A low-noise amplifier with automatic gain control and anticlipping control in CMOS technology

Hauptmann, J.; Dielacher, Franz; Steiner, Reto; Enz, Christian; Krummenacher, F.

doi:10.1109/4.142591

Cited by 28 publications

(23 citation statements)

References 6 publications

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“…Prior works on AGCs have mainly focused on either digital or analog approach [1][2][3][4][5][6][7] for low power implementation. The digital implementation [1] is capable of complex control and offers maximum flexibility.…”

Section: Introductionmentioning

confidence: 99%

“…In a contrast, the gain transition in an analog implementation is continuous and smooth during the sound compression. Categorically, the analog implementation may be realized in two ways: one is to vary the trans-conductance of the closed (the seriesseries feedback) or open loop operational amplifier (op-amp) [2][3][4], while the other is to adjust the shunt-shunt feedback coefficient of the operational trans-conductance amplifier (OTA) by adopting the MOS resistive circuit (MRC) [5][6][7]. However, it has been found that the total harmonic distortion (THD) in such designs usually degrades considerably with the output swing being increased, as reported in [2][3][4][5][6][7], where the THD higher than -46 dB was measured for the output swing equal to 500 mV p-p .…”

Section: Introductionmentioning

confidence: 99%

“…This is because the way to minimize the THD in the case is usually by increasing the op-amp trans-conductance, inevitably at the cost of extra power. Although employing an MRC feedback network could lead to lower power and higher gain [5][6][7], the nonlinearity caused by the MRC (referring to Fig. 1(a)) should get worse in terms of THD.…”

Section: Introductionmentioning

confidence: 99%

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Dual-mode gain control for a 1 V CMOS hearing aid device with enhanced accuracy and energy-efficiency

Yang

Liu

et al. 2012

Analog Integr Circ Sig Process

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A dual-mode gain control (DMGC) technique is presented for accurate and energy-efficient pre-amplification in the front-end system of a hearing aid chip. Compared with the conventional automatic gain control (AGC) approach, the DMGC approach is characterized by an amplification switching mechanism between the prolinearity discrete gain setting mode and the energy-efficient AGC mode. Thus, the total harmonic distortion (THD) should be significantly improved without incurring any degradation concerning other performances parameters (e.g. gain, noise and power consumption). In order to further enhance the system power efficiency, a self currentadapting (SCA) circuit design technique is proposed. Such SCA circuits are capable of automatically adjusting the bias current in accordance with the sound level. A prototype chip was designed with a 0.13 lm standard CMOS process and tested with 1 V supply voltage. The measurement results show that, for a typical output level of 500 mV p-p , the THD is somewhere below -64 dB, achieving approximately ten times reduction compared to the previously reported works. The power consumption of less than 45 lW has also been obtained. In addition, the typical input referred noise is only 2 lV rms and the maximum gain attainable is up to 39 dB.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dual-mode gain control for a 1 V CMOS hearing aid device with enhanced accuracy and energy-efficiency

Yang

Liu

et al. 2012

Analog Integr Circ Sig Process

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show abstract

“…The capacitance value of is also much smaller (20 versus 200 fF). Finally, we can obtain the overall gain of the circuit given by (11) The gain also has a peaking point around the zero frequency and the bandwidth of the circuit can be improved.…”

Section: B Vga Circuitmentioning

confidence: 99%

“…One is to build a discrete gain step VGA with a digital control signal [8]- [10], and the other is to build a continuous VGA controlled by an analog gain control signal [1]- [7]. In general, digitally controlled VGAs use binary weighted arrays of resistors or capacitors for gain variations [11] and analog VGAs adopt a variable transconductance or a variable resistance to control the gain. For a code division multiple access (CDMA) system requiring a power control range larger than 80 dB, the VGA with continuously variable gains is preferred because it avoids signal phase discontinuity that is expected to cause problems [3], [12] Manuscript received October 16, 2006 and it reduces the large number of control bits required with digitally controlled VGAs.…”

Section: Introductionmentioning

confidence: 99%