Protection
The most common form of SOA protection used with bipolar junction transistors senses the collector-emitter current with a low-value series resistor; the voltage across this resistor is applied to a small auxiliary transistor that progressively 'steals' base current from the power device as it passes excess collector current.
This approach is effective but not bullet-proof. In practice it is very difficult to design a protection circuit that will work under all conditions, and it is left up to the design engineer to weigh the likely fault conditions against the complexity and cost of the protection.
Read more about this topic: Safe Operating Area
Famous quotes containing the word protection:
“As Jerome expanded, its chances for the title, “the toughest little town in the West,” increased and when it was incorporated in 1899 the citizens were able to support the claim by pointing to the number of thick stone shutters on the fronts of all saloons, gambling halls, and other places of business for protection against gunfire.”
—Administration in the State of Ariz, U.S. public relief program (1935-1943)
“Freedom of religion, freedom of the press, and freedom of person under the protection of habeas corpus, and trial by juries impartially selected. These principles form the bright constellation which has gone before us, and guided our steps through an age of revolution and reformation.”
—Thomas Jefferson (1743–1826)
“The protection of a ten-year-old girl from her father’s advances is a necessary condition of social order, but the protection of the father from temptation is a necessary condition of his continued social adjustment. The protections that are built up in the child against desire for the parent become the essential counterpart to the attitudes in the parent that protect the child.”
—Margaret Mead (1901–1978)