Idd Measurement In Dynamic Run Mode; Calibration Procedure; Figure 19. Low Power Mode Idd Measurement Timing - ST STM32L476G-EVAL User Manual

Hardware layout and configuration
2.30.3

IDD measurement in dynamic run mode

In dynamic run mode, the IDD_CNT_EN remains high. The T2 is in conductive state, setting
the shunt resistor to 1 Ω. The U13 path from port 1 to 2 is permanently conductive and the
voltage on the capacitor C73 follows the MCU current consumption. R122 allows filtering
fast changes.
2.30.4

Calibration procedure

For the measurement to be precise, it is mandatory to perform a calibration before the
measurement. The calibration allows subtracting, from the voltage measured across C73,
the offset at the differential amplifier output, described in
The calibration procedure consists in measuring the offset voltage when the current through
the shunt resistor is zero. The current consumption values measured by the microcontroller
are then compensated for offset, by subtracting the now-known offset number from the
measured number. Setting the current through the shunt resistor to zero is reached through
appropriate setting jumpers in the JP11 jumper header.
58/100
All manuals and user guides at all-guides.com

Figure 19. Low power mode IDD measurement timing

DocID027351 Rev 3
UM1855
Section 2.30.1.