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公开(公告)号：US20180152174A1
公开(公告)日：2018-05-31
申请号：US15365451
申请日：2016-11-30
Inventor： Ramin Zanbaghi , Tejasvi Das , John L. Melanson , Axel Thomsen
Abstract: A variable resistor may be coupled between a reference voltage source and components of an integrated circuit to reduce issues relating to thermal noise from a reference voltage signal generated by the reference voltage source. The variable resistor may be set to a low level during a first time period and a high level during a second time period, in which the time periods correspond to a sampling period of a switched-capacitor circuit. The low resistance time period may allow quick settling of an input reference voltage signal, whereas the high resistance time period may reduce a bandwidth of noise on a sampling capacitor coupled to the reference voltage signal. The variable resistor and switched-capacitor network may be used in an analog-to-digital converter (ADC), such as in audio circuits.
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公开(公告)号：US12283928B2
公开(公告)日：2025-04-22
申请号：US17586111
申请日：2022-01-27
Inventor： Sven Soell , Paul Wilson , James T. Deas , Axel Thomsen
Abstract: A circuit may include a two-stage feedforward compensated operational transconductance integrated amplifier, and the two-stage feedforward compensated operational transconductance integrated amplifier may include an input terminal, an output terminal, a signal path between the input terminal and the output terminal, the signal path comprising a first signal path gain stage and a second signal path gain stage, and ripple rejection circuitry coupled between the input terminal and an intermediate node of the signal path located between the first signal path gain stage and the second signal path gain stage. The ripple rejection circuitry may include a first ripple rejection circuitry gain stage coupled at its input to the input terminal and coupled at its output to an input terminal of a chopper circuit, a notch filter coupled at its input to an output terminal of the chopper circuit, and a second ripple rejection circuitry gain stage coupled at its input to an output terminal of the notch filter and coupled at its output to the intermediate node.
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公开(公告)号：US12257601B2
公开(公告)日：2025-03-25
申请号：US18615241
申请日：2024-03-25
Inventor： Axel Thomsen , Eric J. King , Anthony S. Doy , Thomas H Hoff , John L. Melanson
Abstract: This application relates to methods and apparatus for driving a transducer with switching drivers. A driver circuit has first and second switching drivers for driving the transducer in a bridge-tied-load configuration, each of the switching drivers having a respective output stage for controllably switching the respective driver output node between high and low switching voltages with a controlled duty cycle. Each of switching drivers is operable in a plurality of different driver modes, wherein the switching voltages are different in said different driver modes. A controller controls the driver mode of operation and the duty cycle of the switching drivers based on the input signal. The controller is configured to control the duty cycles of the first and second switching drivers within defined minimum and maximum limits of duty cycles; and to transition between driver modes of operation when the duty cycle of one of the switching drivers reaches a duty cycle limit.
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14.发明授权公开(公告)号：US12132494B2
公开(公告)日：2024-10-29
申请号：US17939166
申请日：2022-09-07
Inventor： Arashk Norouzpourshirazi , John L. Melanson , Axel Thomsen
CPC classification number: H03M1/0629 , H03L7/0991 , H03M1/1009 , H03H11/04
Abstract: A method may include, for a signal path comprising a passive antialiasing filter sampled by a switched-capacitor front-end, monitoring a change of a first impedance of a resistor of the passive antialiasing filter responsive to an environmental condition relative to a second impedance of a switched capacitor of the switched-capacitor front end and compensating the signal path for a change in gain of the signal path resulting from the change of the first impedance.
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15.发明公开公开(公告)号：US20240192715A1
公开(公告)日：2024-06-13
申请号：US18077402
申请日：2022-12-08
Inventor： Angel C. Abusleme Hoffman , Axel Thomsen
Abstract: A circuit and method for generating a protection voltage includes a pair of voltage-generating circuits that generate voltages from the power supply voltage. The voltages have a differing dependence on the power supply voltage so that a difference between the first voltage and the second voltage changes sign for a particular value of the power supply voltage. The voltages are supplied to a protection voltage generating circuit that includes a pair of amplifiers having inputs that receive a respective one of the voltages and each of the amplifiers provides negative feedback to the other. An output circuit generates the protection voltage according to a maximum or a minimum value among the amplifier outputs, so that the protection voltage is monotonic with respect to variation of the power supply voltage.
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Patent Agency Ranking
公开(公告)号：US11980913B2
公开(公告)日：2024-05-14
申请号：US18323779
申请日：2023-05-25
Inventor： Axel Thomsen , Eric J. King , Anthony S. Doy , Thomas H. Hoff , John L. Melanson
CPC classification number: B06B1/0223 , B06B1/0215 , B06B1/0688 , G06F3/016 , H10N30/802
Abstract: This application relates to methods and apparatus for driving a transducer with switching drivers. A driver circuit has first and second switching drivers for driving the transducer in a bridge-tied-load configuration, each of the switching drivers having a respective output stage for controllably switching the respective driver output node between high and low switching voltages with a controlled duty cycle. Each of switching drivers is operable in a plurality of different driver modes, wherein the switching voltages are different in said different driver modes. A controller controls the driver mode of operation and the duty cycle of the switching drivers based on the input signal. The controller is configured to control the duty cycles of the first and second switching drivers within defined minimum and maximum limits of duty cycles; and to transition between driver modes of operation when the duty cycle of one of the switching drivers reaches a duty cycle limit.
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公开(公告)号：US11791816B2
公开(公告)日：2023-10-17
申请号：US17590943
申请日：2022-02-02
Inventor： Axel Thomsen , Eric J. King , Anthony S. Doy , Thomas H. Hoff , John L. Melanson
IPC: H03K17/687 , H02N2/00 , H02M3/158
CPC classification number: H03K17/6871 , H02M3/158 , H02N2/0075
Abstract: This application relates to methods and apparatus for driving a transducer with switching drivers. A switching driver has first and second supply node for receiving supply voltages and includes an output bridge stage, a capacitor and a network of switches. The network of switches is operable in different switch states to provide different switching voltages to the output bridge stage. A controller is configured to control the switch state of the network of switches and a duty cycle of output switches of the output bridge stage based on an input signal to generate an output signal for driving the transducer.
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公开(公告)号：US11777516B2
公开(公告)日：2023-10-03
申请号：US17667953
申请日：2022-02-09
Inventor： John L. Melanson , Axel Thomsen , Mucahit Kozak , Paul Wilson , Eric J. King
IPC: H03M3/00
Abstract: A signal processing system may include a sensor readout channel configured to convert an electronic signal into a digital quantity. The sensor readout channel may include a first-order sigma-delta modulator having a modulator input and a modulator output, first outside chopping switches located at the modulator input, second outside chopping switches located at the modulator output, an auxiliary path having an analog-to-digital converter (ADC) having an auxiliary path input and an auxiliary path output, the auxiliary path input configured to receive as its input signal a signal output by a memory element of the first-order sigma-delta modulator, and a signal combiner configured to combine a modulator output signal generated by the first-order sigma-delta modulator with an auxiliary path output signal generated by the auxiliary path to generate a combined output signal.
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公开(公告)号：US11777495B2
公开(公告)日：2023-10-03
申请号：US17740468
申请日：2022-05-10
Inventor： John L. Melanson , Eric J. King , Thomas H. Hoff , Axel Thomsen
IPC: H03K17/687 , H02N2/00 , H02M3/158
CPC classification number: H03K17/6871 , H02M3/158 , H02N2/0075
Abstract: This application relates to methods and apparatus for driving a transducer with switching drivers where the switching driver has an output bridge stage for switching an output node between switching voltages and a modulator for controlling the duty cycle of the output bridge stage based on an input signal. The switching driver also includes a voltage controller for providing the switching voltages which is operable to provide different switching voltages in different driver modes. A controller is provided to control the driver mode of operation and the duty cycle of the switching driver based on the input signal, and the controller is configured to transition from a present driver mode to a new driver mode by controlling the voltage controller to provide the switching voltages for the new mode and controlling the modulator to vary the duty cycle of the output bridge stage. The change in duty cycle is controlled such that there is no substantial discontinuity in switching ripple due to the mode transition.
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公开(公告)号：US11684950B2
公开(公告)日：2023-06-27
申请号：US17314890
申请日：2021-05-07
Inventor： Axel Thomsen , Eric J. King , Anthony S. Doy , Thomas H. Hoff , John L. Melanson
CPC classification number: B06B1/0223 , B06B1/0215 , B06B1/0688 , G06F3/016 , H10N30/802
Abstract: This application relates to methods and apparatus for driving a transducer with switching drivers. A driver circuit has first and second switching drivers for driving the transducer in a bridge-tied-load configuration, each of the switching drivers having a respective output stage for controllably switching the respective driver output node between high and low switching voltages with a controlled duty cycle. Each of switching drivers is operable in a plurality of different driver modes, wherein the switching voltages are different in said different driver modes. A controller controls the driver mode of operation and the duty cycle of the switching drivers based on the input signal. The controller is configured to control the duty cycles of the first and second switching drivers within defined minimum and maximum limits of duty cycles; and to transition between driver modes of operation when the duty cycle of one of the switching drivers reaches a duty cycle limit.
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