MEMS relay with integrated condition monitoring and method for operating a MEMS relay

Abstract

The invention relates to a MEMS relay with integrated condition monitoring and a method for operating a MEMS relay.

Description

[0001] The invention relates to a MEMS relay with integrated condition monitoring and a method for operating a MEMS relay. State of the art

[0002] When a signal is switched on or on, a decaying oscillation typically occurs before the signal is present without interference. This behavior is referred to as debouncing time in signal processing [1]. Debouncing time is a critical factor that affects the reliability and accuracy of signal processing. Various approaches to debouncing an electrical signal have been proposed in the literature.

[0003] References [3, 4, 5, 6] describe general methods for debouncing electrical signals. These methods include both hardware-based and software-based techniques. Hardware-based techniques utilize electronic circuits, such as RC networks (resistor-capacitor networks) or dedicated debouncing circuits, to dampen decaying oscillations and generate a clean signal. Software-based techniques, on the other hand, employ algorithms implemented in microcontrollers or digital signal processors to minimize debouncing time and smooth the signal.

[0004] A mechanical approach to optimizing debouncing is pursued in [2]. This involves using mechanical structures and materials to physically dampen the vibrations and thus reduce the debouncing time. This method can be particularly useful in applications where electronic debouncing techniques are insufficient or where additional mechanical stability is required.

[0005] Another aspect of this invention is the detection of an overload at the MEMS relay. MEMS relays are sensitive components that must be protected from overvoltages or electrical overload to ensure their functionality and service life. In [7], an electronic circuit is proposed that was specifically designed to protect electronic components, especially MEMS, from such overloads. This circuit can detect overvoltages and take appropriate protective measures to prevent damage to the MEMS relays. [1] Roman Yershov, Volodymyr Voytenko, Volodymyr Bychko, “Software-Based Contact Debouncing Algorithm with Programmable Auto-Repeat Profile Feature” in IEEE International Scientific-Practical Conference Problems of Infocommunications, Science and Technology (PIC S&T), 2019 [2] TW202040327 A SWITCH DEVICE WITH SWITCH DEBOUNCING AND METHOD OF SWITCH DEBOUNCING THEREOF [3] US 2020 / 0328735 A1 METHOD FOR DEBOUNCING AN ELECTRICAL INPUT SIGNAL, AND DEBOUNCING MODULE [4] US 2009 / 0303088 A1 MODULAR DEBOUNCING DEVICE [5] DE 3526416 A1 Circuit arrangement for debouncing a contact [6] US2008062017 AA DEBOUNCING CIRCUIT [7] US06671149 B1 CIRCUIT TOPOLOGY FOR PROTECTING VULNERABLE MICRO ELECTRO-MECHANICAL SYSTEM (MEMS) AND ELECTRONIC RELAY DEVICES Disclosure of the invention

[0006] Providing a status interface for MEMS relays, which gives the user additional information about the relay's condition, offers several significant advantages over the previous state of the art.

[0007] Real-time monitoring of the mechanical contact and the provision of information about the complete debouncing phase ensure that loads are only switched on when the contact is stably and reliably closed. This minimizes the risk of malfunctions and increases operational safety, especially in safety-critical applications.

[0008] The self-diagnostic measurement of voltage drop at the contact allows for the early detection of wear or overloads. This enables proactive maintenance and prevents unexpected failures, thus extending the service life of the MEMS relay and the entire system.

[0009] The temperature monitoring of the MEMS relay provides indirect information about excessively high rated currents or excessive electrical resistance at the contact. This helps to identify overload situations and take appropriate measures before damage occurs.

[0010] The ability to implement the status interface as both an analog and a digital interface offers flexibility in integration and adaptation to different system requirements and architectures.

[0011] The additional information provided via the status interface enables detailed diagnostics of the MEMS relay. This assists the user in troubleshooting and resolving issues and contributes to optimizing system operation.

[0012] Precise monitoring and diagnosis of the MEMS relay prevent inefficient operating conditions. This leads to more efficient use of electrical energy overall and reduces component wear.

[0013] The status interface extends the functionality of the MEMS relay by serving not only as a switching element but also as a sensor for various operating parameters. This opens up new application possibilities and improves integration into complex systems.

[0014] Thus, by providing a status interface for MEMS relays, the invention offers significant advantages in terms of reliability, safety, maintenance, diagnostics, and system efficiency. These additional functions and information contribute to optimizing the performance and lifespan of MEMS relays and their associated systems.

[0015] Further advantages can be gleaned from the characters and the character descriptions. Drawings

[0016] They show: Fig. 1: A first implementation of a MEMS relay according to the invention in schematic representation, Fig. 2: A first implementation of a MEMS relay according to the invention in schematic representation. Description

[0017] The same reference numbers are used for the identical components that appear in the different embodiments.

[0018] Fig. Figure 1 shows an implementation of a MEMS relay 10 in a housing 12 with at least the following components: • Power supply 14 for the entire system, • Control signals 16 for an evaluation and test unit 18, • Evaluation and test unit 18, which performs the tests and evaluates the results. It receives power supply 14, control signals 16 and forwards signals to a MEMS driver unit 20 and a status interface 22. • MEMS driver unit 20 drives a MEMS switch S. • MEMS switch S is connected to the MEMS driver unit 20 and the inputs In1 and In2. • In1 & In2: Input signals or voltages for the MEMS switch. • Status interface 22, which outputs the status of the system. • Out: Output signal of the system. • Control lines 1 to 4.

[0019] Fig. Figure 2 shows an implementation of a MEMS relay 10 in a housing 12 with at least the following components: : • Power supply 14 for the entire system, • Control signals 16 for an evaluation and test unit 18, • Evaluation and test unit 18, which performs the tests and evaluates the results. It receives power supply 14, control signals 16 and forwards signals to a MEMS driver unit 20 and a status interface 22. • MEMS driver unit 20 drives a MEMS switch S. • MEMS switch S is connected to the MEMS driver unit 20 and the input In1. • In1: Input signal or voltage for the MEMS switch S. • Status interface 22, which outputs the status of the system. • Out: Output signal of the system. • Control lines 1 to 4.

[0020] The MEMS relay offers integrated condition monitoring, providing users with valuable information for diagnostics and system optimization. Feedback on the internal condition enables more precise and reliable switching. For example, the load on the In1 / Out pins can only be switched on once the mechanical contact is fully closed, thus minimizing arcing and contact bounce. Furthermore, continuous monitoring of the electrical load on the mechanical contact allows for the early detection of wear or defects. This information enables users to take preventative measures, significantly increasing the reliability and lifespan of the relay, particularly in safety-critical applications.

[0021] According to the invention, various scenarios are provided for. Scenario 1: Monitoring the debounce time

[0022] In this scenario, the evaluation and test unit 18 receives the command to close the MEMS relay 10 at pin 16. The evaluation and test unit 18 then activates the MEMS driver unit 20 to close the mechanical contact between pins In1 and Out. The contact can be implemented as a combined normally open / normally closed contact, as shown in Fig. 1 shown, or as a normally closed contact, as in Fig. 2 shown, will be carried out.

[0023] In parallel with the switching of the contact, the evaluation and test unit 18 monitors the contact's state using control lines 1 and 4 or 2 and 4. As soon as the contact is fully closed and the debounce time has elapsed, a flag is set at the status interface 22. This flag can be signaled either via an analog pin or a digital interface.

[0024] Unlike the methods described in sources [3, 4, 5, 6], this scenario does not involve any subsequent signal processing to suppress debouncing. Instead, the contact state is monitored directly, and the user receives immediate feedback as soon as the debouncing phase is complete. Scenario 2: Self-diagnosis of wear and electrical resistance

[0025] In this scenario, the MEMS relay 10 is located out Fig. 1 in the deactivated state. Pins In2 ​​and Out form an electrically conductive connection. A test current is applied to the evaluation and test unit 18 via control lines 2 and 4. The resulting voltage drop across the MEMS relay 10 represents the electrical resistance of the contact and thus its wear.

[0026] This self-test can be performed with the relay deactivated, without the user being aware of it. Alternatively, the voltage drop across the MEMS relay can also be monitored without an additional test current. An increased voltage drop indicates contact wear or overload operation. Limit values ​​from existing characterization data provide information about the operating state. A prerequisite for this application is that the user has applied an electrical load. Scenario 3: Self-diagnosis of overload, wear and electrical resistance

[0027] In this scenario, the MEMS relay 10 can either be used as a combined normally open / normally closed contact, as in Fig. 1 shown, or as a closing contact, as in Fig. Figure 2 shows how it can be implemented. Pins In1 and Out form an electrically conductive connection. The resulting voltage drop across the MEMS relay is determined using control lines 1 and 4.

[0028] The measured voltage drop represents the electrical resistance of the contact or, if the electrical resistance is known, the magnitude of the impressed current by the user. If the measured voltage drop is too large, the impressed current is outside the specified range.

[0029] Alternatively, an increased voltage drop indicates damage or wear of the mechanical contact. In both cases, a message can be sent to the user via the status interface. This use case requires that the user has applied an electrical load. Scenario 4: Self-diagnosis of wear, electrical resistance and overload

[0030] In this scenario, the evaluation and test unit 18 monitors the thermal load of the relay using a temperature sensor. Both embodiments, as a combined normally open / normally closed contact, as in Fig. 1 shown, or as a closing contact, as in Fig. The two options shown are possible.

[0031] Excessive thermal stress indicates either a faulty mechanical contact in the MEMS relay or operation outside the specified current range. The status interface can provide the user with feedback about the impermissible operating mode. Repeated occurrences of thermal overload suggest wear of the mechanical contact. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] TW 202040327 A

[0005] US 2020 / 0328735 A1

[0005] US 2009 / 0303088 A1

[0005] DE 3526416 A1

[0005] US 2008062017 AA

[0005] US 06671149 B1

[0005] Zitierte Nicht-Patentliteratur

[0000] Roman Yershov, Volodymyr Voytenko, Volodymyr Bychko, „Software-Based Contact Debouncing Algorithm with Programmable Auto-Repeat Profile Feature“ in IEEE International Scientific-Practical Conference Problems of Infocommunications, Science and Technology (PIC S&T), 2019

[0005]

Claims

MEMS relay (10) with integrated condition monitoring, wherein the relay (10) has at least one switchable contact (S) and an interface (22) for outputting condition information, characterized in that the condition information includes at least one of the following:◯ state of the switchable contact, wherein the contact may be open or closed;◯ electrical load of the switchable contact;◯ temperature of the relay. MEMS relay (10) according to claim 1, characterized in that the relay (10) is designed as a normally open / normally closed contact or as a normally closed contact. MEMS relay (10) according to claim 1 or 2, characterized in that the status information about the state of the switchable contact includes a signal indicating when the contact is completely closed and the debounce time has subsided. MEMS relay (10) according to one of the preceding claims, characterized in that the status information about the electrical load of the switchable contact is determined by measuring the voltage drop at the contact. MEMS relay (10) according to claim 4, characterized in that the measurement of the voltage drop is carried out in the activated state of the relay. MEMS relay (10) according to claim 4, characterized in that the measurement of the voltage drop in the deactivated state of the relay is carried out by means of an impressed test current. MEMS relay (10) according to one of the preceding claims, characterized in that the status information about the temperature of the relay is determined by an integrated temperature sensor. MEMS relay (10) according to one of the preceding claims, characterized in that the interface for outputting the status information is designed as an analog pin or as a digital interface. A method for operating a MEMS relay with a switchable contact, a MEMS driver unit, and an evaluation and test unit, comprising the following steps: ◯ Applying a control signal to the evaluation and test unit to switch the MEMS relay; ◯ Controlling the MEMS driver unit by the evaluation and test unit to switch the switchable contact; ◯ Monitoring the state of the switchable contact by means of the evaluation and test unit; and ◯ Outputting a status signal when the switchable contact has reached a predetermined state. Method according to claim 9, wherein the predetermined state of the switchable contact is a fully closed state after the expiry of a debounce time. Method according to claim 9, wherein the predetermined state of the switchable contact is a fully open state after the expiry of a debounce time. Method for monitoring the wear of a MEMS relay with a switchable contact, a MEMS driver unit and an evaluation and test unit, wherein the method comprises the following steps: ◯ Applying a test current to the switchable contact in the deactivated state of the MEMS relay; ◯ Measuring the voltage drop across the switchable contact; and ◯ Determining the electrical resistance of the switchable contact based on the measured voltage drop. Method for monitoring the electrical load of a MEMS relay with a switchable contact, a MEMS driver unit and an evaluation and test unit, wherein the method comprises the following steps:◯ Measuring the voltage drop across the switchable contact in the activated state of the MEMS relay; and◯ Determining the electrical load of the switchable contact based on the measured voltage drop. Method for monitoring the thermal load of a MEMS relay using a temperature sensor, wherein the method comprises the following steps:◯ Measuring the temperature of the MEMS relay using the temperature sensor; and◯ Outputting a warning signal when the measured temperature exceeds a threshold value. Method according to one of the preceding claims, wherein the status information is provided either analogously or digitally. Method according to one of the preceding claims, wherein the contacts of the MEMS switch are configured as a combined normally open / closed contact or as a normally closed contact. Method according to one of the preceding claims, wherein the evaluation and test unit monitors the mechanical contact of the MEMS switch and sends a message to the status interface in case of wear or overload of the contact.

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