How digital oscilloscopes measure the loss of switching power supply power
With the growing demand for switching power supplies in many industries, measuring and analysing the power loss of next generation switching power supplies is of paramount importance. In this application area, the TDS5000 or TDS7000 series digital fluorescence oscilloscopes, together with the TDSPWR2 power measurement software, can help you easily complete the required measurement and analysis tasks.
The new switching mode power supply (SMPS: Switch Mode PowerSupply) architecture, the need to have high data speeds and GHz-class processors to provide very high current and low voltage, which gives the power supply device designers in the efficiency, power density, reliability and cost of several aspects, adding invisible new pressure. In order to take these needs into account in the design, designers have adopted new architectures such as synchronous rectification, active power filter correction and increased switching frequency. These technologies also bring some higher challenges, such as higher power losses on the switching device, thermal dissipation and excessive EMI/EMC.
From the "off" (on) to "on" (off) state of the transition period, the power supply device will appear high power loss. (Switching devices in the "on" or "off" state have lower power losses because the current through the device or the voltage across the device is small). Inductors and transformers isolate the output voltage and smooth the load current. Inductors and transformers are also susceptible to switching frequencies, which can lead to power dissipation and occasional failure due to saturation.
Since the power dissipated in a switching power supply unit determines the overall efficiency of the thermal effect of the power supply, the determination of the power losses in the switching unit and inductor/transformer is an extremely important measurement. This measurement determines the power efficiency and thermal dissipation.
