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Chapter 27
Voltage Comparator
Preliminary User’s Manual U17566EE1V2UM00
27.1.1
Description
Each Voltage Comparator consists of an operation amplifier and a logic block.
The operation amplifier is connected to the external voltage (V
CMPn
) with one
input and to an internal reference voltage (V
LVI
) with the other. It shares the
reference voltage supply with the power regulators. The comparator output is
fed into a logic block that generates the interrupt signal INTVCn and sets or
clears the flag VCSTRn.VCFn. The comparison result of Voltage Comparator 0
is also output to the VCMPO0 pin.
The figure below shows a block diagram of the Voltage Comparator.
Figure 27-1
Voltage
Co
mparator block diagram
27.1.2
Comparison results
Voltage comparison leads to the following results:
• Output signal VCMPO0 and flag VCSTRn.VCFn
– V
CMPn
< V
LVI
:
The output signal VCMPO0 of the Voltage Comparator is low (for n = 0)
and the flag VCSTRn.VCFn is cleared.
– V
CMPn
> V
LVI
:
The output signal VCMPO0 of the Voltage Comparator is high (for n = 0)
and the flag VCSTRn.VCFn is set.
• Interrupt signal INTVCn
Depending on the settings of bits VCCTLn.ESn[1:0], the interrupt signal
INTVCn is generated upon one or both of the above transitions of V
CMPn
.
27.1.3
Stand-by mode
In order to reduce power consumption during STOP mode, the Voltage
Comparator can be set into stand-by mode. This is done by setting
VCCTLn.VCEn = 0.
If the Voltage Comparator is set in stand-by mode it assumes that
V
CMPn
> V
LVI
(VCSTRn.VCFn = 1 and VCMPO0 = high level).
Logic
Block
+
-
V
LVI
V
CMPn
VCMPn
VCMPO0
INTVCn
VCSTRn.VCFn
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