Super Class-AB OTAs With Adaptive Biasing and Dynamic Output Current Scaling

Galán, J.; Lopez-Martin, A.J.; Carvajal, R.G.; Ramírez-Angulo, J.; Rubia-Marcos, C.

doi:10.1109/tcsi.2006.887639

Cited by 104 publications

(58 citation statements)

References 12 publications

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“…However, the previous research [7][8][9][10] did not demonstrate subtle power adaption to sophisticated analog signals. Some previous articles [7][8][9] focused mostly on OTAs' slew rate improvement in driving square pulses.…”

Section: Introductionmentioning

confidence: 89%

“…Bias control based-on input motoring [7,8] improved slew rate with little additional power, and thus achieved the same performance consuming less power. Load adaptation also improved slew rate by 400%-500% with only additional 5% power and 20% chip area [9].…”

Section: Introductionmentioning

confidence: 95%

“…To improve OTAs' power efficiency, various bias control techniques were proposed [7][8][9][10]. Bias control based-on input motoring [7,8] improved slew rate with little additional power, and thus achieved the same performance consuming less power.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

An OTA with Positive Feedback Bias Control for Power Adaptation Proportional to Analog Workloads

Kim¹,

Sim²,

Park³

2015

JSTS:Journal of Semiconductor Technology and Science

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Abstract-This paper reports an adaptive positive feedback bias control technique for operational transconductance amplifiers to adjust the bias current based on the output current monitored by a current replica circuit. This technique enables operational transconductance amplifiers to quickly adapt their power consumption to various analog workloads when they are configured with negative feedback. To prove the concept, a test voltage follower is fabricated in 0.5-μm CMOS technology. Measurement result shows that the power consumption of the test voltage follower is approximately linearly proportional to the load capacitance, the signal frequency, and the signal amplitude for sinusoidal inputs as well as square pulses.

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Section: Introductionmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 95%

See 1 more Smart Citation

An OTA with Positive Feedback Bias Control for Power Adaptation Proportional to Analog Workloads

Kim¹,

Sim²,

Park³

2015

JSTS:Journal of Semiconductor Technology and Science

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“…1(c) [3]. The OTA [C] features dynamic current sourcing capability depending on the differential input signal [5]. The OTA [C] consists of two matched transistors, M03 and M04 acting as DC level shifters.…”

Section: Proposed Scheme Descriptionmentioning

confidence: 99%

“…Typically, the conventional current mirror OTA is modified by class AB type to achieve a high DC gain [2,3,4,5], and the constant tail current source is substituted by a dynamic biasing tail current for low power and a high slew rate [3,4,5]. However, applications still require more improved OTA performance to suit the demands of users.…”

Section: Introductionmentioning

confidence: 99%

Low power high-gain class-AB OTA with dynamic output current scaling

Kim

Lee

2013

IEICE Electron. Express

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A high-performance operational transconductance amplifier (OTA) is proposed. In order to increase DC gain, gain bandwidth, and the slew rate under low standby quiescent current, the proposed OTA has the dynamic output current scaling and class AB operation. Under the condition of 250 A quiescent current and a 30 pF load capacitance with a step voltage from 1.2 to 1.5 V at a rise time of 1 nsec in a unit gain configuration, HSPICE simulation results are presented to show a higher DC gain, gain bandwidth and slew rate than conventional OTAs.

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Super class AB OTA without open‐loop gain degradation based on dynamic cascode biasing

Pourashraf

Ramírez-Angulo

López-Martín

et al. 2017

Circuit Theory & Apps

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A scheme to achieve simultaneously extremely high slew-rate improvement and avoiding open-loop gain degradation in one-stage super class AB op-amps is introduced. It overcomes the serious shortcoming of super class AB operational transconductance amplifiers that shows very high-output current enhancement factors at the expense of degrading the open-loop gain. The proposed scheme uses dynamically biased cascode transistors to avoid gain and slew-rate degradation. Experimental results of a super class AB operational transconductance amplifier in 180-nm complementary metal-oxide semiconductor technology with open-loop gain of 67 dB, a factor 2 improvement in GBW, and a current enhancement factor of 270 verify the proposed scheme.

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Super Class-AB OTAs With Adaptive Biasing and Dynamic Output Current Scaling

Cited by 104 publications

References 12 publications

An OTA with Positive Feedback Bias Control for Power Adaptation Proportional to Analog Workloads

An OTA with Positive Feedback Bias Control for Power Adaptation Proportional to Analog Workloads

Low power high-gain class-AB OTA with dynamic output current scaling

Super class AB OTA without open‐loop gain degradation based on dynamic cascode biasing

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