Three state output method and apparatus for high speed amplifiers
Granted: September 15, 1998
Patent Number:
5808514
Three state high speed amplifiers having a high output impedance when disabled and a minimum glitch when enabled and disabled. The amplifiers utilize complementary emitter followers for the output stage. When the amplifiers are disabled, circuitry provided for the purpose drives is responsive to the voltage on the output of the amplifier to maintain the base-emitter voltages of the output emitter followers at a substantially constant level below the turn-on voltages of the transistors,…
Laser diode driver having automatic power control with smooth enable function
Granted: September 1, 1998
Patent Number:
5802089
A laser diode driver with automatic power control in which start-up characteristics are controlled to avoid unsafe power levels at a driven laser is disclosed. The laser diode driver according to the invention produces a bias control signal that controls a bias current source such that the bias current supplied to the laser is maintained below a predetermined level during a start-up period.
Communication interface circuit having network connection detection capability
Granted: August 25, 1998
Patent Number:
5799194
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…
Phase detector
Granted: July 14, 1998
Patent Number:
5781036
A phase detector biased in a manner to alleviate the mismatch between the biasing current sources and the phase detector core bias currents. The bias setting resistors are coupled together at a common node that forms the negative input of a differential feedback amplifier. The positive input to the amplifier is referenced to a reference voltage, and the output of the amplifier controls the biasing current sources. The feedback amplifier forces the average voltage at the current source…
Multiple battery switchover circuits
Granted: June 9, 1998
Patent Number:
5764032
Multiple battery switchover circuits for selective interconnecting any one of multiple batteries to a load or a charger while maintaining isolation with other batteries of the system. The present invention maintains the required isolation and interconnection capabilities using only three MOSFETs per battery instead of the four required by the prior art. The three MOSFETs for any one battery in the switchover circuit are connected with one current carrying connection in common, with the…
Method and apparatus for logic network interfacing with automatic receiver node and transmit node selection capability
Granted: June 2, 1998
Patent Number:
5761463
A method and apparatus for providing serial interface capability that detects whether another communications system transmits or receives data on a particular node, and in response, automatically selects to either receive or transmit data on that node. An interface circuit is included that determines whether a particular node is coupled to a receiver circuit or a driver circuit based on the voltage level detected on that node. Based on this determination, the interface circuit is…
Output stage for buffering an electrical signal and method for performing the same
Granted: May 19, 1998
Patent Number:
5754066
The present invention teaches a variety of output stages, buffer circuits, and power amplifiers as well as methods for buffering electrical signals. According to one embodiment of the present invention, an output stage includes an input, an output, an error stage coupled between the input and the output and responsive to a difference between an input signal present on the input and an output signal present on the output, the error stage being operative to generate a current control…
Logic signal level translation apparatus having very low dropout with respect to the powering rails
Granted: May 5, 1998
Patent Number:
5748010
A logic signal level translation method and apparatus having very low dropout with respect to the powering rails and having a tri-state mode of operation allowing the output terminal to be driven to voltages beyond the highest supply voltage coupled thereto without significant power dissipation within the circuit. The output circuit includes well or body snatching devices which are controlled to assure that the wells of the output devices are able to follow extremes in voltage of the…
Low power, high linearity log-linear control method and apparatus
Granted: May 5, 1998
Patent Number:
5748027
Low power, high linearity log-linear control method and apparatus wherein a master log-linear cell generates a control voltage that is buffered and applied to a slave log-linear cell. By breaking this function up into two pieces, the control loop characteristics are isolated from the signal path. Low impedance buffers can be used to drive the slave log-linear cell control ports, independent of the control loop, providing improved gain control range and linearity. This log-linear control…
Multi-stage current feedback amplifier
Granted: April 21, 1998
Patent Number:
5742154
A multi-stage current feedback amplifier having a first stage and a second stage. The multi-stage amplifier comprises a transistor device having a base, an emitter, and a collector, as well as a replicating device having a base, an emitter, and a collector. The base of the replicating device is coupled to the base of the transistor device, wherein a voltage in the emitter of the transistor device is substantially replicated in the emitter of the replicating device. Further, the inventive…
Method and apparatus for amplifying an electrical signal
Granted: April 7, 1998
Patent Number:
5736900
In accordance with the objectives of the present invention, a variety of apparatus and methods for amplifying an electrical signal are disclosed. According to one embodiment of the present invention, a dual-output stage amplifier includes an amplifier stage having an input and an output, a first output stage having an input and an output, a second output stage having an input and an output and an error stage having an input and an output. The first output stage output is coupled with the…
High-gain common-emitter output stage
Granted: April 7, 1998
Patent Number:
5736902
A high gain common-emitter output stage for an amplifier is disclosed. In one embodiment, an output stage for an amplifier circuit according to the invention includes: a first transistor having a base, an emitter and a collector, the emitter being connected to a first potential through a first resistor, the collector being connected to a second potential through a series connection of a second resistor and a bias current source, the base being connected between the second resistor and…
Methods and apparatus for signal amplitude control systems
Granted: March 3, 1998
Patent Number:
5724003
A method for obtaining a rectified signal from a first alternating current signal. The method includes the step of inputting the first alternating current signal into a variable gain amplifier to obtain a second alternating current signal. The second alternating current signal has a substantially constant peak-to-peak voltage irrespective of a power level of the first alternating current signal. The method further includes the step of rectifying the second alternating current signal,…
Method and apparatus for enabling a step-up or step-down operation using a synchronous rectifier circuit
Granted: February 24, 1998
Patent Number:
5721483
A DC--DC converter capable of both step-up and step-down operations includes a synchronous rectifier coupled between a rectifier connection and an output node, an inductor coupled between an input node and the rectifier connection, a rectifier control circuit for controlling the synchronous rectifier, the rectifier control circuit coupled to the input node, to the synchronous rectifier, to the rectifier connection and to the output node, and a switch coupled between the rectifier…
Method and apparatus for providing limiting transimpedance amplification
Granted: January 13, 1998
Patent Number:
5708392
A limiting transimpedance amplifier includes an amplifier stage including a feedback resistor, a limiting diode coupled across the feedback resistor, and a stabilization diode coupled to the amplifier stage to compensate for feedback instability introduced by the limiting diode. The amplifier stage includes an input transistor and an output transistor, where the feedback resistor couples an output of the output transistor to an input of an input transistor. A stabilization voltage…
Substrate clamp for non-isolated integrated circuits
Granted: December 2, 1997
Patent Number:
5694075
A substrate clamp for non-isolated integrated circuits is disclosed. The substrate clamp comprises a circuit that controls the voltage on a substrate so that the substrate is connected to a specific node if the parasitic PN diodes at all the circuit nodes are not forward biased. If a specific node is then forced with an applied voltage to forward bias, the substrate is disconnected from its original node and maintains itself at a forward biased diode voltage drop away from the powered…
Phase locked loop with improved phase-frequency detection
Granted: December 2, 1997
Patent Number:
5694088
A phase locked loop including an in-phase detector (IPD), a quadrature phase detector (QPD), a frequency detector (FD), a squelch, a filter, and a voltage controlled oscillator (VCO). The in-phase detector has an IPD sample input, an IPD input, and an IPD output, where the IPD sample input is coupled to a data input. The quadrature phase detector has a QPD sample input, a QPD input, and a QPD output, where the QPD sample input is coupled to the data input. The frequency detector has a…
Method and apparatus for transmitting signals over a wire pair having activity detection capability
Granted: November 11, 1997
Patent Number:
5687321
A method and apparatus for transmitting and receiving information over a network that allows the detection of data transmission activity over a wire pair on the network. Within a computer system or other network device a driver-receiver circuit along with an activity detector circuit are coupled to the wire pair such that when the wire pair is inactive, an Inactive signal is asserted, and the activity detector circuit will notify the network device that the network is not currently…
Temperature compensated logarithmic detector
Granted: October 14, 1997
Patent Number:
5677561
A temperature compensated logarithmic detector biased with a proportional to absolute temperature (PTAT) voltage produced in accordance with an area ratio of biasing transistors is disclosed. According to one implementation of the invention, the temperature compensated logarithmic detector includes biasing circuitry and a logarithmic detector cell. The biasing circuitry receives an input signal and produces a PTAT bias voltage from the input signal. The PTAT characteristic of the PTAT…
Method and apparatus for multiple output regulation in a step-down switching regulator
Granted: October 14, 1997
Patent Number:
5677619
A step-down switching regulator of the present invention includes (1) a magnetic storage device having at least one primary output and one secondary output, (2) a current sensing device for detecting current through a primary winding of the magnetic storage device, (3) a first switch, (4) a second switch, (5) a first comparator for detecting whether the current through the primary winding is greater than a limit value, (6) a second comparator for detecting loss of regulation in the…
