Abstract: A power amplification device includes a power amplifier core stage and a power amplifier driver stage. The power amplifier driver stage receives a radio frequency signal to be amplified by the power amplification device. The power amplifier driver stage includes a first source follower input transistor and a first current source transistor. A source of the first source follower input transistor is coupled to a drain of the first current source transistor. The source of the first source follower input transistor is directly coupled to the power amplifier core stage to drive the power amplifier core stage. An input match and passive voltage gain device is coupled to the power amplifier driver stage to generate a voltage gain at an input of the power amplifier driver stage. A first bias source is configured to generate a first bias signal to bias the power amplifier driver stage.

Abstract: A signal amplifying system comprising: an amplifying module with a plurality of PGAs coupled in series; a test signal generating circuit, for generating a test signal fed to one test input PGA; and a control circuit. If the test input PGA is not a final PGA, the final PGA outputs an output test signal amplified by the test input PGA and the PGA following the test input PGA, wherein each of the PGA following the test input PGA has a known amplifying gain. The control circuit acquires an accumulated gain for the test input PGA and the PGA following the test input PGA based on the output test signal, and acquires an amplifying gain of the test input PGA based on the accumulated gain.

Abstract: A balun device for UHF signals includes two conductive connection pads, a printed conductive track and a conductive ground pattern that are formed on a dielectric base plate. The conductive connection pads are connectable respectively with a pair of first signal lines for a pair of differential signals. One of the conductive connection pads is further connectable with a second signal line for a single-ended signal. The printed conductive track interconnects electrically the conductive connection pads. The conductive ground pattern is surrounded by and spaced apart from the printed conductive track and the conductive connection pads.

Abstract: Data communication having improved electromagnetic interference (EMI) rejection when communicating through a coaxial cable is provided by using differential transmission and/or reception through a common-mode choke and a dissipative element resulting in extremely low radiated emissions and high immunity to external radiation interference in a low-cost way.

Abstract: A transceiver includes: a power amplifying circuit arranged to generate differential output signals during a transmitting mode of the transceiver; a balance-unbalance circuit arranged to convert the differential output signals into a single-ended output signal; a switchable matching circuit arranged to receive the single-ended output signal on a signal port of the transceiver during the transmitting mode, and to convert a single-ended receiving signal on the signal port into a single-ended input signal during a receiving mode of the transceiver; and a low-noise amplifying circuit arranged to convert the single-ended input signal into a low-noise input signal during the receiving mode. The power amplifying circuit, the Balun, the switchable matching circuit, and the low-noise amplifying circuit are configured as a single chip.

Abstract: A balun includes an unbalanced port having a single-ended terminal, a balanced port having first and second differential terminals, and first and second series resonant LC circuits. The first series resonant LC circuit is connected between the first and second differential terminals, and includes a first element of a first type and one element of a second type connected in series. The second series resonant LC circuit is connected between the single-ended terminal and ground, and includes second and third elements of the first type and the one element of the second type connected in series. The one element of the second type is shared by the first and second series resonant LC circuits. The first differential terminal is connected between the one element of the second type and the third element of the first type.

Abstract: A push-pull amplifier is provided for amplifying an input signal, having first and second amplifier elements. Each of the amplifier elements has a current-emitting electrode, a current-collecting electrode, and a current-controlling electrode. The input signal is supplied to the current-controlling electrodes of the amplifier elements via a respective input connection and a respective input inductor arranged between the respective input connection and the respective current-controlling electrode. The current-collecting electrodes are connected via a respective supply inductor having a common supply voltage. The current-emitting electrode of each amplifier element is connected to the current-collecting electrode of the other amplifier element via a respective capacitor. The current-emitting electrodes are connected to output connections on which the output signal can be picked up, and to a reference potential via a respective output inductor.

Abstract: An RF power amplifier includes a push-pull amplifier having field effect transistors. Temperature compensating bias circuitry provides a temperature compensated bias voltage to the transistors for decreasing the bias voltage thereof as temperature increases. The temperature compensating bias circuitry includes a temperature sensor generating a temperature signal. A first amplifier provides a first temperature dependent voltage based on the temperature signal. A second amplifier provides a second temperature dependent voltage based on the temperature signal. The first and second temperature dependent voltages change at substantially the same rate in response to the temperature signal. A potentiometer receives the first and second temperature dependent voltages such that a voltage across the potentiometer remains substantially constant when the first and second temperature dependent voltages change.

Abstract: An RF power amplifier includes a push-pull amplifier having field effect transistors. Temperature compensating bias circuitry provides a temperature compensated bias voltage to the transistors for decreasing the bias voltage thereof as temperature increases. The temperature compensating bias circuitry includes a temperature sensor generating a temperature signal. A first amplifier provides a first temperature dependent voltage based on the temperature signal. A second amplifier provides a second temperature dependent voltage based on the temperature signal. The first and second temperature dependent voltages change at substantially the same rate in response to the temperature signal. A potentiometer receives the first and second temperature dependent voltages such that a voltage across the potentiometer remains substantially constant when the first and second temperature dependent voltages change.

Abstract: An RF power amplifier includes first and second field effect transistors having a gate, a source, and a drain, having an output power rating of at least 200 watts, and operating with a drain-to-source voltage that is greater than 50 VDC. The transistors are configured as a push-pull amplifier. The amplifier further includes an RF signal input. A input transformer is connected to the RF signal input. The input transformer has respective balanced outputs connected to the gates of the transistors. A broadband output transformer has a first balanced input connected to the drain of one the transistors, and a second balanced input connected to the drain of the other transistor. The broadband output transformer has an input to output impedance ratio of 1:4.

Abstract: The invention relates to a preamplifier circuit with at least one transistor that couples a signal input to a signal output. The signal input is supplied with a radio-frequency signal. In addition, the preamplifier circuit includes a switch that switchably couples the input to a reference potential and which, when the preamplifier is inactive, is closed. Hence, when the preamplifier is inactive, the input is put into a low-impedance state and the amplifier and downstream assemblies are protected from unwanted high-power interference signals. It is thus also possible to use other, fully integratable filter types in a transceiver's reception signal processing chain instead of external surface acoustic wave filters with a low level of complexity and without drawbacks.

Abstract: Disclosed is a differential amplifier which includes first and second input terminals, an output terminal, first and second differential pairs, and first and second current sources for supplying currents to the first and second differential pairs. The first differential pair has first and second inputs of an input pair connected to the first input terminal and the output terminal, respectively. The second differential pair has first and second inputs of an input pair connected to the second input terminal the output terminal, respectively.

Abstract: A power amplifier with an active bias circuit and operating method thereof are provided. The power amplifier comprises a power amplifier transistor and an active bias circuit. The active circuit receives input power and applies a bias voltage to the gate of the power amplifier transistor. The bias voltage will increase in correspondence with an increase in the input power. Therefore, the power amplifier of this invention has excellent output power, linearity of operation and power-added efficiency in a range of input power.

Abstract: A differential pair of transistors includes a first transistor and a second transistor having their sources coupled together. Their sources are further coupled to ground via a pull-down network. A single-ended output is coupled to the drain of the second of the pair of differential transistors. A differential current adjust circuit is coupled to a drain of the first of the pair of differential transistors, and the current adjust circuit is configured so that the second side of the differential output driver circuit conducts approximately the same current as the first side of the differential output driver circuit.

Abstract: A converter includes an input circuit to receive a single-ended input signal to generate a number of control signals. The control signals have a delay different from one another relative to the single-ended input signal. The converter also includes a first output circuit and a second output circuit. The first output circuit responds to the control signals to generate a first output signal. The second output circuit responds to the control signals to generate a second output signal. The first and second output signals are non-overlapping and form a complimentary signal pair.

Abstract: A high gain, highly linear mixer includes an input section, mixing section, at least one tuning component, and at least one stand by current source. The input section is operably coupled to receive an input voltage signal and perform a linear transconductance thereon to produce an input current signal. The mixing section is operably coupled to mix a local oscillation with the input current to produce a mixed current signal. The tuning component is operably coupled to the mixing section and to convert the mixed current signal into a mixed voltage signal that function as the output of the mixer. The standby current source is operably coupled to the mixing section and provides a standby current to the mixing section.

Abstract: A radio frequency integrated circuit includes a power amplifier, a low noise amplifier, a first transformer balun, and a second transformer balun. The power amplifier includes a first power amplifier section and a second power amplifier section. When enabled, the first and second power amplifier sections amplify an outbound radio frequency (RF) signal to produce a first amplified outbound RF signal and a second amplified outbound RF signal, respectively. The power amplifier provides the first amplified outbound RF signal to the first transformer balun and the second outbound RF signal to the second transformer balun, where the first transformer balun is coupled to a first antenna and the second transformer balun is coupled to a second antenna. The low noise amplifier includes a first low noise amplifier section and a second low noise amplifier section.

Abstract: A balanced high-frequency device is constituted by a balanced device and a phase circuit. The input side of the balanced device is connected to an input terminal IN serving as an unbalanced input/output terminal and the output side of it is connected to output terminals OUT1 and OUT2 serving as balanced input/output terminals. Moreover, the phase circuit is connected between the output terminals.

Abstract: Apparatus, methods and articles of manufacture are shown for modifying electromagnetic waves. Through using various wave characteristics such as amplitude to regulate a current source, a current is output that may be used in any number of ways, such as driving an antenna or other load.

Abstract: A radio frequency integrated circuit includes a power amplifier, a low noise amplifier, a first transformer balun, and a second transformer balun. The power amplifier includes a first power amplifier section and a second power amplifier section. When enabled, the first and second power amplifier sections amplify an outbound radio frequency (RF) signal to produce a first amplified outbound RF signal and a second amplified outbound RF signal, respectively. The power amplifier provides the first amplified outbound RF signal to the first transformer balun and the second outbound RF signal to the second transformer balun, where the first transformer balun is coupled to a first antenna and the second transformer balun is coupled to a second antenna. The low noise amplifier includes a first low noise amplifier section and a second low noise amplifier section.

Abstract: An RF circuit configured to inteface a balanced port (1, 2, 11, 12) with an unbalanced port (4, 14) by emulating the function of a balun. Reactive components (20, 30, 120, 130) in both branches of a balanced circuit form two resonant circuits by resonating with parasitic reactance. At a predetermined operating centre frequency, one of the two resonant circuits is above resonance and the other is below resonance, resulting in a 180° phase difference between the signals delivered by the two branches. When used to interface an unbalanced signal source (10) to a balanced load (40), the input impedance may be set to a real value matching the output impedance of the signal source by selection of the reactive component (20, 30) values.

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 high-frequency power amplifier circuit offers the advantages of high input impedance, good linearity, high power efficiency and accurate bias current control in a compact and economical circuit configuration. The amplifier includes a single-ended output stage driven by a symmetrical push-pull emitter follower stage with both active pull-down and active pull-up capability. The emitter follower stage is driven by an active phase-splitter stage, with bias current for the phase-splitter stage and subsequent stages being provided by a bias-current control stage which is directly connected to the phase splitter stage. A linear voltage-to-current converter stage receives a high-frequency input voltage and provides a high-frequency current signal to the input terminal of the bias-current control stage that controls the current in the output stage.

Abstract: A high-frequency power amplifier circuit offers the advantages of high input impedance, high power efficiency and accurate bias current control in a compact and economical circuit configuration. The amplifier includes a single-ended output stage driven by a symmetrical push-pull emitter follower stage with both active pull-down and active pull-up capability. The emitter follower stage is driven by an active phase-splitter stage, with bias current for the phase-splitter stage and subsequent stages being provided by a bias-current control stage which is isolated at high frequencies from the high-frequency input signal to the amplifier.

Abstract: An amplifier circuit (30) has the capability for driving a large number of loads while still maintaining the desirable gain response. The amplifier circuit (30) includes two push-pull amplifier circuits (31 and 41). A first push-pull amplifier circuit (31) has a pair of bipolar transistors (33 and 34) connected in a cascode circuit configuration and a second pair of bipolar transistors (35 and 36) connected in a cascode circuit configuration. In addition, the second push-pull amplifier circuit (41) has a first pair of bipolar transistors (43 and 44) connected in a cascode circuit configuration and a second pair of bipolar transistors (45 and 46) connected in a cascode circuit configuration. The channel distortion and gain response of the amplifier circuit (30) are significantly improved by the push-pull amplifier circuits (31 and 41).

Abstract: A multiplexed audio-video signal transmission system has a camera-equipped intercom which produces a balanced audio-video signal. A twisted pair-wire connected to the intercom transmits a multiplexed signal of audio signal, video signal modulated to a frequency band not overlapping the audio signal frequency, and DC power. The audio signal and video signal are carried in the pair-wire in opposite phase in a balanced condition, and the DC power is carried between the pair-wire. A relay device is inserted in the pair-wire to refine the video signal. Main line branching device and door branching device are provided to branch out the multiplexed signal to a television equipped control unit 17.

Abstract: The invention is an operational amplifier having an output stage for enhancing the output driver capability near the negative source voltage. The output stage of the invention includes a voltage detector in combination with a current redirector or redirecting arrangement. The voltage detector converts the voltage difference between the amplifier output and the input to the output stage of the amplifier to a control current, which is redirected at the positive source voltage and applied to the negative output driver. The current redirector, which is operably connected to the voltage detector, allows the amplifier output to be driven at full rated current (e.g., approximately 40 mA) close to the negative source voltage (e.g., within approximately 1.5 volts) while maintaining an output configuration appropriate for stability.

Abstract: A current flowing from a power supply to a power amplification circuit is detected at two adjacent transmission periods having a non-transmission period therebetween. Between the two transmission periods, whether the current is increased or decreased is detected. When the increase is detected, an efficiency control signal is obtained to be supplied to the power amplification circuit by subtracting an increased amount between the two preceding transmission periods from an efficiency control signal used at the last preceding transmission period, and, when the decrease is detected, the efficiency control signal is obtained to be supplied to the power amplification circuit by adding the increased amount to the efficiency control signal used at the last preceding transmission period.

Abstract: A linearized power amplifier is provided which comprises a non-linear radio frequency (RF) power amplifier, a linearization circuit such as a Cartesian Feedback circuit, an RF feedback circuit; an IF feedback circuit; or a feedforward circuit, and a dynamic bias modulation circuit for modulating an operating voltage of the amplifier. The dynamic bias modulation means includes an envelope determining circuit, signal processing circuits in which predetermined data or a simplified transfer function determined from measured characteristics of the amplifier is stored and used to produce power bias and/or base or gate bias signals, and driver circuits for modulating the power supply voltage and/or base or gate bias voltage of the RF amplifier in response to the bias signals. The dynamic bias modulation may be used with a BJT-based, and FET-based or any other type of RF power amplifier.

Abstract: A family of wideband amplifier circuits using series and shunt feedback over two stages to achieve constant impedance, including single-ended, single-ended input/differential output and differential input/differential output forms.

Abstract: A differential amplifier which utilizes a pair of wideband operational amplifiers as output stages for two differential output signals, a pair of high performance DC operational amplifiers to buffer input signals to the pair of wideband operational amplifiers used as output stages and reduce offset voltage error by the amount of the DC gain of the pair of high performance DC operational amplifiers, apparatus for biasing the pair of high performance DC operational amplifiers to provide exceptional DC characteristics and eliminate common mode response from those amplifiers, and apparatus for feeding forward high frequency AC input to the wideband operational amplifiers operating as the output stages without loading the common mode input impedance of the differential amplifier.

Abstract: An operational amplifier achieves higher operating speed by using an all NPN transistor output drive stage. A control circuit in output drive stage receives an input signal and providing first and second control signals. The first and second control signals in turn drive first and second NPN output drive transistors arranged in a totem pole configuration between first and second power supply conductors.

Abstract: A transceiver interface device in accordance with the present invention includes features which allow the transceiver to be switched for operation in either a differential or a single-ended mode. First, the output levels of the transceiver's differential line driver are switchable between TTL levels and non-TTL levels with small differential swings. Second, the transceiver's differential receiver is switchable between a differential threshold and a single-ended TTL threshold. Third, while in differential mode, both outputs of the driver may be placed in the high impedance state or active at the same time, but it is also possible to switch to a single-ended mode in which one driver output is in the high impedance state while the other can be switched between being active or being in the high impedance state. Fourth, the transceiver uses the SCSI standard DIFFSENS pin or driver enable signal for switching between differential mode and single-ended mode operation.

Abstract: A two terminal line driver employing predistortion is disclosed, for driving data over a lossy transmission line such as a twisted pair cable at speeds on upwards of 10 Mbit/s. The driver is designed for voltage output operation wherein fullstep and halfstep information is actively encoded into a voltage level provided for at the output terminals. The driver provides a fullstep voltage spanning the supply rails and a halfstep voltage having a selectable controlled amplitude of a predetermined value. Fat bits resulting from the biphase encoding format are predistorted by dropping the amplitude to a predetermined value, equalizing the relative power content.

Abstract: A phase inverter includes first, second, third and fourth terminals, a first coupling circuit coupled between the first and second terminals, a second coupling circuit coupled between the second and third terminals, a third coupling circuit coupled between the third and fourth terminals, and a fourth coupling circuit coupled between the first and fourth terminals. The first to fourth terminals and the first to fourth coupling circuits are arranged into a ring. The first coupling circuit is of a type different from a type of the fourth coupling circuit. The second and third coupling circuits are identical in type. Two output signals having a phase difference of 180.degree. are drawn from the second and fourth terminal when an input terminal is applied to the first terminal, and an output signal is drawn from the first terminal when two input signals having a phase difference of 180.degree. are applied to the second and fourth terminals.

Abstract: A balun is formed by printed tracks (20,22) on a printed circuit board. A first conductor to one side of the board extends between ground (13) and single ended signal port 11. A second conductor to the other side of the board extends between ground 21 and a balanced signal port (12) in electrical symmetry. The arrangement provides a construction wherein the balanced side of the balun is entirely on one side of the board, resulting in symmetrical parasitic effects in the balanced limbs. Also cross board connections are not required. The balun allows a printed circuit form to be used where parasitic effects are likely, such as high frequency power amplifiers with their associated large heat sink, replacing other forms, such as coaxial cable types.

Abstract: This application concerns a simple passive circuit that improves current balance in paralleled power MOSFETs that are not precisely matched and that are operated in their active region from a common gate drive. A nonlinear circuit consisting of diodes and resistors generates a differential gate potential required to correct for unbalance while maintaining low losses over a range of current.

Abstract: A radio frequency amplifier includes a first pair of quadrature couplers arranged to provide in response to an input signal first and second radio frequency signals having equal amplitudes and a first single-ended amplifier is fed by said first radio frequency signal to provide at an output thereof an amplified first signal having frequency components corresponding to a fundamental frequency of the input signal and second order products of the input signal. A second single-ended amplifier is fed by said second radio frequency signal for providing at an output thereof an amplified, second signal having second order products of the input signal and 180.degree. phase shifter frequency of the input signal.

Abstract: A double balun circuit is provided by connecting two pairs of circut types. The first circuit, a distributed divider circuit, includes first and second pluralities of field effect transistors, a common input transmission line, and a first and second output transmission lines. The common input transmission line is disposed to successively couple the input electrodes of each transistor of both the first and second pluralities of transistors. The output lines are disposed to successively couple the output electrodes of the respective ones of the plurities of transistors. Each output transmission line is coupled to one of the pair of output terminals of the circuit.

Abstract: A hot melt adhesive applicator operable at a number of selected temperatures having a portion of the circuitry for control of the applicator temperature at a point remote from the applicator body. The remotely located circuitry employs a differential amplifier and a zero crossing detector for controlling the operation of a triac which, when turned on, increases the temperature at the applicator. The operational amplifier is protected by a clamping circuit from receiving a signal, when a temperature setting is changed from a high to a low setting, that would otherwise cause the differential amplifier to provide an output required for turning on the triac which would cause a run away condition to exist.

Abstract: An amplifier with double rail output being a switchable to single rail output is provided by power pumping circuitry which is controllable by an error detector to deliver modulated power pulses from a d.c. power source to on-following current steering circuits for coupling to either or both of first and second output terminals. In one embodiment the amplifier is envisaged in an integrated circuit form wherein the current steering circuits are provided by switched voltage multipliers of novel structure so that voltage stress of some capacitive elements is reduced, thereby reducing the area these elements would otherwise occupy in the integrated circuit.

Abstract: A transistor circuit is provided with a symmetrical floating configuration for attaining multifunction operation of a transistor having symmetrical source and drain characteristics, preferably a GaAs MESFET. The circuit includes a balun which may be configured as a transformer, a differential amplifier, or a magic-tee waveguide depending on the frequency of signals to be processed by the circuit. Balanced terminals of the balun may be directly or capacitively coupled to source and drain terminals of the transistor. Tuning circuits are employed for applying signals having different frequencies to the transistor and for extracting intermodulation products generated by the transistor in response to the signals at the different frequencies. With the direct connection between the balun and the transistor, alternating voltages may be impressed between the terminals of the transistor to alternate source and drain regions of the transistor.

Abstract: A transformer isolated high voltage, high power system is disclosed which is suitable for driving servo motors in servo loop control systems or the like. A D.C. current control loop is provided for preventing transformer saturation without gapping the transformer core. An output control loop is provided which minimizes signal crossover distortion and input/output phase shift. Crossover distortion adjustment is also implemented.

Abstract: A low voltage sixteen bit digital-to-analog converter operable between +5 and -5 volt power supplies and capable of providing output voltage levels to within about 1.4 volts of +V.sub.CC and -V.sub.CC includes a push-pull output stage with only a pullup transistor and a pulldown transistor connected in series between the positive and negative supply voltages. The output stage includes circuitry that reduces the base voltage of the pullup transistor or pulldown transistor enough to reduce its collector current to near zero, greatly increasing its effective collector-to-emitter breakdown voltage.

Abstract: A class B IC transistor output stage, using a pair of NPN transistors, is described. A quasi-complementary transistor is employed to establish the stage quiescent bias. An NPN bias transistor is coupled to the output sink transistor and is driven from the emitter of the input driver transistor. Therefore, the input signal is coupled to apply the signal directly to the base of the sink transistor as well as to the source transistor. This feedforward arrangement by-passes the PNP transistor when a signal is applied so that the asymmetrical performance of the PNP transistor does not adversely affect the signal performance.

Abstract: A deflection control circuit for a plural-tube color television camera adjusts the deflection sawtooth waves furnished to the red and blue image pickup tubes to register the images thereof with the image of the green pickup tube, and eliminate any centering, skew, rotation, or other errors. The circuit includes a pair of controllable complementary transistors, with current outputs connected together in series. An impedance is connected to the junction of the current outputs, and a sawtooth wave, furnished directly to the green pickup tube, is also supplied therethrough. A correction signal generator preferably formed of an integrated-circuit operational amplifier supplies a correction voltage to control terminals of the transistors so that the current through the latter changes complementarily. An adjusted output sawtooth wave is provided from the junction to the transistors to one of the red and blue pickup tubes. Because the correction signal generator operates at low voltage, such as .+-.

Abstract: An operational amplifier includes an input stage, an output stage including first, second and third NPN output transistors, and an intermediate stage. The first NPN output transistor sources load current to an output terminal while the second and third output transistors sink load current therefrom. The output of the intermediate stage is coupled to the base of the third NPN transistor and, via a resistor, to the base of the second NPN transistor. A first Miller capacitor is coupled between the input of the intermediate stage and the amplifier's output terminal, and a second Miller capacitor is coupled between the base of the second NPN transistor and the output terminal.

Abstract: An operational amplifier is disclosed which is capable of handling input voltages in excess of 200 volts, comprising at least in the input stage thereof a plurality of low voltage transistors including at least a pair of low voltage lateral PNP transistors each having two collectors. These lateral PNP transistors act as level shifters for the amplifier and also a bias arrangement for the input stage. A single high voltage lateral PNP is in the signal path providing the lowest pole in the transfer function and to compensate for low to medium loop gains.

Abstract: The invention provides an improved class-B push-pull output stage comprising a first and a second output transistor of a first conductivity type, which stage is provided with a control loop for driving the second transistor in phase opposition as a function of the drive of the first transistor. Said control loop is adapted so that a stable quiescent-current setting is obtained and that the effect of poor high-frequency properties of a third transistor of a conductivity type opposite to the first conductivity type, which transistor is necessarily included in the control loop, is eliminated, so that a wide frequency range is obtained.

Abstract: A bridge amplifier is provided wherein one end of a load device is driven by a first amplifier and the other end of the load device is driven by a second amplifier. The second amplifier is an inverting amplifier comprising P and N-channel field-effect transistors, having complementary symmetry conduction characteristics. The input to the second amplifier is directly coupled to the output of the first amplifier.