Radio frequency amplifier with reduced intermodulation distortion
Granted: March 20, 2001
Patent Number:
6204728
Apparatus and methods of broadband amplification with high linearity and low power consumption are described. An apparatus configured to amplify a signal includes an input transistor and an output transistor coupled together in a cascode configuration with the input transistor defining an input of the amplifier and the output transistor defining an output of the amplifier. A feedback network is coupled between the input and the output and is characterized by an impedance of substantially…
Voltage-controlled current source with variable supply current
Granted: March 20, 2001
Patent Number:
6204655
A method and apparatus for providing electrical output current. The method includes providing a supply current, providing a first and second voltage input signal for controlling output current and generating an output current based on a differential voltage measured between the first and second input voltage signals including increasing the supply current as the output current increase. The apparatus for providing electrical current includes biasing circuitry providing a biasing current…
Electrostatic discharge protection for analog switches
Granted: February 13, 2001
Patent Number:
6188088
Electrostatic discharge protection for analog switches using silicon-controlled rectifiers. Two silicon-controlled rectifiers (SCRs) may be formed in a common isolation region of an integrated circuit. Each SCR has its gate and cathode coupled together so as to be self triggering. The SCRs are connected in parallel in reverse polarity and coupled between the analog switch input or output and ground. In normal switch operation, both SCRs will be off, though when the voltage of the…
Differential amplifier with gain linearization through transconductance compensation
Granted: February 13, 2001
Patent Number:
6188280
Disclosed is a differential amplifier including an emitter follower pair, a first differential pair, and a main differential amplifier. The emitter follower pair is operative to receive an input differential voltage signal for shifting the input differential voltage signal to develop a shifted differential voltage signal. The first differential pair is configured to feed a first differential current inversely to the emitter follower pair so that a transconductance of the emitter follower…
Linear transconductance circuits having class AB amplifiers parallel coupled with concave compensation circuits
Granted: February 13, 2001
Patent Number:
6188281
The present invention teaches a variety of transconductance circuits formed having a class AB transconductor amplifier coupled in parallel with at least one concave compensation circuit. When the transconductance circuit has only one concave compensation circuit, the concave compensation circuit is designed with no offset so that the concave transconductance gain of the compensation circuit compensates for the convex transconductance gain of the class AB amplifier thereby providing a…
Local control for burst mode optical transmitters
Granted: February 13, 2001
Patent Number:
6188498
The present invention is a method and apparatus for controlling a drive current of an optical transmitter having a laser. A sensing circuit generates a sensing signal responsive to an intensity of an optical radiation emitted by the laser. An error circuit is coupled to the sensing circuit to generate an error quantity in response to the sensing signal. An updating circuit is coupled to the error circuit to update a control quantity based on the error quantity synchronously with an input…
Linear and multi-sinh transconductance circuits
Granted: January 30, 2001
Patent Number:
6181204
The present invention teaches a variety of transconductance circuits formed having two or more class AB transconductor amplifiers coupled in parallel. The class AB transconductor amplifiers have non-linear voltage to current transfer functions and are each designed with an offset chosen such that the combination of the individual nonlinear transfer functions achieve a more linear transconductance circuit.
Current mode transmitter
Granted: January 2, 2001
Patent Number:
6169445
A current mode transmitter is provided including a charge circuit connected to an enable node and adapted to generate a charge current upon the receipt of an activation signal at the enable node. Also included is a discharge circuit connected to the enable node and adapted to generate a discharge current upon the cessation of the receipt of the activation signal at the enable node. An output circuit is connected between an output node and the charge and discharge circuits. The output…
Pulse frequency operation of regulated charge pumps
Granted: January 2, 2001
Patent Number:
6169444
A regulating system (10) for a charge pump (12) employing a detection sub-circuit (28) and an enable sub-circuit (30) to operate an oscillator (26) and a channel-switching sub-circuit (32) in an automatic manner producing many of the advantages of previously unreconcilable skip mode and constant frequency mode type regulation. The detection sub-circuit (28) compares a feedback signal (52) from the output terminal (18) of the charge pump (12) to a reference signal (56) and produces an…
Single supply voltage to frequency converter optimized for low voltage sensing above and below ground
Granted: January 2, 2001
Patent Number:
6169428
A voltage to frequency converter using a charge pump to restore the output voltage of the input integrator. The charge pump implementation allows the voltage to frequency converter's input to sense voltage above and below ground with a single supply using a charge pump, which can provide either a positive charge or a negative charge as the restoring force to the integrator. Inclusion of an interleaved charge pump provides advantages of implementation simplicity and of high…
Infrared transceiver module and method for making same
Granted: January 2, 2001
Patent Number:
6169295
An IR transceiver module includes a lead frame, a sensor, an emitter, and a body encapsulating the sensor and emitter, where the body has an integrally formed lens aligned with both the sensor and with the emitter. The sensor is supported proximate to a support surface of the lead frame and has a sensing area which is generally parallel to the support surface. The emitter is supported proximate to the sensor and within a vertical projection of the sensing area, i.e. it is vertically…
Class-ab output stages with improved distortion performance
Granted: December 26, 2000
Patent Number:
6166603
The present invention teaches output stages having distortion performance improved relative to prior art class-AB output stage distortion performance. The general concept is to constantly bias the feed-forward circuitry of the output stage into a low-distortion operating state. This can be done through several different methods, each of which has its own particular circuit requirements. For example, in one embodiment the bias circuitry generates a near constant bias current suitable for…
Log-linear variable gain amplifiers and amplifier control apparatus and methods
Granted: December 19, 2000
Patent Number:
6163198
Log-linear variable gain amplifiers and amplifier control apparatus and methods providing temperature compensated log-linear gain characteristics with a wide range of control for a current steered variable gain amplifier. The invention provides the sum of scaled linear and exponential terms, proportional to absolute temperature and responsive to an input control voltage. The sum of these terms is applied to a current steered variable gain amplifier to provide the desired log-linear…
Class AB emitter follower buffers
Granted: November 28, 2000
Patent Number:
6154063
Buffers having an output pull-up transistor controlled by the input signal, an output pull-down transistor and a pull-down transistor control circuit. A current source provides a current that is divided between the pull-up transistor and the pull-down transistor control circuit to maintain the desired output voltage. A boost capacitor is coupled between the output and the pull-down transistor control circuit to provide good dynamic response to the circuit even in the presence of…
Constant gate drive MOS analog switch
Granted: November 28, 2000
Patent Number:
6154085
A constant gate drive metal-oxide semiconductor ("MOS") analog switch. In one embodiment, the analog switch includes first, second, and third devices, and a level shifter. The first device includes a source coupled to an input terminal, a drain coupled to an output terminal, and a gate. The second device includes a source coupled to the input terminal, a drain, and a gate. The third device includes a source coupled to the drain of the second device, a drain coupled to the output…
Circuits for preventing unwanted output transients in amplifiers during power-up
Granted: November 28, 2000
Patent Number:
6154092
The present invention reduces certain unwanted transients in an output stage by sensing the power supply and disabling the output stage output devices in correlation with the sensing of an invalid bias. In preferred embodiments, the bias is measured at a node that is the last bias node to reach a steady state during power up or power glitches. This ensures that all portions of the output stage are being provided a valid bias prior to enabling the output devices of the output stage. By…
Stress isolated integrated circuit and method for making
Granted: November 14, 2000
Patent Number:
6147397
A stress-isolated integrated circuit includes a semiconductor die (24) having first and second surfaces (28, 32) and a semi-circumferential trench (44) formed into the first surface of the die to define a stress-isolated region (48). At least some of the active IC components are located in the stress-isolated region. A cavity (46) is formed into the second surface of the die, the cavity being sized so that the trench opens into the cavity to create a cantilevered stress-isolated region…
High VSWR mismatch output stage
Granted: October 24, 2000
Patent Number:
6137366
The present invention teaches a variety of high VSWR mismatch output stages and methods for protecting output stages during high VSWR operation. To accomplish these goals, the present invention teaches absorbing reverse base current arising at the base of the power transistor of the output stage. In one embodiment, a variable impedance device such as a transistor is coupled to the base of the power transistor such that when the base-emitter voltage exceeds a predefined voltage, the…
Current monitors with independently adjustable dual level current thresholds
Granted: October 3, 2000
Patent Number:
6127882
Current sensing circuits having independently adjustable dual-level trip thresholds for use in hot swap controllers, solid state circuit breakers and other current sensing circuits. The dual-level trip threshold is user-programmable to provide one current level for power-up conditions and another current level for normal operation. The two separate thresholds are also useful during normal operation to monitor both the steady state current and to set a limit on the upper current which…
Current source having high impedance current output and method therefor
Granted: September 19, 2000
Patent Number:
6121764
Low voltage current sources having a high effective output impedance over a wide voltage range, including when individual transistors exhibit low output impedance states at low voltages. The low voltage current source replicates its output current and compares the replicated current to the desired current. The error between the replicated current and the desired current is used as feedback to force the output current to equal the desired current.
