W83782G Nuvoton Technology Corporation of America, W83782G Datasheet - Page 15

• Manufacturer Part Number: W83782G
• Description: IC MONITOR H/W 48-LQFP
• Manufacturer: Nuvoton Technology Corporation of America

Specifications of W83782G

• Output Type: I²C™, ISA
• Function: Hardware Monitor
• Topology: ADC, Fan Speed Counter, Register Bank
• Sensor Type: External
• Sensing Temperature: External Sensor
• Output Alarm: No
• Output Fan: Yes
• Voltage - Supply: 4.5 V ~ 5.5 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 48-LQFP
• Temperature Sensor Function: Temp Sensor
• Operating Temperature (min): -40C
• Operating Temperature (max): 120C
• Operating Supply Voltage (typ): 5V
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

6.3.1 Monitor over 4.096V voltage:
The input voltage +12VIN can be expressed as following equation.
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 maximum
input range of the 8-bit ADC. Similarly, the node voltage of 5VSB (measure standby power VSB for
ATX power supply) also can be evaluated by using two series resistors R3 and R4 which real value
can be 5.1K ohms and 7.5K ohms so as to obtain the 5VSB is limited to less than 4.096V. The Pin 33
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 W83782D/G and the second function is that this
voltage with 5V is connected to internal serial resistors to monitor the +5V voltage. The values 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.
where VCC is set to 5V.
6.3.2 Monitor negative voltage:
The negative voltage should be connected two series resistors and a positive voltage VREF (is equal
to 3.6V). In the Figure 11, the voltage V3 and V4 are two negative voltages which are -12V and -5V,
respectively. The voltage V3 is connected to two serial resistors then is connected to another terminal
VREF which is positive voltage. So as that the voltage node N12VIN can be obtain a posedge voltage
if the scales of the two serial resirtors are carefully selected. It is recommended from Winbond that
the scale of two serial resistors are R5=232K ohms and R6=56K ohm. The input voltage of node -
12VIN can be calculated by following equation.
where VREF is equal 3.6V.
If the V
to 35h by the 8-bit ADC with 16mV-LSB.This monitored value should be converted to the real negative
voltage and the express equation is shown as follows.
Where
The other 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.
5
β
is equal to -12V then the voltage is equal to 0.567V and the converted hexdecimal data is set
is 232K/(232K+56K). If the N2VIN is 0.567 then the V5 is approximately equal to -12V.
12
V
V
N VIN
in
5
12
VIN
=
=
N VIN
VCC
12
=
V
=
1
×
(
VREF
×
50
1
−
R
−
1
K
VREF
R
β
+
Ω
50
2
+
R
+
K
V
2
Ω
34
5
×
) (
K
×
β
Ω
232
≅
- 12 -
2 98
K
232
.
Ω
V
+
K
Ω
56
K
Ω
W83782D/W83782G
)
+
V
5