Dynamic safe operating area control

A method of dynamically maintaining operation of a transistor within a safe operating area, the method comprising:

• employing the transistor to control delivery of electrical power from a power source to a load;
• detecting a differential signal and controlling operation of the transistor to produce variations in resistance of the transistor to offset the differential signal;
• sensing an instantaneous current through the transistor and an instantaneous voltage across the transistor;
• generating a representation of thermal energy being added to the transistor from the circuit based on the sensed instantaneous current and sensed instantaneous voltage;
• generating a representation of a thermal response of the transistor to the representation of thermal energy dissipated in the transistor;
• and
• when the representation of the thermal response of the transistor meets predetermined criteria, controlling at least one of the current through the transistor or the voltage across the transistor.

A method comprising:

• extracting thermal characteristics of a transistor;
• providing a system having characteristics based upon the derived thermal characteristics of the transistor;
• using the transistor in a circuit;
• detecting a differential signal and controlling operation of the transistor to produce variations in resistance of the transistor to offset the differential signal;
• determining a current carried by the transistor and a voltage across the transistor;
• stimulating the system using information produced from the determined current or voltage;
• and
• controlling operation of the transistor as a function of a response by the system to the stimulation.

A method comprising:

• providing transistor for use in a circuit;
• detecting a differential signal and controlling operation of the transistor to produce variations in resistance of the transistor to offset the differential signal;
• sensing the voltage and current stresses on the transistor during operation in the circuit;
• modeling instantaneous temperature conditions in the transistor;
• and
• controlling operation of the transistor as a function of the instantaneous temperature conditions.

A method of dynamically maintaining operation of a power transistor within a safe operating area (SOA), the method comprising:

• sensing input signals including an instantaneous current through the power transistor and an instantaneous voltage across the power transistor;
• generating a first signal based on the instantaneous current and instantaneous voltage sensing,
• filtering the first signal to produce a second signal, the filtering having a response that includes the characteristics of at least one zero and at least one pole;
• controlling at least one of the instantaneous current through the power transistor or the instantaneous voltage across the power transistor in response to the second signal from the filtering.