Transimpedance amplifiers with improved gain-bandwidth product
Granted: September 5, 2000
Patent Number:
6114913
Transimpedance amplifiers with improved gain-bandwidth products. The transimpedance amplifiers include a boost current circuit to increase the gain-bandwidth product of the transimpedance device, particularly useful when using low voltage power supplies. The boost current can be made responsive to the input current of the amplifier, better accommodating large input currents. The boost current may also be responsive to the power supply voltage, reducing the boost current with increasing…
DC output level compensation circuit
Granted: August 15, 2000
Patent Number:
6104232
Disclosed is a circuit and method for compensating DC output level variations in a differential emitter-coupled logic circuit. The DC output level compensating differential emitter-coupled logic circuit includes a differential pair, an output stage, and a compensation circuit. The differential pair is configured to receive a differential signal and is operative to generate a differential signal. The output stage is coupled to the differential pair to receive the differential signal and…
Linear quad variable gain amplifier and method for implementing same
Granted: July 18, 2000
Patent Number:
6091275
A VGA control circuit includes a differential control voltage generator having an input coupled to an external control voltage and having a pair of control voltage outputs, a transfer function compression region TFCR compensator coupled to the differential control voltage generator, and a TFCR detector coupled to the TFCR compensator and developing a compensator activation signal in response to the detection of a TFCR state in the transfer curve. A method for controlling a VGA circuit…
Step-up/step-down switching regulators and pulse width modulation control therefor
Granted: July 11, 2000
Patent Number:
6087816
Step-up/step-down switching regulators and pulse width modulation control therefor which can provide a high output current, high efficiency, use physically smaller inductor and transistors, have lower output voltage ripple, excellent line and load regulation stability and very fast transient response. The modulation control includes three operating states. The improved operating characteristics are obtained by including, as one of the operating states, the direct flow of current from the…
Multipoint controlled high dynamic range variable gain amplifier
Granted: July 4, 2000
Patent Number:
6084473
Variable gain amplifiers comprised of multiple variable gain stages, wherein the gain of the various stages is controlled by comparisons of a control voltage with various reference voltages, in the preferred embodiment generated by the use of a series connection of multiple resistors connected to a supply voltage. These relative comparisons control current ratios determining the gain of each variable gain amplifier stage. By staggering the changes in current ratios, an overall gain…
Lock-in aid frequency detector
Granted: June 27, 2000
Patent Number:
6081572
Circuit and method for generating a signal for use in locking a second signal on a first signal. The first and second signals have an associated frequency. A first beat note signal and a second beat note signal are generated from the first and second signals, respectively, when the frequencies of the first and second signals are not equal. The circuit includes a first and second flip-flop and detector circuitry. The first flip-flop is configured to receive the first and second beat note…
Compact voltage biasing circuitry for enhancement of power MOSFET
Granted: May 30, 2000
Patent Number:
6069516
Disclosed is a biasing circuit for bringing a power FET to a substantial full enhancement. The biasing circuit includes: (a) a rail power voltage that is coupled to a drain terminal of the power field effect transistor; (b) a load being coupled between an other potential and a source terminal of the power field effect transistor; and (c) a micromachined DC/DC converter that is coupled between a gate terminal of the power field effect transistor and the rail power voltage. The…
Micromachined circuit elements driven by micromachined DC-to-DC converter on a common substrate
Granted: May 2, 2000
Patent Number:
6058027
The present invention comprises the combination of one or more micromachined circuit elements and a micromachined DC-to-DC step-up converter on the same or different substrates, so as to allow the operation of the micromachined circuit element at a different voltage, typically a higher or a negative voltage, in comparison to the input power supply to the system. The micromachined structure of such a converter requires little chip area and is normally fully compatible with the…
Wide-dynamic-range variable-gain amplifier
Granted: April 11, 2000
Patent Number:
6049251
A very-wide-dynamic-range amplifier with very low-noise in the high-gain mode and very high-input-overload in the low-gain mode. The amplifier utilizes two parallel signal paths, one a high-gain, low-noise path and the other a low-gain, high-input-overload path. Each path includes a gain-control capability so that the gain of each path, and the contribution of the gain of each path to the overall gain of the amplifier may be smoothly varied from a very low-gain to a very high-gain.…
Direct-conversion tuner integrated circuit for direct broadcast satellite television
Granted: February 29, 2000
Patent Number:
6031878
A converter for the direct down-conversion of direct broadcast satellite signals such as those used for digital television. The direct broadcast satellite signal received from the satellite dish is amplified and then downshifted within the Low Noise Block (LNB), a subsystem contained with the satellite dish assembly, to a predetermined frequency band, typically in the L-band in the range 950 MHz to 2150 MHz. The signal is then sent via a coaxial cable to the set-top box unit located…
Fixed gain operational amplifiers
Granted: February 1, 2000
Patent Number:
6020785
A method and apparatus for customizing the gain of a closed loop operational amplifier during fabrication to a fixed value. The fabricated circuit includes a feedback resistance and a gain resistance coupled to an operational amplifier core. The feedback resistance is set to a preset value by setting links coupled to resistors which make up the feedback resistance.
Minimal headroom, minimal area multi-terminal current steering circuits
Granted: January 11, 2000
Patent Number:
6014045
Minimal headroom, minimal area, multi-terminal current steering circuits for steering a current from a current source to any one of a plurality of outputs. The steering circuit provides controls to individual steering transistors so as to turn on the selected one of the plurality of steering transistors responsive to steering control signals. Minimal headroom is required, and beta dependent errors in the current output are minimized, by steering the current source through only a single…
High efficiency base current helper
Granted: January 4, 2000
Patent Number:
6011427
High efficiency base current helper to improve the accuracy of current mirrors particularly useful for current mirror utilizing relatively low beta bipolar junction transistors. The high efficiency base current helper utilizes two feedback loops, the first attempting to force the bias rail voltage to a mirror reference voltage and the second sensing excess current in the first loop and forcing it to match a reference level. This causes the first loop to be biased with no more excess…
Piezoresistive pressure sensor with sculpted diaphragm
Granted: December 28, 1999
Patent Number:
6006607
The present invention is a semiconductor pressure sensor. In one embodiment, the semiconductor pressure sensor includes a diaphragm having a first thickness and at least cone raised boss that is coupled to a first side of the diaphragm. The at least one raised boss increases the diaphragm thickness in the region occupied by the at least one raised boss to a second thickness. A plurality of piezoresistors are disposed on a second side of the diaphragm in regions of the first thickness. In…
Body grabbing switch
Granted: December 28, 1999
Patent Number:
6008689
The present invention provides a switch circuit having a switch and a first body grabbing circuit. The switch includes a first transistor and a second transistor. The first transistor has a body and is coupled to the second transistor in parallel to form a common source and a common drain. The common source defines an input node and the common drain defines an output node. The first body grabbing circuit is coupled to the body of the first transistor. The first body grabbing circuit is…
Switching power supplies with linear precharge, pseudo-buck and pseudo-boost modes
Granted: December 7, 1999
Patent Number:
5998977
The present invention teaches a variety of startup modes for operating a boost type switching power supply. A linear charging mode couples the input voltage directly to the output voltage, thereby precharging the output capacitor of the switching power supply. The linear mode serves to reduce inrush battery current and limit the stress voltage on the power switching devices. A pseudo-buck mode, preferably entered into after the linear mode has precharged the output capacitor, operates…
Communication circuit having network connection detection capability
Granted: December 7, 1999
Patent Number:
6000003
Methods and apparatus for providing network communications capability to a computer system in accordance with standard communication line protocols are described, including interface circuits which sense various characteristics of the communication lines to control or provide signals to control power to line drivers and/or other substantial power consuming circuitry to conserve power when communication line conditions indicate powering such circuits is not useful. Various embodiments are…
Driver amplifiers with low noise standby mode characteristics
Granted: November 30, 1999
Patent Number:
5994955
The present invention teaches a variety of driver amplifiers having a transmit mode suitable for driving the load resistance of a network with an amplified version of the input signal, and a standby mode wherein the driver amplifier consumes substantially no current and isolates the load resistance from the input signal. These amplifiers are also characterized in that during transitions back and forth between standby mode and transmit mode, a minimum of standby transient leaks out onto…
Linearized amplifier core
Granted: November 30, 1999
Patent Number:
5994959
A circuit for linearizing the input/output characteristics of a differential amplifier core circuit is described. The differential amplifier core circuit comprises an input stage, a buffer stage, and an output stage. The input stage includes input transistors connected in a common emitter configuration, where the bases of the input transistors are coupled to input terminals. The input stage further includes load circuits coupled between the input transistors and a power supply terminal.…
Single output transistor output stage for interface applications
Granted: November 23, 1999
Patent Number:
5988819
An interface output stage includes a pull-up circuit and a pull-down circuit connected to a positive power supply signal line having a first voltage, an output signal line having an output voltage and a negative power supply signal line having a second voltage. The pull-up circuit includes a single output transistor and a body snatcher circuit, both interconnected between the positive power supply signal line and the output signal line. The body snatcher circuit ties the bodies of the…
