Power amplifier circuit
AssigneeMurata Manufacturing Co., Ltd.
InventorYuri Honda
Life of this patent
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Abstract
A power amplifier circuit includes a first amplifier that operates in accordance with a first voltage supplied from a voltage supply source, amplifies a first signal, and outputs an amplification signal, a bias transistor that includes a base or a gate to which a bias control current is supplied and an emitter or a source supplying a bias to the first amplifier through a first resistor element, and a protection circuit that causes part of the bias control current to flow to a ground on the basis of the amplification signal and a second signal based on the first voltage.
Claims17
A power amplifier circuit comprising:
- a first amplifier configured to operate in accordance with a first voltage supplied from a voltage supply source, to amplify a first signal, and to output an amplification signal;
- a bias transistor that has a base or a gate to which a bias control current is supplied, and an emitter or a source configured to supply a bias to the first amplifier through a first resistor;
- and
- a protection circuit configured to cause part of the bias control current to flow to ground based on the amplification signal and a second signal based on the first voltage,
- wherein the protection circuit comprises:
- a first transistor that has a base or a gate connected to ground via a first capacitor, and an emitter or a source to which the amplification signal is input through a second capacitor;
- and
- a second transistor that has a collector or a drain connected to the base or the gate of the bias transistor, a base or a gate connected to the emitter or the source of the first transistor, and an emitter or a source connected to ground,
- wherein the second capacitor has a first end connected to a connection node between a second inductor and a third inductor and a second end connected the second transistor, and
- wherein the emitter or source of the second transistor is connected to ground.
A power amplifier circuit comprising:
- a first amplifier configured to supply power to a load;
- a bias transistor that has a base or a gate to which a bias control current is supplied, and an emitter or a source configured to supply a bias to the first amplifier through a first resistor;
- a protection circuit configured to cause part of the bias control current to flow to ground based on a third signal based on a change in the load;
- a first differential pair that comprises a second amplifier and a third amplifier, and that is in a stage subsequent to the first amplifier;
- a first clamp circuit that is between an output terminal of the second amplifier and ground, and that comprises a second diode;
- and
- a second clamp circuit that is between an output terminal of the third amplifier and ground, and that comprises a third diode,
- wherein the third signal is output from a cathode of the second diode and a cathode of the third diode.
Dependencies are inferred from the claim text.