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US 2018/0241351 A1Published application
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.
Claims21
A linear amplifier, comprising:
- a first stage amplifier circuit, comprising:
- two input transistors, for receiving a differential input signal to generate an amplified differential signal;
- a first circuit;
- a second circuit;
- and
- a switch module, for coupling the two input transistors to the first circuit or the second circuit;
- wherein at least one of a bandwidth and a gain of the linear amplifier when the two input transistors couple to the first circuit is different from the one of the bandwidth and the gain of the linear amplifier when the two input transistors couple 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.
Dependencies are inferred from the claim text.