Dallas Semiconductor Corporation

Microtune (texas), Inc.

Microtune, Inc.

Richard William Ezell

James M Douglass

Richard E Downs

A variable gain low noise amplifier is disclosed that offers flat gain versus frequency throughout the entire cable and broadcast television signal spectrum. The circuit uses multiple stages and buffering techniques to cancel the primary source of high frequency gain degradation. The invention also uses variable capacitor networks which track with gain control to control peaking within the circuit so as to have consistent gain control with frequency and gain. A further aspect of the invention is in the use of capacitors within the circuit to act as simple band-pass filters to roll off segments of the spectrum away from the channel of interest, thus reducing system-level distortion in a receiver.

System and method for low-noise amplifier with a high frequency response

An initializer that responds to change in a power supply potential level, for generating an initialize signal to initialize a circuit to a select state, the initializer includes a power-on reset circuit that switches between an active and a powered-down state, and is for generating the initialize signal. The initializer also includes a wake-up circuit that monitors the power supply potential level and switches the power-on reset circuit from the powered-down state to the active state when selected change in the power supply potential level occurs.

Low power power-on reset circuitry having dual states

A rechargeable battery pack with low powered, gas gauge circuitry for monitoring and accumulating various operating parameters of the rechargeable battery pack, includes a current monitor for measuring the current flow into and out of a battery cell in the rechargeable battery pack. An integrated current accumulator connected to the current monitor is used to maintain a measure of the net charge having flowed into and out of the battery cell. A charging current accumulator, which is also coupled to the current monitor, is used to maintain a measure of the total charge having flowed into the battery cell, while a discharging current accumulator is used to maintain a measure of the total charge having flowed out of the battery cell. A highly accurate oscillator is used to drive the accumulators to greatly increase the accuracy of the gas gauge functions derived therefrom.

Battery pack

A highly linear variable-gain low noise amplifier is constructed using a transistor pair having variable gain control. The gain of the transistor pair is achieved by a segmented resistor having controllable PMOS (or NMOS) components. The circuit includes a variable voltage source and operates to handle wideband radio transmissions via broadcast or cable.

Method for a highly linear variable-gain low noise amplifier

A method for monitoring various parameters and conditions of a rechargeable battery to accurately determine the remaining charge level of the rechargeable battery, and includes using a temperature sensor to monitor the temperature of the rechargeable battery. The potential level of the rechargeable battery is monitored with a voltage meter coupled to the rechargeable battery. The current flow into and out of the rechargeable battery is monitored with current meter coupled to the rechargeable battery. A current accumulator coupled to the current meter is used to accumulate the net total of current flow, an oscillatory circuit is used to generate a timing signal to time selected functions, and a timestamp will be generated indicative of a time when the battery ceases to be charged such that a self discharge correction is capable of being calculated.

Method for monitoring operating parameters of a rechargeable power supply

Method for initializing an electronic device using a dual-state

A high linearity transconductance stage is arranged with a loss cancellation method to remove the nonlinearity of a typical transconductance circuit. The loss cancellation method uses a series of transistors and resistors to supply a controlled feedback current to cancel the result of the change (.DELTA.) in voltage across the input of the transistor used to provide the transconductance for the transconductance stage of a circuit, such as an amplifier, a mixer or other active circuit.

Highly linear transconductor with passive feedback

Highly linear variable-gain low noise amplifier

Gas gauge circuitry for monitoring and accumulating various operating parameters of a rechargeable battery with selected parameters being used to determine the remaining operating life of a rechargeable battery, and includes a current monitor for measuring the current flow into and out of the rechargeable battery. An integrated current accumulator is connected to the current monitor and is used to maintain a net accumulated total of current flowing into and out of the rechargeable battery. A charging current accumulator, which is also coupled to the current meter is used to maintain the total current flowing into the rechargeable battery, while a discharging current accumulator is used to maintain the total current flowing out of the rechargeable battery. A highly accurate, oscillatory circuit is used to drive the accumulators to increase the accuracy of the gas gauge functions therefrom.

Circuit for determining the remaining operating life of a system

Low power wake up circuitry, with internal power down of the wake up

A digital potentiometer capable of being connected directly to an electronic switch is disclosed. The digital potentiometer for example may utilize a 64 step resistor array, which would then have 64 steps. Each of the steps have precise values so as to accurately attenuate a signal in logarithmic steps. The logarithmic resistor is connected to a gate device which in turn has a voltage source connected to it designed to provide the threshold or turn-on voltage for the device for each of the 64 steps and wiper points of the resistor array.

Logarithmic taper resistor with zero crossing changes

A comparator which for example can be used for a digital potentiometer is shown. Specifically, a dual differential input circuit with a push/pull amplifier at the output stage is disclosed wherein a crossing is detected in an inputted signal as the crossing occurs and wherein the push/pull amplifier pair at the output stage provides very fast detection of a crossing. This is particularly useful in acting as a trigger mechanism for changes in a digital potentiometer for example to elements noise caused as 'wiper changes' occur.

Circuit for providing a switch signal to trigger changer in a digital

A voltage bias generating circuit is disclosed which comprises a voltage-controlled charge pump which operates at a high frequency relative to audio frequencies wherein a plurality of low pass filters are used to prevent the introduction of noise and distortion of audio signals being amplified through a digital potentiometer or resistor array.

Charge pump for digital potentiometers

A digital potentiometer adapted for and connected to and interacting directly with a plurality of external switches. Specifically, the various wiper points of a semiconductor resistor array are selected, for each channel of an audio amplification device according to various switch selections. The method and apparatus disclosed also makes priority determinations if more than one external switch is selected at the same time according to which switch was selected first.

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Carrollton, TX, United States of America

Richard William Ezell