How to Measure the Power Loss of Switching Power Supplies with an Oscilloscope
With the increasing demand for switch mode power supplies in many industries, measuring and analyzing the power loss of the next generation of switch mode power supplies has become crucial. In this application field, the TDS5000 or TDS7000 series digital fluorescence oscilloscopes, combined with TDSPWR2 power measurement software, can help you easily complete the required measurement and analysis tasks.
The new switch mode power supply (SMPS) architecture requires high current and low voltage to be provided to processors with high data speed and GHz level, which adds intangible new pressures on power device designers in terms of efficiency, power density, reliability, and cost. In order to consider these requirements in the design, the designers adopted new architectures such as synchronous rectification technology, active power filtering correction, and increased switching frequency. These technologies also bring higher challenges, such as higher power losses, thermal dissipation, and excessive EMI/EMC on switch devices.
During the transition from "off" (conducting) to "on" (shutting down) state, the power supply device will experience high power loss. The power loss of switch devices in the "on" or "off" state is relatively low because the current passing through the device or the voltage on the device is small. Inductors and transformers can isolate the output voltage and smooth the load current. Inductors and transformers are also susceptible to the influence of switching frequency, leading to power dissipation and occasional faults caused by saturation.
