Analog Devices,inc.

Other

Analog Devices Global

Fast Technology Ag

Adrian P Brokaw

Modesto A Maidique

Jeffrey G Barrow

Jerome F Lapham

Barrie Gilbert

Lutz May

Yang Zhao

Alexander Dribinsky

Kimo Y F Tam

Chau Cuong Tran

Stefano I D'Aquino

Albert M Leung

Thomas J Conway

David Hall Whitney

Patrick J Meehan

Donal G O'Sullivan

Gregory P Pucci

Michael E Rebeschini

Michael P Timko

A circuit and method to filter a signal is provided. The circuit includes a notch filter circuit to receive an input signal and first and second tuning signals and to provide an output signal. The notch filter circuit has an input-output frequency response that includes a stopband region. The stopband region has a center frequency and has an attenuation level that is based at least on a tuning signal. The tunable filter circuit further includes a tuning circuit operable in at least two modes to generate the tuning signal. The at least two modes includes a tuning mode and a filtering mode. The tuning circuit generates the tuning signal such that the attenuation level of the stopband region is greater in the filtering mode than in the tuning mode.

Resonance detection and filtering circuitry

A high gain amplifier includes a differential amplifier stage having a pair of transistors; first and second input circuits for providing input signals to the pair of transistors; transistor means arranged as a differential-to-single-ended converter driven by the differential amplifier stage to provide a single ended output signal; an intermediate gain stage having an input responsive to the single ended output signal; bias means for the differential amplifier, the bias means including circuit means for maintaining the currents through the pair of transistors in constant ratio independently of changes in load at the intermediate gain stage; and an inverting gain output stage driven by the intermediate gain stage and having an output for driving a load substantially from rail to rail. Also disclosed is a frequency compensation capacitor circuit connected between the input of the intermediate gain stage and the output of the inverting gain output stage.

High gain amplifier with rail to rail range and frequency compensation

An integrated convective accelerometer device. The device includes a thermal acceleration sensor having a thermopile and a heater element; control circuitry for providing closed-loop control of the thermopile common-mode voltage; an instrumentation amplifier; clock generation circuitry; voltage reference circuitry; a temperature sensor; and, output amplifiers. The device can be operated in an absolute or ratiometric mode. Further, the device is formed in a silicon substrate using standard semiconductor processes and is packaged in a standard integrated circuit package.

Thermal convection accelerometer with closed-loop heater control

A current mirror replica biasing system where the resistor-programmable base current of a current reference transistor is accurately and scalably mirrored and input to the base of an output transistor, the current provided by the output transistor being useful as bias current to a load circuit, including a current reference transistor and an output transistor of like polarity; a pair of bipolar transistors, of like polarity to each other and opposite polarity to the current reference transistor and output transistor, arranged as a current mirror to mirror the base current of the current reference transistor, which base is exclusively interconnected to the input of the current mirror; and a current source to establish a desired reference current in the current reference transistor; wherein variations in the current source circuitry can result in circuit performance of the current mirror replica biasing system that is proportional to absolute temperature, or other desired function.

Current mirror replica biasing system

A high gain amplifier includes an intermediate gain stage; an output gain stage driven by the intermediate gain stage; an input stage, for driving the intermediate gain stage, which is balanced between positive and negative feedback in normal operation; bias means for driving the input stage to maintain balance between positive and negative feedback in normal operation; and a resistance for limiting the output current of the intermediate stage in response to the input stage being overdriven into positive feedback.

High gain amplifier with current limited positive feedback

A dynamic bridge system with common mode range extension includes a dynamic bridge circuit having a pair of input terminals for receiving common mode and normal signals, a pair of intermediate terminals and an output terminal and reference terminal; a differential amplifier has its inputs connected to the intermediate terminals and its output connected to the output terminal; a pair of balanced loads is each connected at one end to an intermediate terminal; and an inverting amplifier responsive to the common mode signal at the inputs of the differential amplifier drives the other ends of the balanced loads in opposition to changes in the common mode signals at the inputs of the differential amplifier.

Dynamic bridge system with common mode range extension

A circuit for sensing a magnetic field has at least one saturable coil (L ). The circuit includes switches (S , S ) controlled by a comparator ( ) to drive the coil (L ) to saturation by alternating polarities of current. In the absence of an external magnetic field the currents are balanced. An applied external magnetic field causes an unbalance in the coil (L ) in reaching saturation. An unbalance current is applied through a sensing resistor (R ) to an integrator ( ) to develop an output voltage (V ) as a measure of the applied magnetic field. The switches (S , S ) are implemented by transistor switches. Dual (FIG. ) and single (FIG. ) supply rail circuits are disclosed. The circuit finds particular application in torque transducers using magnetoelastic elements.

Conditioner circuit for magnetic field sensor

An Early voltage and beta current compensated cascode current mirror includes a cascode current mirror having an input stage responsive to an input current, a current mirror circuit having a first stage responsive to the input stage and a second stage responsive to the first stage, and an output stage responsive to the second stage for providing an output voltage and current; and a compensation circuit, responsive to the cascode current mirror, having a first compensation stage, a second compensation stage and a bootstrapping buffer, the first compensation stage, in response to a change in the output voltage, impressing a corresponding change in voltage on the second compensation stage, the second compensation stage thereby providing a change in current to the cascode current mirror for cancelling current errors induced by base current modulation in the output stage, the bootstrapping buffer, in response to the change in voltage, impressing a corresponding change in voltage on the first compensation stage to prevent errors from base current modulation effects in the first compensation stage, the first and second compensation stages further providing a base current to the cascode current mirror for cancelling base current errors in the output current induced by the cascode current mirror.

Early voltage and beta compensation circuit for a current mirror

A single-loop voltage regulator controller includes a high-gain transconductance amplifier that accommodates common mode inputs as low as its negative supply rail. The input stage of the amplifier produces a proportional to absoulte temperature (PTAT) input offset voltage. The transconductance amplifier's inverting input is connected to the circuit common, or negative supply rail, and a tap from a feedback network is connected to the amplifier's noninverting input. The feedback network provides, at this tap, a PTAT measure of the regulator's regulated output. The amplifier's output is connected to drive a noninverting driver which, in turn, is connected to drive the control terminal of the regulator's pass transistor. A compensation capacitor connected between the amplifier's output and the regulated output terminal ensures the regulator's stability even for relatively low level load impedances.

Stable low dropout voltage regulator controller

A low-leakage-current JFET having electrically isolated top and bottom gates. The structure employs enclosed geometry wherein one source/drain region fully surrounds the other source/drain region. Connection to the top gate is made through a diffusion-barrier to prevent penetration of metallization into the top gate contact region. A non-penetrating contact layer is provided on the upper surface of the top gate so that the material of the contact layer does not enter the top gate region to any significant extent. Both the channel region and the shield layer are formed by ion-implantation.

Low-leakage JFET having increased top gate doping concentration

An auto-TC voltage reference wherein an operational amplifier receives at one input the voltage of a Zener diode and at its other input receives a compensation signal from a feedback circuit comprising a transistor and resistor network. When one of the resistors of the network is trimmed to give a nominal output voltage for the reference, the TC of the reference voltage will have been reduced to zero, or nearly so. The circuitry is capable of compensating Zener diodes of either positive or negative TC.

Apparatus and method for temperature-compensating Zener diodes having

A trimmable resistor network including a plurality of series-connected sections each including a plurality of paralleled link resistors each capable of being cut so as to be eliminated from the network, the paralleled resistors in each section having resistance values such that the section resistance changes by at least approximately integral multiples of a fixed amount when the resistors are cut.

Trimmable resistor network providing wide-range trims

Low-leakage JFET

An IC band-gap voltage reference including a pair of transistors having different emitter areas and driven by an amplifier feedback circuit to produce equal collector currents so as to develop an output voltage corresponding to the band-gap voltage. The amplifier output network includes a resistor network arranged to produce an output voltage which is a predetermined multiple of the band-gap voltage. The circuit provides for independent trimming of elements for adjusting the output voltage magnitude and its temperature coefficient.

Growing community of inventors

Burlington, MA, United States of America

Adrian P Brokaw