Circuit for reducing voltage stress across a transformer

摘要

Disclosed is a circuit for protecting a transformer from high voltages in those cases where a differential and a common mode output exist at the secondary of the transformer. The differential output is a load having a relatively small voltage thereacross; the common mode output is an output terminal connected to said load and having a relatively high voltage applied thereto. The present invention replaces the transformer with two or more smaller transformers cascaded together. A resistor is connected between the primary and the secondary of each transformer. Together the resistors form a voltage dividing network which splits the single high voltage among all of the transformers, relieving the stress on each. Optional capacitors are connected in parallel across each of the resistors in the case where the interwinding capacitances of the transformers are not equal. Each of the load and the output terminal can be either an a.c. or a d.c. component. If the load is a d.c. component, a rectifier/filter is inserted between the secondary of the last transformer in the chain and the load.