IL322248A - Application-specific integrated circuit for a measuring device - Google Patents

Description

CGS:CGS VEGA GRIESHABER KG Our ref: V10793WOIL / CGS ----------------------------------------------------------------------------------------------------- VEGA Grieshaber KG Hauptstraße 5, 77709 Wolfach, Germany ------------------------------------------------------------------------------------------------------ Application-specific integrated circuit for a measuring device ------------------------------------------------------------------------------------------------------ Reference to related applications The present application claims priority from German patent application No. 10 20200 484.4, filed on January 23, 2023, which is incorporated herein by reference in its entirety.

Field of the invention The present invention relates to measuring device technology for process automation in industrial or private environments. In particular, the invention relates to an application-specific integrated circuit, ASIC, for a measuring device, a measuring device with an application-specific integrated circuit, and a use of an ASIC for a measuring device.

Technical background Measuring devices for process automation in industrial or private environments can have radar circuits that generate and emit a high-frequency radar measurement signal. This radar measurement signal is reflected, for example, by a product surface or an object to be detected and is picked up by the antenna of the measuring device. The distance to the product surface or object can be calculated from this. 30 Examples of such measuring devices are radar level measuring devices that can be installed in a container. These radar level gauges can be free-radiating or use the principle of guided microwaves. In the latter case, an elongated measuring probe is provided which is immersed in the product.

Such measuring devices usually have a clearly limited energy supply, for example in the form of a 4 to 20 mA two-wire line or, particularly in the case of a stand-alone measuring device, in the form of a battery. In order to reduce the energy requirement of such a measuring device, the frequency of measurements can be reduced. However, level changes during the measuring pause are then only recorded at a later point in time.

Summary of the invention It is an object of the present invention to provide a radar measuring device which allows for energy-efficient operation and high measuring accuracy.

This object is solved by the features of the independent patent claims. Further embodiments of the invention result from the sub-claims and the following description of embodiments.

A first aspect of the present disclosure relates to an application-specific integrated circuit, ASIC, for a measuring device, comprising a first finite state machine and a second finite state machine.

The first finite state machine is configured to control an external radar chip of the measuring device, which is configured to generate a radar measurement signal and to detect the measurement signal reflected at an object or a product surface. The second finite state machine is configured to monitor a memory of the application-specific integrated circuit, which is configured to determine a measured value from the radar measurement signals detected by an external radar chip, and/or the external radar chip. The second finite state machine can additionally or alternatively be configured to monitor a processor of the measuring device, which is configured to determine a measured value from the radar measurement signal detected by the external radar chip, and/or the external radar chip.

The measuring device is, for example, a level measuring device, in particular a level radar measuring device, or another radar measuring device.

The external radar chip is configured to generate a radar measurement signal, which is then emitted by an antenna or a beam element. The processor is configured to determine a measured value from the radar signals received. The external radar chip and the ASIC are separate components and are interconnected via corresponding control and supply lines. The ASIC and external radar chip can also be designed as an integrated component.

The ASIC can be designed as a radar companion ASIC, which performs control tasks and/or measured value acquisition tasks in the radar circuit of the measuring device. In this way, essential control and detection tasks can be inexpensively combined in a compact unit when using different radar chips and, at the same time, energy-efficient operation of the corresponding radar chip can be enabled.

According to an embodiment, the ASIC has a phase-locked loop (PLL).

According to a further embodiment, the ASIC comprises an analog-to-digital converter circuit (ADC).

According to a further embodiment, the ASIC has a digital interface to the processor.

According to a further embodiment, the first finite state machine and the second finite state machine are designed as an integrated component.

According to a further embodiment, the external radar chip is a radar MMIC (Monolithic Microwave Integrated Circuit).

According to a further embodiment, the ASIC is configured to wake the processor from a sleep mode and then transmit measurement data to the processor.

According to a further embodiment, the ASIC is configured to supply a voltage-controlled oscillator, VCO, of the external radar chip and/or a multiplier of the external radar chip.

PLL, ADC, power management and safety functions can all be integrated on the ASIC. In particular, the ASIC can be configured to support different radar chips with different operating frequencies, for example 6 GHz, 24 GHz, 80 GHz, 180 GHz and 240 GHz. To achieve this, the finite state machine can be programmed accordingly.

The radar chip and the ASIC can be optimized with regard to the energy requirement for detecting an echo curve. In particular, it can be provided that parts of the radar chip, the ASIC and/or the processor are only switched on when they are actually needed. Circuit parts that are not required can be switched off quickly. In particular, the radar circuit can be optimized in terms of size and cost.

In particular, the radar circuit of the measuring device can be configured to be supplied from a limited energy source (e.g. 4 to 20 mA supply or energy harvesting). A supply voltage of 3.3 V can be provided, both for the processor and for the ASIC. The ASIC can also be configured for several different supply voltages. The ASIC and the radar chip can be positioned on the same PCB.

The radar circuit and in particular the ASIC can be configured to be operated in an energy-saving operating mode after completion of the measurement and in particular during the process of determining the measured value, the nature of which depends on the radar chip used.

The term "process automation in an industrial environment" can be understood as a branch of technology that includes measures for the operation of machines and systems without human intervention. One aim of process automation is to automate the interaction of individual components of a plant in the chemical, food, pharmaceutical, petroleum, paper, cement, shipping or mining industries. A variety of sensors can be used for this purpose, which are adapted in particular to the specific requirements of the process industry, such as mechanical stability, insensitivity to contamination, extreme temperatures and extreme pressures. Measured values from these sensors are usually transmitted to a control room, where process parameters such as fill level, limit level, flow rate, pressure or density can be monitored and settings for the entire plant can be changed manually or automatically.

One area of process automation in the industrial environment concerns the logistics automation of plants and the logistics automation of supply chains. Distance and angle sensors are used in the field of logistics automation to automate processes inside or outside a building or within an individual logistics system. Typical applications for logistics automation systems include baggage and freight handling at airports, traffic monitoring (toll systems), retail, parcel distribution and building security (access control). What the examples listed above have in common is that presence detection in combination with precise measurement of the size and position of an object is required by the respective application. Sensors based on optical measurement methods using lasers, LEDs, 2D cameras or 3D cameras, which detect distances according to the time-of-flight (ToF) principle, can be used for this purpose. Another area of process automation in the industrial environment is factory/production automation. Applications for this can be found in a wide variety of sectors, such as automotive manufacturing, food production, the pharmaceutical industry and packaging in general. The aim of factory automation is to automate the production of goods using machines, production lines and/or robots, i.e. to run them without human intervention. The sensors used here and the specific requirements with regard to measuring accuracy when detecting the position and size of an object are comparable to those in the previous example of logistics automation. In the following, embodiments of the present disclosure are described with reference to the figures. If the same reference signs are used in the following description of the figures, these designate the same or similar elements. The illustrations in the figures are schematic and not to scale. A further aspect of the present disclosure relates to a measuring device comprising a radar chip configured to generate and detect a radar measurement signal, and an application-specific integrated circuit as described above and hereinafter, and which is arranged, for example, between the radar chip and the processor. 30 A further aspect of the present disclosure relates to the use of an application-specific integrated circuit described above and hereinafter for a measuring device, in particular for a level radar measuring device comprising a radar chip.

Brief description of the figures Fig. 1 shows a circuit diagram of a radar MMIC with a peripheral circuit using discrete components.

Fig. 2 shows an application-specific integrated circuit that can perform control and detection tasks when operating a purely analog MMIC.

Fig. 3 shows the structure of a radar measuring device with an application-specific integrated circuit.

Fig. 4 shows the universal usability of the application-specific integrated circuit for widely used radar MMICs for level measurement.

Fig. 5 shows the overall sequence of a self-test function in the application-specific integrated circuit.

Fig. 6 shows a partial test sequence of the externally connected MMIC.

Fig. 7 shows a measuring device with a radar circuit.

Detailed description of embodiments Fig. 1 shows a radar MMIC 101 with a peripheral circuit using discrete components. The radar MMIC generates a radar measurement signal of 80 GHz, which is emitted via the antenna 118 in the direction of the product. The MMIC has a voltage-controlled oscillator (VCO) 107, which is controlled by an external PLL 104. A TCXO oscillator 115 is provided, which controls the PLL with a frequency of 40 MHz. The TCXO oscillator 115 also controls the analog-to-digital converter circuit 105.

In addition to the VCO 107, the MMIC has a multiplier 108, which is controlled by the VCO 107 at 40 GHz. The multiplier doubles the frequency and controls the TX 25 amplifier 109, which is connected to the antenna 118 via a transmit/receive switch, for example a circulator. In addition, a down converter 110 is provided, which receives signals from the multiplier 108 and the transmit/receive switch.

All other components are located outside the MMIC. The down converter 110 passes its signal to an amplification and filter circuit 113, which then passes it on to the ADC 105. The ADC 105 is connected to the processor 103 of the measuring device via an SPI interface. The processor 103 can exchange data with an external memory 116. In addition, the processor 103 is connected to a fieldbus modem 117 for measured value transmission.

Fig. 2 shows a radar companion ASIC 102, which can take over control and detection tasks during operation of a purely analog MMIC. The ASIC 102 has a linearization circuit, for example an integer or fractional rational PLL 104, a power supply 111, a self-test circuit 112, for example in the form of a second finite state machine 112, an amplification and filter circuit 113 or IF gain AAF circuit 113, an analog-to-digital converter circuit 104 (which is configured, for example, to convert analog signals into digital values with an accuracy of 16 bits and a sampling frequency of 40 MHz), a first-in-first-out (FiFo) memory 114 and a finite state machine 106. The ASIC 102 is a separate component, but can be arranged on the same circuit board as the MMIC 1(see Fig. 3). Fig. 3 shows the structure of a radar circuit 100 for a radar measuring device, which has the ASIC 102 described above. The ASIC 102 is connected between the radar chip 101 and the processor 103. Communication between ASIC 102 and processor 103 takes place, for example, via the FiFo 114 using a QSPI interface and, starting from the processor 103, via an SPI interface to the FSM 106.

The FSM 106 can be configured to be programmed to match the connected radar chip. The FSM can contain suitable hardware units for this purpose. In particular, the FSM can be configured by the processor to set the parameters of a distance measurement using an FMCW method. Depending on the operating frequency of the connected radar chip, the start frequency, the stop frequency, the time duration, the transmission power and/or other parameters of the radar chip used in each case can be stored in the FSM 106, for example, due to technical approval specifications, which 30 then enables the MMIC 101 to carry out the desired measurement in a later measurement run by activating it with suitable signals. In particular, it may be provided that the FSM completely realizes the control of the MMIC during the execution of a measurement, which means that intervention or cooperation of the processor core 103 is no longer required. For example, in order to save energy, the processor core 103 can be switched to an energy-saving state by the FSM 106 while a radar measurement is being carried out, and can be reactivated by the FSM 106 once the data has been recorded.

The FSM 106 can furthermore be configured to pass on the information about the respectively connected radar chip 101 to the second finite state machine 112. It may also be provided that the second finite state machine 112 is configured to independently recognize the type of MMIC 101 connected in each case. The second finite state machine 112 can use the information about the type of the connected MMIC 101 in order to optimize a sequence of a self-test and carry it out appropriately for the connected MMIC.

The ASIC 102 may power the VCO 107 and the multiplier 108 of the MMIC 101 and perform or trigger a self-test of the MMIC 101 (see Fig. 3). In particular, the RC-ASIC 102 can be used to check the function of the MMIC 101. This is particularly advantageous for SIL applications. It is possible that the processor 103 is integrated on the ASIC 102. However, it can also be a separate component, as shown in Fig. 3.

In particular, the MMIC 101 and the RC-ASIC 102 can be manufactured using different semiconductor technologies and chip materials. For example, the MMIC can be optimized for use at high frequencies, for example 80 GHz or above, whereas the RC-ASIC 102 is optimized for applications at significantly lower frequencies, for example MHz. This can save energy compared to integrating the ASIC module on an MMIC.

Fig. 4 shows the universal usability of the RC-ASIC 102 for radar MMICs for level measurement, which are designed for very different frequency ranges, for example for 6 GHz, 24 GHz, 80 GHz, 180 GHz and 240 GHz.

Fig. 5 shows the overall sequence of a self-test function in the companion ASIC 102. The procedure starts with step 501. In step 502, the radar companion ASIC 102 is configured. In step 503, the safety setup is configured. In step 504, it is determined whether the time period since the last FiFo memory test is greater than a predeterminable minimum time period t safe.

If this is not the case, the procedure continues with step 507. In this case, no test of the FiFo memory integrated in the Radar Companion ASIC 102 is necessary.

If the time period since the last FiFo memory test is greater than a predeterminable minimum time period t safe, the next step is step 505, in which the FiFo memory is tested internally. In step 506, the test result is then provided externally.

In step 507, it is assessed whether the time period since the last MMIC test is greater than a predeterminable minimum time period tMMICsafe. If this is not the case, the procedure jumps to step 510, as no test of the MMIC is necessary. If this is the case, step 508 takes place, in which an MMIC test is performed. In step 509, the test result is then made available to the outside world.

Finally, in step 510, the normal measurement of the measuring device is started, for example a level measurement. The procedure ends in step 511.

Fig. 6 shows the partial sequence of a test of the externally connected MMIC. The procedure starts with step 601. In step 602, a test signal in the kHz range is provided. The measurement sequence in the MMIC starts in step 603. In step 604, the measurement data is read into the FiFo and in step 605 the MMIC is deactivated. In step 606, the FiFo data is analyzed for the test signal, and in step 607 it is determined whether the test signal was recorded correctly. If this is not the case, the procedure jumps to step 609, in which the status "uncertain" or something similar is output. If this is indeed the case, the method jumps to step 608, in which the status "safe" or something similar is output. The procedure then ends with step 610.

Fig. 7 shows a measuring device 200, for example a radar level measuring device, with the circuit 100 described above, which has a level radar antenna 118 for emitting the radar measurement signal and for receiving the radar measurement signal reflected at the product surface.

The present disclosure provides a radar companion ASIC that inexpensively combines essential control and sensing tasks in a compact unit when using commercial radar chips, and in particular is adapted to monitor itself and an external connected commercially available MMIC for reliable operation according to IEC61508.

PLL, ADC, power management and safety functions can be combined in one chip. In particular, the ASIC can support different radar chips with different operating frequencies and different Built-In-Self-Tests (BIST). The ASIC can be configured to provide a corresponding signal that provides the safe state of the overall system and/or an unsafe state of the overall system to the outside.

The signal provided to the outside can be indicative of the current safety status of the Radar Companion ASIC and/or the externally connected Radar MMIC.

The terms used in the claims should be construed so as to give them the broadest reasonable interpretation consistent with the foregoing description. For example, the use of the article "a" or "the" when introducing an element should not be construed to exclude a plurality of elements. Similarly, the mention of "or" should be construed to include a plurality of elements, so that the mention of "A or B" does not exclude "A and B" unless it is clear from the context or the preceding description that only one of A and B is meant. Furthermore, the phrase "at least one of A, B and C" should be understood as one or more of a group of elements consisting of A, B and C, and should not be interpreted as requiring at least one of each of the listed elements A, B and C, regardless of whether A, B and C are combined as categories or otherwise. Furthermore, the mention of "A, B and/or C" or "at least one of A, B or C" should be construed to include any single unit of the listed elements, e.g., A, any subset of the listed elements, e.g., A and B, or the entire list of elements A, B and C.

Claims (13)

1. - 11 - Claims 1. Application-specific integrated circuit for a measuring device, comprising: a first finite state machine configured to control an external radar chip configured to generate and/or detect a radar measurement signal; a second finite state machine configured to monitor a memory of the application-specific integrated circuit, which is configured to determine a measured value from the radar measurement signal detected by the external radar chip, and/or to monitor the external radar chip.

2. Application-specific integrated circuit according to claim 1, wherein the application-specific integrated circuit, ASIC, comprises a phase locked loop, PLL.

3. Application-specific integrated circuit according to claim 1 or 2, wherein the ASIC comprises an analog-to-digital converter circuit, ADC.

4. Application-specific integrated circuit according to any one of the preceding claims, wherein the ASIC comprises a digital interface to a processor of the measuring device.

5. 5, Application-specific integrated circuit according to any one of the preceding claims, wherein the first finite state machine and the second finite state machine are implemented as an integrated component.

6. Application-specific integrated circuit according to any one of the preceding claims, wherein the external radar chip is a radar MMIC.

7. Application-specific integrated circuit according to any one of the preceding claims, wherein the ASIC is a radar companion ASIC that performs control tasks and/or measurement acquisition tasks of the measuring device. - 12 -

8. Application-specific integrated circuit according to any one of the preceding claims, wherein the ASIC is configured to wake up the processor from a sleep mode and thereupon transmit measurement data to the processor.

9. Application-specific integrated circuit according to any one of the preceding claims, wherein the ASIC is configured to supply a voltage-controlled oscillator, VCO, of the external radar chip and/or a multiplier of the external radar chip.

10. Measuring device, comprising a radar chip configured to generate a radar measurement signal; an application-specific integrated circuit, ASIC, according to any one of claims to 9.

11. Measuring device according to claim 10, wherein the ASIC and the radar chip are separate components.

12. Measuring device according to claim 10 or 11, embodied as a level radar measuring device

13. Use of an application-specific integrated circuit, ASIC, according to any one of claims 1 to 9 for a measuring device, in particular for a level radar measuring device comprising a radar chip.