Current-mode pseudo-exponential-control variable-gain amplifier using fourth-order Taylor's series approximation

Arthansiri, T.; Kasemsuwan, Varakorn

doi:10.1049/el:20060083

Cited by 26 publications

(7 citation statements)

References 6 publications

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“…However, designing an AGC system based on the current VLSI circuit approach is limited in that MOS transistors are designed to operate in saturation mode, which is a characteristic of the square law function. This work designs a novel VGA by applying an estimation method of a pseudo-exponential function developed earlier [1]- [3] and shown as Eq. (1).…”

Section: Variable Gain Amplifiermentioning

confidence: 99%

A Hearing-Aid Front-End Circuit Based on Low Power and Low Area Mix Mode Agc

Wang¹,

Ho²,

Tseng³

et al. 2010

Biomedical Engineering

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This work develops automatic gain control (AGC) system based on a low power and low area mix mode for the front-end circuitry of a hearing aid. By incorporating a direct feedback method for the sigma-delta modulator output without a decimation filter, the proposed AGC system can reduce the chip area, latency and system power consumption. Additionally, an operational transconductance amplifier (OTA) based on an inverter structure of the CMOS transistor is developed to design a sigma-delta modulator in order to decrease system power consumption. Moreover, a novel algorithm is also developed by rectifying the output bit stream of the sigma-delta modulator to detect the average waveform of the proposed AGC system. The proposed AGC system is implemented using TSMC 0.18 μm CMOS technology with an IC chip area of 600×680 μm 2. Furthermore, the system power consumption is 42.3 μW with a DC supply voltage of 1 V. Measurement results verify that the proposed system can implement an IC chip that capable of providing a digital output signal of 6 bits, which is feasible for hearing aid systems.

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Section: Variable Gain Amplifiermentioning

confidence: 99%

A Hearing-Aid Front-End Circuit Based on Low Power and Low Area Mix Mode Agc

Wang¹,

Ho²,

Tseng³

et al. 2010

Biomedical Engineering

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“…where g m5, 6 is the transconductance of M5 and M6, R deg is MOS degeneration resistance. In order to reduce the error in the linear-in-dB gain characteristic and improve the linearity, the resistance of the MOS resistor must be set much larger than 1/g m5, 6 .…”

Section: Vga Architecturesmentioning

confidence: 99%

“…In order to reduce the error in the linear-in-dB gain characteristic and improve the linearity, the resistance of the MOS resistor must be set much larger than 1/g m5, 6 . Transconductance boosting circuits are normally used to enhance the transconductance of the input drivers [10], but it might limit the bandwidth and cause stability issues.…”

Section: Vga Architecturesmentioning

confidence: 99%

“…In recent CMOS-based VGA designs, dB-linear gain variation characteristics are realized by the circuit implementations of rational expressions (pseudo-exponential) [2][3][4] and Taylor series approximation functions [5,6]. In order to realize wide dB-linear range, high order approximation must be adopted.…”

Section: Introductionmentioning

confidence: 99%

“…In order to realize wide dB-linear range, high order approximation must be adopted. A fourth-order Taylor series approximation is proposed in [6] to realize a 30 dB-linear range within 0.5-dB error, which used four four-quadrant current-mode multipliers. Similarly, a second-order rational expression is present in [4], and about 60 dB-linear is realized.…”

Section: Introductionmentioning

confidence: 99%

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A low-distortion CMOS IF VGA with linear-in-dB control and temperature compensation

Yun

Yin

Huang

et al. 2007

Analog Integr Circ Sig Process

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A CMOS intermediate-frequency (IF) variablegain amplifier (VGA) is presented in this paper. A transconductance linearization scheme is proposed for the VGA core based on a signal-subtracting structure to achieve low distortion. Temperature-independent decibel-linear gain control characteristic is achieved by an exponential voltage generator based on transfer characteristics of differential pair. The whole VGA, including a highly-linear output stage, is fabricated in 0.25 µm CMOS technology. Measurements show that the VGA provides a total gain control range of 43 dB with less than 1.2 dB error over 0-80 • C, and a constant 3-dB bandwidth of 100 MHz. The third-order intermodulation (IM3) distortion at differential output of 2 V PP is better than − 55 dB. The VGA dissipates 22.6 mA averagely from 3.3 V supply, and occupies approximately 0.53 mm 2 .

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An integrated LNA‐phase shifter in 65 nm CMOS for Ka‐band phased‐array receivers

Liu,

Guo,

Han

et al. 2023

Circuit Theory & Apps

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SummaryIn this paper, a vector‐sum phase shifter (VSPS) integrated with a wideband high‐gain low‐noise amplifier (LNA) for Ka‐band phased‐array receivers is presented. The digitally controlled VSPS based on the RF phase shifting architecture consists of a modified I/Q signal generator with additional inductor resonance and a programmable variable gain amplifier (VGA) based on Four 3 × 4 transistor arrays. Besides the reduced parasitic effect of the I/Q signal generator, an Equidistant Contraction Technology (ECT) is used in the VGA, to maintain higher phase shift accuracy of the VSPS. A multistage LNA with series inductor peaking is adopted to fulfill the flat wideband gain, where LC resonance networks are used as interstage matching to compensate for gain roll‐off at a higher frequency. Based on simulations in 65 nm CMOS technology, the presented LNA‐Phase shifter has achieved an average NF of 3.24–3.66 dB, and an average gain of 13.1–23.6 dB. Moreover, an RMS phase error of 1.1–12.6°, an RMS gain error of 4.2–5.6 dB, and an RMS magnitude error of 2.1–2.8 dB are maintained across 27–40 GHz, with a 360° phase shift coverage in steps of approximately 2.8125°. The chip consumes 16.83 mW from a 1.2 V supply voltage, and the occupied area is 0.65 mm2.

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Current-mode pseudo-exponential-control variable-gain amplifier using fourth-order Taylor's series approximation

Cited by 26 publications

References 6 publications

A Hearing-Aid Front-End Circuit Based on Low Power and Low Area Mix Mode Agc

A Hearing-Aid Front-End Circuit Based on Low Power and Low Area Mix Mode Agc

A low-distortion CMOS IF VGA with linear-in-dB control and temperature compensation

An integrated LNA‐phase shifter in 65 nm CMOS for Ka‐band phased‐array receivers

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