An overvoltage protection controller has been developed by Linear Technology Corp. Operating from 9V to greater than 500V, the LTC4366 floating surge stopper utilises an adjustable floating topology to enable very high voltage operation independent of the voltage rating of the internal circuitry. 

Two internal shunt regulators coupled with the external voltage-dropping resistors generate the internal supply rails. The maximum operating voltage is set by a breakdown of the external resistors and MOSFETS.

The device is claimed to be the first product of its kind to protect, for example, a 12V circuit from a 500V transient without the need for additional protection components.

The device monitors the voltage at its output and reacts quickly to input supply overvoltage by controlling the gate of an N-channel MOSFET. 

It regulates the output to a user-defined voltage during an overvoltage transient allowing the load to remain operational while the overvoltage is dropped across a MOSFET. An adjustable fault timer ensures safe shutdown if the fault persists.

The controller comes in eight-lead TSOT-23 and 3mm by 2mm DFN packages.

During operation, the entire circuit consumes only a few milliamperes, and the device may be shut down to less than 20µA conserving power usage.

Linear Technology Corp.