UM-B-114
DA14531 Development Kit Pro Hardware User Manual
User Manual
Revision 1.4
23-Apr-2020
43 of 82
© 2021 Dialog Semiconductor
8
Current Measurements
Current drawn from the DA14531 PRO-DB can be measured with a good accuracy by using the
current sensing circuit and the power profiler of
Dialog’s SmartSnippets Toolbox.
In this section, the current measurement circuit as well as the setup and the measurements of the
power profiler are described, and the measurement accuracy is presented.
8.1
Current Measurement Circuit of PRO-MB
Figure 36: Current Measurement Circuit of DA14531 PRO-MB
Current measurement circuit is a section of the PRO-MB. The input to the circuit is the voltage across
the sense resistor (R28). The output is the differential pair VINP, VINN which are connected to the
inputs of the A/D converter.
The functional blocks of the current measurement circuit include:
●
Sense resistor R28 (2.37
Ω)
●
High scale C/V converter (Gain: 9.98 V/mA)
●
Low scale C/V converter (Gain: 4989 V/mA)
●
High/Low comparator: switches to high scale above ~300
μΑ and back to low scale below ~250
μA (with hysteresis)
●
Voltage buffers. The V
SS
pin gets a -228 mV rail to allow the output to reach true zero
●
Analog multiplexers: the low scale output is presented to the A/D converter with a negative
polarity
●
Single-ended to differential converter: it converts the ground referenced input to a differential pair
aligned with the mid-scale reference voltage (V
REF
= 2.5 V) and a gain of ±0.5
