Analog Devices,inc.

Linear Technology Corporation

Analog Devices International Unlimited Company

Linear Technology Holding LLC

Xin Qi

Eric Stephen Young

Keith Szolusha

Chad Cosby

Keith D Szolusha

Qiuzhong Wu

This disclosure describes techniques for extending a range of bidirectional bus communications through the use of a differential signal path. The disclosed techniques include first separating the bidirectional bus into first and second unidirectional buses that transmit and receive signals, respectively, and then communicating the signals from the first and second unidirectional buses over a differential signal path. The separation of the bidirectional bus into the first and second unidirectional buses is performed using logic circuitry that blocks or permits communication between a given one of the first and second buses and the bidirectional bus based on whichever one of the first and second buses becomes dominant first. If the logic circuitry determines that the first bus becomes dominant before the second bus, the logic circuitry permits communications between the first bus and the bidirectional bus and blocks communications between the second bus and the bidirectional bus.

Bidirectional signal separation

An electronic circuit comprises an analog-to-digital converter (ADC) circuit. The ADC circuit includes a pre-amplifying transistor and a quantizer circuit. The pre-amplifying transistor includes a base, an emitter and a collector. The pre-amplifying transistor is configured to receive an input voltage at the base that varies logarithmically; and produce an output voltage at the collector according to a comparison of a reference voltage and a difference between the input voltage and a voltage at the emitter. The quantizer circuit is operatively coupled to the pre-amplifying transistor and is configured to generate a digital value for the input voltage using the output voltage produced by the pre-amplifying transistor.

Logarithmic scale analog to digital converter for wide dynamic range avalanche photodiode current companding

Techniques for an integrated slew-rate control circuit are provided. In certain examples, an adjustable, integrated slew-rate control circuit for a bypass transistor can provide three decades of adjustability. In an example, a slew-rate control circuit can include a load bypass transistor, a slew-rate control capacitor, electrically coupled between a conduction node of the load bypass transistor and a control node of the load bypass transistor, and a current mirror circuit. The current mirror circuit can include a sense transistor electrically coupled in series with the slew-rate control capacitor and the control node, and a mirror transistor electrically coupled between a power supply and the control node, to selectively provide, to or from the control node, a shunt current that bypasses the slew-rate control capacitor to limit a slew rate of a voltage at the conduction node.

Load bypass slew control techniques

A technique to eliminate perceptible flickering by LEDs being dimmed by PWM pulses is disclosed. A controllable oscillator controls a switching frequency of a converter for supplying a regulated current or regulated voltage. The converter controls a first switch at a switching frequency. A varying second signal level is generated by a spread spectrum control (SSC) circuit for controlling the oscillator to vary the switching frequency during operation. A PWM dimming circuit generates a string of PWM pulses that control a switch in series with the LEDs. The SSC circuit is synchronized with the PWM pulses to generate the same second signal level at a start of each PWM pulse, such that the switching frequency of the converter is forced to be substantially the same at the start of each PWM pulse while the pulse widths are constant. The repeating driving current waveform eliminates perceptible flicker by the LEDs.

Growing community of inventors

Cary, NC, United States of America

Xin Qi