Freescale Semiconductor,inc.

Nxp Usa, Inc.

Nxp B.v.

Cirrus Logic Inc.

Khoi Mai

Michael Todd Berens

Hector Adrian Sanchez

Jon Scott Choy

Lipeng Cao

Ashutosh Jain

James Robert Feddeler

Andre Luis Vilas Boas

Charles Eric Seaberg

Sanjay Ramakrishna Pillay

Dale John McQuirk

Tommi M Jokinen

Paul C Rossbach

Andrew Augustus Bjorksten

Felipe Ricardo Clayton

George E Baker

Joshua Siegel

Jose A Camarena

Luo Zheng

Dimitri Pantelakis

Dylan John Rosser

An analog-to-digital converter (ADC) includes a digital-to-analog converter (DAC), a comparator coupled to an output of the DAC, a successive approximation register (SAR) logic unit coupled to an output of the comparator, and a programmable delay unit. The comparator includes a preamplifier having an input coupled to the output of the DAC and a latch having an input coupled to the output of the preamplifier and an output coupled to the input of the SAR logic unit. SAR logic unit generates a control signal, and programmable delay unit adjusts a delay between the control signal and a delayed control signal based on at least one parameter, such that comparator receives control signal and delayed control signal. In some implementations, the parameter is at least one of a frequency of a signal input to the DAC, a source impedance of a circuit driving the input signal, and a preamplifier power mode.

Successive approximation register analog-to-digital converter with programmable sampling noise cancellation

An integrated circuit includes a plurality of analog inputs, and an analog multiplexer (MUX). The MUX includes a common output node configured to provide a MUX output, a plurality of analog switches, and a shared buffer. Each switch includes a corresponding bootstrap circuit coupled to a control electrode of a corresponding pass transistor in which the corresponding bootstrap circuit includes a corresponding boosting capacitor. Each analog switch of the plurality of analog switches has a first input coupled to a corresponding analog input of the plurality of analog inputs, a second input, and an output coupled to the common output node. The shared buffer has an input coupled to the common output node and coupled to provide a common buffered MUX output to the second input of each of the plurality of analog switches.

Integrated circuit (IC) having an analog multiplexer (MUX)

A transmission gate includes a first P-type transistor and a second P-type transistor coupled in series between a first signal node and an internal node. The transmission gate is enabled by turning on the first P-type transistor and the second P-type transistor to communicate signals between the first signal node and the internal node. The transmission gate is disabled by turning off the first P-type transistor and the second P-type transistor to stop communicating signals between the first signal node and the internal node. While the transmission gate is disabled, a third P-type transistor having a first current electrode coupled to a circuit node between the first and second P-type transistors and a control electrode coupled to the first signal node is used to track voltage of the first signal node and, in response to the tracking, control a voltage level at the circuit node to limit a gate-to-source voltage of the first P-type transistor.

Charge injection protection devices and methods for input/output interfaces

In an integrated circuit, a first current source is coupled between a first supply voltage and a first node. An output stage includes a first current steering PMOS transistor coupled to the first node, a first current steering NMOS transistor including a first current electrode coupled to the first current steering PMOS transistor at a second node, a second current steering PMOS coupled to the first node, and a second current steering NMOS transistor including a first current electrode coupled to the second current steering PMOS transistor at a third node. Voltage at the second node is used to drive a gate of the second current steering PMOS transistor, and voltage at the third node is used to drive a gate of the first current steering PMOS transistor. First and second programmable slew rate pre-drivers provide outputs to the gates of the first and second current steering NMOS transistors, respectively.

Integrated circuit having a differential transmitter circuit

A receiver includes an input node coupled to receive an analog signal, a first switch coupled between the input node and a first node, a second switch coupled between the input node and a second node, a first resistive element coupled between the first node and a reference node, a second resistive element coupled between the second node and the reference node, a first capacitive element coupled to the first node, and a second capacitive element coupled to the second node. The receiver also includes a comparator having a first input coupled to the input node to receive the analog signal, and a second input coupled to the reference node to receive a reference voltage, wherein an output of the comparator controls the first and second switches.

Tracking voltage reference for single ended receiver

A voltage sampling circuit and method are provided. The voltage sampling circuit includes a capacitor having a first terminal and a second terminal. A first pre-charge circuit is coupled to a first voltage supply terminal and to the first terminal of the capacitor. The first pre-charge circuit is configured to receive a first control signal and pre-charge the capacitor to a first voltage. A switch circuit includes a first transistor having a first current electrode coupled to an input terminal of the voltage sampling circuit, a control electrode coupled to the first terminal of the capacitor, and a body electrode coupled to the second terminal of the capacitor. A second transistor having a first current electrode coupled to a second current electrode of the first transistor, a body electrode coupled to the second terminal of the capacitor, and a second current electrode coupled to an output terminal of the voltage sampling circuit.

Voltage sampling switch

An analog-to-digital converter (ADC) includes a split-capacitor digital-to-analog converter (DAC) having a Most Significant Bits (MSBs) sub-DAC with one or more MSBs encoded with one or more binary capacitors and one or more MSBs encoded with one or more thermometer capacitors, a Least Significant Bits (LSBs) sub-DAC, a termination capacitor coupled to the LSBs sub-DAC, and a scaling capacitor coupled between the LSBs and MSBs sub-DACs, and coupled to receive an analog input voltage, a high reference voltage, and a low reference voltage, and to provide an output voltage. The ADC includes a comparator coupled to receive the output voltage, successive-approximation-register (SAR) circuitry coupled to the comparator and providing an uncalibrated digital value corresponding to an uncalibrated digital representation of the input voltage, and calibration circuitry configured to apply one or more calibration values to the uncalibrated digital value to obtain a calibrated digital value corresponding to a calibrated digital.

Analog-to-digital converter (ADC) having calibration

A method and apparatus are provided for controlling an SAR ADC by generating a first signal to control sampling of an analog input voltage at a DAC, and then generating a second signal to start a successive approximation sequence at a comparator and SAR engine to convert the analog input voltage to an N-bit digital value, where the successive approximation sequence includes a settling phase for each bit of the N-bit digital value and is controlled to synchronously end in response to a first synchronous clock signal, and also includes a comparison phase for each bit of the N-bit digital value to allow for comparison of the analog input voltage to a reference voltage, where each comparison phase is controlled to synchronously start in response to the first synchronous clock signal and asynchronously end in response to a second asynchronous clock signal that is self-generated by the comparator.

Partially asynchronous clock scheme for SAR ADC

A determination is made if a temperature of a system has exceeded a hot threshold or a cold threshold. At room temperature, a first adjustment is determined for first nominal settings. The first nominal settings are for a first input to a first comparator. At room temperature, a second adjustment is determined for second nominal settings. The second nominal settings are for a first input to a second comparator. The temperature is monitored, during normal operation of the system, using a temperature dependent voltage with the first comparator adjusted with the first adjustment and second comparator adjusted with the second adjustment.

Systems and methods for calibrating a temperature detection module

A voltage switch for handling negative voltages includes an input terminal coupled to a voltage that is greater than a voltage rating of oxide in the voltage switch, a top capacitor plate pre-charge module including three cascoded p-channel transistors coupled between a supply voltage and a top plate of a capacitor, a bottom capacitor plate pre-charge module including two cascoded n-channel transistors coupled between a bottom plate of the capacitor and ground, and an output voltage module including an output terminal and four cascoded n-channel transistors with control electrodes of a first and fourth of the cascoded n-channel transistors coupled to a boost node. Control electrodes of a second and third of the cascoded n-channel transistors coupled to the top plate of the capacitor. A voltage switch for positive voltages is also disclosed.

Voltage sampling switch and method therefor

A thermal sensor system including at least one thermal sensor, a voltage control network, a current gain network, a current compare sensor, and a controller. The voltage control network applies reference and delta voltage levels to a thermal sensor, which develops reference and delta current signals. The current gain network is used to adjust current gain. The current compare sensor is responsive to the reference and delta current signals and provides a comparison metric. The controller selects a temperature subrange and controls the current gain network to adjust the gain of the delta current signal to determine a gain differential value indicative of the temperature. The controller may select from among different sized thermal sensors, current mode gain values, and control voltages corresponding with each of multiple temperature subranges. Any one or more of these parameters may be adjusted to adjust an operating point for selecting a corresponding temperature subrange.

Thermal sensor system and method based on current ratio

A thermal sensor system which includes a thermal sensor and a voltage control network which applies a reference voltage level and a delta voltage level to the same or different thermal sensors. The thermal sensor develops a reference current signal in response to the reference voltage level and a delta current signal in response to the delta voltage level. A current gain network adjusts gain of the delta current signal. A current compare sensor, which is responsive to the reference current signal and the delta current signal, provides a comparison metric. A controller controls the current gain network to adjust gain of the delta current signal while monitoring the comparison metric to determine a gain differential value indicative of a current ratio between the current signals. The controller determines a temperature value based on the gain differential value. A LUT may be used to retrieve the temperature.

A band gap reference circuit including a band gap reference generator having an output for providing a reference voltage and a startup circuit for controlling current provided to the band gap reference generator when activated. The startup circuit includes a turnoff circuit having an output to deactivate the startup circuit to not control current to the band gap reference generator based on a voltage of the output of the band gap reference generator. The turnoff circuit includes an inverter having a first transistor of a first conductivity type in series with a second transistor of a second conductivity type opposite the first conductivity type. The startup circuit includes a body bias circuit connected to a body of the first transistor to provide a voltage differential between the body of the first transistor and a source terminal of the first transistor.

Bandgap reference circuit with startup circuit and method of operation

Signal edge alignment embodiments include multiple delay stages connected in series. Each delay stage includes a delay line, an interface circuit, and a tap selection circuit. The delay line applies fixed-width delays to an input signal to produce delayed versions of the input signal at a plurality of taps. The interface circuit, which is characterized by an inherent interface circuit delay, passes one of the delayed versions to an interface circuit output in response to a control signal. The tap selection circuit determines a finally-identified tap of the plurality of taps by determining an initially-identified tap at which a delayed version of the input signal most closely has a desired alignment with the input signal, and by identifying the finally-identified tap in the control signal as a tap that occurs earlier in the delay line than the initially-identified tap. This compensates for the inherent delay of the delay stage.

Multiple-stage, signal edge alignment apparatus and methods

Apparatus are provided for a voltage-controlled oscillator module. A voltage-controlled oscillator module comprises an input node for receiving an input voltage, a voltage-controlled oscillator, and voltage translation circuitry coupled between the input node and the voltage-controlled oscillator. The voltage translation circuitry is configured to generate a control voltage based on the input voltage and the voltage-controlled oscillator generates an oscillating signal at an oscillation frequency in response to the control voltage. Biasing circuitry is coupled to the voltage translation circuitry, and the biasing circuitry is configured to adjust the ratio of the control voltage to the input voltage.

Growing community of inventors

Austin, TX, United States of America

Khoi Mai