DE102020208281A1 - Sensor arrangement and method for operating a sensor arrangement - Google Patents

Abstract

The invention relates to a sensor arrangement comprising a sensor timer which is designed to generate a sensor time signal using a clock signal provided, a rate device which generates a countdown signal above an ODR threshold value based on a specifiable output data rate and using the sensor time signal generates,a countdown timer which is designed to provide the countdown signal independently of the sensor time signal for a sensor frontend if the predefinable output data rate is below the ODR threshold value, andwherein the sensor frontend, the countdown timer and the rate device are designed to interact in such a way that the sensor front end outputs data from a measurement when the countdown signal has expired.

Description

Technical area

The invention relates to a sensor arrangement comprising a sensor timer which is designed to generate a sensor time signal on the basis of a provided clock signal and a rate device which generates a countdown signal on the basis of the sensor time signal.

The invention further relates to a method for operating a sensor arrangement and a sensor arrangement comprising a sensor front end.

State of the art

Although the present invention is generally applicable to any sensor arrangements, the present invention is explained with reference to inertial measuring units.

Inertial measuring units, for example a combination of an acceleration sensor with a gyroscope, have a wide range of applications, for example in smartphones, wearables or the like. In this case, the corresponding sensor is given an output data rate - output-date rate ODR - which can be selected in a limited manner from a given list, for example 100 Hz, 200 Hz or 400 Hz et cetera.

In order to be able to freely choose the output data rate so that the post-processing of the data provided by the sensor and thus the synchronization to environmental requirements is simplified, it has become known, on the one hand, to select the output data rate higher than the output data rate required for the respective application and then to interpolate it. This can be done both by means of the sensor driver firmware or also by the sensor itself, for example by means of a microcontroller integrated into the sensor. Problems here, however, are any interpolation errors that may occur, latency in the provision of the data due to (post) processing, and additionally required memory and computing resources.

Disclosure of the invention

In one embodiment, the present invention provides a sensor arrangement comprising
a sensor timer which is designed to generate a sensor time signal based on a provided clock signal,
a rate device that generates a countdown signal above an ODR threshold based on a predefinable output data rate and on the basis of the sensor time signal,
a CountDown timer which is designed to provide the CountDown signal independently of the sensor time signal for a sensor front end when the predeterminable output data rate is below the ODR threshold value and
wherein the sensor front end, the countdown timer and the rate device are designed to work together so that when the countdown signal expires, the sensor front end outputs data from a measurement.

• - Bereitstellen eines Sensorzeit-Signals mittels des Sensortimers anhand eines Taktsignals,
• - Bereitstellen einer Ausgabedatenrate,
• - Vergleichen der Ausgabedatenrate mit einem ODR-Schwellwert, und wenn die Ausgabedatenrate unterhalb des ODR-Schwellwerts liegt:
  • ◯ Bereitstellen eines CountDown-Signals für ein Sensor-Frontend mittels eines Count-Down-Timers unabhängig vom Sensorzeit-Signal,
  und wenn die Ausgabedatenrate oberhalb des ODR-Schwellwerts liegt,
  • ◯ Bereitstellen eines CountDown-Signals mittels einer Rateneinrichtung, basierend auf der Ausgabedatenrate und anhand des Sensorzeit-Signals,
• - Bereitstellen von Daten einer Messung des Sensor-Frontends, derart, sodass bei Ablauf des CountDown-Signals das Sensor-Frontend Daten einer Messung ausgibt.

In a further embodiment, the present invention provides a method for operating a sensor arrangement according to one of claims 1-5, comprising the steps:

• - Provision of a sensor time signal by means of the sensor timer based on a clock signal,
• - Providing an output data rate,
• - Compare the output data rate with an ODR threshold value, and if the output data rate is below the ODR threshold value:
  • ◯ Provision of a countdown signal for a sensor front end by means of a countdown timer independent of the sensor time signal,
  and if the output data rate is above the ODR threshold,
  • ◯ Provision of a CountDown signal by means of a rate device, based on the output data rate and on the basis of the sensor time signal,
• - Provision of data from a measurement of the sensor front end in such a way that when the CountDown signal expires, the sensor front end outputs data from a measurement.

In a further embodiment, the present invention provides a sensor arrangement comprising a sensor front end and a countdown timer, the sensor front end being predominantly switched off and the countdown timer being designed to provide a countdown signal for the sensor front end and wherein the sensor front end is connected exclusively to the countdown timer for initiating an output of data from a measurement, and wherein the sensor front end and countdown timer are designed such that the sensor front end is switched on so that a measurement is carried out and when a CountDown signal has elapsed, the data of the measurement carried out are output.

The CountDown signal is in particular continuously provided to the sensor front end. The sensor front end uses the CountDown Signal to record the internal processes of the sensor front end, such as recording raw signals, filtering raw signals, compensating temperature errors and the like, i.e. timed them so that the measurement data, i.e. the output sensor value, is precisely timed when the countdown timer reaches the value '0', i.e. the countdown signal has expired.

One of the advantages achieved in this way is that on the one hand, in particular when the sensor arrangement is in an energy-saving mode, the output data rate can be freely selected. On the other hand, there is an advantage that no interpolation of data has to be carried out, so that sensor data can be provided without additional calculations and memory requirements and with extremely low latency. Another advantage is that several sensors can be operated absolutely synchronously by means of the CountDown signal and that the age of the signals provided by the sensor front end is minimal.

Further features, advantages and further embodiments of the invention are described below or become apparent as a result.

According to a further development, the sensor front end is temporarily switched off at an output data rate below the threshold value and the sensor front end is switched on in a controlled manner such that data of the measurement are output when the countdown signal expires. In other words, the sensor front end is only switched on temporarily and in a controlled manner so that data of a measurement are provided by the sensor front end when the CountDown signal is received and expired. The advantage here is that energy can be saved by the sensor front end being switched off, but at the same time data from measurements are made available according to the desired output data rate.

According to a further development, the sensor timer and the countdown timer are implemented in the form of a timer and a DPLL circuit controlled by means of the timer via sync signals. The advantage of this is simple embedding in sensor arrangements with a digital phase locked loop DPLL, which receives clock signals from a timer.

According to a further development, the sensor front end has an inertial measuring unit, in particular comprising an acceleration sensor, a gyrometer and / or a temperature sensor. The advantage of this is that an inertial measuring device with a freely selectable output data rate can be provided.

According to a further development, the output data rate can be freely set according to a multiple of the clock signal and / or the operator frequency of the inertial measuring unit by means of a setting device. One of the advantages achieved in this way is that the output data rate can be set in a simple manner on the basis of the clock or operator signal.

According to a further development of the method for operating a sensor arrangement, the sensor front end is temporarily switched off at an output data rate below the threshold value and the sensor front end is switched on again in a controlled manner so that the data of a measurement through the sensor front end when the CountDown signal expires are issued. The advantage here is that energy can be saved, but at the same time data from measurements are provided according to the desired output data rate. Among other things, this improves the running time of smartphones, wearables or the like with a corresponding sensor arrangement.

Further important features and advantages of the invention emerge from the subclaims, from the drawings, and from the associated description of the figures on the basis of the drawings.

It goes without saying that the features mentioned above and those yet to be explained below can be used not only in the respectively specified combination, but also in other combinations or on their own, without departing from the scope of the present invention.

Preferred designs and embodiments of the invention are shown in the drawings and are explained in more detail in the following description, with the same reference symbols referring to the same or similar or functionally identical components or elements.

Figure list

• 1 eine bekannte Sensoranordnung;
• 2 eine Sensoranordnung gemäß einer Ausführungsform der vorliegenden Erfindung;
• 3 eine Sensoranordnung gemäß einer Ausführungsform der vorliegenden Erfindung;
• 4 eine Sensoranordnung gemäß einer Ausführungsform der vorliegenden Erfindung; und
• 5 Schritte eines Verfahrens zum Betreiben einer Sensoranordnung gemäß einer Ausführungsform der vorliegenden Erfindung.

It shows in schematic form

• 1 a known sensor arrangement;
• 2 a sensor arrangement according to an embodiment of the present invention;
• 3 a sensor arrangement according to an embodiment of the present invention;
• 4th a sensor arrangement according to an embodiment of the present invention; and
• 5 Steps of a method for operating a sensor arrangement according to an embodiment of the present invention.

Embodiments of the invention

1 shows a known sensor arrangement.

In detail is in 1 a known sensor arrangement 1 is shown, comprising a sensor timer 2, a rate device 3 and a sensor front end 5. The sensor timer 2 receives a clock signal 100 and generates a sensor time signal 101, for example a continuous CountUp signal. This signal 101 is transmitted to the rate device 3 by means of a signal 105 together with an output data rate 20 specified in particular by a user of the sensor arrangement 1. The rate device 3 then generates a countdown signal 104, for example in the form of a sawtooth signal, which is transmitted to the sensor front end 5 from the sensor time signal 101 and the signal 105, with which the output data rate is transmitted to the rate device 3 . On the basis of the CountDown signal 104, all data paths and sensor front ends 5 are synchronized, that is to say corresponding output signals are provided when the CountDown signal 104 expires, that is to say assumes the value 0. The sensor front end 5 usually generates raw sensor data on a regular basis on the basis of a fixed frequency. These then have to be filtered. Since the options for filtering are also limited, the options for selecting the output data rate are also limited. For example, this can only be selected from the list: 3.2 kHz, 1.6 kHz, 800 Hz, 400 Hz, ..., 12.5 Hz. If a higher output data rate is required, the number of raw sensor data required for data output from the sensor front end exceeds the number of recorded sensor data. The sensor timer 2 can be implemented, for example, as a simple counter which counts up at a predetermined frequency, as shown in FIG DE 10 2015 209 129 B3 is shown, which is hereby incorporated by reference into the present application.

2 shows a sensor arrangement according to an embodiment of the present invention.

In detail, a sensor arrangement 1 is essentially shown in FIG 1 shown. In contrast to the sensor arrangement 1 according to 1 is in the sensor arrangement 1 according to 2 a countdown timer 4 is arranged, which takes over the provision of the countdown signal 104 in the energy-saving mode of the sensor arrangement 1, for example. For this purpose, the CountDown timer 4 is configured automatically with any desired time 21 by a user or in some other way and this is provided, for example, in a corresponding register. For example, 40 microseconds can be specified as time 21, which corresponds to the cycle time of a gyroscope or 150 ns, which corresponds, for example, to the internal clock frequency of the sensor arrangement when operating a sensor front end with an acceleration sensor. This time 21 is made available to the CountDown timer 4, which then - if no CountDown signal 104 is generated by the rate device 3 - takes over the generation and provision of the CountDown signal 104 for the sensor front end. This is particularly the case when the output data rate to be provided falls below a predetermined value. In other words, the value in the register is used to initiate the countdown timer 4, which counts down to the value 0. If the value is 0, then data of a sensor measurement are provided. The CountDown-Timer 4 then counts down again to the value 0, and so on.

3 shows a sensor arrangement according to an embodiment of the present invention.

In detail is in 3 a sensor arrangement 1 is shown which essentially corresponds to the sensor arrangement 1 according to FIG 2 is equivalent to. In contrast to the sensor arrangement 1 according to 2 is in the sensor arrangement 1 according to 3 The sensor timer 2 is now implemented in the form of a timer 2a and a DPLL circuit 2b controlled by means of the timer 2a via sync signals. The timer 2a again receives a clock signal 100 and transmits this as signal 100b to the DPLL circuit 2b. In addition, the timer 2a uses a predetermined time 22 to generate a synchronization signal 100a in the form of a pulse as soon as it has counted up to the predetermined time and also transmits this to the DPLL circuit 2b. This then counts up again up to the specified time 22. The DPLL circuit 2b can then lock onto this synchronization signal 100a. The timer 2a provides signals with a resolution corresponding to the system clock with the clock signal 100a. According to the synchronization count signal 101 'provided by the DPLL circuit 2b, a countdown signal 104 is provided by means of a rate device 3' and the number 20 of data to be recorded per synchronization pulse made available to it - samples per sync, SPS - by means of the signal 105 ', which is then transmitted to the sensor front end 5. On the basis of the CountDown signal 104, all data paths and sensor front ends 5 are synchronized, that is to say corresponding output signals are provided when the CountDown signal 104 expires.

A possible advantage of this embodiment is that what is known as “upsampling” is made possible, that is to say, for example, four raw sensor data per synchronization pulse. Another possible advantage is that the accuracy of providing a desired output data rate by the Control loop of the DPLL circuit 2b is higher compared to the embodiment of FIG 2 .

4th shows a sensor arrangement according to an embodiment of the present invention.

Shows in detail 4th essentially a sensor arrangement according to 2 . In contrast to the sensor arrangement 1 according to 2 are absent in the sensor arrangement 10 according to FIG 4th the components 2 and 3, that is to say the timer 2 and the rate device 3. Using the countdown timer 4, the countdown signals 104 are generated according to a freely selectable output data rate and transmitted to the sensor front end 5. On the basis of the CountDown signal 104, all data paths and sensor front ends 5 are synchronized again, that is to say corresponding output signals are provided when the CountDown signal 104 expires.

The advantage of such a sensor arrangement 10 is that it is extremely inexpensive to manufacture and has a low energy consumption with a freely selectable output data rate at the same time.

5 shows steps of a method for operating a sensor arrangement according to an embodiment of the present invention.

• - Bereitstellen S1 eines Sensorzeit-Signals mittels des Sensortimers anhand eines Taktsignals,
• - Bereitstellen S2 einer Ausgabedatenrate,
• - Vergleichen S3 der Ausgabedatenrate mit einem ODR-Schwellwert, und wenn die Ausgabedatenrate unterhalb des ODR-Schwellwerts liegt:
  • o Bereitstellen S3a eines CountDown-Signals für ein Sensor-Frontend mittels eines Count-Down-Timers unabhängig vom Sensorzeit-Signal,
  und wenn die Ausgabedatenrate oberhalb des ODR-Schwellwerts liegt,
  • o Bereitstellen S3b eines CountDown-Signals mittels einer Rateneinrichtung, basierend auf der Ausgabedatenrate und anhand des Sensorzeit-Signals,
• - Bereitstellen S4 von Daten einer Messung des Sensor-Frontends, derart, sodass bei Ablauf des CountDown-Signals das Sensor-Frontend Daten einer Messung ausgibt.

Shows in detail 5 Steps of a method for operating a sensor arrangement. This includes the following steps:

• - Providing S1 a sensor time signal by means of the sensor timer on the basis of a clock signal,
• - Providing S2 an output data rate,
• - Compare S3 the output data rate with an ODR threshold value, and if the output data rate is below the ODR threshold value:
  • o Provision S3a of a countdown signal for a sensor front end by means of a countdown timer independent of the sensor time signal,
  and if the output data rate is above the ODR threshold,
  • o Providing S3b a CountDown signal by means of a rate device, based on the output data rate and on the basis of the sensor time signal,
• Provision S4 of data from a measurement of the sensor front end in such a way that when the CountDown signal expires, the sensor front end outputs data from a measurement.

• - Frei wählbare Ausgabedatenrate
• - Sensordaten mit äußerst geringer Latenz
• - Reduzierter Energieverbrauch
• - Reduzierte Herstellungskosten
• - Möglichkeit des Upsamplings
• - Hohe Genauigkeit der Ausgabedatenrate

In summary, at least one of the embodiments of the invention can provide at least one of the following advantages and / or at least one of the following features:

• - Freely selectable output data rate
• - Sensor data with extremely low latency
• - Reduced energy consumption
• - Reduced manufacturing costs
• - Possibility of upsampling
• - High accuracy of the output data rate

Although the present invention has been described on the basis of preferred exemplary embodiments, it is not restricted thereto, but rather can be modified in many ways.

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• DE 102015209129 B3 [0022]

Claims (8)

Sensor arrangement (1), comprising a sensor timer (2, 2a, 2b) which is designed to generate a sensor time signal (101, 101 ') based on a provided clock signal (100), a rate device (3) which generates a countdown signal (104) above an ODR threshold value based on a predeterminable output data rate (20) and on the basis of the sensor time signal (101, 101 '), a countdown timer (4) which is designed to provide the countdown signal (104) independently of the sensor time signal (101) for a sensor front end (5) when the predeterminable output data rate (20) is below the ODR threshold value and wherein the sensor front end (5), the countdown timer (4) and the rate device (3) are designed to work together so that when the countdown signal (104) expires, the sensor front end (5) outputs data of a measurement. Sensor arrangement (1) according to Claim 1 , wherein the sensor front end (5) is temporarily switched off at an output data rate (20) below the threshold value and the sensor front end (5) is switched on in a controlled manner so that data of the measurement are output when the CountDown signal (104) expires. Sensor arrangement (1) according to one of the Claims 1 - 2 , the sensor timer (2) and the countdown timer (4) being implemented in the form of a timer (2a) and a DPLL circuit (2b) controlled by means of the timer (2a) via sync signals. Sensor arrangement (1) according to one of the Claims 1 - 3 wherein the sensor front end (5) has an inertial measuring unit, in particular comprising an acceleration sensor, a gyrometer and / or a temperature sensor. Sensor arrangement (1) according to one of the Claims 1 - 4th , the output data rate (20) being freely adjustable by means of a setting device corresponding to a multiple of the clock signal (100) and / or the operator frequency of the inertial measuring unit. Method for operating a sensor arrangement (1) according to one of the Claims 1 - 5 comprising the steps: - providing (S1) a sensor time signal (101) by means of the sensor timer (2) on the basis of a clock signal (100), - providing (S2) an output data rate (20), - comparing (S3) the output data rate (20) ) with an ODR threshold value, and if the output data rate (20) is below the ODR threshold value: o Provision (S3a) of a countdown signal (104) for a sensor front end (5) by means of a countdown timer (4 ) independent of the sensor time signal (101), and if the output data rate (20) is above the ODR threshold value, o providing (S3b) a countdown signal (104) by means of a rate device (3) based on the output data rate (20) and on the basis of the sensor time signal (101, 101 '), - provision (S4) of data from a measurement of the sensor front end (5) in such a way that the sensor front end (5) receives data when the countdown signal (104) expires a measurement. Procedure according to Claim 6 , wherein the sensor front end (5) is temporarily switched off at an output data rate (20) below the threshold value and the sensor front end (5) is switched on again in a controlled manner so that when the CountDown signal (104) expires through the sensor front end (5) the data of a measurement are output. Sensor arrangement (10), comprising a sensor front end (5) and a countdown timer (4), the sensor frontend (5) being predominantly switched off and the countdown timer (4) being designed to provide a countdown signal ( 104) for the sensor front end (5) and wherein the sensor front end (5) is connected exclusively to the countdown timer (4) to initiate an output of data from a measurement and wherein the sensor front end (5) and CountDown-Timer (4) are designed so that the sensor front end (5) is switched on so that a measurement is carried out and when a CountDown signal (104) expires, the data of the measurement carried out are output.

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