电流变压器DN-41 Design Note EXTEND CURRENT TRANSFORMER RANGE by PHILIP C. TODD Transformers are used extensively for current sensing because they can monitor currents with very low power loss and they have wide bandwidth for good waveform fidelity. Current transformers perform well in applications with symmetrical AC currents such as push-pull or full bridge converter topologies. In single-ended applications, especially boost converters, problems can arise because of the need to accurately reproduce high duty factor, unipolar, waveforms. Unipolar pulses may saturate the current transformer and, if this happens, over current protection will be lost and, for current mode control, regulation will be lost and an over voltage condition will result. The transformer core must be reset after each pulse so ……