Overcurrent protection for an ink-jet printhead

摘要

A protection circuit prevents snapback events in MOS transistors associated with semiconductor or micromechanical structures, such as ink-jet ejectors. A bulk electrode associated with the MOS transistor is monitored for unusual high voltages which are consistent with an impending snapback event. The voltage on the bulk electrode is then used to turn on the control transistor which connects the gate of the MOS transistor to ground and thereby protects the device.