Characterizing switch-mode power supplies with an oscilloscope
Characterizing the operation of switch-mode power supplies requires a broad range of measurements using an oscilloscope. You must analyze the power supply's input, switching, and output. You will also need to make frequency response measurements like power supply rejection ratio (PSRR) and control loop response. These measurements are typically made with a vector network analyzer (VNA).
Perform these measurements using an oscilloscope with power measurement software, a deskew fixture, a high-voltage differential probe, a current probe, and a passive voltage probe. The deskew fixture nulls the difference in propagation delay between the probes for more accurate measurements. Deskewing is critical for the switching loss measurement. Time delay can cause significant differences in power and energy measurements during the turn-on and turn-off phases of transistor switching.
Switch-mode power supply characterization solution
Characterizing a switch-mode power supply requires deskewing to equalize the time delay between probes. The Keysight InfiniiVision 4000 X-Series oscilloscope, paired with power analysis software, enables quick power measurements using differential and current probes calibrated by a deskew fixture. The U1880A power measurement deskew fixture deskews the time delay between voltage and current, driving both probes with the same pulse signal.
DSOX4WAVEGEN2 WaveGen Built-in Dual-chan Function and Arbitrary Waveform Generator for 4000 X-Series Oscilloscopes
You can use the built-in waveform editor to create custom waveforms to output on the WaveGen of the scope. You can also capture a known good or golden waveform on a scope channel and save that to the ARB and generate it through BNC output.