W83627HF Datasheet, PDF (111/185 Pages) Winbond – WINBOND I/O

W83627HF/F
PRELIMINARY
11.3 Analog Inputs
The maximum input voltage of the analog pin is 4.096V because the 8-bit ADC has a 16mv LSB.
Really, the application of the PC monitoring would most often be connected to power suppliers. The
CPU V-core voltage ,+3.3V ,battery and 5VSB voltage can directly connected to these analog inputs.
The +12V,-12V and -5V voltage inputs should be reduced a factor with external resistors so as to
obtain the input range. As Figure 11.2 shows.
R1
V1
Positive Input
Positive Inputs
+12VIN
R2
VCOREA
VCOREB
+3.3VIN
AVCC(+5V)
VBAT
5VSB
Pin 100
Pin 99
Pin 98
Pin 97
Pin 74
Pin 61
Pin 96
8-bit ADC
with
16mV LSB
V2
Negative Input
R5
V3
Typical Thermister Connection
R3
N12VIN
Pin 95
N5VIN
Pin 94
R6
R4
R
10K, 1%
VREF
Pin 101
VTIN3
Pin 102
RTHM
10K, 25 C
VTIN2
VTIN1
Pin 103
Pin 104
**The Connections of VTIN1 and VTIN2
are same as VTIN3
Figure. 11.2
11.3.1 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 97 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
W83627HF 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.
- 94 -
Publication Release Date: Jul 1999
Revision 0.53