Infineon Cypress PSoC 4500S Pioneer Kit, Manual

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Application Note 27 of 38 001-86233 Rev. *I
2021-11-04
PSoC™ 4 MCU low -power modes and power reduction techniques
Code examples
Get ADC reading
Convert to temp
Send out UART
UART
done?
Go into
deep sleep
WDT0
1 sec?
Ready to
trim ILO?
Trim
ILO
Reset
Trim ILO every
60th time through
the loop.
Make sure data is
totally sent before
going to sleep.
No
Yes
No
No
Yes
Yes
Init HDWR
Set up WDT0 for 1-
second wakeup
Figure 14 AN86233_DeepSleepADC program flow
7.3.3.1 Average power
To determine the average power of this example, you need to measure both the time and current in each mode,
assuming that the duty cycle between power modes is consistent. This period of the firmware is about 1
second. So, if you add up the time that the
PSoC™ 4 MCU device stays in Active and deep sleep modes in one
period, it would be about 1 second.
First, measure the current consumption and the time that the device stays in active mode. Figure 15 shows
that the duration in active mode is about 630 µs, and it consumes about 5000 µA (5.0 mA) during that time. You
can also see the UART communication in
Figure 15 and notice that the PSoC™ 4 MCU device does not return to
deep sleep until the UART has completed its transmission. The duration of the LED drive (active LOW) signal,
along with the current measurement, is used to determine whether the device is in active mode versus deep
sleep mode. In deep sleep mode, the current is about 3.5 µA, and the signal duration is about 999.4 ms.