US 11,671,138 B2Granted

Self-calibrating on-off keying based digital isolator

AssigneeTexas Instruments Incorporated

InventorsRR Manikandan, Kumar Anurag Shrivastava, Robert Floyd Payne, Anant Shankar Kamath, Swaminathan Sankaran, Kishalay Datta, Siraj Akhtar, Mark Edward Wentroble, Suvadip Banerjee, Rakesh Hariharan, Gurumurti Kailaschandra Avhad

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Abstract

In described examples, an integrated circuit includes an on-off keying (OOK) digital isolator, which includes a first circuitry, a multiplexer, an OOK modulator, an isolation barrier, an OOK envelope detector, and a second circuitry. The first circuitry generates and outputs a calibration signal. The multiplexer has a data signal input, and an input coupled to a first circuitry output. An OOK modulator input is coupled to a multiplexer output. An isolation barrier input is coupled to an OOK modulator output. An OOK envelope detector input is coupled to an isolation barrier output. The second circuitry includes an input coupled to an OOK envelope detector output, and an output coupled to an OOK envelope detector control input. The second circuitry detects a duty cycle distortion (DCD) of the OOK envelope detector output, and outputs a control signal to change the OOK envelope detector output's duty cycle based on the detected DCD.

Claims20

Dependent claims

An on-off keying (OOK) digital isolation transceiver, the transceiver comprising:

a transmitter side calibration circuitry including a calibration signal output, the transmitter side calibration circuitry configured to output a calibration signal;
a multiplexer including an isolator input, a calibration signal input, a calibration enable input, and a multiplexer output, the isolator input adapted to receive a data signal, the calibration signal input coupled to the calibration signal output, and the calibration enable input adapted to receive a calibration enable signal, the multiplexer configured to output a signal corresponding to one of the isolator input or the calibration signal input in response to the calibration enable signal;
an OOK modulator including a modulator input and a modulator output, the modulator input coupled to the multiplexer output, the OOK modulator configured to selectively output a transmitted signal having a reference frequency in response to a value of the modulator input corresponding to an on state or an off state of the OOK modulator;
an OOK envelope detector including a detector input, a control input, and a detector output, the OOK envelope detector configured to:
output a signal having a first value in response to detecting a signal received via an isolation barrier;
output a signal having a second value in response to not detecting the signal received via the isolation barrier;
and
change a duty cycle of the detector output in response to the control input;
and
a receiver side calibration circuitry including a calibration input and a control output, the calibration input coupled to the detector output, the control output coupled to the control input, the receiver side calibration circuitry configured to detect a duty cycle distortion (DCD) of the detector output and to output the control output in response to the detected DCD.

7 more elements

An integrated circuit, comprising:

an on-off keying (OOK) envelope detector including a detector input, a control input, and a detector output, and configured to output a signal having a first value in response to detecting a signal received via an isolation barrier, and to output a signal having a second value in response to not detecting the signal received via the isolation barrier, wherein the OOK envelope detector is configured to change a duty cycle of the detector output in response to the control input;
and
a receiver side calibration circuitry including a calibration input and a control output, the calibration input coupled to the detector output, the control output coupled to the control input, the receiver side calibration circuitry configured to detect a duty cycle distortion (DCD) of the detector output and to output the control output in response to the detected DCD.

A method for digital signal isolation, the method comprising:

utilizing a digital isolator transmitter side circuitry:
selecting a data input signal or a calibration signal as a target signal in response to whether a calibration enable signal is activated;
generating a carrier wave signal having a reference frequency;
modulating, utilizing an on-off keying (OOK) modulator, the target signal utilizing the the carrier wave signal to generate a transmitted signal;
transmitting the transmitted signal across an isolation barrier;
receiving the transmitted signal from the isolation barrier as a received signal;
and
utilizing a digital isolator receiver side circuitry:
detecting, utilizing an OOK envelope detector, portions of the transmitted signal that include the carrier wave signal to generate a recovered target signal;
and
in response to receiving a calibration start signal:
detecting a duty cycle of the recovered target signal;
comparing the detected duty cycle to a designed duty cycle;
and
controlling the OOK envelope detector to increase or decrease the duty cycle of the recovered target signal in response to the comparing.

12 more elements

Dependencies are inferred from the claim text.

Facts

Application: 17/489,483Filed 29 Sep 2021 · us provisional application
Priority: 20 Jul 2021
Published: US 2023/0025757 A126 Jan 2023
Granted: 6 Jun 2023
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

H04B 1/44
Circuits: transmit/receive switching
H03K 3/017
Details: adjustment of width or dutycycle of pulses
H03K 5/24
Circuits having more than one input and one output for comparing pulses or pulse trains with each other according to input signal…
H03K 19/0175
Logic circuits, i.e. having at least two inputs acting on one output ; Inverting circuits: coupling arrangements; Interface arrangements