Semiconductor protection against high energy transients

In a circuit having at least one avalanche-capable field-effect switching transistor having a conductive state and a nonconductive state, the transistors switching a system voltage across a load in series with the transistors, a method for protecting the transistors from transients in the system voltage, the method comprising the steps of:

• storing a digital signal representative of the level of a reference voltage;
• sensing the system voltage and developing an analog voltage representative of the level of the system voltage sensed;
• converting the analog voltage to a digital signal representative of the level of the system voltage sensed;
• processing the signal representative of the level of the system voltage sensed and the signal representative of the level of the reference voltage;
• generating, if the level of the system voltage represented by the former signal exceeds the level of the reference voltage represented by the latter signal, an output control signal;
• and
• switching into a state of conduction, with the output control signal, each transistor so that the system voltage, including any voltage transients, essentially appears entirely across the load.

A circuit having protection from system voltage transients, the circuit switching a system voltage across a load, the circuit comprising:

• a switching device including an avalanche-capable field-effect switching transistor and having a conductive state and a nonconductive state;
• means for generating a transient detection signal as a function of a transient appearing in the system voltage;
• and
• a microprocessor for processing the transient detection signal and providing an output control signal to the switching device to switch the switching device into its conductive state so that the system voltage, including any voltage transients, appears substantially entirely across the load.

In a circuit having at least one avalanche-capable field-effect switching transistor having a conductive state and a nonconductive state, the transistors switching a system voltage across a load in series with the transistors, a method for protecting the transistors from transients in the system voltage, the method comprising the steps of:

• comparing the system voltage to a reference voltage to detect a transient in the system voltage;
• generating a transient detection signal in response to detecting a transient;
• processing the transient detection signal to produce an output control signal in response thereto;
• and
• switching into a state of conduction, with the output control signal, each transistor so that the system voltage, including any voltage transients, appears substantially entirely across the load.

In a circuit having at least one avalanche-capable field-effect switching transistor having a conductive state and a nonconductive state, the transistors switching a system voltage across a load in series with the transistors, a system for protecting the transistors from transients in the system voltage, the system comprising:

• means for comparing the system voltage to a reference voltage to detect transients in the system voltage;
• means for generating a transient detection signal in response to detecting a transient;
• a microprocessor for processing the transient detection signal to produce an output control signal in response thereto;
• and
• means for switching into a state of conduction, with the output control signal, each transistor, so that the system voltage, including any voltage transients, appears substantially entirely across the load.