# US 2024/0201233 A1 · Supply voltage monitoring apparatus

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- Number: US 2024/0201233 A1
- Document ID: US20240201233A1
- Status: Published application
- Kind: A1
- Application number: 18/526,480
- Filed: 2023-12-01
- Published: 2024-06-20
- Earliest claimed: 2022-12-14
- Assignees: ZF Automotive UK Limited
- Applicants: ZF Automotive UK Limited
- Inventors: Naiwu Yuan; Mansoor Shah
- Web page: https://patentgrep.com/patent/US20240201233A1

## CPC

- G01R 19/16528: {using digital techniques or performing arithmetic operations (using digital techniques to measure a voltage or a current, see G01R19/25)}
- B60R 16/03: for supply of electrical power to vehicle subsystems {or for (circuit arrangements for charging batteries H02J7/00)}
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR

## Abstract

A supply voltage monitoring apparatus for use in an automotive vehicle, having a circuit comprising, an analogue-to-digital converter having an input receiving an analogue voltage signal and an output outputting a digital signal, and an input stage connecting the input of the ADC to the power supply at a point where the value of the link voltage is to be measured. An input stage comprises a potential divider having an upper resistance R1 and a lower resistance R2, the two resistances R1, R2 connected in series two nodes. A first node provides a connection to the link voltage. A second node provides a connection to ground. A centre tap of a potential divider is connected to the input of the ADC. A switchable lower resistance R3 is connected in series with a switch S between the centre tap and the ground, and a control circuit which is arranged to hold the switch S open when the voltage at the centre tap is below a threshold value and to hold the switch closed when the voltage at the centre tap is above the threshold value.

## Claims

### Claim 1

A supply voltage monitoring apparatus for use in monitoring a value of a supply voltage of an automotive vehicle, a circuit comprising:
An analogue to digital converter (ADC) having an input for receiving an analogue voltage signal and an output for outputting a digital signal, and
An input stage which connects the input of the ADC to a power supply at a point where the value of the supply voltage Vlink is to be measured, the input stage comprising:
a potential divider having an upper resistance and a lower resistance, the two resistances connected in series to two nodes, a first node providing a connection to the supply voltage and a second node providing a connection to ground, the centre tap of the potential divider being connected to the input of the ADC,
a switchable lower resistance which is connected in series with a switch between the centre tap of the potential divider and the ground, and
a control circuit which is arranged to hold the switch open when the voltage at the centre tap is below a threshold value and to hold the switch closed when the voltage at the centre tap is above the threshold value.

### Claim 2 (depends on 1)

A supply voltage monitoring apparatus according to claim 1 in which the control circuit includes a processing unit which monitors a value of the output signal and when the output signal reaches or is above the threshold value transmits a voltage signal to the switch to hold the switch closed (ON).

### Claim 3 (depends on 1)

A supply voltage monitoring apparatus according to claim 1 in which the control circuit comprises a second potential divider comprising a second upper resistance in series with a second lower resistance connected between the centre tap and the ground, a voltage at the centre tap of the second potential divider varying as a function of the supply voltage and controlling the opening or closing of the switch.

### Claim 4 (depends on 2)

A supply voltage monitoring apparatus according to claim 2 in which the switch comprises a MOSFET transistor and a gate of the transistor is supplied with the voltage signal.

### Claim 5 (depends on 1)

A supply voltage monitoring apparatus according claim 1, further comprising a processing unit which receives the digital signal output from the ADC and maps the digital signal to a value for the supply voltage.

### Claim 6 (depends on 3)

A supply voltage monitoring apparatus according to claim 3 in which the switch comprises a MOSFET transistor and a gate of the transistor is supplied with the voltage signal.

### Claim 7 (depends on 3)

A supply voltage monitoring apparatus according claim 3, further comprising a processing unit which receives the digital signal output from the ADC and maps the digital signal to a value for the supply voltage.

### Claim 8 (depends on 4)

A supply voltage monitoring apparatus according claim 4, further comprising a processing unit which receives the digital signal output from the ADC and maps the digital signal to a value for the supply voltage.

### Claim 9 (depends on 6)

A supply voltage monitoring apparatus according claim 6, further comprising a processing unit which receives the digital signal output from the ADC and maps the digital signal to a value for the supply voltage.