Abstract: An amplifier includes a differential pair including a pair of input ports and a pair of output ports and a nonlinear load coupled to the differential pair. The pair of output ports is coupled to the pair of input ports to provide negative feedback. The pair of output ports is coupled to the non-linear load to provide positive feedback. A method includes receiving a signal at an input port of an amplifier and processing the signal in the amplifier by coupling negative feedback and positive feedback produced in the amplifier by the signal to the input port.

Abstract: Circuitry including Miller-effect feedback for use as part of a closed loop system such as a low dropout voltage regulator that provides current to a load at a specified voltage close in value to the power supply voltage. Various aspects of the presently claimed invention include using, within the Miller-effect feedback loop: a buffer amplifier to reduce loading effects upon an internal high impedance circuit node, output compensation circuitry to introduce a transfer function pole for substantially canceling a transfer function zero associated with external load circuitry; and Miller-effect compensation circuitry to introduce a transfer function zero for substantially canceling a transfer function pole associated with the Miller-effect feedback.

Abstract: A multistage amplifier includes a first gain stage having a first input terminal and a first output terminal, and a second gain stage having a first input terminal. A first inter-stage resistive element is coupled in series to the first output terminal of the first gain stage and the first input terminal of the second gain stage to reduce the adverse affects of one gain stage on a previous gain stage. The multistage amplifier may also have a differential pair with a local feedback path for each transistor of the differential pair. Such local feedback helps to stabilize an imaginary component of the input impedance of the differential amplifier. Such stabilization also helps to reduce the adverse affects one gain stage may have on a previous gain stage.

Abstract: Improved differential amplifiers are provided for use with switched-capacitor structures. Amplifier embodiments include a differential pair of high-transconductance transistors for generation of differential currents and routing of common-mode feedback signals along an independent path so that sufficient headroom is provided for other high-transconductance transistors that generate common-mode currents. The differential and common-mode currents preferably generate differential and common-mode output signals in finite output impedances of active loads.

Abstract: An analog buffer with low harmonic distortion and low power supply voltage buffers a signal with wide voltage swing. The lower output voltage swing is increased, by adding a voltage level shifter to the feedback path of a servo. The upper output voltage swing is increased by coupling the output load to Vdd.

Abstract: A transconductor tuning circuit for controlling transconductance of a transconductor. The tuning circuit includes a first MOS (Metal-Oxide Semiconductor) transistor. A source terminal of the first MOS transistor is connected to a power source. A gate terminal and a drain terminal of the first MOS transistor being connected to each other. A gate terminal and a drain terminal of a second MOS transistor being connected. A first input terminal of a first error amplifier is connected to the gate terminal of the first MOS transistor. A second input terminal of the first error amplifier is connected to the gate terminal of the second MOS transistor. The first error amplifier outputs an output signal in form of a bias signal for controlling tuning of the transconductor.

Abstract: An output buffer is configured to receive differential input signals and to transmit differential output signals. A pre-driver is coupled to the output buffer and is configured to receive a data input signal and to generate the differential input signals for the output buffer. A feedback loop is coupled between the output buffer and the pre-driver. The feedback loop is configured to generate a feedback signal on the basis of a signal level present in the output buffer. The pre-driver is configured to receive the feedback signal generated by the feedback loop.

Abstract: A comparator circuit includes a differential amplifier including load resistors, for amplifying difference between two input voltages of the comparator circuit; an emitter follower circuit for applying positive feedback with respect to a differential amplifier and outputting an output voltage of the comparator circuit; and a grounded-base amplifier, and outputting an output voltage of the comparator circuit, for realizing both voltage output and current output. A grounded-base amplifier includes two transistors each of which has a base supplied with a reference voltage. The differential amplifier includes two load resistors respectively connected to each emitter of the transistors of the grounded-base amplifier. The load resistor flowing a current which is obtained through a collector of the transistor as an output current of the comparator. With this arrangement, it is not necessary to provide a current switch circuit for obtaining current output of the comparator circuit.

Abstract: An integrated circuit includes an analog amplifier connected to a terminal pad and has a Miller compensation of a section of the analog amplifier. The Miller compensation circuit is connected to a terminal for reference-ground potential through a capacitive element. An EMC interference radiation that can be coupled in through the terminal pad is attenuated by the capacitive element. The operating points of the internal nodes of the analog amplifier are, thereby, stabilized.

Abstract: The present invention is directed to a current amplifier. The current amplifier according to the present invention includes a voltage amplifier with a predetermined gain, an input and an output. A transistor is connected to the output of the voltage amplifier. A differential pair of transistors is connected between the transistor and the input of the voltage amplifier. The gain of the current amplifier varies according to the to the voltage applied to the input of the differential pair of transistors. Further, a current through the transistor will be divided into a feedback current and an output current according to the voltage applied to the input of the differential pair of transistors.

Abstract: An ultra-low distortion electronic amplifier wherein the global dominant pole is formed by the selection of circuit and component arrangement within the input stage, such that the global dominant pole, is of third order, at audio frequencies. This audio power amplifier implements a high order global dominant pole with the use of operational amplifiers, and this high order dominant pole is distributed across both the voltage amplification stage and input stage without adverse reduction in the slew rate. The amplifier has increased negative feedback at audio and ultrasonic frequencies, giving a reduction in distortion across the entire audio band and some of the lower ultrasonic band.

Abstract: An audio signal amplifier circuit includes an external output terminal of an IC to which an output line of a power amplifier circuit is connected, a first resistor connected between a certain terminal of the IC other than the external output terminal and a feedback input of a differential amplifier circuit, a first capacitor connected between the external output terminal and a loud speaker, a second capacitor between the certain terminal of the IC and a wiring line between the external output terminal and the loud speaker, a filter circuit provided on a signal input side of the differential amplifier circuit and including a second resistor and a third capacitor for attenuating signal components having frequencies in a middle and high frequency ranges and voltage follower means provided between an input stage and an output stage of the audio signal amplifier circuit, wherein the first capacitor is a small capacitor having a capacitance value in the order of 30 &mgr;F or smaller and an attenuation characteristi

Abstract: The invention pertains to an integrated circuit arrangement, in particular, in accordance with the CMOS technology, with at least one transconductance amplifier (1) in order to generate a current signal (outp, outm) from an input voltage signal (inp-inm), wherein the transconductance amplifier consists of a first transconductance stage (gm1) and a second transconductance stage (gm2) that are connected in parallel, wherein the first transconductance stage (gm1) has a transconductance that is essentially defined by an ohmic resistance and the second transconductance stage (gm2) has an adjustable transconductance that is essentially defined by a transistor arrangement, and wherein the transconductance of the first transconductance stage (gm1) is higher than the transconductance of the second transconductance stage (gm2).

Abstract: A new all digital transistor CMOS very high DC-gain amplifier (30) that uses an internal positive-feedback technique. This amplifier (30) does not require perfect matching of transistors (M2,M3) to achieve the very high DC gain. The DC gain has a very low sensitivity to the output voltage swing. An implementation of a sample and hold circuit (60) constructed using the amplifier (30) is also described. A special layout pattern (80) is used to cut the parasitic capacitance to enhance the amplifier speed.

Abstract: A load responds to a voltage-to-current converter including a differential amplifier. A sensing resistor is series connected with the load and first and second feedback resistors, respectively included in first and second voltage dividers having taps connected to non-inverting and inverting inputs of the amplifier. One divider is connected between a first terminal of the sensor resistor and one voltage responsive input terminal of the converter. Another divider is connected between the second terminal of the sensor resistor and a second converter input terminal, that can be grounded or voltage responsive. The feedback resistors have the same value that is much greater than the sensor resistor value. The first divider can be connected to the first or second terminal of the sensor resistor and vice versa for the second divider.

Abstract: Quake Transistor Logic (QTL) circuits of the embodiments of the invention are low power, high-speed circuits that can be manufactured by the same process as the lower-speed complex circuits, and are thus capable of being integrated on the same device. A number of techniques are employed to give QTL circuits their unique advantages. Lower power without loss of speed is achieved through the use of a self-biasing clock buffer to eliminate the need for tail current sources in the logic; differential signals are employed throughout to improve noise immunity with a low logic signal swing; an optional tuning circuit provides extension of the frequency response to achieve an even higher clock frequency and logic circuit bandwidth.

Abstract: A circuit and method for calibrating an active termination resistor irrespective of changes in process, voltage, or temperature is provided. The method includes the steps of (a) calibrating a first variable resistor to have the same resistance as that of an external resistor; (b) at the same time calibrating a second variable resistor to have the same resistance as that of the first variable resistor; and (c) calibrating the active termination resistor to have the same resistance as that of the external resistor. The step of calibrating the first variable resistor to have the same resistance as that of the external resistor is in response to a first control code, and at the same time the step of calibrating the second variable resistor to have the same resistance as that of the first variable resistor is in response to a second control code.

Abstract: A direct current input power supply voltage Vcc is outputted to the load side via a PNP type transistor having a small Vce. A base thereof is driven by a base current from which noise is removed in a power source noise removing circuit. An input to the noise removing circuit is produced by shifting a level from the Vcc side by a direct current level shift circuit. Since an output voltage Vs varies with reference to Vcc and a voltage drop is relatively small owing to the transistor, an operation voltage on the load side can be ensured. The noise removing circuit is constituted by a gm amplifier. In order to increase a noise removing rate at low frequencies, by setting gm of a time constant C/gm to a small value, it is possible to set a capacity to a value which allows integration.

Abstract: The invention relates to an amplifier circuit (20) and a method for reducing stray feedback, wherein an additional feedback compensation terminal is provided at the output of the amplifier circuit. A predetermined fraction of the output signal of the amplifier circuit is output at the feedback compensation terminal (RFB) so as to reduce the stray feedback of the output signal. The feedback compensation terminal (RFB) enables a reduction of the stray feedback by providing an additional stray feedback signal which is negatively added at the input of the amplifier circuit (20) to thereby reduce overall stray feedback. The gain may be adjusted once during manufacturing, or each time when operation of the device is initiated. The amplifier circuit (20) may be a transimpedance amplifier for use in a read head of a reproducing device for a record carrier.

Abstract: A Miller-compensated amplifier circuit. The circuit includes an amplifier stage, and a compensation capacitor arranged in parallel with the amplifier stage. A current multiplier circuit path, adapted to multiply a current through the compensation capacitor, includes an inversion stage in the current multiplier circuit path. In this way, the circuit is Miller compensated by only a single capacitor that has its capacitance multiplied in accordance with current-mode multiplication.

Abstract: An amplifier includes a differential pair including a pair of input ports and a pair of output ports and a nonlinear load coupled to the differential pair. The pair of output ports is coupled to the pair of input ports to provide negative feedback. The pair of output ports is coupled to the non-linear load to provide positive feedback. A method includes receiving a signal at an input port of an amplifier and processing the signal in the amplifier by coupling negative feedback and positive feedback produced in the amplifier by the signal to the input port.

Abstract: A data signaling apparatus includes a differential amplifier for providing an amplified differential output on a pair of outputs in response to a differential signal provided on a pair of inputs, and a clamping resistor between the pair of inputs. The clamping resistor acts to effectively reduce the swing in differential inputs, thereby allowing high gain that does not result in problematic differential outputs. Further, since the resistor is operative for all voltage ranges, it is useful in small signal applications where diodes cannot be used or are too difficult to implement. A data signaling method includes receiving a differential signal on a pair of inputs, reducing the magnitude of the differential signal by a scale factor using a clamping resistor across the pair of inputs, and providing an amplified differential output on a pair of outputs in response to the scaled differential signal provided on the pair of inputs.

Abstract: The amplifier circuit includes at least one amplification branch having an input transistor, an output transistor, having a source terminal connected to the input terminal and a drain terminal connected to a first output terminal, and a gain raising stage, having an input and an output connected to the source terminal and, respectively, to a gate terminal of the output transistor. The amplifier circuit includes, moreover, a compensation capacitor connected between the gate terminal and the drain terminal of the output transistor.

Abstract: A circuit for establishing the input impedance of an amplifier includes an amplifier, a circuit component, a first feedback resistor, and a second feedback resistor. The amplifier has an input impedance and is coupled to a load having a load impedance. The circuit component is coupled to the load and shares at least a portion of a bias current with the amplifier. The first feedback resistor is coupled the amplifier and the load, and has a first impedance. The second feedback resistor is coupled to the amplifier and has a second impedance. The input impedance of the amplifier is established based at least in part upon the first impedance and the second impedance.

Abstract: A low noise differential amplifier structure comprising a first amplifier provided with an output stage with a Miller capacitor having a first electrode and a second electrode connected to the input and the output of the output stage, respectively. A second amplifier is provided with an output stage with a Miller capacitor having a first electrode and a second electrode connected to the input and the output of the output stage, respectively. The structure is characterized in that it comprises: at least a first trimming capacitor having a first electrode connected to the first electrode of the first Miller capacitor; at least a second trimming capacitor having a first electrode connected to the first electrode of the second Miller capacitor; and a cascode stage having an input receiving the output common mode voltage and an output connected to the second electrode of the first and second trimming capacitors.

Abstract: The present invention provides a variable gain amplifier with a plurality of gain stages in which each of the gain stages is implemented using a circuit that implements a neutralization approach. This variable gain amplifier provides stable operation characteristics as different gain stages within the variable gain amplifier are turned on and off. This variable gain amplifier also increases linearity across the entire operating range. Additionally, the variable gain amplifier of the present invention provides a constant input impedance through different gain settings. Further, the present invention provides a variable gain amplifier in which each of the various gain stages therein maximize the available voltage swing. Finally, this variable gain amplifier improves common-mode rejection performance and attenuates unwanted harmonics.

Abstract: The present invention is directed to a current amplifier. The current amplifier according to the present invention includes a voltage amplifier with a predetermined gain, an input and an output. A transistor is connected to the output of the voltage amplifier. A differential pair of transistors is connected between the transistor and the input of the voltage amplifier. The gain of the current amplifier varies according to the to the voltage applied to the input of the differential pair of transistors. Further, a current through the transistor will be divided into a feedback current and an output current according to the voltage applied to the input of the differential pair of transistors.

Abstract: A variable gain amplifier includes an input stage that receives an input signal and converts the input signal into a corresponding intermediate signal. An output stage provides an output signal based on the intermediate signal and a gain control signal, with feedback signal being provided to the input stage as a function of the gain control signal, so that the intermediate signal varies as a function of the input signal and the feedback signal. The linearity performance of the VGA is substantially constant at the output over the useful input range of signal amplitudes.

Abstract: An output distortion correction amplifier system includes an input stage; a current mirror connected to the input stage; an output stage having its input connected to the input stage and a current mirror and its output connected to the input stage; a compensation impedance connected to the input of the output stage; and a distortion correction circuit for directly sensing the distortion voltage across the output stage and providing to the current mirror a current representative of the distortion voltage for delivering to the compensation impedance a correction current to develop a correction voltage at the input of the output stage to nullify the effect of the distortion voltage.

Abstract: An amplifying circuit includes an amplifying stage for receiving input signals to generate output signals. A swing detect unit detects signal levels of the output signals. A clamp unit variably limits signal levels of the input signals based on the signal levels of the output signals detected by the swing detect unit to improve the speed of the amplifying circuit.

Abstract: The stage includes two channels each connecting an input to an output. Each channel includes a first device for adding to the input voltage of the channel concerned a feedback voltage from the other channel to the channel concerned. For remote power feeding a terminal, the stage further includes respective means in each channel for adding a DC voltage to the output voltage of that channel. The feedback voltage is a function only of the AC component of the output voltage of the first device of the channel concerned. Application to telephone exchanges.

Abstract: A voltage controlled transconductor (VCT) for receiving a differential input signal comprising a first voltage signal and a second voltage signal, and for providing a differential output signal comprising a first output current signal and a second output current signal. The VCT includes a first side transconductor circuit having two parts of the same construction, the first part being capable of conducting a first current signal and the second part being capable of conducting a second current signal, the first current signal and the second current signal being controlled by the first voltage signal. The VCT also includes a second side transconductor circuit having two parts of the same construction, the first part being capable of conducting a third current signal and the second part being capable of conducting a fourth current signal, the third current signal and the fourth current signal being controlled by the second voltage signal.

Abstract: A low-power differential optical receiver useful for high-speed optical communication between CMOS chips includes a multi-stage differential amplifier circuit including a first differential transimpedance stage (22) followed by a plurality of differential feed-forward, high-bandwidth gain stages (24) and a final, differential-to-single-ended converter output stage (26). The inputs of the transimpedance stage receive input signals from a MSM or PIN diode photo-detector. Transistors having plural, different threshold levels are employed within each differential amplifier stage to reduce the size of the footprint of the circuit and improve the gain and bandwidth while decreasing the parasitic capacitance. The optical receiver is fabricated on a silicon on insulator chip, such as in an ultra-thin silicon on sapphire CMOS process which enables the design of high speed circuits with low power consumption and no substrate cross-talk.

Abstract: A high gain amplifier circuit includes two differential transistor pairs and a current generator coupled to each differential pair to control tail current. Each differential transistor pair has a first transistor and a second transistor and an output node for each. Bias terminals of the first transistors serve as inputs for the amplifier circuit. The output node of each first transistor serves as an output for the amplifier circuit and is respectively coupled to the bias terminal of the second transistor of the same differential pair. The amplifier circuit has applications in a comparator circuit that also has a load circuit, which may have active components or only passive components. The amplifier circuit may also be used as a sense amplifier in a receiver of a communications system.

Abstract: An operational amplifier circuit (10) uses a first operational amplifier (16) to selectively provide a boosted drive current in response to an input signal voltage transitioning. The boosted driver current is used by a second operational amplifier (22) having a single high gain stage (76). The output drive current of the operational amplifier circuit (10) is increased to a predetermined maximum value for a predetermined time after an input signal transition in order to source increased current to a capacitive or inductive load only during output signal transitions. Separate current boost circuits (30, 70) in each of the first and second operational amplifiers enable early signal transition detection and ensure continuation of increased current until completion of the signal transition.

Abstract: An amplifier circuit which includes a differential amplifier, drive circuitry for driving an output of the amplifier circuit in response to an output of the differential amplifier and frequency compensation circuitry switchable between a low current mode and a high current mode of operation. Control circuitry is provided configured to switch the frequency response circuitry between the low and high current modes in response to a magnitude of current provided to a load connected to the amplifier circuit output. In the low current mode, the frequency compensation circuitry produces a frequency response having a first pole located at a first frequency. In the high current mode, the frequency compensation circuitry produces a zero at a second frequency sufficiently close to the first frequency so as to stabilize the amplifier circuit, with the first zero being absent for the frequency response in the low current mode.

Abstract: A CMOS gain stage includes biasing circuitry configured to insure saturation of a subsequent stage without a source follower circuit. The CMOS gain stage is optionally powered by a supply voltage that is greater than a permitted supply voltage for a processes technology that is used to fabricate the CMOS gain stage. In order to protect CMOS devices within the CMOS gain stage, optional drain-to-bulk junction punch-through protection circuitry is disclosed. A variety of optional features can be implemented alone and/or in various combinations of one another. Optional features include process-voltage-temperature (“PVT ”) variation protection circuitry, which renders a gain relatively independent of process, voltage, and/or temperature variations. Optional features further include bandwidth enhancement circuitry.

Abstract: In one system embodiment, the system is characterized by: a differential amplifier including but not limited to at least one amplifying transistor having an emitter coupled directly to a ground. In one embodiment of a method of making a system, the method is characterized by: operably coupling at least one amplifying transistor of a differential amplifier directly to a ground. In one embodiment of a method of driving a system, the method is characterized by: driving at least one amplifying transistor of a differential amplifier with an emitter-follower feedback loop. In one system embodiment, the system is characterized by: a differential amplifier including but not limited to a first amplifying transistor having a base operably coupled with a first emitter-follower feedback loop.

Abstract: A gain boost circuit is provided in a differential amplifier including differentially connected first and second input transistors the drains of which are coupled to sources of first and second cascode transistors. A third cascode transistor has a source coupled to a drain of the first cascode transistor and a drain coupled to a bias current source. A gain boost amplifier has an output coupled to the gate of the third cascode transistor, a first input coupled to the drain of the first cascode transistor, and a second input coupled to the drain of the second cascode transistor.

Abstract: An amplifier includes an input stage with one or more input terminals for receiving a signal to be amplified, and an output terminal. An inverting gain stage includes an input terminal connected to the output terminal of the input stage, an output terminal for delivering an amplified signal, and a variable feedback resistor connected between the output terminal and input terminal thereof. The input stage is a transconductor stage biased by a current source. A transconductance thereof is set by a resistor of the current source so that the amplifier has a gain proportional to the product of the variable feedback resistor multiplied by the transconductance.

Abstract: A preamplifier system is provided for connection through an interconnect to a read head. The interconnect has a characteristic impedance associated therewith. The preamplifier system includes an amplifier circuit having an input for connection to the interconnect. The amplifier circuit amplifies an input signal carried from the read head through the interconnect, yielding an amplified input output signal. A feedback resistance is connected between the amplified output signal and the input of the amplifier circuit. The feedback resistance has a value selected to provide an effective input impedance of the preamplifier system to match the characteristic impedance of the interconnect.

Abstract: An apparatus for effecting high speed switching of a communication signal between a first component and a second component includes: (a) a switching circuit configured for receiving the signal from the first component that includes a plurality of switch elements responding to the signal to produce an interim signal that is substantially a model of the signal; (b) a follower circuit having an input locus coupled with the switching circuit for receiving the interim signal; the follower circuit has an output locus configured for presenting an output signal that is substantially duplicating the interim signal; and (c) a control circuit coupling the follower circuit with the switching circuit and receives a feedback signal from the follower circuit representative of the output signal; the control circuit responds to the feedback signal to effect operation of the switching circuit to control at least one first parameter relating to the interim signal.

Abstract: A variable gain amplifier is described which comprises a first device to which a first control signal (Vc, Vc1) is applied so that the gain (Ai1, Ai) of an output signal (iout, io) of the first device (11, 22, Q45-Q48) with respect to a first input signal (in, i1, ir) is a function of the exponential type of the first control signal (Vc, Vc1). The amplifier comprises a feedback network (25, Q51-Q58) connected between an output terminal and an input terminal of the first device (22, Q45-Q48) so as to assure that the gain (Ai) in decibel of the first device (22, Q45-Q48) is a linear function of the first control signal (Vc1).

Abstract: Known differential pair amplifier circuits can suffer from transistor saturation resulting in a reduction in switching speed. An alternative to the differential pair amplifier circuit is a common-emitter configuration, but the common-emitter configuration lacks differential operability and results in ground bounce. An amplifier circuit is provided for an output stage of a driver circuit comprising a pair of common emitter circuits cross-coupled by a pair of transistors. Slow operation is therefore overcome while providing a differential output signal in response to a differential input signal.

Abstract: An amplifier circuit includes a first input device coupled to a first input node and controlling a first current, a second input device coupled to a second input node and controlling a second current, a current source device coupled to a bias node and controlling a summed current of the first and second currents, a current mirror circuit, a first feedback circuit, a second feedback circuit, and a capacitor. The current mirror circuit generates a load current by mirroring the first current so as to provide an output signal voltage to an output node couple to the second output node. The first feedback circuit supplies a mirrored first current to the bias node, and the second feedback circuit pulls a mirrored second current from the bias node. The capacitor is coupled to the bias node and provides the bias voltage to the current source device.

Abstract: Continuous alternating current is derived from a differential operational amplifier supplied by direct current. The differential operational amplifier produces alternating current located on the positive input of the differential operational amplifier. Output of the differential operational amplifier is received by a transformer to produce alternating current. Voltage from the transformer is fed back to the negative input of the differential operational amplifier to provide feedback for the differential operational amplifier. Whereby direct current provided to a differential operational amplifier is transformed to continuous alternating current.

Abstract: A current feedback amplifier is disclosed for providing a differential output based on a single-ended or differential input signal, having first and second low impedance inputs to receive first and second input signals, and first and second phase shifting systems providing first and second phase shifted input signals based on the second and first input signals. A first intermediate system provides a first intermediate signal comprising the first input signal and the first phase shifted input signal, and a second intermediate system provides a second intermediate signal comprising the second input signal and the second phase shifted input signal, wherein gains may be applied to one or more of the input and/or phase shifted signals. The amplifier further comprises first and second output buffers providing first and second differential output signals based on the first and second intermediate signals, respectively.

Abstract: A circuit includes a differential amplifier providing a differential signal to a voltage follower. The output of the voltage follower is fed back through resistors to an additional differential amplifier to the respective inputs to the voltage follower. The feedback is negative at low frequencies and less negative or positive about the clock frequency.

Abstract: Expansion of the bandwidth of a wideband CMOS data amplifier is accomplished using various combinations of shunt peaking, series peaking, and miller capacitance cancellation. These various combinations are employed in any of the amplifier input stage, in intermediate stages, or in the last stage.

Abstract: A differential difference amplifier is provided for amplifying an input signal having a magnitude close to zero (or a negative supply voltage) and adding an offset voltage to the amplified input signal.