# US 12,761,256 B2 · Method for determining the system resistance of a device

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- Number: US 12,761,256 B2
- Document ID: US12761256B2
- Status: Granted
- Kind: B2
- Application number: 18/448,566
- Filed: 2023-08-11
- Published: 2023-12-07
- Granted: 2026-10-13
- Earliest claimed: 2018-04-24
- Assignees: Roche Diagnostics Operations, Inc.
- Applicants: Roche Diagnostics Operations, Inc.
- Inventors: Michael Lambertson
- Web page: https://patentgrep.com/patent/US12761256B2

## CPC

- G01R 27/14: Measuring resistance by measuring current or voltage obtained from a reference source (G01R27/16, G01R27/20, G01R27/22 take precedence)
- G01R 31/3648: {comprising digital calculation means, e.g. for performing an algorithm}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

A method for determining system resistance of at least one power supply of a handheld medical device, the method including: a) generating at least one excitation voltage signal, wherein the excitation voltage signal comprises at least one direct current (DC) voltage signal, wherein the excitation voltage signal has a fast transition DC flank of 20 ns or less; b) applying the excitation voltage signal to at least one reference resistor having a predetermined or pre-defined resistance value, wherein the reference resistor is arranged in series with the power supply; c) measuring a response signal of the power supply; d) determining a signal flank from the response signal and determining an ohmic signal portion from one or both of shape and height of the signal flank; and e) determining the system resistance of the power supply from the ohmic signal portion.

## Claims

### Claim 1

A method for determining system resistance of at least one power supply of a device, the method comprising
a) generating at least one excitation voltage signal, wherein the excitation voltage signal defines a time varying change in voltage having a fast transition DC flank of 20 ns or less;
b) applying the excitation voltage signal to a power supply via at least one reference resistor having a predetermined or pre-defined resistance value, wherein the reference resistor is electrically connected in series with the power supply at a reference node;
c) measuring a response signal of the power supply at the reference node, wherein the response signal determines a time varying signal corresponding to an impedance at the reference node;
d) comparing a shape and height of the excitation voltage signal with a corresponding shape and height of the response signal to determine a difference in the signal flank of the response signal;
e) determining an ohmic signal portion based on the difference in the signal flank of the response signal; and
f) determining the system resistance of the power supply from the ohmic signal portion.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the excitation voltage signal defines a square wave signal or a sine wave signal.

### Claim 3 (depends on 1)

The method according to claim 1, wherein the excitation voltage signal comprises a non-continuous signal.

### Claim 4 (depends on 1)

The method according to claim 1, wherein the reference resistor is connected to at least one electrical contact of the power supply.

### Claim 5 (depends on 1)

The method according to claim 1, wherein step d) comprises determining one or both of at least one deviation or difference from an induced signal shape of the excitation voltage signal.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the system resistance Rsystem of the power supply is determined by
R
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,
wherein Utarget is a pulse height of the excitation voltage signal, Rref is the reference resistance and Umeasured is a height of the response signal at a start of a rising signal flank of the response signal.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the method comprises at least one condition determining step, wherein at least one condition information of the power supply is determined by comparing the determined system resistance of the power supply with at least one predetermined or predefined system resistance value.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the method comprises at least one failsafe step, wherein in the failsafe step the determined system resistance of the power supply is compared to at least one predetermined or predefined threshold value.

### Claim 9 (depends on 8)

The method according to claim 8, wherein in the failsafe step one or both of a warning is generated if the determined system resistance exceeds the threshold value by a predefined or predetermined value or an abortion of the power supply is initiated if the determined system resistance exceeds the threshold value by a predefined or predetermined value.

### Claim 10 (depends on 1)

The method of claim 1 in which the device using a low voltage source to power a system.

### Claim 11 (depends on 1)

The method of claim 1 in which the device requires a critical power supply which needs a first failure mode to monitor the power supply.

### Claim 12 (depends on 1)

The method of claim 1 in which the device is a handheld, portable device.

### Claim 13

A device comprising at least one element, wherein the device further comprises:
at least one power supply for powering said at least one element of the device;
at least one reference resistor having a predetermined or pre-defined reference resistance, wherein the reference resistor is electrically connected in series with the power supply at a reference node;
at least one signal generator device adapted to generate at least one excitation voltage signal, wherein the excitation voltage signal defines a time varying change in voltage having a fast transition DC flank from 20 ns or less, wherein the signal generator device is adapted to apply the excitation voltage signal to a power supply via the reference resistor;
at least one measurement unit adapted to measure at least one response signal at the reference node, wherein the at least one response signal determines a time varying signal corresponding to an impedance at the reference node;
at least one evaluation device adapted to compare a shape and height of the excitation voltage signal with a corresponding shape and height of the at least one response signal to determine a difference in the signal flank of the response signal, to determine an ohmic signal portion based on the difference in the signal flank of the response signal, and to determine a system resistance of the power supply from the ohmic signal portion.

### Claim 14 (depends on 13)

The device according to claim 13, wherein the device is selected from the group consisting of: at least one handheld analytical device; at least one insulin pump; and at least one portable sensor for monitoring at least one body function.

### Claim 15 (depends on 13)

The device according to claim 13, wherein the power supply comprises at least one power source selected from the group consisting of: at least one battery; at least one rechargeable battery, at least one electric double layer capacitor (EDLC).

### Claim 16 (depends on 13)

The device according to claim 13, wherein the evaluation device comprises at least one microprocessor.

### Claim 17 (depends on 13)

The device according to claim 13, wherein the evaluation device comprises one or both of at least one analog-to-digital convertor or at least one digital-to-analog convertor.

### Claim 18 (depends on 13)

The device according to claim 13, wherein the device comprises at least one power supply circuit configured for providing power to the at least one element of the device and at least one system resistance measurement circuit configured for determining the system resistance, wherein the device comprises at least one switching element adapted to separate the power supply circuit and the system resistance measurement circuit.

### Claim 19 (depends on 13)

The method according to claim 13, wherein the non-continuous signal is a pulse.

### Claim 20 (depends on 14)

The method according to claim 14, wherein the at least one handheld analytical device comprises at least one handheld meter.

### Claim 21 (depends on 14)

The method according to claim 14, wherein the at least one portable sensor for monitoring at least one body function comprises at least one long-term ECG, or an implantable or insertable continuous glucose sensor.

### Claim 22 (depends on 13)

The method of claim 13 in which the device using a low voltage source to power a system.

### Claim 23 (depends on 13)

The method of claim 13 in which the device requires a critical power supply which needs a first failure mode to monitor the power supply.

### Claim 24 (depends on 13)

The method of claim 13 in which the device is a handheld, portable device.