Hello,
My project is based on _twr_emeter_demo(old one with KM34 128 series).
I can see a document: DRM143 Kinetis-M One-Phase Power Meter Reference Design.
Here is the question details.
Does U_MAX and I_MAX come from this schematic?
Then U_MAX should be 325.26V as it mentioned?
However, on page 25, it mentioned:286V not 325.26V.
I am not sure which value is correct one.
If my circuit use smaller register values such as two 150 Kohm instead of four 150 Kohm, then U_MAX value should be changed? then how?
There is no note about I_MAX though. Anyone know how to pick the value?
Thanks,
Hyunwoo
- page 25,
- page 13,
The U_MAX has two factors could affect that value, one is the meter AC_DC SMPS related circuit design, which should match with the meter spec design requirement, the other one to meet the current measurement requirement.
The I_MAX value is based on hardware design and the ADC measure range (VREFH voltage), the ADC measurement value should not exceed the measure range to make current value in a range. The hardware schematics (shunt resistor value) also affect the I_MAX value, which also affect the U_MAX value.
Wish it helps.
Have a great day,
Ma Hui
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