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BAT32G1x9 user manual | Chapter 33 Temperature sensor and internal reference voltage
1129 / 1149
Rev.1.02
33.4 Internal reference voltage
The Band-gap reference voltage
(VBG)
is an internal fixed reference voltage that is not affected by an
external power supply. The VBG
output can be converted by connecting internally to
the ADC, so
the VDD
can be
calculated from the
ADC
conversion result
of the
VBG.
Due to the process, the VBG
of each chip
is slightly different, so
the calculation of
VDD
will be a
little biased. This product has built-in
A/D conversion result
of
VDD=3.0v
when
VDD
=3.0v is built into
the factory
, and users can accurately calculate it through this value and
the
A/D
conversion result
of the
current
VBG
The voltage value of VDD.
33.4.1
VDD calibration data register VDDCDR
Address: 0x500C64
symbol
15
14
13
12
11
10
9
8 7
6
5
4
3
2
1
0
After
reset
R/W
VDDCDR
-
-
-
-
VDDCDR[11:0]
-
R
Read-only register for recording VDD=3
The A/D
conversion result
of
VBG
at
0v
is automatically
loaded when power is turned on or reset is started, and each chip has its own calibration data.
33.4.2
Instructions for using the internal reference voltage
In this product, the VDD
CDR register stores the internal reference voltage conversion
values measured
at Ta=Tj=25°C and
VDD=3.0v. Using this result, the user can calculate the current
VDD
voltage
according to the following formula:
VDD = 3.0V*VDDCDR/CALVBG
CALVBG: Using an A/D converter, using VBG
as the ADC
input channel, the current VBG
conversion
result is obtained.