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US 10,608,592 B2Granted
Linear amplifier having higher efficiency for envelope tracking modulator
AssigneeMediatek Inc.
InventorsChen-Yen Ho, Yu-Hsin Lin
Life of this patent
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Abstract
A linear amplifier is provided to have higher efficiency for an envelope tracking modulator. In one embodiment, a first stage amplifier circuit can be simply operated in a high gain mode or a high bandwidth mode for different applications, without using large chip area. In another embodiment, an output stage has a cascode structure whose dynamic range is controlled according to a voltage level of a supply voltage, to make a core device within the output stage have better protection and suitable dynamic range.
Claims20
A linear amplifier, comprising:
- a first stage amplifier circuit, comprising:
- input circuits, for receiving differential input signals to generate amplified differential signals;
- a first circuit;
- a second circuit;
- and
- a switch module, for coupling the input circuits to only one of the first circuit and the second circuit, wherein the input circuits are not coupled to the first circuit and the second circuit simultaneously;
- wherein the input circuits are coupled to only one of the first circuit and the second circuit, and at least one of a bandwidth and a gain of the linear amplifier when the input circuits are coupled to the first circuit is different from the one of the bandwidth and the gain of the linear amplifier when the input circuits are coupled to the second circuit.
4 more elements
A linear amplifier, comprising:
- at least one amplifier circuit, for receiving an differential input signal to generate a differential driving signal;
- and
- an output stage, coupled to the amplifier circuit and supplied by a supply voltage, for generating an output signal according to the differential driving signal, wherein the output stage has a cascode structure whose dynamic range is controlled according to a level of the supply voltage;
- wherein the differential driving signal comprises a first driving signal and a second driving signal, and the output stage comprises:
- a first cascode circuit, comprising:
- a first output transistor, coupled to the supply voltage, for receiving the first driving signal;
- and
- a first buffer transistor, coupled between the first output transistor and an output node of the output stage;
- and
- a second cascode circuit, comprising:
- a second output transistor, coupled to a ground voltage, for receiving the second driving signal;
- and
- a second buffer transistor, coupled between the second output transistor and the output node of the output stage.
10 more elements
Dependencies are inferred from the claim text.