Current protection is accomplished through the use of a regulating current loop, otherwise known as current mode. They can correct voltage, but they have no effect on power factor. They are a voltage source, they add or subtract. What is a high voltage box? The High Voltage Power Box combines the functionality of an Onboard Charger (OBC), a DC/DC converter and a PDU (Power Distribution Unit). It converts the energy from the network grid AC (Alternative Current). View the TI High-voltage power distribution box block diagram, product recommendations, reference designs and start designing. This handbook is dedicated to electricians and future electricians, and explains the contents of high and low voltage switchboards.