So the idea seems to be to measure over a large dynamic range without auto-ranging? The point being to accurately measure the power consumption of microcontroller/microprocessor that is switching between standby/sleep/full power modes.
The patent link appears to require a plugin I don't have, so I don't know how agilent does this. One approach is to simply brute force dynamics range by using low offset, low leakage amplifiers and high resolution ADCs. This is probably the best way to do it if you want the best possible linearity and accuracy. Clever ways to do this would be with logarithmic converters or analog charge integrators. Logarithmic converters have amazing dynamic range but mediocre accuracy. Charge integrators can give you good accuracy but don't tell you the instantaneous current waveform, only the total energy used in a defined integration period.
Another possibility might be to have multiple ranges amplified digitized in parallel, and have software pick the one that is most accurate for any given conversion point.
hi and thanks. that is almost what im thinking about.
the task is to measure a wireless sensor current while in sleep/work modes accurately, but i not shure do i need emulate seamless technology or similar.
Sensor power goes from 0 to 5V and the peak current 100mA. So, yes we need accurately measure a 0-100mA range with great accuracy in standby time.
now im thinking of an like a BeagleBoard-xM addon board with an 1-4Msps 18bit Analog Device(or TI) ADC with level translators, wich goes directly to the microSD (brute force logger) + ethernet => matlab(gui or just get() function).
the point is: do i need like uCurrent like circuit with the ADC's in parralel with the 2 channels 1-100ma and 0-1ma ranges and then let the matlab do it job ?
if so, can i work with this adc's with 48mhz spi master from the board (will it be fast enough) ?