Power amplifier
AssigneeTokyo Shibaura Denki Kabushiki Kaisha
InventorsMinoru Ooishi, Teruji Mochizuki, Yutaka Suzuki
Life of this patent
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Abstract
A power amplifier which has a muting circuit bringing the power amplifier into a muting condition when an excessively large input signal is applied. The power amplifier comprises a preamplifying stage and a power amplifying stage. The preamplifying stage includes at least one transistor for driving the power amplifying stage. The collector of the transistor is coupled to one power source terminal. The emitter of the transistor is coupled to the other power source terminal through an electronic switch, and to the first power source terminal through a resistor. The electronic switch selectively connects the emitter of the transistor to one of the power source terminals.
Claims12
A power amplifier comprising:
- an input circuit means;
- a power supply having first and second power source terminals;
- a preamplifying stage having at least one transistor with first, second and third electrodes, said first electrode being connected to said input circuit means;
- a resistance load, said second electrode being connected to said first power source terminal through said resistance load, and said third electrode being connected to said second power source terminal;
- a power amplifying stage connected at its input to said second electrode of said at least one transistor;
- an electrode switch means connected between said third electrode of said at least one transistor and said second power source terminal, and having a control terminal;
- resistance means connected between said third electrode of said at least one transistor and said first power source terminal, in parallel with said at least one transistor and said resistance load;
- and
- control circuit means connected to said control terminal of said electronic switch means for applying a muting signal to said electronic switch means in the event excessive input signals are applied to the power amplifier or overloading occurs to prevent damage to the power amplifier.
Dependencies are inferred from the claim text.