RAMÍREZ ANGULO , Jaime

A methodology to design currentmode circuits for piecewise-linear function approximation is presented. The technique is based on the utilization of current mirrors as basic building blocks. The resulting circuits are very compact, modular, programmable and can operate at very high frequencies. Experimental results are presented that verify the...

A simple and power efficient approach for the implementation of continuous-time common mode feedback networks using a capacitive averaging network is introduced. It is shown that low voltage, continuous-time, fully differential rail to rail operation can be achieved using the proposed technique. This at the expense of very small additional...

A new high performance second-generation CMOS current conveyor architecture is presented. It is built using a differential flipped voltage follower as its input buffer stage and a cascode current mirror as output stage. It is characterized by very low output impedance. It provides gain independent high bandwidth when used to implement a...

This paper presents the implementation of a crossquad circuit suitable for low-voltage operation. The proposed cell exploits a dynamic positive feedback gm boosting technique to achieve linear voltage-to-current conversion, while it manages to work with low-voltage with no extra bias current and minimal additional hardware. Results for a 0.5 m...

An alternative approach to the design of super class AB recycling folded cascode operational transconductance amplifiers is proposed. Instead of using local common-mode feedback for boosting dynamic currents, simple current mirrors with input transistors entering triode region for large currents are employed. Measurement results from a 0.5 μm...

A CMOS fully integrated all-pass filter with an extremely low pole frequency of 2 Hz is introduced in this paper. It has 0.08-dB passband ripple and 0.029-mm 2 Si area. It has 0.38-mW power consumption in strong inversion with ±0.6-V power supplies. In subthreshold, it has 0.64-μW quiescent power and operates with ±200-mV dc supplies. Miller...

A 1.5V programmable-gain differential amplifier is implemented using a novel design technique for operating closed-loop amplifier circuits at very low supply voltages. It is based on the use of quasi-floating gate transistors, avoiding issues encountered in true floating-gate structures such as the initial floating-gate charge, offset drift...

A low distortion low-voltage BiCMOS OTA with wide gm adjustment range and constant input range is presented. It is based on a highly linear voltage-to-current converter input stage merged with translinear loops that implement linear electronically programmable current mirrors. Experimental results are provided that confirm the characteristics...

In this paper, a highly power-efficient class-AB–AB Miller op-amp is discussed. The structure uses gm enhancement based on local common-mode feedback to provide class-AB operation with enhanced effective gm , open-loop gain, unity-gain frequency, and slew rate ( SR ) without significant increase in quiescent power consumption. Utilization of a...

A novel CMOS tunable transconductor is presented. The circuit operates in classAB hence featuring power efficiency. The internal feedback employed and the use of a linearized triode transistor for voltage-to-current conversion allows achieving high linearity. Rail-to-rail input range is obtained by using floatinggate transistors. Measurement...

It is shown that the operational transconductance amplifier, as the active element in basic building blocks, can be efficiently used for programmable nonlinear continuous-time function synthesis. Two efficient nonlinear function synthesis approaches are presented. The first approach is a rational approximation, and the second is a...

The suitability of operational transconductance amplifiers (OTAs) as the main active element to obtain basic building blocks for the design of programmable nonlinear continuous-time networks is examined. The main purpose is to show that the OTA, as the active element in basic building blocks, can be efficiently used for nonlinear...

The implementation of large-valued floating resistive elements using MOS transistors in subthreshold region is addressed. The application of these elements to bias wideband AC coupled amplifiers is discussed. Simple schemes to generate the gate control voltages for the MOS transistors implementing large resistors so that they remain in high...

In this paper a novel transconductor based on floating gate techniques that performs current multiplication for tuning is presented. The multiplication is achieved using transistors operating in weak and moderate inversion together with floating voltage sources implemented conveniently by floating capacitors. Besides, a tuning scheme is...

The application of the flipped voltage follower to implement two high-performance circuits is presented: (1) The first is a class AB cascode flipped voltage follower that shows an improved slew rate and an improved bandwidth by very large factors and that has a higher output range than the conventional flipped voltage follower. It has a small...

A novel tunable third order low-pass Gm-C filter is introduced. Programmable transconductors operating in class AB have been used for its implementation hence featuring low quiescent power consumption. The operation in class AB is achieved using quasi-floating gate transistors. This filter is suitable for channel filtering of highly integrated,...

A new internally compensated low drop-out voltage regulator based on the cascoded flipped voltage follower is presented in this paper. Adaptive biasing current and fast charging/discharging paths have been added to rapidly charge and discharge the parasitic capacitance of the pass transistor gate, thus improving the transient response....

In this paper, an internally compensated low dropout (LDO) voltage regulator based on the Flipped Voltage Follower (FVF) is proposed. By means of capacitive coupling and dynamic biasing, the transient response to both load and line variations is enhanced. The proposed circuit has been designed and fabricated in a standard 0.5 mm CMOS...

This brief proposes a fully differential track and hold circuit using a new dc offset compensation scheme. It stores an amplified version of the offset during the hold phase, which is used in attenuated fashion during the track phase to compensate offset. This scheme is less sensitive to charge injection and other errors than conventional...

An efficient clocked class AB fully differential rail to rail differential difference amplifier is introduced. It is based on a two stage operational amplifier architecture with resistive local common mode feedback, floating gate transistors in the input stages and in the common mode feedback network. Its application in fully differential rail...

Two approaches to implement variable gain amplifiers based on Miller op-amps are discussed. One has true constant bandwidth while the other has essentially reduced bandwidth variations with varying gain. Servo-loops and ac coupling techniques with quasi floating gate transistors are used to provide a bandpass response with very low cutoff...

A systematic approach for the design of two-stage class AB CMOS unity-gain buffers is proposed. It is based on the inclusion of a class AB operation to class A Miller amplifier topologies in unity-gain negative feedback by a simple technique that does not modify quiescent currents, supply requirements, noise performance, or static power. Three...

Reduction of minimum supply requirements is a crucial aspect to decrease the power consumption in VLSI systems. A high-performance capacitance multiplier able to operate with supplies as low as ±0.25 V is presented. It is based on adaptively biased class-AB current mirrors which provide high current efficiency. Measurement results of a factor...

Class-AB circuits, which are able to deal with currents which are orders of magnitude larger than their quiescent current, are good candidates for low-power analog design. This paper presents a new, simple, class-AB current-mirror, based on the Flipped Voltage Follower [1]. In the authors knowledge this is the first class-AB current-mirror...

An efficient class-AB OTA with enhanced output current, slew rate, open loop gain, and gain bandwidth is presented. The circuit is based on a class-AB input stage with adaptive biasing, and an output stage with dynamically biased cascode transistors. It can deliver output currents 100 times larger than the bias current with a total quiescent...