than 4.096V for the maximun
input range of the 8-bit ADC. The Pin 24 is connected to the power supply VCC with +5V. There are
two functions in this pin with 5V. The first function is to supply internal analog power in the W83783S
and the second function is that this voltage with 5V is connected to internal serial resistors to monitor
the +5V voltage. The value of two serial resistors are 34K ohms and 50K ohms so that input voltage
to ADC is 2.98V which is less than 4.096V of ADC maximum input voltage. The express equation can
represent as follows.
V_in
=
VCC
×
50KΩ
50KΩ + 34KΩ
≅
2.98V
where VCC is set to 5V.
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Publication Release Date: April 1999
Revision 0.55