Transistor power amplifier overload protector - is integrable on same substrate and consists of input shunting transistor switched by AND=gate connected to output and inverted input

摘要

The device consists of an inverter which takes in the signal input and provides the input to the power amplifier and a logic circuit. The circuit contains an anomaly detector connected to the signal input and the power amplifier output and a switched shunt across the power amplifier input. The power amplifier is an MOS transistor with input to its gate, and output from its drain with its source taken to ground. The anomaly detector consists of an inverter with a rise time greater than that of the first inverter and the power amplifier, connected to one input of an AND gate, the other gate input being connected to the drain of the power amplifier. The gate output is connected to the gate of an MOS transistor which shunts the power amplifier input, and to a latched input of an alarm circuit. The power amplifier and alarm and protection may be integrated on the same substrate.