High-bandwidth high-swing linear amplifier applied to envelope tracking power supply modulator

Abstract

The invention belongs to the field of integrated circuit design, and particularly relates to a high-bandwidth high-swing linear amplifier applied to an envelope tracking power supply modulator. The linear amplifier includes a bias circuit, an amplifier circuit, and a compensation circuit. The bias circuit is composed of a bias current selection module and a bias module. The first stage of the amplifier circuit is a rail-to-rail input folded cascode transconductance amplifier, and the second stage of the amplifier circuit is a Class-AB type amplifier. The compensation circuit adopts two compensation modes of CASCODE miller compensation and feedforward compensation. The Miller compensation capacitor realizes separation of primary and secondary poles. The feed-forward compensation capacitor can provide a feed-forward path for high-frequency signals, the bandwidth is expanded, and the high-frequency performance of the amplifier is improved. In addition, the feedforward compensation capacitor can solve the problem of high-frequency oscillation caused by packaged inductance introduced into the output end of the power supply modulator. And the Class-AB type output stage adopts a core tubeand I / O tube superposed structure. The linear amplifier can achieve tracking of envelope signals of LTE-100M at most, and the following dynamic range reaches 0.5 V-3V.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, and in particular relates to a linear amplifier applied to an envelope tracking power supply modulator. Background technique [0002] With the rapid growth of the data transmission rate required by the wireless communication system, the spectrum resources are increasingly scarce. In order to improve the spectrum utilization, the wireless communication signal begins to adopt a modulation method with higher spectrum efficiency, and the signal modulation develops from the original constant envelope modulation to With complex variable envelope modulation, the bandwidth of the envelope signal and the peak-to-average power ratio (PAPR) continue to increase. A radio frequency power amplifier (RFPA) system powered by a constant supply voltage degrades significantly as the signal PAPR increases. Envelope tracking (ET) technology is an effective means to improve the efficiency of power amplifi...

AI Technical Summary

Problems solved by technology

Although the linear amplifier only provides a low proportion of high-frequency energy, since the linear amplifier is a relatively low-efficiency module in the entire power modulator, the linear amplifier needs to pay more when tracking the signal envelope with higher bandwidth and larger amplitude. Therefore, in order to improve the efficiency of tracking the signal envelope of different bandwidths, the efficiency improvement of the linear amplifier is also very important

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