Frequency compensation in two stage operational amplifier using common gate stage

Raj, Aditya; Yadav, Ravi; Akashe, Shyam

doi:10.1109/iccn.2015.31

Cited by 3 publications

(1 citation statement)

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“…What's more, the gainbandwidth (GBW) of two-stage SMC amplifiers is one-half of that of single-stage amplifiers [27]. To solve the problem of RHP zero in the two-stage SMC amplifier, several techniques have been proposed in the past years [28]- [34]. For example, the scheme called single Miller compensation with a nulling resistor (SMCNR) which can reduce the current flowing through feedforward path by connecting a nulling resistor in series with the miller capacitance was proposed in [12].…”

Section: Introductionmentioning

confidence: 99%

A High Current Efficiency Two-Stage Amplifier With Inner Feedforward Path Compensation Technique

et al. 2020

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A high current efficiency two-stage amplifier with inner feedforward path compensation (IFPC) technique is proposed in this paper. To improve the current utilization of the whole structure, the recycling folded cascode amplifier (RFC) is adopted as the first stage, and the inner feedforward path which is used to eliminate the non-dominant pole is composed of the input stage of RFC and the tail current transistor of the second stage amplifier. By using the IFPC technique, the proposed amplifier achieves an extended gain-bandwidth (GBW) and sufficient phase margin (PM) compared to that of the two-stage amplifier using single Miller compensation (SMC). Moreover, this compensation technique avoids extra power consumption since it does not require additional circuits. The proposed two-stage IFPC amplifier was fabricated in a 0.18 µm CMOS technology and the chip area of it is about 0.076mm 2. The simulated open loop AC response shows the DC gain, GBW, and PM are 130dB, 2.01MHz, and 58.3 • , respectively. Measured results of transient response show when driving a 120pF load capacitance, the proposed amplifier achieves 368ns average 1% settling time, and about 1.56V/µs average slew rate (SR). Note that under the condition of 1.8V power supply, the power consumption is only 108µW , proving the proposed two-stage IFPC amplifier can achieve high current efficiency while maintaining stability. INDEX TERMS Two-stage amplifier, current efficiency, frequency compensation, inner feedforward path.

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