Detection circuit and detection method

Abstract

A detection circuit includes an input circuit and a sensing circuit. The input circuit includes a first input node and a second input node. The first input node is coupled to a first detection node and the second input node is coupled to a second detection node. The sensing circuit includes a current source providing a predetermined current. The current source is coupled to the first input node. The sensing circuit generates a sensing voltage at an output node in response to the predetermined current. The first detection node is directly connected to the second detection node or electrically connected to the second detection node via a trace, and the sensing voltage is related to impedance between the first detection and the second detection node.

Description

Technical Field

[0001] This invention relates to a detection circuit, and more particularly to a detection circuit capable of accurately detecting electronic characteristic parameters. Prior Technology

[0002] With the rapid development of technology, display panels have become ubiquitous, possessing touch sensing and control functions, and are widely used in many electronic products, such as smartphones, tablet PCs, and laptop PCs. In recent years, the application of display panels has further expanded to automotive display systems.

[0003] However, the display performance requirements of electronic products vary depending on the usage scenario. For example, unlike the high resolution required for devices such as mobile phones or computers, when display panels are used in automotive display systems, the primary consideration is that the display panel can maintain normal operation while the vehicle is in motion, as the accurate display of driving-related information and vehicle control are crucial for driving safety.

[0004] Therefore, how to prevent abnormalities in the display and touch functions of the display panel is an important issue in the field of automotive displays. Summary of the Invention

[0005] According to one embodiment of the present invention, a detection circuit includes an input circuit and a sensing circuit. The input circuit includes a first input node and a second input node. The first input node is coupled to a first detection node, and the second input node is coupled to a second detection node. The sensing circuit includes a current source that provides a predetermined current. The current source is coupled to the first input node, and the sensing circuit generates an induced voltage at an output node in response to the predetermined current. The first detection node is electrically connected to the second detection node either directly in contact with or through a trace, and an impedance value between the first detection node and the second detection node is related to the induced voltage.

[0006] According to an embodiment of the present invention, a method for detecting an impedance value between two nodes using a detection circuit includes: coupling a first detection node to a first input node of the detection circuit, and coupling a second detection node to a second input node of the detection circuit, wherein the first detection node is directly in contact with or electrically connected to the second detection node through a trace; controlling a current source of the detection circuit to provide a first current; receiving a first induced voltage from an output node of the detection circuit in response to the first current; controlling the current source to provide a second current; receiving a second induced voltage from the output node in response to the second current; and determining the impedance value between the first detection node and the second detection node based on a difference between the second induced voltage and the first induced voltage. Simple Explanation of the Diagram

[0007] Figure 1 shows a schematic example of incomplete contact caused by thermal expansion and contraction of the conductive layer distributed on the contact surface between the driver chip and the panel glass. Figure 2 shows another schematic example of incomplete contact between the conductive layer on the contact surface of the driver chip and the panel glass due to pressure deformation. Figure 3 shows an example block diagram of a detection circuit according to an embodiment of the present invention. Figure 4 shows an example circuit diagram of a detection circuit according to an embodiment of the present invention. Figure 5 shows an example circuit diagram of a detection circuit according to another embodiment of the present invention. Figure 6 shows an example of several endpoints providing ground voltage in a display system. Figure 7 shows an example of setting up a detection circuit in a display system to perform the required detection according to an embodiment of the present invention. Figure 8 shows another example of arranging a detection circuit in a display system to perform the required detection according to an embodiment of the present invention. Figure 9 shows a flowchart of a detection method according to an embodiment of the present invention. Figure 10 shows an example of error code display according to an embodiment of the present invention. Implementation

[0008] As mentioned above, display panels have become a basic feature of modern automobiles. In automotive display systems, display panels are used to display important driving-related information, such as vehicle speed, mileage, tire pressure, and navigation maps. They can also be used to provide control interfaces for in-vehicle equipment, such as controlling audio volume and air conditioning temperature.

[0009] Display panels are typically driven by driver chips, which are mounted on the panel glass using pressing or bonding techniques (for simplicity, the term "bonding" will be used in the following paragraphs). However, due to product aging or thermal expansion and contraction, poor or incomplete contact may occur between the driver chip and the conductive layer of the panel glass. This causes the bonding impedance (also known as pressing impedance), which should theoretically be zero, to increase and become a non-zero value. In this article, bonding impedance or pressing impedance refers to the impedance between two layers (e.g., metal layers or conductive layers) or two contacts that are directly in contact or electrically connected through bonding techniques.

[0010] Figure 1 shows a schematic example of incomplete contact caused by thermal expansion and contraction of the conductive layer distributed on the contact surface between the driver chip and the panel glass. As shown in Figure 1, the driver chip 100 is mounted on the display panel 150 by bonding technology, and the driver chip 100 and the display panel 150 can be electrically connected through multiple contacts, for example, through contacts 102, 104, 106 and 108 of the driver chip 100 and contacts 152, 154, 156 and 158 of the display panel 150.

[0011] Contacts 102, 104, 106, and 108, and contacts 152, 154, 156, and 158 can be pins or bonding pads of the driver chip 100 and the display panel 150, respectively; they can also be metal layers or conductive layers of the driver chip 100 and the display panel 150, respectively; or they can be contacts contained in or disposed on a metal surface or metal ball. Ideally, contacts 102 and 152 should be in complete contact, contacts 104 and 154 should be in complete contact, contacts 106 and 156 should be in complete contact, and contacts 108 and 158 should be in complete contact. Here, complete contact means that the conductive portions of the two contacts are in contact with each other in a manner that achieves optimal electrical connection (e.g., minimum impedance), for example, the conductive portions of the two contacts are in complete contact or completely overlap.

[0012] However, due to the effect of thermal expansion and contraction, the drive chip 100 or the display panel 150 begins to deform, resulting in incomplete contact at the contacts. For example, contacts 108 and 158 are displaced due to product deformation, causing the contact or overlap area between them to become significantly smaller, resulting in a weak connection (weekly connected) state.

[0013] Because the electrical connection between contacts 108 and 158 is not completely broken, the transmission of electrical signals through contacts 108 and 158 is not immediately interrupted, making the weak connection difficult to detect. However, as the product continues to be used, if the deformation of the driver chip 100 or the display panel 150 intensifies, the electrical connection between contacts 108 and 158 may break at any time, which could lead to an obvious error that the user can detect.

[0014] Figure 2 shows another schematic example of incomplete contact between the conductive layer on the contact surface of the driver chip and the panel glass due to pressure deformation. As shown in Figure 2, the driver chip 200 is mounted on the display panel 250 through bonding technology, and the driver chip 200 and the display panel 250 can be electrically connected through multiple contacts, for example, through contacts 202, 204, 206 and 208 of the driver chip 200 and contacts 252, 254, 256 and 258 of the display panel 250.

[0015] Similarly, contacts 202, 204, 206, and 208, and contacts 252, 254, 256, and 258 can be pins or pads of the driver chip 200 and the display panel 250, respectively; they can also be metal layers or conductive layers of the driver chip 200 and the display panel 250, respectively; or they can be contacts contained in or disposed on a metal surface or metal ball. Ideally, contacts 202 and 252 should be in complete contact, contacts 204 and 254 should be in complete contact, contacts 206 and 256 should be in complete contact, and contacts 208 and 258 should be in complete contact.

[0016] However, the driver chip 200 may deform due to external pressure, which may lead to incomplete contact at the contacts. For example, contacts 202 and 252, and contacts 208 and 258 may completely or partially separate due to product deformation, resulting in a significant reduction in the contact or overlap area between the two contacts, resulting in a weak connection (weekly connected) state.

[0017] Since weak connections can affect the display function or touch sensitivity of the panel, thereby endangering driving safety, this invention proposes a detection circuit and corresponding detection method that can accurately detect electronic characteristic parameters of automotive displays to detect weak connections or incomplete contacts within the display device as early as possible. In other words, the detection circuit proposed in this invention can detect whether the connection between the display chip and the panel is incomplete, or can detect the connection status of the display chip and the panel in real time. Once an incomplete or poor connection is detected, the user will be notified for subsequent repairs. Simply put, the detection circuit in this invention can also determine the connection status of the circuit by referring to a table of circuit connection status and resistance values.

[0018] Figure 3 shows an example block diagram of a detection circuit according to an embodiment of the present invention. The detection circuit 300 may include an input circuit 310 and a sensing circuit 320. The input circuit 310 includes input nodes In_1 and In_2. The sensing circuit 320 includes at least a current source 321 that provides a predetermined current Is. The current source 321 is coupled to the input node In_1, and the sensing circuit 320 generates an induced voltage VSEN at the output node Out in response to the predetermined current Is.

[0019] The detection circuit 300 can be used to detect an impedance value between two nodes. According to one embodiment of the invention, the input node In_1 of the detection circuit 300 is coupled to the detection node Node_A, and the input node In_2 is coupled to the detection node Node_B. The induced voltage VSEN generated by the detection circuit 300 is related to the impedance value between the detection nodes Node_A and Node_B. That is, the induced voltage VSEN generated by the detection circuit 300 can be used to determine or derive the impedance value between the detection nodes Node_A and Node_B.

[0020] According to one embodiment of the present invention, detection nodes Node_A and Node_B are two nodes that should theoretically have equal potentials. More specifically, detection nodes Node_A and Node_B can be two nodes that are directly in contact or electrically connected through a trace. For example, detection nodes Node_A and Node_B can be two nodes that are electrically connected through a bonding wire, or two nodes that are directly in contact through bonding or crimping techniques.

[0021] According to one embodiment of the present invention, detection nodes Node_A and Node_B are nodes of different devices or different nodes of the same device. For example, detection node Node_A may be a node within the driver chip of the display panel (e.g., any contact of the driver chip shown in FIG1 or FIG2), and detection node Node_B may be a node of the display panel (e.g., the corresponding contact on the display panel shown in FIG1 or FIG2). As another example, detection nodes Node_A and Node_B may be two nodes on the driver chip, the display panel, the printed circuit board (PCB), or the flexible printed circuit (FPC).

[0022] Since detection nodes Node_A and Node_B are in direct contact or electrically connected, they should theoretically have equal potentials. Therefore, the impedance between detection nodes Node_A and Node_B should theoretically be zero. However, in reality, product aging, thermal expansion and contraction, external pressure, or any other factors may cause poor or incomplete contact between detection nodes Node_A and Node_B, resulting in a small impedance value.

[0023] Generally speaking, accurately detecting minute impedance values ​​between two nodes is not easy. The detection circuit must be capable of achieving extremely high accuracy to make the detection results meaningful. Furthermore, the difficulty of detection is further increased when the node voltage equals the ground voltage. For example, existing technologies require the use of a negative voltage or multiple power supplies with different voltage levels to detect ground voltage, thus increasing the cost and complexity of the detection circuit. The detection circuit proposed in this invention overcomes these difficulties, achieving accurate detection of electronic characteristic parameters at low cost. Moreover, the detection circuit proposed in this invention can accurately detect changes in zero-ohm impedance.

[0024] According to an embodiment of the present invention, the detection circuit 300 may include a plurality of transistors, and the detection circuit 300 uses the source of the transistors as input. For example, the detection nodes Node_A and Node_B shown in FIG3 can be coupled to the source of the transistors through the input nodes In_1 and In_2, respectively, thereby detecting impedance changes at zero volt level or zero ohm, or impedances close to zero volt level or close to zero ohm (e.g., small junction impedance). It can also perform current detection in reverse, overcoming the difficulty in the prior art of detecting small impedances or ground voltages using low-cost circuits.

[0025] According to one embodiment of the present invention, the processing circuit 330 may be coupled to the sensing circuit 320 and detects the impedance value based on the induced voltage VSEN. It should be noted that in some embodiments, the processing circuit 330 may be independent of the sensing circuit 300, while in other embodiments, the processing circuit 330 may be included within the sensing circuit 300. For example, in some embodiments, multiple sets of sensing circuits may be configured within the system to detect the impedance values ​​between multiple pairs of nodes. The processing circuit may be coupled to these sensing circuits to control their operation and detect or derive the impedance values ​​between each pair of nodes. A more detailed description follows.

[0026] Figure 4 shows an example circuit diagram of a detection circuit according to an embodiment of the present invention. The detection circuit 400 may include an input circuit 410 and a sensing circuit 420.

[0027] In this example, the object under test is the impedance value between detection nodes Node_A and Node_B, represented by resistor RSEN in the diagram. Input node In_1 of detection circuit 400 is coupled to detection node Node_A, and input node In_2 is coupled to detection node Node_B, used to detect the impedance value between nodes Node_A and Node_B.

[0028] The input circuit 410 may include transistors T1 and T2. The source of transistor T1 may be coupled to input node In_1, for example, the source of transistor T1 may be coupled to input node In_1 through resistor R1. The source of transistor T2 may be coupled to input node In_2, for example, the source of transistor T2 may be coupled to input node In_2 through resistor R2.

[0029] The sensing circuit 420 includes a current source module 421 and a current mirror circuit 422. The current source module 421 may include a plurality of current sources, such as a current source for providing a predetermined current Is, and one or more current sources for providing current to the source, drain, or gate of transistors T1 and T2. The current mirror circuit 422 may generate a current flowing through the output node Out according to a predetermined ratio, such as 1:N, where N is a positive number. The sensing circuit 420 may generate an induced voltage VSEN at the output node Out in response to the current generated by the current sources in the current source module 421 (e.g., at least including the predetermined current Is). The output node Out may be coupled to the sensing node Node_B via a resistor R3.

[0030] As described above, detection nodes Node_A and Node_B can be nodes from different devices or different nodes from the same device. For example, detection node Node_A can be a node within the driver chip of the display panel, and detection node Node_B can be a corresponding node on the display panel. Alternatively, detection nodes Node_A and Node_B can be two nodes on the driver chip, the display panel, the printed circuit board, or the flexible circuit board.

[0031] The induced voltage VSEN generated by the detection circuit 400 is related to the impedance value between detection nodes Node_A and Node_B. That is, the induced voltage VSEN generated by the detection circuit 400 can be used to determine or derive the impedance value between detection nodes Node_A and Node_B.

[0032] According to one embodiment of the present invention, detection nodes Node_A and Node_B are two nodes that should theoretically have equal potentials. More specifically, detection nodes Node_A and Node_B can be two nodes that are in direct contact or electrically connected through a trace. For example, detection nodes Node_A and Node_B can be contained in two different devices and electrically connected through a bonding wire. As another example, detection nodes Node_A and Node_B can be contained in two different metal surfaces, and the two metal surfaces are in direct contact, for example, through a bonding technique.

[0033] Furthermore, according to one embodiment of the present invention, detection nodes Node_A and Node_B are each coupled to a system voltage, for example, the system voltage of the display system. In one embodiment, both detection nodes Node_A and Node_B are coupled to the power supply voltage VDD. In another embodiment, both detection nodes Node_A and Node_B are coupled to the ground voltage GND.

[0034] According to one embodiment of the present invention, the detection circuit 400 is implemented in the driver chip. For example, the detection circuit 400 may be a built-in circuit of the driver chip of the display panel to perform a built-in self-test (BIST).

[0035] Figure 4 illustrates the dividing line 450 used to distinguish the driver chip from the non-driver chip. The circuitry above dividing line 450 is within the driver chip, while the circuitry below dividing line 450 may be contained within the display panel, printed circuit board, or flexible circuit board. It should be noted that dividing line 450 in Figure 4 is for illustrative purposes only; the actual circuitry does not include this line.

[0036] In an embodiment of the present invention, the detection circuit 400 implemented in the driver chip can be used to detect the impedance value between any two nodes on the driver chip, display panel, printed circuit board, or flexible circuit board.

[0037] According to one embodiment of the present invention, the processing circuit 430 may be coupled to the sensing circuit 420 and detect the impedance value based on the induced voltage VSEN. It should be noted that, as described above, in some embodiments, the processing circuit 430 may be independent of the sensing circuit 400, while in other embodiments, the processing circuit 430 may be included within the sensing circuit 400. The present invention is not limited to any one embodiment.

[0038] According to one embodiment of the present invention, the processing circuit 430 can control the current amount of a predetermined current Is to switch from a first current amount to a second current amount. In response to the first current amount, the processing circuit 430 receives a first induced voltage VSEN1 from the output node Out, and in response to the second current amount, the processing circuit 430 receives a second induced voltage VSEN2 from the output node Out. The processing circuit 430 can determine or deduce the impedance value between detection nodes Node_A and Node_B based on the difference between the second induced voltage VSEN2 and the first induced voltage VSEN1.

[0039] According to one embodiment of the present invention, in addition to being related to the impedance value between detection nodes Node_A and Node_B, the induced voltage VSEN is also related to a predetermined proportional value N of the current mirror circuit, a predetermined current Is, and the resistance or impedance values ​​of resistors R1 and R2, wherein the value N, the current Is, and the resistance or impedance values ​​of resistors R1 and R2 can be known design parameters. Furthermore, the induced voltage VSEN also includes a voltage component resulting from non-ideal effects.

[0040] Processing circuit 430 removes voltage components caused by non-ideal effects by obtaining the difference in induced voltages, retaining voltage components related to known design parameters. Therefore, the obtained difference is related to the value N, current Is, and the resistance or impedance values ​​of resistors RSEN, R1, and R2. Processing circuit 430 can deduce the resistance or impedance value of resistor RSEN based on the obtained difference.

[0041] According to one embodiment of the present invention, the first current can be set to 0 amperes, so the resulting induced voltage can be used to correct for non-ideal effects. The second current can be set to another value greater than 0 amperes. In one embodiment of the present invention, the processing circuit 430 can first control or set the current of the predetermined current Is to 0 and obtain the corresponding first induced voltage VSEN1, and then control or set the current of the predetermined current Is to another value and obtain the corresponding second induced voltage VSEN2. The processing circuit 430 can deduce the resistance value or impedance value of the resistor RSEN based on the difference between the second induced voltage VSEN2 and the first induced voltage VSEN1.

[0042] Through the detection circuit structure and detection process control described above, low-complexity (e.g., requiring only a few current sources) and low-power current, voltage, or impedance detection can be achieved, and the detection accuracy can support impedance changes at zero volt level or zero ohm, or impedance close to zero volt level or close to zero ohm (e.g., minute junction impedance).

[0043] According to one embodiment of the present invention, the processing circuit 430 further determines whether the impedance value of the obtained resistor RSEN is abnormal. For example, the processing circuit 430 can determine whether the impedance value is abnormal based on a threshold value. An abnormal impedance value may reflect that two nodes that should theoretically have equal potentials no longer have equal potentials, or it may reflect that the voltage level or current magnitude of the node is abnormal, for example, it has deviated from the ideal or predetermined value. In response to a determination result of an abnormal impedance value, the processing circuit 430 can generate an error code or a warning message, and can control the display of the error code or warning message on the display panel. In addition, the processing circuit 430 can store the abnormal information in the memory device inside the chip for reference by maintenance personnel, which will help to locate the point of abnormality and improve maintenance efficiency.

[0044] Figure 5 shows an example circuit diagram of a detection circuit according to an embodiment of the present invention. In this embodiment, the detection circuit 600 may include an input circuit 610 and a sensing circuit 620 composed of operational amplifiers OP_4 and OP_5 and multiple resistors R11, R12, R13, and R14. In this embodiment, the detection circuit 600 may use the source or gate of a transistor (e.g., a transistor contained within operational amplifier OP_4) as an input. For example, detection nodes Node_A and Node_B may be coupled to the source or gate of the transistor, respectively, and the device under test is the resistance RSEN between detection nodes Node_A and Node_B. The detection circuit 600 may detect impedance changes at zero volt level or zero ohm level, or impedance close to zero volt level or close to zero ohm level (e.g., a small junction impedance), through the obtained induced voltage VSEN, and may also perform current detection in reverse, achieving low-complexity, low-power, and high-accuracy current, voltage, or impedance detection.

[0045] Figure 6 shows an example of several endpoints providing ground voltage in a display system. In this example, several ground voltage nodes GND on the display panel providing ground voltage can be electrically connected to the corresponding ground voltage node GND_PCB on the printed circuit board via traces or bonding wires, and can be further electrically connected to the ground voltage detection node GND_DET on the display panel via traces or bonding wires. Alternatively, the ground voltage node GND on the display panel can be electrically connected to the ground voltage detection node GND_DET on the display panel via traces or bonding wires through the flexible circuit board and the printed circuit board (i.e., in another example, there is no ground voltage node GND_PCB, and the ground voltage node GND on the display panel is directly connected to the ground voltage detection node GND_DET only via traces or wires on the flexible circuit board and the printed circuit board).

[0046] To detect whether the ground voltage provided by each node is correct, or to detect the impedance value between multiple nodes providing ground voltage, either the ground voltage node GND, the ground voltage detection node GND_DET, or the ground voltage node GND_PCB on the printed circuit board can be the detection node Node_A in this disclosure, and the other can be the detection node Node_B in this disclosure, and the required current, voltage, or impedance detection is performed using the detection circuit described in this disclosure.

[0047] Figure 7 illustrates an example of arranging a detection circuit in a display system to perform desired current, voltage, or impedance detection according to an embodiment of the present invention. A driver chip 800 within the display system is mounted on a display panel 850 via bonding technology, and the driver chip 800 and the display panel 850 are electrically connected through multiple contacts. A portion of the trace 820 is a winding within the driver chip 800, and a portion is a winding within the display panel 850. In this example, the detection circuit 810 can be coupled to any two nodes on the trace 820 (therefore, the detection circuit 810 is not actually limited to the arrangement shown in Figure 7), and the detection circuit 810 can be used to detect the bonding impedance between the driver chip 800 and the display panel 850. If the bonding impedance value between the driver chip 800 and the display panel 850 is not zero ohms, it may reflect incomplete contact of the conductive layer bonded at the contact surface between the driver chip 800 and the display panel 850.

[0048] Figure 8 illustrates another example of arranging a detection circuit in a display system to perform desired current, voltage, or impedance detection according to an embodiment of the present invention. A driver chip 900 within the display system is mounted on a display panel 950 via bonding technology, and the driver chip 900 and the display panel 950 are electrically connected through multiple contacts. The driver chip 900 is electrically connected to a ground voltage node GND_PCB on a printed circuit board 940 via a trace 920. The trace 920 can be pulled back from the end of the printed circuit board 940 to the driver chip 900; therefore, the trace 920 may include the driver chip 900, the display panel 950, the flexible circuit board 930, and the wiring within the printed circuit board 940.

[0049] In this example, the detection circuit 910 can be coupled to any two nodes on the trace 920 (therefore, the detection circuit 910 is not actually limited to the position shown in Figure 8), and the detection circuit 910 can be used to detect ground voltage. Therefore, the detection circuit 910 can detect whether there is an anomaly in the ground voltage along the entire path of the trace 920. For example, it can determine whether the two nodes are not in complete contact by detecting the impedance value between them. If the impedance value is not zero ohms, it reflects that the two nodes, which should have equal voltage levels, are not in complete contact.

[0050] It should be noted that in other embodiments, the ground voltage node GND_PCB shown in FIG8 can be replaced with a node coupled to the power supply voltage, so that the detection circuit 910 can be used to detect anomalies in the power supply voltage (e.g., VDD).

[0051] Furthermore, in embodiments of the present invention, the static current information inside the driver chip can be calculated through the obtained impedance value, and it can be further determined whether the static current is abnormal, so as to avoid excessive current causing the ground potential inside the driver chip to rise and causing the driver chip to malfunction.

[0052] Figure 9 shows a flowchart of a detection method according to an embodiment of the present invention, including the following steps:

[0053] Step S1002: Couple the first detection node to the first input node of the detection circuit, and couple the second detection node to the second input node of the detection circuit. According to an embodiment of the present invention, the first detection node is directly in contact with or electrically connected to the second detection node through a trace, or the first detection node and the second detection node are two nodes that should theoretically or in product design have equal potential.

[0054] Step S1004: Control a current source of the detection circuit to provide a first current.

[0055] Step S1006: Receive the first induced voltage at the output node of the first current self-detection circuit in response to the first current self-detection circuit.

[0056] Step S1008: Control the current source to provide a second current, wherein the current amount of the first current is different from the current amount of the second current.

[0057] Step S1010: Receive the second induced voltage at the output node of the second current self-detection circuit in response to the current.

[0058] Step S1012: Determine the impedance value between the first detection node and the second detection node based on the difference between the second induced voltage and the first induced voltage.

[0059] As described above, the impedance value obtained in step S1012 can be used to determine whether the voltage level or current magnitude of the detection node is abnormal. In response to a determination that the voltage, current, or impedance is abnormal, the processing circuit can generate an error code or a warning message, and can control the display of the error code or warning message on the display panel. In embodiments of the present invention, the abnormality detection performed by the detection circuit can be combined with on-screen display (OSD) to alert the user to the abnormality status via the OSD.

[0060] It should be noted that, taking an automotive display system as an example, the OSD can be used to display or notify the user of abnormalities or errors in the vehicle system, whether these abnormalities or errors pertain to the vehicle itself or are related to driving. Examples include abnormal tire pressure or temperature. In embodiments of this invention, in addition to displaying existing vehicle system errors, the OSD can also display or notify the user of abnormalities in the display panel, driver chip, or electronic characteristics within the automotive display system, namely, the voltage, current, or impedance abnormalities detected by the aforementioned detection circuit. Therefore, by implementing the detection circuit and detection method proposed in this invention, the OSD of the automotive display system can not only display abnormalities or errors in the vehicle itself, but also display abnormalities or errors within the display system.

[0061] Figure 10 shows an example of an error code display according to an embodiment of the present invention. As shown, when the processing circuit determines that an abnormality has occurred in voltage, current, or impedance, it can display an error code (e.g., error code E05 shown in the figure) in the display area 1100 of the display panel to remind the user to arrange vehicle maintenance as soon as possible to ensure driving safety. In addition, the processing circuit can store the abnormality information in the memory device inside the chip for reference by maintenance personnel, which will help to locate the point of abnormality and improve maintenance efficiency.

[0062] In summary, the detection circuit proposed in this invention enables accurate detection of zero-ohm impedance changes with low cost and low complexity. It can detect impedance changes at zero volt level or zero ohm, or impedances close to zero volt level or close to zero ohm (e.g., minute junction impedance), and can also perform reverse current detection, overcoming the difficulty in using low-cost circuits to detect minute impedances or ground voltages in the prior art.

[0063] Furthermore, the detection circuit proposed in this invention is more conducive to performing multi-point detection due to its low cost and low complexity. For example, multiple detection circuits can be configured within the display system to detect the impedance values ​​between different pairs of nodes, making the detection more comprehensive and improving the safety of the product.

[0064] Furthermore, since weak connections between devices or nodes, as well as abnormal current, voltage, or impedance, pose potential risks, the detection circuit proposed in this invention can detect abnormal states with potential risks within the system, making the product's safety protection more comprehensive and helping to improve the product's Automotive Safety Integrity Level (ASIL). The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made in accordance with the claims of the present invention shall be covered by the present invention.

[0065] 100, 200, 800, 900: Driver chips 102, 104, 106, 108, 152, 154, 156, 158, 202, 204, 206, 208, 252, 254, 256, 258: contacts 150, 250, 850, 950: Display panel 300, 400, 600, 810, 910: Detection circuit 310, 410, 610: Input circuit 320, 420, 620: Induction circuit 321: Current Source 330, 430: Processing circuits 421: Current source module 422: Current Mirror Circuit 450: Separator line 820, 920: Wiring 930: Flexible Circuit Board 940: Printed Circuit Board 1100: Display area GND, GND_PCB: Grounding voltage node GND_DET: Ground voltage detection node Is: Electric current In_1, In_2: Input nodes Node_A, Node_B: Detection nodes OP_4, OP_5: Operational amplifiers Out: Output node R1, R2, R3, R11, R12, R13, R14, RSEN: Resistors T1, T2: Transistors VSEN: Induced voltage

Claims

1. A detection circuit, comprising: An input circuit includes a first input node and a second input node, wherein the first input node is coupled to a first detection node and the second input node is coupled to a second detection node; and a sensing circuit includes a current source providing a predetermined current, wherein the current source is coupled to the first input node, the sensing circuit generates an induced voltage at an output node in response to the predetermined current, wherein the first detection node is directly in contact with or electrically connected to the second detection node through a trace, and an impedance value between the first detection node and the second detection node is related to the induced voltage; wherein the input circuit further includes: a first transistor, wherein a source of the first transistor is coupled to the first input node; and a second transistor, wherein a source of the second transistor is coupled to the second input node.

2. The detection circuit as described in claim 1 further includes: A processing circuit is coupled to the sensing circuit and detects the impedance value based on the induced voltage. The processing circuit controls a current quantity of the predetermined current to switch from a first current quantity to a second current quantity. In response to the first current quantity, the processing circuit receives a first induced voltage from the output node. In response to the second current quantity, the processing circuit receives a second induced voltage from the output node. The processing circuit further determines the impedance value based on a difference between the second induced voltage and the first induced voltage.

3. The detection circuit as described in claim 1, wherein the first detection node and the second detection node are each coupled to a system voltage of a display system.

4. The detection circuit as described in claim 3, wherein the system voltage is a power supply voltage or a ground voltage.

5. The detection circuit as claimed in claim 1, wherein the first detection node is contained in a first device, the second detection node is contained in a second device, and the first detection node and the second detection node are electrically connected via a bonding wire.

6. The detection circuit as claimed in claim 1, wherein the first detection node is contained on a first metal surface of a first device, the second detection node is contained on a second metal surface of a second device, and the first metal surface is in direct contact with the second metal surface.

7. The detection circuit as described in claim 2, wherein the processing circuit further determines whether the impedance value is abnormal based on a threshold value, and in response to a determination that the impedance value is abnormal, the processing circuit generates an error code or a warning message.

8. A detection method comprising detecting an impedance value between two nodes using a detection circuit, comprising: A first detection node is coupled to a first input node of the detection circuit, and a second detection node is coupled to a second input node of the detection circuit, wherein the first detection node is directly in contact with or electrically connected to the second detection node through a trace; a current source of the detection circuit is controlled to provide a first current; a first induced voltage is received from an output node of the detection circuit in response to the first current; a second current is controlled to provide a second current; a second induced voltage is received from the output node in response to the second current; and the impedance value between the first detection node and the second detection node is determined based on a difference between the second induced voltage and the first induced voltage; wherein the first detection node is coupled to a source of a first transistor of the detection circuit through the first input node, and the second detection node is coupled to a source of a second transistor of the detection circuit through the second input node.

9. The detection method as described in claim 8, wherein the first detection node and the second detection node are each coupled to a system voltage of a display system.

10. The detection method as described in claim 9, wherein the system voltage is a power supply voltage or a ground voltage.

11. The detection method as described in claim 8, wherein the first detection node is contained in a first device, the second detection node is contained in a second device, and the first detection node and the second detection node are electrically connected via a bonding wire.

12. The detection method as claimed in claim 8, wherein the first detection node is contained on a first metal surface of a first device, the second detection node is contained on a second metal surface of a second device, and the first metal surface is in direct contact with the second metal surface.

13. The detection method as described in claim 8 further includes: Determine whether the impedance value is abnormal based on a critical value; In response to a judgment result indicating an abnormal impedance value, an error code or a warning message is generated and displayed on a display panel.

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