CHAPTER 12 A/D CONVERTER
202
User’s Manual U11302EJ4V0UM
12.5 A/D Converter Precautions
(1) Power consumption in standby mode
The A/D converter operates on the main system clock. Therefore, its operation stops in STOP mode or
in HALT mode with the subsystem clock. As a current still flows in the AV
REF
pin at this time, this current
must be cut in order to minimize the overall system power consumption.
In this example, the power consumption can be reduced if a low level is output to the output port in the
standby mode. However, the actual AV
REF
voltage is not so accurate and, accordingly, the converted
value is not accurate and should be used for relative comparison only.
Figure 12-8. Example of Method of Reducing Power Consumption in Standby Mode
V
DD
Output port
AV
REF
= V
DD
AV
SS
Series resistor string
AV
REF
PD780205
µ
Содержание mPD780204
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