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Amplifier and class AB amplifier

A technology of amplifiers and transistors, applied in amplifiers, power amplifiers, improved amplifiers to improve efficiency, etc., can solve problems such as inability to fully amplify the full wave

Active Publication Date: 2009-09-02
MEDIATEK INC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the output waveform of a class B amplifier, the waveform of the first half cycle or the second half cycle may be truncated, so the full wave cannot be fully amplified

Method used

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  • Amplifier and class AB amplifier
  • Amplifier and class AB amplifier
  • Amplifier and class AB amplifier

Examples

Experimental program
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Embodiment Construction

[0011] figure 1 It is a schematic diagram of an embodiment of the amplifier of the present invention. Such as figure 1 As shown, the amplifier 100 includes an input transistor 110, an impedance unit 120, a current source 130, a push-pull output circuit 140, and a level conversion unit 150.

[0012] The input transistor 110 receives the input voltage Vin+. In this embodiment, the input transistor 110 is an NMOS transistor, its gate receives the input voltage Vin+, its drain is coupled to the impedance unit 120 at a node, and its source is coupled to the current source 130. The voltage of the node is the voltage V1, where the voltage V1 is the intermediate voltage generated by the input transistor 110.

[0013] The impedance unit 120 is coupled to the input transistor 110. In this embodiment, the impedance unit 120 is an NMOS transistor 121. The gate of the NMOS transistor 121 receives the voltage Vbn2, the drain thereof receives the voltage VDD (such as the supply voltage), and ...

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PUM

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Abstract

The invention provides an amplifier and a class AB amplifier. The amplifier comprises a first input transistor, a first impedance unit, a current source, a first push-pull output circuit and a first level shifting unit. The first input transistor receives a first input voltage. The impedance unit is coupled to the first input transistor. The current source is coupled to the first input transistor. The push-pull output circuit comprises a first PMOS transistor and a first NMOS transistor which are connected in series to output a first output voltage. The first input transistor is coupled to a control terminal of the first NMOS transistor. The level shifting unit is used for shifting a voltage of the first input transistor and providing a first shifted voltage to the PMOS transistor. The inventive amplifier and class AB amplifier are capable of amplifying an input signal in full wave to keep high power efficiency while eliminating crossover distortion.

Description

Technical field [0001] The present invention relates to an amplifier, in particular to an amplifier and a class AB amplifier. Background technique [0002] Power amplifiers can be classified into Class A, B, C, and AB amplifiers according to their different operating points. Class A amplifier has the best signal facsimile (almost no distortion of the voltage waveform). When the class A amplifier has not received the input signal, there is still current flowing at its output end. Therefore, the power efficiency (Power Efficiency) of the class A amplifier is only about 20% to 30%. The power efficiency of Class B amplifiers can reach 75%. In the output waveform of the Class B amplifier, the waveform of the first half or the second half of the cycle may be truncated, so the full wave cannot be fully amplified. Class AB amplifiers combine the advantages of Class A amplifiers and Class B amplifiers. The power efficiency of Class AB amplifiers is greater than that of Class A amplifiers....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H03F3/21H03F1/02H03F1/32
CPCH03F3/3022H03F2203/45668H03F3/45183H03F2203/30117H03F2203/30084
Inventor 林育信廖学坤
Owner MEDIATEK INC
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