Power amplifier capable of switching gain while suppressing noise power in reception band
First Claim
1. A power amplifier having first and second modes as operation modes, comprising:
- a first amplifying element which amplifies an input signal in said first mode and is set in an inactive state in said second mode;
a second amplifying element for further amplifying an output of said first amplifying element in said first mode and amplifying said input signal in said second mode; and
a transmission circuit performing a first operation of blocking transmission of said input signal to said second amplifying element in said first mode and a second operation of transmitting said input signal to said second amplifying element in said second mode, and switching said first and second operations in accordance with a mode setting signal.
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Accused Products
Abstract
An amplification part of a power amplifier includes first to third amplifier stages and a signal transmission part provided in parallel with the first amplifier stage. When a mode select voltage Vmod2 is set to the L level, an input signal is amplified by the first to third amplifier stages. At this time, the signal transmission part does not transmit signals. On the other hand, when mode select voltage Vmod2 is set to the H level, the signal transmission part transmits the input signal to a transistor via a diode. At this time, a control voltage Vmod1800 is set to the L level, and the first amplifier stage is turned off, so that power consumption is reduced. Thus, a power amplifier capable of switching a gain in accordance with GSM/EDGE modes while suppressing noise power in a reception band can be provided.
20 Citations
13 Claims
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1. A power amplifier having first and second modes as operation modes, comprising:
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a first amplifying element which amplifies an input signal in said first mode and is set in an inactive state in said second mode;
a second amplifying element for further amplifying an output of said first amplifying element in said first mode and amplifying said input signal in said second mode; and
a transmission circuit performing a first operation of blocking transmission of said input signal to said second amplifying element in said first mode and a second operation of transmitting said input signal to said second amplifying element in said second mode, and switching said first and second operations in accordance with a mode setting signal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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Specification