Abstract: A compensating circuit for providing a compensating control signal to a regulating circuit is provided. The compensating circuit includes a multiplying circuit and a miller capacitor. The multiplying circuit may provide a predetermined multiplication factor to a miller current level based on a resistor ratio. The multiplying circuit may also provide a voltage gain stage before the miller capacitor. Both multiplying circuits enable the size of the miller capacitor to be reduced resulting in valuable printed circuit board space savings.

Abstract: A system is provided for activating gain stages in an amplification module. The system includes an amplification module including a first group of amplifiers. Inverting output ports of each of the first group of amplifiers are coupled to a module inverting output terminal, and non-inverting output ports are coupled to a module non-inverting output terminal. A divider network is provided and is coupled to the input ports of the first group of amplifiers. A second group of amplifiers is also provided. Each amplifier of the second group corresponds to one of the amplifiers in the first group, has an inverting input port coupled to the second module inverting input terminal and to output ports of the divider network, and a non-inverting input port coupled to the second non-inverting input terminal.

Abstract: A differentail amplifier with input gate oxide breakdown avoidance amplifies a difference between two signals while maintaining voltage drops across transistor utilized in the differential amplifier to below a gate oxide breakdown level. A pull up structure added to a traditional differential amplifier allows the circuit to be utilized in IO pads of an integrated circuit and to be composed of thin oxide transistor normally only found in the core circuitry of the integrated circuit and. The pull up structure is composed of three thin oxide transistors, the first transistor is connected in series with the other two, and the other two connected in parallel with respect to each other.

Abstract: The invention provides a method and apparatus for performing a voltage to current conversion. In particular, the invention provides a voltage to current converter configured to vary its transconductance (Gm). Such a converter is configured to receive a voltage input signal combined with a reference voltage signal to be converted to a current output. Optionally, the reference voltage signal may be provided by a parabolic impedance network that includes a bank of resistors and a plurality of corresponding current sources. Each current source corresponds to each node between two resistors, and may be varied in order to program changes in the comparator's Gm. Each resistor and corresponding current source is configured to create an individual reference voltage reference having a value that occurs in a parabolic manner in relation to other voltage references occurring across the impedance network.

Abstract: A driving current flowing through a first output transistor is given to a stator coil of a three-phase motor (first operation), a driving current flowing through the stator coil is output to the ground through a second output transistor (second operation), and no current flows through the stator coil during the off-state of both the first and second output transistors (third operation). Charge remaining in a gate of the first output transistor is rapidly output to the ground through an n-channel transistor for a short time at both the end of the first operation and the start of the second operation. Charge of a high voltage remaining in the stator coil is output to the ground through a voltage clamp circuit as a clamp current during the first and second operations while controlling the clamp current to a low value in a constant current circuit.

Abstract: A variable offset amplifier circuit includes two differential transistor pairs and a variable current generator coupled to each differential pair to control tail current. Each differential transistor pair has a first transistor and a second transistor. The first transistors are matched in size, as are the second transistors. The bias terminals of the first and second transistors serve as inputs to the amplifier circuit. The output of the amplifier circuit is associated with the differential pair output nodes of only similarly sized transistors, such that loads at the output of the amplifier circuit are sourced with current only from similarly sized transistors of the transistor pairs. The variable current generators may be adjusted to create offset in the output of amplifier circuit. The amplifier circuit has applications in a comparator circuit that also has a regenerative latch circuit, and as a sense amplifier in a receiver of a communications system.

Abstract: A method and apparatus for calibrating a Gm cell using a Gm replica cell. A digital to analog converter receives a Gm setting code and generates a reference current. The Gm replica cell adjusts the tuning voltage until the difference between a pair of drain currents is substantially equal to the reference current. Where this condition is satisfied, the proper tuning voltage has been acquired. This results in proper calibration for the tuning voltage, which then may be utilized by a Gm cell connected with the Gm replica cell.

Abstract: A mirroring circuit operating at high frequencies is provided. The mirroring circuit includes a first branch having a first transistor in series with a first resistor, a second branch having a second transistor in series with a second resistor, and a servo circuit for controlling current flowing in the first branch and the second branch. The servo circuit includes a third transistor configured as a diode, a source of the third transistor coupled to a source of the first transistor, a fourth transistor configured as a shift lever, a source of the fourth transistor coupled to ground via a third resistor, a fifth transistor configured as a diode, a source of the fifth transistor coupled to a source of the second transistor, and a sixth transistor configured as a shift lever, a source of the sixth transistor coupled to ground via the third resistor.

Abstract: Various methods and apparatuses that multiply the effects of feedback current on an amplifier. In an embodiment, a buffer circuit controls the transition rate on an output pad of the buffer circuit. An amplifier has an input terminal and an output terminal. The output terminal couples to the output pad. A feedback component couples feedback current from the output pad to the input terminal. A current mirror multiplies the effects of the feedback current on the input terminal without increasing the feedback current through the feedback component.

Abstract: A differential line driver includes first, second, third and fourth cascode transistors connected in parallel, wherein drains of the first and third transistors are connected to a negative output of the differential line driver, and wherein drains of the second and fourth transistors are connected to a positive output of the differential line driver. First, second, third and fourth switching transistors are connected in series with corresponding first, second, third and fourth cascode transistors and driven by a data signal. First and second compound transistors inputting a class AB operation signal at their gates, wherein the first compound transistor is connected to sources of the first and second switching transistors, and wherein the second compound transistor is connected to sources of the third and fourth switching transistors.

Abstract: A data comparator using a dynamic reference voltage and an input buffer using the same. The data comparator comprises a comparator circuit for receiving a data signal and a pair of non-inverting/inverting signals, which are periodic and complementary. The output signal is generated by comparing twice the data signal with the sum of the non-inverting signal and the inverting signal. The non-inverting/inverting signals are used as a dynamic reference voltage in the data comparator.

Abstract: An amplifying circuit includes a differential amplifier for receiving input signals to generate output signals. A current regulator unit and an input enhancement unit allow the input signals to exceed the normal input range of the differential amplifier. The current regulator unit regulates current in the differential amplifier. The input enhancement unit steers current from a first current path to a second current path based on signal levels of the input signals.

Abstract: A gain stage is disclosed. The gain stage comprises a first stage that provides two voltages of equal and opposites polarities and a plurality of devices cross coupled to the first stage. The plurality of devices minimize the Miller Effect capacitance in the differential stage by providing an out-of-phase signal to the first stage. Accordingly, a system and method in accordance with the present invention utilizes an at least one extra device on the same die as the first stage to provide an impedance match. In so doing, a broadband cancellation of the Miller Effect is achieved. Moreover, the matching is valid over an extended temperature range.

Abstract: The driver circuit includes a constant current section, a first pad, a second pad, a first switching element, a second switching element, a first resistor, a second resistor, and a control section. The constant current section outputs a prescribed positive or negative current. The first switching element is connected between an output node of the constant current section and the first pad and turned ON/OFF in response to a first signal. The second switching element is connected between the output node of the constant current section and the second pad and turned ON/OFF in response to a second signal. The second signal is complementary to the first signal. The first resistor is connected between a first node receiving a first voltage and the first pad. The second resistor is connected between the first node and the second node. The control section controls a potential at the output node of the constant current section to a prescribed potential.

Abstract: A protection circuit for extending the dynamic range of an amplifier circuit is described. Off-chip impedances, such as inductors, cause the output of the circuit to swing above and below the bias voltage. A protection circuit is included, either on-chip or off-chip, to protect the integrated circuit components if there is a fault condition in either of the off-chip impedances.

Abstract: An inductive amplifier having a feed forward boost is provided, thereby improving the gain of the inductive amplifier at frequencies greater than 1 GigaHertz. The inductive amplifier includes a feed-forward boost circuit coupled to intermediate nodes of an inductive amplifier circuit, whereby the feed-forward boost circuit generates boost currents that are added to the currents of the inductive amplifier circuit. In one embodiment, the feed-forward boost circuit includes a boost current supply, a first boost transistor coupled between the current supply and a first intermediate node of the inductive amplifier circuit, and a second boost transistor coupled between the current supply and a second intermediate node of the inductive amplifier circuit. In one embodiment, the first and second boost transistors and the inductive amplifier circuit are controlled by the same differential input signals.

Abstract: A MOS differential amplifier circuit has a differential pair having first and second MOS transistors. The source electrodes of the first and second MOS transistors are commonly coupled and driven by a constant current source. The current sources can be controlled so that the difference between the common mode voltage and the common source voltage becomes constant, and a level shifter may be provided for level-shifting the common source voltage of the first and second MOS transistor. The MOS differential amplifier circuit so designed can be used in a voltage adder/subtractor circuit.

Abstract: A bi-directional buffer includes the capability to turn the current mirror off when the bi-directional buffer is in the receive mode and quickly turn the current mirror on when the bi-directional buffer goes into the transmit mode. This is accomplished in part by a pair of switches included in the current mirror, which are controlled by enable signals. The switches are configured such that the output transistor of the current mirror is turned on when the bi-directional buffer is in the transmit mode, and turned off when the bi-directional buffer is in the receive mode. Further, a pull up circuit may be added to the current mirror to more quickly bring the gate of the output transistor of the current mirror to its conduction threshold voltage.

Abstract: An operational amplifier comprises multiple stages. A differential input stage that includes an adaptive high voltage differential pair generates up and down output currents in response to up and down input voltages. The differential input stage includes adaptive common input high voltage (HV) bias. An intermediate stage converts the up and down output currents into a first output voltage signal. The intermediate stage includes a folded cascode arrangement. The intermediate stage is biased by fixed voltage bias signals. The intermediate stage also includes unaffected slew rate stability compensation and a combined split stability compensation. An output stage includes a class AB source follower driver that generates a second output voltage signal in response to the first output voltage signal. The output stage is biased with an adaptive push-pull source follower output HV bias. The output stage includes feed-forward slew rate enhancement.

Abstract: A circuit (100) for accurately tuning the absolute values of multiple parameters in a VLSI circuit by reusing a single external resistor. In the illustrative embodiment, the invention includes a first circuit (10) for generating an accurate transconductance using a single external resistor; a second circuit (20) for generating an accurate current reference using the same external resistor; and a switching circuit (60) for alternately switching on and off the first and second circuits in order to share the external resistor. The switching circuit (60) includes several switches controlled by a digital counter for turning off portions of the circuit which are not in use. In the illustrative embodiment, the invention further includes a third circuit (40) for generating one or more additional accurate reference signals. The third circuit can generate an accurate internal resistance Rint, an accurate drain to source resistance of a transistor rDS, and/or an accurate internal capacitance Cint.

Abstract: The performance of a conventional op amp, having a gm stage and an integrator, is improved by placing a current mode filter between the gm stage and the integrator, which has a current gain of much less than one and is substantially without phase shift at the op amp's resonant frequency, permitting stabilization with a relatively small compensation capacitor. This improves the signal slew rate and harmonic distortion.

Abstract: A variable offset amplifier circuit includes two differential transistor pairs and a variable current generator coupled to each differential pair to control tail current. Each differential transistor pair has a first transistor and a second transistor. The first transistors are for coupling to first and second loads. A current mirror and shunt is coupled to shunt a portion of current flowing through one of the first transistors from flowing through a correspondingly coupled load. The shunt current is mirrored from one of the second transistors to provide either positive current feedback or negative current feedback. The amplifier circuit has applications in a comparator circuit that also has a regenerative latch circuit, and as a sense amplifier in a receiver of a communications system.

Abstract: According to a particular example application, the present invention is embodied in the form of first and second current-steering sections arranged to steer a differential current input signal. Each of the first and second current-steering sections is current driven via differential current paths. The first current-steering section configured and arranged to source current and thereby drive the second current-steering section. Another aspect of the invention employs stacked Gilbert cells, as described above, to form a variable gain amplifier (“VGA”) circuit that achieves a large dynamic range, a wide frequency response and improved linearity, while consuming relatively low amounts of power.

Abstract: A multistage analog circuit for independently controlling a bias current in each stage of the multistage analog circuit having an input stage, an intermediate stage, and an output stage, includes a first current source which controls the input stage of the circuit, a second current source which controls the intermediate stage of the circuit, and a third current source which controls the output stage of the circuit. The bias current in each stage of the circuit is set by the first, second, and third current sources. An output voltage of the circuit is capable of remaining the same when the first current source is changed to affect an input transconductance of the circuit.

Abstract: A differential comparator having offset correction and common mode control providing stable op amp output that changes only due to the original inputs coming into the comparator. The difference comparator has increased common-mode difference tolerance, and large op-amp offset tolerance, as well as fast decision time.

Abstract: An isolated integrated differential current comparator for comparatively measuring the current passing through one or two resistors using a thermal difference sensor employing the Seebeck effect in an integrated circuit that is coupled to the resistors. The thermal difference sensor detects the temperature difference between the resistors, which is proportional to the square of the current passing through them. The output of the current comparator is electrically isolated from the inputs. The output is scalable and in circuit topologies requiring full signal isolation. The integrated differential current comparator is applicable to hot swap applications and applications where isolation of a number of signals is needed.

Abstract: An amplifier stage for a buffer with negative feedback includes an input stage having an input terminal, an output terminal, a first and a second supply terminal, a biasing branch, a first and a second balancing branch each comprising an active transistor for supplying, at the output terminal, a current depending on the current difference in the first and second balancing branches. The biasing branch and the first and second balancing branches are connected in parallel between the first and second supply terminals. The input terminal divides the biasing branch into two input branches having a constant-current generator. Each active transistor is connected to a corresponding current generator for receiving a control voltage correlated with a voltage at the terminals of the current generator.

Abstract: An active digital voltage regulator circuit is a two terminal device that is connected in shunt to first and second power supply input lines. The active digital voltage regulator circuit stores energy during times when the local power supply voltage is greater than a predefined voltage, e.g., during times when the parasitic inductances supplement the local power supply voltage. The active digital voltage regulator circuit uses the stored energy to supplement the local power supply voltage during times when the local power supply voltage starts to collapse, e.g., during periods when inductive losses are preventing the power supply from maintaining the local power supply voltage. Consequently, digital active voltage regulator circuit smooths the local power supply voltage by greatly ameliorating the ripple voltages associated with parasitic inductances and resistances. A control circuit within the regulator circuit is a combination of two self-biasing and off-set nulling power supply monitor circuits.

Abstract: The common-mode feedback circuit generates currents representing the output voltages of a fully differential amplifier, and sums these current to produce a summation current. Based on the comparison of the summation current to a reference current, the common-mode feedback circuit generates a feedback voltage for stabilizing the fully differential amplifier.

Abstract: An elementary cell structure for programmable time-continuous analog filters and in particular for the processing of analog signals in read/write operations on magnetic supports comprises an amplifier stage provided with a pair of structurally identical transconductance half-cells connected together in a common circuit node. With a cascade of cells of this type is provided a time-continuous analog delay line which is used in a transverse time-continuous analog filter. This filter comprises a cascade of identical delay lines connected through multiplier nodes to a final summation node.

Abstract: A metal-oxide semiconductor field-effect transistor (MOSFET) amplifier circuit includes a compensation circuit with a low cost MOSFET and a constant current circuit providing a constant drain current of the MOSFET, which maintains an operational point of the amplifier at an optimal state at all times. The MOSFET amplifier circuit includes a first MOSFET, a constant current circuit including a variable resistor, an operational amplifier, a power supply and a resistor, a second MOSFET having a constant current generated by the constant current circuit as a drain current thereof, and a voltage control circuit including operational amplifiers and resistors for applying a gate source voltage of the second MOSFET to the first MOSFET as a gate-source voltage thereof.

Abstract: A fully differential circuit in which all inputs and outputs of transconductors Gm1+, Gm1−, Gm2+, Gm2− and fixed gain amplifier GA are fully differential signals. The number of feedback loop elements is made odd by the addition of a fixed gain amplifier with a gain of 1 which is not used in conventional filter architecture, each element of the configuration consequently inverts the common voltage, and since the feedback loop has negative feedback with respect to the common voltage, the operating point can be determined without a need for a dedicated DC feedback circuit.

Abstract: A tunable integrator circuit having a main amplifier with an input resistor R and a feedback capacitor C and a tuning amplifier having a variable gain k between the output of the main amplifier and the feedback capacitor. The circuit has an effective capacitance of kC. Thus the integrator can be tuned to compensate for temperature and processing variations of the RC product by adjusting the gain of the tuning amplifier. The tuning amplifier can also be used to multiply the effective capacitance of the filter, kC, by increasing the gain k of the tuning amplifier beyond that needed to compensate for RC variations, thus reducing the area required for on-chip capacitances while maintaining a constant resistance. The circuit can be used independently or in conjunction with a capacitor array.

Abstract: A semiconductor integrated circuit device for a magnetic disk apparatus has analog circuits such as a read/write circuit and digital circuits such as an interface driver circuit, a control circuit, and a stepping motor driver circuit, all of these circuits operating on a single supply voltage. The semiconductor integrated circuit device further has a voltage regulator whose output voltage is lower than the supply voltage and variable according to the voltage applied to an output voltage adjustment terminal. The control circuit operates on the output voltage of this regulator.

Abstract: An integrated transconductor circuit has an active load element and two parallel sets of transconductor stages. The active load element provides a high impedance without requiring a large area within the integrated transconductor circuit, and provides linear impedance when the active load devices are biased in the triode region of their respective characteristic curves. The multiple transconductor stages prevent saturation from reducing the dynamic range available at the output of the transconductor circuit. The parallel sets of transconductor stages are used to improve output linearity by reducing the differences between the threshold voltages of the serially-connected transconductor stages.

Abstract: A clock buffer circuit includes an amplifier section and a control section. The amplifier section amplifies a clock signal in response to a control signal. The control section generates the control signal based on an amplitude of the clock signal.

Abstract: In an emitter follower circuit, a bipolar transistor is connected to a resistor element. The bipolar transistor has a temperature dependent characteristic. A current source circuit is connected to the resistor element to flow a current through the resistor element such that a voltage drop by the resistor element has an opposite temperature dependent characteristic to the first temperature dependent characteristic of the bipolar transistor.

Abstract: An integrated circuit having a passive circuit component that can be adjusted following the manufacturing process to provide a precise absolute value for resistance or capacitance. A plurality of passive elements are selectively combinable using logic gates to include or exclude each element from a network, wherein the combined value of the included passive elements equals the value of the passive circuit component. The logic gates are set by outputs from a decoder to reduce the required inputs to the chip.

Abstract: A mixing circuit for combining biasing and signals using a selectively variable signal gain which is independent of the biasing and using biasing which is independent of the selectively variable signal gain. A Gilbert cell is used to multiply a differential control voltage, which represents a normalized signal gain factor, with input currents which include biasing components and input signal components. The resultant output current includes a bias component which is independent of the differential control voltage and a signal component which is independent of the input current biasing components. The gain factor has a value between zero and unity which varies in relation to the differential input control voltage.

Abstract: A tunable integrator circuit having a main amplifier with an input resistor R and a feedback capacitor C and a tuning amplifier having a variable gain k between the output of the main amplifier and the feedback capacitor. The circuit has an effective capacitance of kC. Thus the integrator can be tuned to compensate for temperature and processing variations of the RC product by adjusting the gain of the tuning amplifier. The tuning amplifier can also be used to multiply the effective capacitance of the filter, kC, by increasing the gain k of the tuning amplifier beyond that needed to compensate for RC variations, thus reducing the area required for on-chip capacitances while maintaining a constant resistance. The circuit can be used independently or in conjunction with a capacitor array.

Abstract: A CMOS output stage for providing stable quiescent current. The output stage includes a circuit that relates the quiescent current to the channel geometry of a power NMOS transistor and of an NMOS reference transistor of a reference current source. This configuration removes the dependency of the quiescent current on a power PMOS transistor used in the CMOS output stage, the threshold voltage of which may drift over time under high current and voltage operation, and adversely affects quiescent current stability.

Abstract: A switchable biasing device for an analog CMOS differential amplifier provides a supply bias current and a corresponding input bias voltage to achieve reliable performance with various power supply voltages. The bias device may include a control element having states corresponding to power supply voltages. The control element controls a supply bias circuit for supplying bias current to a differential amplifier at a level corresponding to the power supply voltage represented by a control signal from the control element. The bias current is made lower for a low power supply voltage to ensure that current source stage elements of the differential amplifier operate within their saturation region, and higher for a high power supply voltage to ensure sufficient current to maintain slew rates. The control element further controls an input bias circuit for providing a dc bias voltage at inputs of the differential amplifier at levels corresponding to the power supply voltage represented by the control signal.

Abstract: A circuit to be used in a power amplifier element to achieve triggered bias control of one or several individual transistors in the amplifier element in relation to their individual tolerances. A control circuit is provided for each transistor, each control circuit being controlled by a common controller and including an integration circuit for suitable balancing of the different individual threshold voltages of each transistor.

Abstract: To compensate the offset of a differential stage, the stage has at least one programmable, floating gate transistor with a programmable threshold, which is initially set to a threshold level other than the required threshold value, so that the differential stage is initially unbalanced. A balance input voltage is applied to the inputs of the differential stage. A programming voltage is applied to the programmable transistor to modify the set threshold until the differential stage switches. Upon switching, the programming voltage is cut off immediately, so that the charge required for the differential stage to be balanced with a balance input voltage is memorized in the programmable transistor.

Abstract: An stable inverted amplifying circuit includes an odd number of CMOS inverters and a feedback capacitance. Balancing resistances decrease the inverter open gain and limit the gain of the entire circuit. Serial capacitances act to prevent low-frequency oscillation. Oscillation-preventing circuits are also provided to reduce high-frequency oscillation. Sleep, refresh, and sleep-refresh switches are used to cancel residual loads and reduce power consumption.

Abstract: A punch-through diode includes a first and second gate forming first and second junctions respectively with and spaced from each other by a first region. The junctions may be PN junction or Schottky barrier junctions with the first region. The diode may be the top gate-channel-bottom gate junctions of an FET or the collector-base-emitter junctions of a bipolar transistor. In either case, the channel or the base is depleted and currents flow between the top and bottom gate or the emitter and collector respectively. The punch-through diode is used as a voltage reference element and can be structured for Kelvin connection.

Abstract: A punch-through diode includes a first and second gate forming first and second junctions respectively with and spaced from each other by a first region. The junctions may be PN junction or Schottky barrier junctions with the first region. The diode may be the top gate-channel-bottom gate junctions of an FET or the collector-base-emitter junctions of a bipolar transistor. In either case, the channel or the base is depleted and currents flow between the top and bottom gate or the emitter and collector respectively. The punch-through diode is used as a voltage reference element and can be structured for Kelvin connection.

Abstract: An operational amplification circuit having no crossover distortion includes a pair of differential amplification circuits, a pair of level shift circuits, a pair of current source circuits, and an output circuit. Each of the differential amplification circuits includes two MOS transistors having gates connected to a respective pair of input terminals. The differential amplification circuits generate first and second signals. The level shift circuits connected to the differential amplification circuits shift the level of the first and second signals. Each of the level shift circuits includes complementary MOS transistors. The current source circuits supply a predetermined current to one of the transistors of the level shift circuits. The output circuit is connected to the level shift circuits for generating an output signal.

Abstract: In a voltage comparator of the present invention, across a gate and a source of an amplifier transistor, a phase compensating capacitor and a first switch circuit are connected with each other in series, and a second switch circuit for short-circuiting the phase compensating capacitor is provided. The second switch circuit is turned on when the first switch circuit is turned off so as to (1) short-circuit the phase compensating capacitor and (2) discharge the phase compensating capacitor which has been charged while the first switch circuit was turned on. This permits to completely turn off the first switch circuit, and to prevent distortion of an output signal outputted from an output terminal, thereby preventing accumulation of unnecessary charges in the phase compensating capacitor.

Abstract: An output circuit includes: a constant voltage source; a first transistor of a first-conductivity type having a gate connected to the constant voltage source; a second transistor of a second-conductivity type that is opposite to the first conductivity type, having a source connected to a source of the first transistor and a gate connected to a circuit input terminal; a third transistor of the first-conductivity type having a drain connected to a circuit output terminal and a gate connected to the circuit input terminal; a current-current converter circuit for outputting current proportional to drain current of the second transistor to the circuit output terminal; and a voltage supply for supplying an output voltage to and operating the first to third transistors and the current-current converter circuit. Here, an output current of the current-current converter circuit and a drain current of the third transistor can be determined according to the output voltage of the constant voltage source in a steady state.