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Appendix A HOW TO MEASURE CURRENT CONSUMPTION
52
EPSON
S5U1C17801T1100 HARDWARE MANUAL
(SOFTWARE EVALUATION TOOL FOR S1C17801)
until being reset.
When this circuit is actually used for your circuit, a proper pull-down resistance value must be selected because the
value affects the current consumption of total system.
(When R21 = 100KΩ IR21= 33 μA approx., and when R21 = 500KΩ R21 = 6.6 μA approx.)
If you do not use battery backup function, input RTCV
DD to #STBY.
GPIO(P43)
RT
C
OSC1
IVRAM
#STBY
R21
(10k )
S1C17801
Fig. A.2 #STBY Related Circuit
A.2 Measuring AVDD Current Consumption
Current consumed by the power supply for ADC (AVDD) can be measured by inserting an ammeter into JP5.
Note that sample software (software flow) for measuring the current consumption, the software referred in the
S1C17801 Current Consumption Measurement Application Note does not control the AV
DD line.
A.3 Measuring RTCVDD Current Consumption
Current consumed by the power supply for IVRAM and RTC inside battery backup area (RTCVDD) can be
measured by inserting an ammeter into JP2.
When JP2 is measured between 2-3 pins, the voltage becomes 3.3V because RTCVDD is supplied from VDD
generated by regulator. When JP2 is measured between 1-2 pins, on the other hand, the voltage becomes 3.0V
because RTCV
DD is supplied from coin cell battery.
Note that sample software (software flow) for measuring the current consumption, the software referred in the
S1C17801 Current Consumption Measurement Application Note causes approximately 3 to 4
μA current to flow in
the RTCV
DD line.