Compact Battery Power Source for Oscilloscope

Abstract

A battery DC power source for a small oscilloscope was designed and constructed. Its output voltage is ca. 300 V and its output power is about 60 W. A series-resonant DC/DC converter with a pulse transformer is the core of this device. The source is supplied from a Li-ion battery with nominal voltage of ca 3.6 V (several cells connected in parallel). It is often necessary in power electronics measurements to have a galvanically separated supplying of the oscilloscope. A mains power supply with low parasitic capacitance is sometimes used but for some special measurements even this small capacitance (e.g., 50 pF) is too high. The battery supplied power source can achieve a lower capacitance. Certainly the possibility to use the oscilloscope without available mains power is advantageous.