Patented solution for measuring sleep / wake-up currents in ECUs
Based on its patent for the highly dynamic, uninterrupted, switching of two current measuring ranges (known from the Precision Current Analyzer – PCA), CGS has developed a cRIO module that can precisely determine the energy consumption of electronic control units with an implemented sleep/wake-up mode. This can considerably simplify the development or quality assurance of devices under test, e.g. keyless-go receivers that wake up briefly at regular intervals and then go to asleep again to conserve energy.
CGS cRIO IWPM (Intelligent Wake-Up Pulse Measurement) module is currently in the final development and testing phase. It will be available as 2 to 4-channel variants at the end of the first quarter. The sampling rate of the channels is 500 kHz in order to be able to measure the short wake-up pulses of a few µs duration precisely. By default, the two current measurement ranges are configured in a ratio of 1000:1, i.e. 10 mA for the wake current and 10 µA for the sleep current consumption. Switching between the two measurement ranges takes place in approx. 1 µs and thus ensures that no measuring data is lost. At market launch, decadic current measuring ranges from 10 µA to 1 A are available. In the future, individual measuring ranges will also be available on customer request.
For the internal calculation of the average current values in the FPGA, 16-bit accurate data is recorded. The IWPM outputs 4 values per channel: I1 (wake current), I2 (sleep current) and the associated time for both states, t1 and t2. If the supply voltage is known, the exact energy consumption of the DUT can be determined using the current measured values and the duration of wake-up pulses and sleep current, and therefore the battery run time can be optimized.
An additional trigger output per channel is also available. By using the IWPM, the DUT can be tested under real conditions without flashing a special firmware which disables the automated wake-up feature for testing purposes.