Microchip EMC1428 Manual


Læs gratis den danske manual til Microchip EMC1428 (6 sider) i kategorien Ikke kategoriseret. Denne vejledning er vurderet som hjælpsom af 15 personer og har en gennemsnitlig bedømmelse på 4.7 stjerner ud af 8 anmeldelser. Har du et spørgsmål om Microchip EMC1428, eller vil du spørge andre brugere om produktet?

Side 1/6
2005-2014 Microchip Technology Inc. DS00001852A-page 1
AN13.19
INTRODUCTION
This application note describes the Resistance Error
Correction feature available on many Microchip
temperature sensor devices.
OVERVIEW
The information presented will show system designers
that the Resistance Error Correction (REC) feature
removes the need to compensate for series resistance
in the thermal diode connection. Figure 1 shows a
typical system and the remote diode-connected
transistor could be a central processing unit (CPU)
thermal diode or a discrete transistor located where the
temperature must be measured.
FIGURE 1: Block Diagram of Typical Temperature Sensing System.
Author: Wayne Little
Microchip Technology Inc.
System Controller
with SMBus
Interface
SMBus
Interface SMBus
Remote
Sensor
DP
DN
Remote
Diode-Connected
Transistor
Resistance Error Correction
AN13.19
DS00001852A-page 2 2005-2014 Microchip Technology Inc.
POSITIVE TEMPERATURE OFFSET
RESULTING FROM SERIES
RESISTANCE
Review of Temperature Sensing Method
A typical temperature sensor forces two fixed currents
(IF1 and IF2) into the thermal diode to measure
temperature, as shown in Figure 2 below. The forward
bias voltage (VF) of the diode is measured as each of
the two fixed currents is sourced into the diode. In
Figure 2, the value of VF measured at the DP/DN pins
inside the chip is equivalent to the value of V
BE at the
remote diode-connected transistor.
FIGURE 2: Two Current Sources.
The difference between the two values of V
F
(VF2 – VF1 = VBE) is used to determine the
temperature, as shown in Equation 1.
EQUATION 1:
I
F2
I
F1
Voltage to
Temperature
Conversion
V
F
V
BE
DP
DN
Remote
Diode-Connected
Transistor
Where:
k = Boltzmann’s constant
T = Absolute temperature in Kelvin
q = Electron charge
η= Diode ideality factor
VF2 V
F1
kT
q
--------- IF2
IF1
-------
 
 
ln=


Produkt Specifikationer

Mærke: Microchip
Kategori: Ikke kategoriseret
Model: EMC1428

Har du brug for hjælp?

Hvis du har brug for hjælp til Microchip EMC1428 stil et spørgsmål nedenfor, og andre brugere vil svare dig