Fully-differential receiver for receiving conducted communication signals

Patent metadata

Field	Value
Publication number	US-12113649-B2
Application number	US-202117538827-A
Country	US
Kind code	B2
Filing date	Nov 30, 2021
Priority date	Nov 30, 2021
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

Abstract

Described herein is a fully-differential receiver for use with an implantable medical device (IMD) and configured to receive conducted communication signals that are transmitted by another IMD or an external device. The fully-differential receiver includes a fully-differential preamplifier, a fully-differential buffer, a first comparator, a second comparator, and an AC coupling network coupled between differential outputs of the fully-differential buffer and a coupled together differential pair of inputs of the first and second comparators. A differential pair of inputs of the fully-differential receiver comprise the differential pair of inputs of the fully-differential preamplifier, and a differential pair of outputs of the fully-differential receiver comprise a first output of the first comparator and a second output of the second comparator. In order to conserve power, the fully-differential receiver is selectively changed from operating in a first mode to operating in a second mode, and vice versa.

First claim

What is claimed is:

1. A fully-differential receiver having a differential pair of inputs and a differential pair of outputs, the fully-differential receiver for use in an implantable medical device (IMD) and configured to receive conducted communication signals that are transmitted by another IMD or an external device, the fully-differential receiver comprising:
a fully-differential preamplifier including a differential pair of inputs and a differential pair of outputs;
a fully-differential buffer including a differential pair of inputs and a differential pair of outputs, wherein the differential pair of inputs of the fully-differential buffer are coupled to the differential pair of outputs of the fully-differential preamplifier;
a first comparator including a differential pair of inputs and a first output;
a second comparator including a differential pair of inputs and a second output, wherein the differential pair of inputs of the second comparator are coupled to the differential pair of inputs of the first comparator such that the differential pair of inputs of the first and second comparators are coupled to one another; and
an AC coupling network coupled between the differential pair of outputs of the fully-differential buffer and the coupled together differential pair of inputs of the first and second comparators;
wherein the differential pair of inputs of the fully-differential receiver comprise the differential pair of inputs of the fully-differential preamplifier; and
wherein the differential pair of outputs of the fully-differential receiver comprise the first output of the first comparator and the second output of the second comparator.

2. The fully-differential receiver of claim 1 , wherein:
the fully-differential receiver is configured to operate in a first mode and a second mode;
when operating in the first mode, the fully-differential receiver draws a first amount of current and monitors for a wakeup signal within a first frequency range; and
when operating in the second mode, the fully-differential receiver draws a second amount of current that is higher than the first amount of current, and is configured to receive one or more message content pulses within a second frequency range that is higher than the first frequency range.

3. The fully-differential receiver of claim 2 , wherein:
the fully-differential receiver is configured to operate in the first mode when the fully-differential preamplifier, the fully-differential buffer, the first comparator, and the second comparator are provided with respective first biasing currents; and
the fully-differential receiver is configured to operate in the second mode when the fully-differential preamplifier, the fully-differential buffer, the first comparator, and the second comparator are provided with respective second biasing currents that are greater than the respective first biasing currents.

4. The fully-differential receiver of claim 1 , wherein:
the differential pair of inputs of each of the first and second comparators include a respective non-inverting (+) input and a respective inverting (−) input;
the first comparator is configured to produce an output pulse at the first output when a voltage potential difference between the non-inverting (+) input and the inverting (−) input of the first comparator exceeds a first offset and is positive relative to a common mode voltage of the fully-differential receiver; and
the second comparator is configured to produce an output pulse at the second output when a voltage potential difference between the non-inverting (+) input and the inverting (−) input of the second comparator exceeds a second offset and is negative relative to the common mode voltage.

5. The fully-differential receiver of claim 1 , wherein:
the differential pair of inputs of the fully-differential receiver are coupled to a pair of electrodes of the IMD; and
the pair of electrodes are used to sense conducted communication signals that are transmitted by another IMD or an external device.

6. The fully-differential receiver of claim 1 , wherein:
the differential pair of outputs of the fully-differential buffer include a non-inverting (+) output and an inverting (−) output;
the differential pair of inputs of each of the first and second comparators include a respective non-inverting (+) input and a respective inverting (−) input;
the non-inverting (+) input of the first comparator is coupled to the inverting (−) input of the second comparator; and
the inverting (−) input of the first comparator is coupled to the non-inverting (+) input of the second comparator.

7. The fully-differential receiver of claim 6 , wherein the AC coupling network comprises:
a first capacitor coupled between the non-inverting (+) output of the fully-differential buffer and the non-inverting (+) input of the first comparator, and between the non-inverting (+) output of the fully-differential buffer and the inverting (−) input of the second comparator;
a second capacitor coupled between the inverting (−) output of the fully-differential buffer and the inverting (−) input of the first comparator, and between the inverting (−) output of the fully-differential buffer and the non-inverting (+) input of the second comparator;
a first resistor coupled between a common mode voltage (vcm) node and the non-inverting (+) input of the first comparator, and between the common mode voltage (vcm) node and the inverting (−) input of the second comparator; and
a second resistor coupled between the common mode voltage (vcm) node and the inverting (−) input of the first comparator, and between the common mode voltage (vcm) node and the non-inverting (+) input of the second comparator.

8. The fully-differential receiver of claim 7 , wherein the AC coupling network:
is configured to remove any DC offset that may be caused by the fully-differential preamplifier and the fully-differential buffer; and
an output DC biasing point of the AC coupling network is a common mode voltage at the vcm node.

9. The fully-differential receiver of claim 1 , wherein:
the differential pair of inputs of the fully-differential preamplifier include a non-inverting (+) input and an inverting (−) input;
a first high pass filter is coupled to the non-inverting (+) input of the fully-differential preamplifier;
a second high pass filter is coupled to the inverting (−) input of the fully-differential preamplifier; and
the first and second high pass filters are configured to filter out signals indicative of cardiac electrical activity sensed by electrodes that are coupled to the differential pair of inputs of the fully-differential preamplifier.

10. The fully-differential receiver of claim 1 , wherein:
the differential pair of inputs of the fully-differential preamplifier include a non-inverting (+) input and an inverting (−) input; and
the fully-differential preamplifier comprises a pair of switches that when selectively closed cause there to be a zero voltage potential difference between the non-inverting (+) input and the inverting (−) input of the fully-differential preamplifier, and thus, cause there to be the zero voltage potential difference between the differential pair of inputs of the fully-differential receiver.

11. The fully-differential receiver of claim 1 , wherein:
the fully-differential receiver is configured to operate in both a first mode and a second mode; and
the fully-differential preamplifier comprises switches that are selectively closed for a period of time to reset the fully-differential receiver whenever there is a change from the first mode to the second mode, or a change from the second mode to the first mode.

Assignees

• Pacesetter Inc

Inventors

• Labbe Eric C
• Persson Benjamin T

Classifications

• H04L25/0292

  Arrangements specific to the receiver end · CPC title

• H04L25/0272 Primary

  Arrangements for coupling to multiple lines, e.g. for differential transmission · CPC title