Fairchild Semiconductor Corporation

Julie Lynn Stultz

Steven M Macaluso

Tyler Daigle

Seth M Prentice

Kenneth Patrick Snowdon

Roy L Yarbrough

Nickole Gagne

Earl Schreyer

Enrique O Rodriguez

Hrvoje Jasa

Yongliang Li

Steven M Leibiger

Myron J Miske

Shawn Barden

Sam Zheng

Graham L S Connolly

James Joseph Morra

Gary Sun

John L Carpentier

This document discusses, among other things, systems and methods to reduce power use of an accessory detection device. The accessory detection device can be configured to be coupled to a mobile device having an audio jack configured to be coupled to a mobile device accessory having a send/end key. In an example, the accessory detection device can include a comparator and a switch. The comparator can be configured to receive mobile device accessory information from the mobile device accessory and to determine activation of the send/end key using the received mobile device accessory information. The switch can be configured to receive connection information indicative of mobile device accessory connection to the audio jack and to isolate a reference input of the comparator from a supply voltage using the connection information, for example, to reduce leakage current.

Enable and disable comparator voltage reference

Systems and methods are disclosed, including, for example, a low-voltage control circuit configured to receive a charge pump voltage, a rail voltage, and a switch control signal, to provide the charge pump voltage when the switch control signal is in a first state, and to provide the higher of the charge pump voltage and the rail voltage when the switch control signal is in a second state. The system can include a first pick-high circuit configured to receive the rail voltage and the charge pump voltage, and to provide the higher of the rail voltage and the charge pump voltage at an output. The switch control signal, in the first state, can include the output of the pick-high circuit. Methods of forming such apparatus are disclosed, as well as methods of operation, and other embodiments.

Low voltage switch control

Systems and methods are disclosed, including a protection multiplexer circuit configured to receive a control signal and a reference voltage, to provide the reference voltage at an output when the control signal is in a first state, and to isolate the reference voltage from the output when the control signal is in a second state. The protection multiplexer circuit includes cascaded first and second transistors, wherein the first transistor is a native transistor. Control inputs of the first and second transistors are configured to receive the control signal, a first terminal of the first transistor is configured to receive the reference voltage, and the first terminal of the second transistor is coupled to the output. Methods of operation are disclosed, and other embodiments.

Enhanced protective multiplexer

This document discusses, among other things, a detection system configured to identify a type of a pole of a four-pole audio jack using first and second comparators. The detection system can include a bias circuit configured to bias a detection input coupled to the pole, and first and second comparators configured to compare the detection input to respective first and second thresholds to provide an indication of the type of the pole.

Audio jack detection circuit

An apparatus comprises at least one transistor configured as analog switch, a well biasing circuit configured to provide a dynamic electrical bias to a bulk region of the at least one transistor, and a comparator circuit in electrical communication with the well biasing circuit and the transistor. The comparator circuit is configured to detect a first operating condition of the transistor and a second operating condition of the transistor. The well biasing circuit is configured to apply a first electrical bias to the bulk region of a transistor when the first operating condition is detected and apply a second electrical bias to the bulk region of the transistor when the second operating condition is detected, and wherein the comparator is configured to apply hysteresis to detection of the first and second operating conditions.

Reverse current blocking comparator

In certain examples an integrated circuit protection circuit can include a circuit module, and an isolation device. The isolation device can be configured to couple a ground node of the circuit module to a power ground in an on state, and to isolate the ground node of the circuit module from the power ground in an off state, wherein the isolation module is configured to enter the off state when the IC receives a negative input voltage.

Method and apparatus for integrated circuit protection

An apparatus comprises a first audio amplifier circuit configured to provide an analog audio signal and an analog switch circuit including a first input configured to receive the analog audio signal, a second input configured to receive a first digital data signal, and a first output configured to provide one of the digital data signal or the analog audio signal. The apparatus also includes a first feedback circuit coupled to the first audio amplifier circuit and the analog switch circuit output, the feedback circuit configured to bias the first audio amplifier circuit.

Audio amplifier performance while maintaining USB compliance and power down protection

An apparatus comprises an input to receive a voltage, a threshold voltage circuit, a comparison circuit, and an output. The threshold voltage circuit provides an adjustable first threshold voltage at a first output and an adjustable second threshold voltage at a second output. The comparison circuit determines when the input voltage is greater than the first voltage threshold, including when the first voltage threshold is adjusted substantially up to a high supply voltage rail, and determines when the input voltage is less than the second voltage threshold, including when the second voltage threshold is adjusted substantially down to a low supply voltage rail. The output provides a first indication when the input voltage is greater than the first voltage threshold and to provide a second indication when the input voltage is less than the second voltage threshold.

Rail to rail comparator with wide hysteresis and memory

This application discusses, among other things, apparatus and methods for driving the bulk of a high-voltage transistor using transistors having gates with low-voltage ratings. In an example, a bulk driver can include an output configured to couple to bulk of a high-voltage transistor, a pick circuit configured to couple the output to an input voltage at an input terminal of the high-voltage transistor or an output voltage at the output terminal of the high-voltage transistor when the high-voltage transistor is in a high impedance state, and a bypass circuit configured to couple the output of the bulk driver to the output voltage when the high-voltage transistor is in a low impedance state.

High-voltage bulk driver using bypass circuit

A switch can be configured to receive a first signal at a first input and provide an output signal at an output, depending on a state of the switch. A switch state change can be delayed until an indication of a requested switch state different than a current switch state is received and the first signal reaches a threshold.

No pop switch

A switch controller is provided that uses one or more capacitors to generate a slow turn on/slow turn off switch control signals to suppress audible switching noise in an audio switch. In some embodiments, an analog inverter and a capacitor are used to generate the switch control signals, while in other embodiments two capacitors are used to generate the switch control signals. To conserve power between switching states, routing logic is provided that ties the switch control signals to respective voltage rails and disables selected portions of the switch controller.

Capacitor controlled switch system

This document discusses, among other things, apparatus and methods including an analog-to-digital controller (ADC) configured to receive an enable signal and to provide an ADC output signal to control logic, wherein the control logic is configured to provide a control voltage to a control input of a switch. In an example, the control voltage includes the ADC output signal when the ADC output signal is below a first threshold or above a second threshold. In certain examples, the control logic is configured to transition the control voltage from the first threshold to the second threshold when the ADC output signal is between the first and second thresholds.

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Scarborough, ME, United States of America

Julie Lynn Stultz