Analog Devices,inc.

Sipex Corporation

Other

Picor Corporation

Alex Gusinov

Jeffrey B Van Auken

Patrizio Vinciarelli

A Paul Brokaw

Moshe Gerstenhaber

Lawrence M DeVito

Scott A Wurcer

John P Clarkin

Douglas W Babcock

Robert A Duris

Claudio Tuozzolo

Lewis W Counts

Manuel R Gheeraert

Bassem M AlNahas

High-performance low-power isolated bootstrapped gate drive apparatus and methods are disclosed for driving high-side and floating transistors. The gate drivers use edge-triggered capacitive-coupled inputs. The gate drivers may include detection and delay circuitry to facilitate zero-voltage-switching of the high side or floating transistor and providing more robust rejection of false triggering. A capacitively coupled differential input edge triggered gate driver provides exceptional immunity to false triggering. The gate drivers may be used in transformer coupled drive circuits using transformers that need only support coupled pulses wide enough to be recognized as an edge by the input circuit.

Capacitively coupled floating gate driver

A bandgap voltage reference circuit wherein a voltage change is induced across one element to compensate for the temperature-induced voltage change across another element. A stable voltage reference is realized across the series combination of the two elements. The circuit includes an operational amplifier, two transistors, a voltage divider and a non-linear temperature-dependent element. The operational amplifier has two input terminals and an output terminal. The voltage divider includes two resistor in series and is coupled to the operational amplifier output terminal. Each of the transistors has a collector corresponding to one of the operational amplifier input terminals, a base corresponding to one of the voltage divider resistor terminals, and an emitter coupled to a common voltage terminal. The non-linear temperature-dependent element is disposed between the voltage divider output terminal providing the lower voltage and the common voltage terminal. In one embodiment, the non-linear temperature-dependent element is a diode. In another embodiment, the non-linear temperature-dependent element is a bipolar junction transistor. The invention also relates to a method of providing a bandgap reference voltage.

Bandgap voltage reference circuit

A method and circuit for error current compensation is presented. The method includes the steps of generating a first current and an associated error current, generating a second current and an associated error current substantially equal to the first current and the first error current, respectively, and generating a third current substantially equal to the first current. The method includes the additional steps of extracting the second error current from the second current, generating a multiplied current equal to the scaled error current plus a multiplier error current, and combining the multiplied current with the first current and first error current. The circuit for error current compensation includes a first, second and third current source, a multiplier, and a first and second subtractor. The first subtractor provides a first difference current equal to the difference of a second current and second error current generated by the second current source and a third current generated by the third current source. The multiplier generates a predetermined multiple of the second error current and a multiplier error current at its output terminal. The second subtractor provides a second difference current at its output equal to the difference of the predetermined multiple of the second error current and a multiplier error current from the output of the multiplier and a first current and first error current generated by the first current source. The second difference current is substantially equal to the first current from the first current source.

Method and apparatus for error current compensation

Control circuit for providing the greater of a supply voltage V.sub.CC and a battery voltage V.sub.BATT. A comparator compares V.sub.CC and V.sub.BATT, and provides output signals to an inverting gain stage. A switch receives output signals from the inverting gain stage and provides the greater of V.sub.CC and V.sub.BATT as the circuit output and as the comparator supply voltage. The circuit output voltage rapidly switches between V.sub.CC and V.sub.BATT as the comparison status of the two voltages changes.

Voltage comparator circuit

A differential line driver having a pair of transistors arranged as a differential pair for driving a transmission line with a differential logic output signal produced in accordance with a differential logic input signal fed to the base electrodes of the pair of transistors. The differential line driver includes circuitry for suppressing EMI emissions generated by common mode voltage switching transients produced at the collector electrodes of the pair of transistors in response to changes in the differential logic input signal. The common mode voltage switching transient suppression circuitry includes a pair of additional transistors. The differential logic input signal is fed to base electrodes of the additional transistors, and through such additional transistors, to the base electrodes of the pair of transistors of the differential pair. In one embodiment of the invention, the additional transistors are connected in a Darlington pair arrangement with the pair of transistors of the differential pair. While switching transients is the common mode voltage is still present because of the transient base current produced in the pair of transistors of the differential pair, the magnitude of the base current is attenuated by a factor .beta.+1, where .beta. is the beta of the additional (i.e., Darlington pair) of transistors. In another embodiment of the invention, the pair of transistors of the differential pair are NPN transistors and the additional, Darlington connected, pair of transistors are PNP transistors.

Differential line driver

A transimpedance amplifier for an optical receiver includes an integrator circuit for receiving a current input from a photodetector; an integrator capacitance between the input and output of the integrator circuit; a gain stage responsive to the output of the integrator circuit for providing an output voltage representative of the current input to the integrator circuit; and a feedback resistance connected between the output of the gain stage and the input of the integrator circuit for establishing the nominal gain of and in conjunction with the integrator circuit for setting the nominal bandwidth of the transimpedance amplifier; the gain stage may have a gain greater than unity for increasing the bandwidth by the factor of the gain and the gain stage may include a trimmable resistance for adjusting the gain both below and above unity.

Transimpedance amplifier for optical receiver

A gain stage for use in an amplifier which provides a rail-to-rail output signal. The gain stage includes a first transistor having a base, an emitter and a collector, the base being coupled to an input signal applied to the gain stage and the emitter being coupled to a first source of operating potential; a second transistor having a base, an emitter and a collector, the collector being coupled to the collector of the first transistor for providing the output signal, the emitter being coupled to a second source of operating potential; and a third transistor having a base, an emitter and a collector, the emitter being coupled to the input signal, the base being coupled to a bias voltage, and the collector being coupled to the second operating potential and the base of the second transistor for providing a drive signal thereto allowing the output signal to swing substantially between the first and second sources of operating potential.

Rail-to-rail gain stage of an amplifier

A circuit for varying the temperature of a first bipolar transistor in order to thermally compensate for self-heating effects of an associated device in a common signal path with the first transistor, the first transistor being configured within an isolated collector region. The circuit includes a second bipolar transistor provided within the isolated collector region and thermally coupled to the first transistor, the second transistor operable for providing heat to the first transistor to alter the temperature to a predetermined level, thus changing the operational voltage characteristics of the first transistor so as to minimize shifts in offset voltage.

Growing community of inventors

Lexington, MA, United States of America

Alex Gusinov