TLE7809G Datasheet, PDF (17/52 Pages) Infineon Technologies AG – Integrated double low-side switch, high-side/LED driver, hall supply, wake-up inputs and LIN communication with embedded MCU (16kB Flash)

TLE7809G
ADC Measurement Interface
Further details on the implementation of the calibration function and location of the calibration figures in Flash
memory can be found in a dedicated application note. The voltage measurement target parameters can be found
in “ADC Battery Voltage Measurement Interface, VBAT_SENSE” on Page 43.
6.2
Temperature Measurement
In the temperature measurement mode the typical internal analog output voltage of the on-chip temperature
sensor can be described with the first order approximation:
V_A ≈ m₀ – m₁ × T_j
(4)
Where:
• T_j is the junction temperature in Kelvin
• m_oand m₁ are typical linear fitting parameters
(see Table “ADC Temperature Measurement Interface” on Page 43)
The output code of the ADC is given by the following equation, where V_AREF and N denote the ADC reference
voltage and the resolution of the ADC:
C_A
=
round
V_A(T_j)
×
-⁽--2----^N----^–-----1---⁾-
V_AREF
,
V_A ≤ V_AREF
(5)
The junction temperature T_J corresponding to the output code C_A is given by:
T_j
=
---1---
m₁
m₀
–
C_-----A---(_---T_----j-)_---×_-----V_{-----A--R---E---F-}
2^N – 1
[unit: K]
(6)
273.15 °C need to be subtracted to convert T_j [K] into Centigrade Scale [°C].
The temperature measurement target parameters can be found in“ADC Temperature Measurement Interface”
on Page 43.
6.2.1 Temperature Measurement Calibration Concept
Best measurement accuracy can be obtained by applying the calibration function:
T_CAL = 586 + f0 • 2^–1–[2^–2 + f1 • 2^–10]CA(T_j)
(7)
The calibration coefficients f_{0 / 1} are computed during the production test and stored in the flash memory of the
microcontroller.
The selection between battery voltage and temperature measurement is done via SPI bit (see “SPI (Serial
Peripheral Interface)” on Page 19).
Further details on the implementation of the calibration function and location of the calibration figures can be found
in a dedicated application note.
Data Sheet
17
Rev. 3.01, 2008-04-15