RELATED APPLICATION

This application claims priority to German Patent No. 102020108928.7, filed on Mar. 31, 2020, which is incorporated herein by reference in its entirety.

FIELD

The present application relates to devices comprising a sensor, controllers and corresponding methods. In this case, some embodiments relate to the communication between such a device and a controller by means of pulse-width-modulated signals.

BACKGROUND

Devices comprising a sensor, also referred to hereinafter as sensor devices, are used to detect one physical variable or a plurality of physical variables. Examples thereof are magnetic field sensors, pressure sensors, temperature sensors, current sensors, voltage sensors and the like. In many systems, signals that are representative of the physical variable detected are then transmitted to a controller, which processes further the information thus obtained regarding one or more detected variables. One example thereof is automotive applications, in which data, for example wheel rotational speed, tire pressure, temperatures and the like, are detected by means of a multiplicity of sensors in a vehicle, and then the information thus detected is transmitted from the sensor devices to one or more controllers, often referred to as ECU (Electrical Control Unit).

For this transmission the variables detected by the respective sensor have to be converted into corresponding electrical signals, which are then transmitted. One procedure for doing this is pulse width modulation (PWM), in which signal pulses are transmitted, wherein a duty cycle corresponding to a ratio of a pulse duration to a total cycle length or to a pause length corresponds to a signal value. By way of example, it is possible to use pulses for transmitting 8-bit signals, which can have 28-1=255 different values, which pulses can have 255 different pulse duration lengths, e.g. 1 to 255 time units, depending on the coded value.

For a fixed frequency of an underlying clock signal that defines the time units of the pulse-width-modulated signal, a high resolution results in a low transmission rate, and respectively a low resolution results in a high transmission rate. For example, with a clock signal of 8 MHz, a time unit has a length of 125 ms. A resolution of 14 bits necessitates 214-1 clock cycles for one cycle of the pulse-width-modulated signal, which corresponds to a cycle duration of the transmitted information of 2.047 ms. A resolution of 8 bits necessitates 28-1 clock cycles corresponding to a cycle duration of the pulse-width-modulated signal of 232 μs. As frequency, this corresponds to an update rate of approximately 30 kHz instead of approximately 500 Hz in the case of a 14-bit resolution.

In this case, cycle (also referred to as PWM duration) of the pulse-width-modulated signal should be understood to mean substantially that time which is required for a pulse of maximum duration, for example 214-1 clock cycles for 14-bit resolution or 28-1 clock cycles for 8-bit resolution. Within a cycle the pulse-width-modulated signal is then in a first state, e.g. high (for example first voltage, first current), for a certain first time duration and in a second state (for example second voltage, second current), e.g. low, for a second time duration and a duty cycle (ratio of the duration of the first state to the duration of a cycle) indicates the value which is coded with the respective pulse. Given a fixed, known cycle duration, the same information is also contained in the duration of the first state, a duration of the second state or a ratio thereof. The duration of the first state (e.g. time in which the signal is at a high level) is also referred to hereinafter as pulse duration.

Some applications, for example for regulating systems, require both a high resolution for accurate regulation and a high update rate, in order to be able to react rapidly to sudden changes in a physical variable detected.

SUMMARY

A device as claimed in claim1, a controller as claimed in claim10and methods as claimed in claims16and22are provided. The dependent claims define further embodiments.

In accordance with one exemplary embodiment, a device is provided, including a sensor configured to output an analog sensor signal. The device further includes an analog-to-digital converter arrangement configured to convert the analog sensor signal into a sigma-delta-modulated second digital signal having a bit width of n bits, and

a pulse width modulator configured to generate a pulse-width-modulated signal based on the second digital signal.

In accordance with a further exemplary embodiment, a controller is provided, including:

an input for receiving a pulse-width-modulated signal from a sensor device, and

a processing circuit configured to generate a first digital signal based on averaging over k cycles of the pulse-width-modulated signal, where k is greater than or equal to 2.

In accordance with a further exemplary embodiment, a method is provided, including:

generating a sigma-delta-modulated second digital signal having a bit width of n bits based on an analog sensor signal, and

generating a pulse-width-modulated signal based on the second digital signal.

Another method is additionally provided, including:

receiving from a sensor device a pulse-width-modulated signal generated based on a sigma-delta-modulated signal, and

generating a first digital signal based on averaging over k cycles of the pulse-width-modulated signal, where k is greater than or equal to 2.

The summary above offers only a brief overview of some embodiments and should not be interpreted as restrictive.

