External antenna state diagnosis circuit

Abstract

The utility model relates to a diagnosis circuit used for detecting the state of a vehicle GNSS external antenna. The diagnosis circuit comprises an interface unit for the access of an external antenna, a first switch unit and a second switch unit which are connected with the interface unit and can be respectively switched on or switched off based on the current state of the external antenna, and an ADC (Analog to Digital Converter) unit for detecting electric information corresponding to the current state of the external antenna from the diagnosis circuit. In addition, the controller unit is connected with the ADC unit so as to receive the electric information and judge the state of the external antenna according to the electric information. The diagnosis circuit can use a single-channel ADC unit to detect whether the external antenna is in a normal connection state.

Description

Technical Field

[0001] This disclosure generally relates to electronic circuits, and more specifically, to a diagnostic circuit for detecting the status of an external antenna of a vehicle's global navigation satellite system. Background Technology

[0002] A T-BOX (Telematics Box), also known as a data communication box (DCM), is an in-vehicle intelligent terminal that integrates multiple technologies such as wireless communication, satellite positioning, and sensors. With the rapid development of vehicle intelligence, the in-vehicle T-BOX has become a key component of intelligent connected vehicles, providing reliable and complete service functions for them.

[0003] T-BOX uses Global Navigation Satellite System (GNSS) to receive positioning information for vehicle navigation. The T-BOX (or DCM) should power a low-noise amplifier (LNA) to the external GNSS antenna. Therefore, a GNSS module may be needed for fault diagnosis and anomaly alerts for the external antenna. However, current diagnostic circuits may not be able to detect an external antenna shorted to the battery, or they still require checking the external antenna's status via GPIO bus ports, which can lead to increased processor resource consumption and the need for more components, thus negatively impacting product reliability and cost-effectiveness. Utility Model Content

[0004] In view of the above problems, the purpose of this disclosure is to provide a diagnostic circuit that can acquire an electrical signal, such as a voltage value, through a single-channel analog-to-digital converter (ADC) unit to detect the status of an external antenna of a vehicle's GNSS.

[0005] This disclosure provides a diagnostic circuit for detecting the status of an external GNSS antenna for a vehicle, including an interface unit for accessing the external antenna, a first switch unit and a second switch unit respectively connected to the interface unit, and an ADC unit for detecting electrical information from the diagnostic circuit. The electrical information detected by the ADC unit can correspond to at least one of the at least one states of the external antenna.

[0006] Furthermore, the diagnostic circuit also includes at least one first power supply unit that provides operating voltage to the first switching unit and the second switching unit, respectively.

[0007] Furthermore, at least one state of the external antenna includes: normal connection, open circuit, ground short circuit, and short-circuit to the battery. The first switching unit and the second switching unit can be controlled to be turned on or off respectively according to at least one state of the external antenna to output electrical information accordingly. This electrical information can be a voltage value corresponding to one of the at least one states.

[0008] Furthermore, the first switching unit may include a first PNP transistor and a first NPN transistor, and the second switching unit may include a second PNP transistor and a second NPN transistor.

[0009] Additionally or alternatively, the second switching unit may include at least one MOSFET.

[0010] Furthermore, a voltage divider filter circuit can be provided between the second PNP transistor and the second NPN transistor.

[0011] Furthermore, the first switching unit is connected to the second switching unit via a unidirectional diode, and then the first switching unit and the second switching unit are connected to the interface unit via an inductor.

[0012] Furthermore, the diagnostic circuit may also include a controller unit connected to the ADC unit and receiving electrical information. This controller unit determines the state of the external antenna based on the electrical information from the ADC unit.

[0013] Furthermore, the diagnostic circuit may also include a clamping circuit. The clamping circuit may include a second power supply unit and a dual diode connected in series between the second power supply unit and ground. The clamping circuit may be located where the ADC unit is connected to the diagnostic circuit to limit the potential at that point to the range of the power supply voltage from ground to the second power supply unit.

[0014] Furthermore, the diagnostic circuit may also include an impedance matching circuit, and the interface unit may also connect the vehicle's NAD unit to an external antenna via the impedance matching circuit. Attached Figure Description

[0015] These and / or other features, aspects, and advantages of this disclosure will be better understood after reading the following detailed description with reference to the accompanying drawings, throughout which like characters represent like parts, wherein:

[0016] Figure 1 A schematic diagram of a diagnostic circuit for detecting the status of an external GNSS antenna of a vehicle, according to one or more embodiments of the present disclosure, is shown.

[0017] Figure 2 A flowchart illustrating a diagnostic circuit for detecting the status of an external GNSS antenna of a vehicle according to one or more embodiments of the present disclosure is shown.

[0018] Figures 3A to 3D A schematic diagram illustrating the principle of a diagnostic circuit detecting various states of an external GNSS antenna of a vehicle according to one or more embodiments of this disclosure; and

[0019] Figure 4 Another schematic diagram of a diagnostic circuit for detecting the status of an external antenna for a vehicle's GNSS, according to one or more embodiments of the present disclosure, is shown. Detailed Implementation

[0020] Various embodiments are described below for illustrative purposes, but are not intended to be exhaustive or limiting of the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

[0021] Vehicles require GNSS antennas to achieve high-precision positioning. Automotive GNSS antennas include external antennas and are equipped with low-noise amplifiers (LNAs) for signal amplification and filtering. The battery voltage supplied by the DCM to the external antenna's LNA is 8–16V, which is then output as VDD_5V = 5V via a buck circuit or low-dropout linear regulator (LDO) to power the vehicle's external GNSS antenna's LNA. Therefore, to prevent and troubleshoot GNSS external antenna malfunctions, a diagnostic circuit can be used to check the current status of the external antenna each time it is powered on.

[0022] The status of the external GNSS antenna can include: normal connection, open circuit, short circuit to ground, and shorted to the battery. The diagnostic circuit can obtain the power supply voltage VDD_5V = 5V provided by the DCM battery. When the external GNSS antenna is powered on, if the diagnostic circuit detects that it is in a normal connection state, it can instruct the DCM battery to supply power to the external antenna normally, ensuring that the GNSS can function properly. Conversely, if the diagnostic circuit detects that the external antenna is in an open circuit, short circuit to ground, or shorted to the battery state, it indicates that the vehicle's external GNSS antenna has malfunctioned, and appropriate maintenance measures should be taken.

[0023] Figure 1 A schematic diagram 100 of a diagnostic circuit for detecting the status of an external GNSS antenna of a vehicle, according to one or more embodiments of the present disclosure, is shown. The diagnostic circuit may include a first switching unit 110 and a second switching unit 120. The first switching unit 110 and the second switching unit 120 are initially in an off state. When the external GNSS antenna is powered on, the diagnostic circuit operates, and the first switching unit 110 and the second switching unit 120 can be turned on or off respectively, corresponding to the status of the external GNSS antenna.

[0024] The diagnostic circuit includes power supply unit 130 and power supply unit 170 to provide operating voltages to the first switching unit 110 and the second switching unit 120, respectively. Figure 1As shown, power supply unit 130 is connected to the first switching unit 110 via current-limiting resistor R4; power supply unit 170 is connected to the second switching unit 120 via current-limiting resistor R9. When the GNSS external antenna is powered on, the first switching unit 110 and the second switching unit 120 in the diagnostic circuit are turned on or off respectively according to the current state of the GNSS external antenna.

[0025] like Figure 1 As shown, the first switching unit 110 may include a PNP transistor 112 and an NPN transistor 114 (device reference numeral T1), thus forming a PNP and NPN transistor switching circuit. The PNP transistor 112 is driven as the high-level terminal, with its PN junction on top (high-level terminal) and its emitter connected to the power supply unit 130; while the NPN transistor 114 is driven as the low-level terminal, with its PN junction on the bottom (low-level terminal) and its emitter connected to ground U.

[0026] The power supply circuit of the power supply unit 130 includes parallel grounding protection capacitors C4 and C5 and a series current-limiting resistor R7, which is connected to the emitter of the PNP transistor 112 in the first switching unit 110. The emitter of the PNP transistor 112 is connected to the base of the PNP transistor 112 via voltage divider resistors R6 and R4, and is also connected to the collector of the NPN transistor 114. The power supply circuit of the power supply unit 130 for the emitter of the PNP transistor 112 is also connected to the base of the NPN transistor 114 via voltage divider resistors R6 and R5.

[0027] like Figure 1 As shown, in the first switching unit 110, the collector of the PNP transistor 112 is connected to the base of the NPN transistor 114, and then connected to the second switching unit 120 via a series unidirectional diode DI1. The unidirectional diode DI1 can prevent current from flowing back to the first switching unit, for example, to prevent the battery voltage from affecting the function of the diagnostic circuit when the external antenna is short-circuited to the battery.

[0028] The emitter of the NPN transistor 114 is connected to ground U via diode DI2. Ground U, as mentioned in this disclosure (e.g., in...), is... Figure 1 Each location marked as ground terminal U represents a ground potential connected at that location as a reference potential for the diagnostic circuit, denoted as, for example, ground terminal U. For instance, ground terminal U could be the relative zero potential of the circuit board containing the diagnostic circuit.

[0029] Diode DI2 can be the same model as diode DI1. When diode DI1 may have a voltage drop, unidirectional diode DI2 clamps the emitter potential of NPN transistor 114 to prevent false turn-on due to a raised emitter potential. For example, when the external antenna is short-circuited to ground, unidirectional diode DI2 can clamp the raised emitter potential of NPN transistor 114, thus avoiding the risk of false turn-on and ensuring the normal operation of the diagnostic circuit.

[0030] Similarly, the second switching unit 120 includes a PNP transistor 122 and an NPN transistor 124 (device reference numeral T2). The collector of the PNP transistor 112 and the base of the NPN transistor 114 in the first switching unit 110 are connected to the emitter of the PNP transistor 122 in the second switching unit 120 via a unidirectional diode DI1. The base of the PNP transistor 122 is supplied with an operating voltage by the power supply unit 170. A current-limiting resistor R9 can be connected in series in the power supply circuit of the power supply unit 170.

[0031] like Figure 1 As shown, the diagnostic circuit has the same potential at node 118 and node 128, meaning that nodes 118 and 128 can be connected. The collector of NPN transistor 124 is connected to voltage divider resistor R8. (The last sentence appears to be incomplete and possibly refers to a different circuit.) Figure 1 As can be seen, the power supply circuit of the power supply unit 130 is connected to the collector of the NPN transistor 124 via voltage divider resistors R6 and R8. The emitter of the NPN transistor 124 in the second switching unit 120 is connected to the ground terminal U.

[0032] In addition, the collector of the PNP transistor 122 is connected to the base of the NPN transistor 124, and a voltage divider filter circuit consisting of, for example, voltage divider resistors R2 and R3 and filter capacitor C6 can be provided between them to adapt to different drive voltages applied to the second switching unit 120 at the emitter of the PNP transistor 122.

[0033] The diagnostic circuit may also include an ADC unit 140. The ADC unit 140 is connected to the diagnostic circuit for detecting electrical information. (Reference) Figure 1In one example, the ADC unit 140 is connected to the base (node ​​116) of the PNP transistor 112 in the first switching unit 110 to detect electrical information at node 116. The base of the PNP transistor 112 is an input that controls whether the first switching unit 110 is turned on, and can present different input voltages under different GNSS external antenna states, thereby allowing the state of the GNSS external antenna to be determined based on the electrical information detected at that point. In one or more examples of this disclosure, the ADC unit 140 can detect voltage values ​​in a diagnostic circuit. In such an example, the ADC unit can detect the current potential at that point and quantize it accordingly into a voltage value using only a single ADC channel, which can correspond to the current state of the GNSS external antenna. Therefore, the diagnostic circuit can use only a single ADC channel to detect electrical information, thereby saving processing and computing resources of the processor (e.g., MCU) in the DCM.

[0034] The diagnostic circuit may further include a clamping circuit 160, which may include a power supply unit 162 and a dual diode DI3 connected in series between the power supply unit 162 and the ground terminal U. Figure 1 As can be seen, the dual diode DI3 is equivalent to two unidirectional diodes connected in series, and the connection between these two diodes is made to the diagnostic circuit. The anode of one diode in the dual diode DI3 is connected to the power supply unit 162, and the cathode of the other diode is connected to ground U. In the diagnostic circuit, this clamping circuit can be connected where the ADC unit 140 is connected to the diagnostic circuit (e.g., at node 116) to limit the potential at that point within a certain range. In the example described, the clamping circuit 160 limits the potential at node 116 to the range between ground U and the power supply voltage of the power supply unit 162. In a real circuit, since the dual diode DI3 may have a voltage drop, the range of the clamping circuit 160 may be slightly larger than the power supply voltage of the power supply unit 162. For example, if the power supply unit 162 can provide, for example, 3.3V, then due to the action of the clamping circuit, the ADC unit 140 can detect that the voltage value at node 116 is limited to, for example, a minimum voltage of approximately 0V and a maximum voltage of approximately 3.3V.

[0035] The diagnostic circuit may also include an interface unit 180. A first switching unit 110 and a second switching unit 120 may be connected to the interface unit 180 via an inductor L1, and then the GNSS external antenna (not shown) may be connected to the diagnostic circuit via the interface unit 180 (e.g., at 182). In one example, the interface unit 180 may include an RF connector to allow the GNSS external antenna to be connected to the vehicle's DCM. In one example, the interface unit 180 may also, for example, allow a network access device (NAD) unit located on the vehicle's DCM to be connected to the GNSS external antenna via an impedance matching circuit (e.g., at 184). In one example, as... Figure 1 As shown, the NAD unit can be connected to the GNSS external antenna via an impedance matching circuit 186 consisting of, for example, capacitors C1, C2 and C3 and resistor R1, so that the GNSS external antenna can function properly.

[0036] Figure 2 A flowchart 200 schematically illustrates a diagnostic circuitry for detecting the status of an external GNSS antenna of a vehicle, according to one or more embodiments of this disclosure. Figure 2 As shown, firstly, in step S210, both the first and second switching units in the diagnostic circuit are initially set to be off. When the GNSS external antenna is initially powered on, the diagnostic circuit starts working to detect whether the GNSS external antenna is properly connected, thereby ensuring that the GNSS external antenna can continue to work safely and stably.

[0037] Next, in step S220, the diagnostic circuit detects the connection status of the GNSS external antenna. As the GNSS external antenna is powered on, the current and voltage in the diagnostic circuit may change, triggering the first and second switching units to turn on or off accordingly. In this way, the diagnostic circuit can detect the corresponding electrical information through the ADC unit, and thus determine the corresponding connection status of the GNSS external antenna in subsequent steps based on the electrical information detected by the ADC unit.

[0038] In step S220 above, the principle of the diagnostic circuit detecting the status of the GNSS external antenna can be referred to... Figures 3A to 3DThis schematic diagram illustrates the principle of a diagnostic circuit according to one or more embodiments of the present disclosure for detecting various states of an external GNSS antenna in a vehicle. The selection and values ​​of the various electrical components in the diagnostic circuit of this disclosure are merely examples and can be adjusted based on debugging results in practical applications. In one or more of the following embodiments, the first and second switching units can respectively employ, for example, bipolar transistors of model PUMD9 manufactured by Nexperia, which are NPN / PNP dual transistors rated at 50V 100mA and equipped with bias resistors. Furthermore, the values ​​of other electrical components can be selected, for example: power supply unit 330 provides a switching operating voltage of VDD_5V, with a series current-limiting resistor R7 = 22Ω; power supply unit 370 provides a switching operating voltage of VDD_5V, with a series current-limiting resistor R9 = 10kΩ; and the voltage divider resistors have values ​​of R4 = 1kΩ, R5 = 33kΩ, R6 = 3kΩ, and R8 = 10kΩ. The electrical signal detected by the ADC unit (not shown) connected to the diagnostic circuit is the voltage value at node 316 of the power supply unit 330 after voltage division by resistors R7, R6, and R4. The voltage value detected by the ADC unit can be limited, for example, by a clamping circuit to a minimum voltage of about 0V and a maximum voltage of about 3.3V.

[0039] Figure 3A The schematic diagram illustrates a diagnostic circuit according to one or more embodiments of the present disclosure, demonstrating the principle of detecting the normal access status of an external antenna. The diagnostic circuit includes an interface unit 380. In one example, the interface unit 380 may include an RF connector (not shown) to allow an external GNSS antenna (not shown) to be connected to the vehicle's DCM, for example, allowing the external GNSS antenna to be connected to the DCM's PCB motherboard via the interface unit 380.

[0040] like Figure 3A As shown, the first and second switching units in the diagnostic circuit can be connected to the interface unit 380 via inductor L1, and then the GNSS external antenna can be connected (e.g., at 382) via the RF connector of the interface unit 380. When a high-frequency signal flows through, the inductor L1 can present a high impedance to isolate the diagnostic circuit from the GNSS RF circuit, where, for example, L1 = 47nH.

[0041] In one example, the interface unit 380 can also, for instance, allow an NAD unit located in the vehicle's DCM to be connected to an external GNSS antenna via an impedance matching circuit (e.g., at 384). Figure 3AIn the example shown, the NAD unit is connected to the GNSS external antenna via an impedance matching circuit 386, for example, consisting of capacitors C1, C2, and C3 and resistor R1. The values ​​of capacitors C1, C2, and C3 and resistor R1 in the impedance matching circuit 386 can be adjusted according to the actual application. For example, C1 and C2 can be set as needed, and R1 can be set to 0Ω and C3 to 100pF, for example, to enable the GNSS external antenna to function properly.

[0042] When the diagnostic circuit is working, refer to Figure 3A First, when the GNSS external antenna is initially powered on, the switching operating voltage (e.g., 5V) provided by the power supply unit 330 initially causes a current I1 to be generated in the diagnostic circuit (e.g., ...). Figure 3A (As shown by the dashed arrow in the middle), then by Figure 3A It can be seen that the voltage at node 318 in the first switching unit becomes:

[0043] V 1(节点318处) =VDD_5V-(R5+R6+R7)I1 (1)

[0044] Therefore, by Figure 3A As can be seen from the configuration, both the PNP transistor 312 and the NPN transistor 314 in the first switching unit will be turned on, resulting in a current I2 (e.g., ...). Figure 3A (As indicated by the solid arrow) flows through the diagnostic circuit. The VDD_5V voltage provided by power supply unit 330 can then power the GNSS external antenna through interface unit 380. At this time, the ADC unit can detect that the voltage at the base of PNP transistor 312 (i.e., at node 316) is approximately:

[0045] V 2(节点316处) =0.3V (2)

[0046] Therefore, in such Figure 3A As shown in the configuration of the diagnostic circuit, when the GNSS external antenna is normally on, the voltage value detected by the diagnostic circuit through the ADC unit is approximately 0.3V.

[0047] Figure 3B This schematic diagram illustrates the principle of a diagnostic circuit according to one or more embodiments of the present disclosure for detecting the unconnected (i.e., open-circuit) state of an external antenna. Figure 3B As shown, an open circuit in the external GNSS antenna is considered a disconnection between the external GNSS antenna and the connector (e.g., Figure 3B(As shown by reference numeral 350). In this case, firstly, when the GNSS external antenna is initially powered on, the power supply unit 330 causes the voltage at circuit node 316 to rise to its power supply voltage (e.g., 5V), and neither the first nor the second switching unit is turned on; that is, both the first and second switching units are turned off. Since a clamping circuit 360 is connected in the diagnostic circuit before the ADC unit 340 detects electrical information, and it has a clamping voltage provided by the power supply unit 362, for example, 3.3V, then... Figure 3B It can be seen that the potential at node 316 is clamped to approximately 3.3V, that is:

[0048] V 1(节点316处) =3.3V (3)

[0049] like Figure 3B In the example shown, the dual diodes DI3 in the clamping circuit 360 can be implemented using, for example, a dual series Schottky barrier diode of model S-LBAT54S. Figure 3B In the example, the anode of the dual diode DI3 is connected to a power supply unit 362 that provides a power supply voltage of 3.3V, and the cathode of the dual diode DI3 is grounded. Then the clamping circuit 360 clamps the voltage value detected by the ADC unit at a minimum voltage of about 0V and a maximum voltage of about 3.3V.

[0050] Therefore, in such Figure 3B As shown in the configuration of the diagnostic circuit, if the GNSS external antenna is in an open circuit state after being powered on, the voltage value detected by the diagnostic circuit through the ADC unit is approximately 3.3V.

[0051] Figure 3C This schematic diagram illustrates the principle of a diagnostic circuit for detecting a ground short circuit in an external antenna according to one or more embodiments of this disclosure. Figure 3C As shown, when the GNSS external antenna is short-circuited to ground (e.g.) Figure 3B As shown in mark 370, when the GNSS external antenna is initially powered on, both the first and second switching units remain open. The VDD_5V operating voltage on the power supply unit 330 then generates a current I1 as follows: Figure 3C As shown. Therefore, when the GNSS external antenna is short-circuited to ground, the VDD_5V power supply voltage on power supply unit 330 is divided by voltage divider resistors R5, R6, and R7. Considering various parameters of the electrical components, the voltage value detected by the ADC unit at node 316 is approximately:

[0052]

[0053] Therefore, in such Figure 3CAs shown in the configuration of the diagnostic circuit, if the GNSS external antenna is in a ground short-circuit state after being powered on, the voltage value detected by the diagnostic circuit through the ADC unit is approximately 2.66V.

[0054] Furthermore, in the diagnostic circuit, a unidirectional diode DI1 can be placed between the first switching unit and the second switching unit. The cathode of diode DI1 is connected to the collector of PNP transistor 312 in the first switching unit and to the base of NPN transistor 314 therein. The anode of diode DI1 is connected to the emitter of PNP transistor 322 in the second switching unit. Figure 3C As shown, when the external antenna is short-circuited to ground, the base potential of the NPN transistor 314 may be raised due to the voltage drop across diode DI1, potentially causing the NPN transistor 314 to conduct, which is undesirable. Therefore, in the second switching unit, a unidirectional diode DI2 is connected in series between the emitter of the NPN transistor and the ground terminal U. Diode DI2 is of the same type as diode DI1, so that the emitter potential of the NPN transistor 314 is raised and clamped, thereby avoiding the risk of the NPN transistor 314 conducting when the external antenna is short-circuited to ground, and ensuring the normal operation of the diagnostic circuit.

[0055] For example, diodes DI1 and DI2 can be unidirectional diodes of the same type, such as a Schottky barrier single diode of type BAT54J.

[0056] Figure 3D This schematic diagram illustrates the principle of a diagnostic circuit detecting the state of an external antenna short-circuited with a battery, according to one or more embodiments of this disclosure. The vehicle's DCM should supply LNA power to the GNSS external antenna; therefore, its rated operating voltage, for example, 8–16V, is supplied by the DCM battery. (Reference) Figure 3D If the GNSS external antenna is shorted to the battery (e.g.) Figure 3D As shown in the diagram (marked 382), when the GNSS external antenna is initially powered on, a battery with a rated voltage of 8-16V becomes the emitter of the PNP transistor 322 (high level end) in the second switching unit, and the emitter of the NPN transistor 324 (low level end) is connected to the ground terminal U. At the same time, the base of the PNP transistor 322 is provided with a working voltage VDD_5V by the power supply unit 370, thereby turning on both the PNP transistor 322 and the NPN transistor 324 in the second switching unit.

[0057] At this time, the battery provides a rated voltage of, for example, 8-16V, which generates a current I1 in the diagnostic circuit (e.g., ...). Figure 3D (As shown by the dashed arrow); the VDD_5V power supply voltage on power supply unit 330 generates current I2 (as shown by the dashed arrow). Figure 3D(As shown by the solid arrow). Since nodes 318 and 328 in the diagnostic circuit are at the same potential (i.e., the two nodes are connected), the VDD_5V power supply voltage on power supply unit 330 is divided by voltage divider resistors R6, R7, and R8. Considering various parameters of the electrical components, the ADC unit will detect a voltage value at node 316 of approximately:

[0058]

[0059] Therefore, in such Figure 3D As shown in the configuration of the diagnostic circuit, when the GNSS external antenna is shorted to the battery, the voltage value detected by the diagnostic circuit through the ADC unit is approximately 1.23V.

[0060] When the GNSS external antenna is short-circuited to the battery, because the battery is connected to the diagnostic circuit, the emitter of the PNP transistor 322 in the second switching unit is connected to a voltage of, for example, 8-16V. Therefore, a voltage divider filter circuit needs to be connected between the PNP transistor 322 and the NPN transistor 324 in the second switching unit. Figure 3D In the example shown, a voltage divider filter circuit 390, consisting of, for example, voltage divider resistors R2 and R3 and a filter capacitor C6, is connected in series between the collector of the PNP transistor 322 and the base of the NPN transistor 324. When the GNSS external antenna is shorted to the battery, since the battery voltage is 8-16V, the base voltage of the PNP transistor 322 is VDD_5V = 5V, causing the PNP transistor 322 to conduct. The voltage divider resistors R2 and R3 divide the collector voltage of the PNP transistor 322 and connect it to the base of the NPN transistor 324, thus turning on the NPN transistor 324 and preventing excessive voltage from being applied to its base, providing protection. The values ​​of the components in the voltage divider filter circuit 390 can be adjusted according to the actual application; for example, R2 = 5kΩ, R3 = 2kΩ, and C6 = 33pF.

[0061] In addition, such as Figure 3D As shown, a current I1 is generated due to the rated voltage of 8-16V provided by the battery (e.g., ...). Figure 3D (As shown by the dashed arrow); the VDD_5V provided by the power supply unit 330 generates a current I2, and the second switching unit in the diagnostic circuit is connected while the first switching unit remains open. Therefore, the unidirectional diode DI1 placed between the first and second switching units can prevent current backflow. When the GNSS external antenna is shorted to the battery, diode DI1 can prevent the battery voltage from affecting the function of the diagnostic circuit.

[0062] Depend on Figures 3A to 3DThe analysis shows that the diagnostic circuit can detect the corresponding electrical signal through the ADC unit after the GNSS external antenna is powered on. In one or more embodiments shown, the ADC unit detects the level and quantizes it into a voltage value. The voltage values ​​detected by the ADC unit when the GNSS is normally connected, open-circuited, short-circuited to ground, and short-circuited to the battery are 0.3V, 3.3V, 2.66V, and 1.23V, respectively. Therefore, each of the four GNSS states corresponds to a voltage value. Thus, the ADC unit can use a single channel at node 316 of the diagnostic circuit to detect the voltage at that node and quantize it into a voltage value. Using such a single-channel ADC unit in the diagnostic circuit results in a simple structure, saves processor resources, and improves computational efficiency.

[0063] return Figure 2 In step 230, the connection status of the GNSS external antenna is determined based on the electrical information detected by the ADC unit. The ADC unit may be connected to the controller unit of the DCM, or the ADC unit may be included in the controller unit. For example, the controller unit of the DCM may include one or more microcontrollers (MCUs) or I / O controllers (IOCs). The controller unit is connected to the ADC unit connected to the diagnostic circuit to receive the electrical information detected by the ADC unit and determine the current status of the GNSS external antenna accordingly.

[0064] Table 1 below lists the current state of the GNSS external antenna that can be determined based on the detected electrical signals when the diagnostic circuit of this disclosure detects the GNSS external antenna:

[0065] Table 1. GNSS external antenna status corresponding to the voltage values ​​detected by the ADC unit

[0066] The rightmost part of Table 1 above lists the corresponding voltage values ​​detected by the ADC unit in the diagnostic circuit. Therefore, the controller unit is connected to the ADC unit to receive the voltage values ​​detected by the ADC unit and is configured to determine the status of the GNSS external antenna based on the voltage values.

[0067] For example, if the controller unit receives a voltage value between 0.1 and 0.5V, the controller unit can determine that the GNSS external circuit is currently in a normal connection state.

[0068] For example, if the controller unit receives a voltage value between 3.1 and 3.3V, the controller unit can determine that the GNSS external circuit is currently in an off state;

[0069] For example, if the controller unit receives a voltage value between 2.46 and 2.86V, the controller unit can determine that the GNSS external circuit is currently in a ground short-circuit state, and

[0070] For example, if the controller unit receives a voltage value between 1.03V and 1.43V, the controller unit can determine that the GNSS external circuit is currently shorted to the battery.

[0071] Finally, in step 240, the current status of the external GNSS antenna is indicated or reported. For example, in step 240, when the diagnostic circuit detects the external GNSS antenna and the controller unit determines that the external GNSS antenna is in a normal connection state, the battery supplies power to the external GNSS antenna to ensure its normal operation. At each initial power-on of the GNSS, the diagnostic circuit detects the external GNSS antenna to ensure its continued normal operation.

[0072] In step 240, based on the diagnostic circuit's detection of the GNSS external antenna, the controller unit determines, according to the voltage value detected by the ADC unit, that the GNSS external antenna is in an open circuit, short-circuited to ground, or short-connected to the battery. In this case, the GNSS external antenna is in an abnormal connection state. When the controller unit determines that the GNSS external antenna is in an abnormal connection state, it can report this abnormal state, enabling timely and targeted troubleshooting of the GNSS external antenna and further preventing more serious consequences for vehicle operation caused by the malfunctioning GNSS external antenna.

[0073] Additionally or alternatively, Figure 4 Another schematic diagram 400 illustrates a diagnostic circuit for detecting the status of an external GNSS antenna of a vehicle, according to one or more embodiments of this disclosure. Figure 4 As shown, the first switching unit 410 and Figure 1 The first switching unit 110 is the same. And... Figure 4 The example of the diagnostic circuit shown is similar to Figure 1 The difference is that, Figure 4 The second switching unit 420 can be implemented using a MOSFET. For example, a PMOS transistor 422 can be used instead. Figure 1 The PNP transistor 122 is combined with the NPN transistor 124 to achieve... Figure 4 The switching circuit of the second switching unit 420 is shown. For example... Figure 4As shown in the second switching unit 420, the second switching unit 420 includes a PMOS transistor 422 (device reference number Q2) and an NPN transistor 424. The collector of the PNP transistor 412 in the first switching unit 410 and the base of the NPN transistor 414 are connected to the source of the PMOS transistor 422 in the second switching unit 420 via a unidirectional diode DI1. The gate of the PMOS transistor 422 is supplied with an operating voltage by a power supply unit 470. A current-limiting resistor R9 can be connected in series in the power supply circuit of the power supply unit 470 to control the gate current from becoming too large. In addition, the drain of the PMOS transistor 422 is connected to the base of the NPN transistor 424, and a voltage divider filter circuit consisting of, for example, voltage divider resistors R2 and R3 and a filter capacitor C6 is connected in series between them.

[0074] Figure 4 The diagnostic circuit shown initially disconnects both the first switch unit 410 and the second switch unit 420 when detecting the status of the GNSS external antenna. When the GNSS external antenna is powered on and in a normal connection state, the first switch unit 410 turns on, while the second switch unit 420 remains off. The circuit principle is as follows: Figure 3A As shown, the power supply unit 430 can supply power to the GNSS external antenna, and at this time, the ADC unit (not shown) can detect that the voltage value at node 416 is between 0.1 and 0.5V. Then the controller unit (not shown) can determine that the GNSS external circuit is currently in a normal connection state.

[0075] When the GNSS external antenna is powered on and in an open circuit state, neither the first switching unit 410 nor the second switching unit 420 will conduct, i.e., they will remain open. The circuit operation principle is as follows: Figure 3B As shown, if the voltage value that the ADC unit can detect at this time is between 3.1 and 3.3V, then the controller unit can determine that the GNSS external circuit is currently in an open circuit state.

[0076] When the GNSS external antenna is powered on and short-circuited to ground, both the first switching unit 410 and the second switching unit 420 remain open. The circuit operation principle is as follows: Figure 3C As shown, if the voltage value that the ADC unit can detect at this time is between 2.46 and 2.86V, then the controller unit can determine that the GNSS external circuit is currently in a ground short circuit state.

[0077] like Figure 4 The diagnostic circuit shown is used to detect when the GNSS external antenna is shorted to the battery. The circuit incorporates the battery voltage (e.g., ...). Figure 3D(As shown in Figure 380). For example, if the battery provides a rated voltage of 8-16V for the GNSS external antenna, this is equivalent to providing an 8-16V drive voltage to the source of the PMOS transistor 422 in the second switching unit 420. If the power supply unit 470 provides an operating voltage of, for example, VDD_5V to the gate of the PMOS transistor 422, then the 8-16V drive voltage at the source of the PMOS transistor 422 will turn on the PMOS transistor 422, and the NPN transistor 424 will also turn on, while the first switching unit 410 will not turn on (remain open). The principle of circuit operation at this time can be found in [reference needed]. Figure 3D As shown, the voltage value at node 416 that the ADC unit can detect is between 1.03V and 1.43V, and the controller unit can determine that the GNSS external circuit is currently shorted to the battery.

[0078] like Figure 4 In the example diagnostic circuit shown, the PMOS transistor 422 in the second switching unit 420 can be, for example, an automotive-grade P-channel enhancement-type MOSFET of model PJA3411-AU.

[0079] Additionally or alternatively, in one or more examples, the second switching unit in the diagnostic circuit may also be implemented using PMOS and NMOS transistors. For example, Figure 4 In the example, the NPN transistor 424 is replaced with an NMOS transistor. Therefore, the second switching unit 420 may include a PMOS transistor 422 and an NMOS transistor (not shown), with the source of the NMOS transistor connected to ground U, the drain of the NMOS transistor connected to a voltage divider resistor R8, and the gate of the NMOS transistor connected via a series voltage divider filter circuit (e.g., Figure 4 The R2, R3 and C6 shown are connected to the drain of the PMOS transistor 422.

[0080] The diagnostic circuit provided in this disclosure has the following advantages: it can detect normal connections, open circuits, ground short circuits, and short circuits to the battery of the GNSS external antenna; it can use a single ADC channel to detect voltage values, thus requiring fewer components, saving resources for the controller unit and reducing the cost of product components. This diagnostic circuit operates stably and reliably.

[0081] Based on the foregoing description of the embodiments, suitable modifications and changes can be made to the embodiments based on the above description, or such modifications and changes can be obtained from practicing the methods described. For example, unless otherwise stated, one or more of the described methods can be performed by suitable means and / or combinations of means. The methods can be performed by executing stored instructions using one or more logical means (e.g., a processor) in conjunction with one or more additional hardware elements (such as storage devices, memories, hardware network interfaces / antennas, switches, power supply units, clock circuits, etc.). In addition to the order described in this application, the described methods and associated actions can also be performed in parallel and / or simultaneously in various orders. The described systems are exemplary in nature and may include additional elements and / or omit elements. The subject matter of this disclosure includes all novel and non-obvious combinations of the various systems and configurations disclosed, as well as other features, functions, and / or properties.

[0082] Elements of various real-time schemes for implementing the methods provided herein may be fabricated as one or more electronic devices residing on the same chip or in a chipset, including but not limited to arrays of fixed or programmable logic elements (e.g., transistors or gates). One or more elements of various embodiments of the devices described herein may also be implemented wholly or partially as one or more instruction sets that can be arranged on one or more arrays of fixed or programmable logic elements (e.g., microprocessors, embedded processors, IP cores, digital signal processors, FPGAs, ASSPs, and ASICs, etc.) for execution.

[0083] Examples of one or more implementations of this disclosure are described in the following clauses:

[0084] Clause 1. A diagnostic circuit for detecting the status of an external antenna of a vehicle's Global Navigation Satellite System (GNSS), characterized in that: the diagnostic circuit comprises:

[0085] An interface unit that allows an external antenna to be connected;

[0086] A first switch unit and a second switch unit are respectively connected to the interface unit;

[0087] An ADC unit is configured to detect electrical information from the diagnostic circuit, the electrical information corresponding to at least one of the states of the external antenna.

[0088] Clause 2. The diagnostic circuit as described in Clause 1, characterized in that:

[0089] It also includes at least one first power supply unit that provides operating voltages to the first switching unit and the second switching unit respectively, wherein the operating voltages of the first switching unit and the second switching unit are both VDD_5V = 5V.

[0090] Clause 3. The diagnostic circuit as described in Clause 1 or 2, characterized in that:

[0091] The at least one state of the external antenna includes: normal connection, open circuit, ground short circuit, and short to battery, wherein the first switching unit and the second switching unit can be controlled to be turned on or off according to the at least one state of the external antenna to output the electrical information accordingly, wherein the electrical information is a voltage value corresponding to one of the at least one states.

[0092] Clause 4. The diagnostic circuit as described in any one of Clauses 1 to 3, characterized in that:

[0093] The first switching unit includes a first PNP transistor and a first NPN transistor;

[0094] The second switching unit includes a second PNP transistor and a second NPN transistor.

[0095] Clause 5. The diagnostic circuit as described in any one of Clauses 1 to 4, characterized in that:

[0096] The second switching unit includes at least one MOSFET.

[0097] Clause 6. The diagnostic circuit as described in any one of Clauses 1 to 5, characterized in that:

[0098] A voltage divider filter circuit is provided between the second PNP transistor and the second NPN transistor.

[0099] Clause 7. The diagnostic circuit as described in any one of Clauses 1 to 6, characterized in that:

[0100] The first switching unit is connected to the second switching unit via a unidirectional diode;

[0101] The first switch unit and the second switch unit are connected to the interface unit via an inductor.

[0102] Clause 8. The diagnostic circuit as described in any one of Clauses 1 to 7, characterized in that:

[0103] It also includes a controller unit, which is connected to the ADC unit and receives the electrical information, wherein the controller unit determines the state based on the electrical information.

[0104] Clause 9. The diagnostic circuit as described in any one of Clauses 1 to 8, characterized in that:

[0105] It also includes a clamping circuit, which includes a second power supply unit and two diodes connected in series between the second power supply unit and a ground terminal, wherein the clamping circuit is located where the ADC unit is connected to the diagnostic circuit to limit the potential within the range of the power supply voltage from the ground terminal U to the second power supply unit.

[0106] Clause 10. The diagnostic circuit as described in any one of Clauses 1 to 9, characterized in that:

[0107] It also includes an impedance matching circuit, and the interface unit connects the vehicle's NAD unit to the external antenna via the impedance matching circuit.

[0108] The terminology used herein is chosen to best explain the principles of the embodiments, their practical application, or improvements to techniques found in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0109] In the foregoing, reference has been made to the embodiments presented in this disclosure. However, the scope of this disclosure is not limited to the specifically described embodiments. Rather, any combination of the foregoing features and elements, whether or not relating to different embodiments, is contemplated as an implementation and practice of the contemplated embodiments.

[0110] Furthermore, while the embodiments disclosed herein may achieve advantages over other possible solutions or over the prior art, the scope of this disclosure is not limited regardless of whether a given embodiment achieves a particular advantage. Therefore, the foregoing aspects, features, embodiments, and advantages are merely illustrative and should not be considered as elements or limitations of the appended claims unless expressly stated in the claims.

[0111] While the foregoing describes embodiments of this disclosure, other and further embodiments of this disclosure may be devised without departing from the basic scope of this disclosure, the scope of which is defined by the appended claims.

Claims

1. An external antenna status diagnostic circuit for detecting the status of an external antenna of a vehicle's Global Navigation Satellite System (GNSS), characterized in that: The external antenna status diagnostic circuit includes: An interface unit that allows an external antenna to be connected; A first switch unit and a second switch unit are respectively connected to the interface unit; An analog-to-digital converter (ADC) unit is configured to detect electrical information in the diagnostic circuit, the electrical information corresponding to one of at least one states of the external antenna.

2. The external antenna status diagnostic circuit as described in claim 1, characterized in that: It also includes at least one first power supply unit that provides operating voltages to the first switching unit and the second switching unit respectively, wherein the operating voltages of the first switching unit and the second switching unit are both 5V.

3. The external antenna status diagnostic circuit as described in claim 1, characterized in that: The at least one state of the external antenna includes: normal connection, open circuit, ground short circuit, and short to battery, wherein the first switching unit and the second switching unit are controlled to be turned on or off according to the at least one state to output the electrical information accordingly, wherein the electrical information is a voltage value corresponding to one of the at least one states.

4. The external antenna status diagnostic circuit as described in claim 3, characterized in that: in, The first switching unit includes a first PNP transistor and a first NPN transistor; The second switching unit includes a second PNP transistor and a second NPN transistor.

5. The external antenna status diagnostic circuit as described in claim 4, characterized in that: in, The second switching unit includes at least one MOSFET.

6. The external antenna status diagnostic circuit as described in claim 4, characterized in that: A voltage divider filter circuit is provided between the second PNP transistor and the second NPN transistor.

7. The external antenna status diagnostic circuit as described in claim 1, characterized in that: in, The first switching unit is connected to the second switching unit via a unidirectional diode; The first switch unit and the second switch unit are connected to the interface unit via an inductor.

8. The external antenna status diagnostic circuit as described in claim 1, characterized in that: It also includes a controller unit, which is connected to the ADC unit and receives the electrical information, wherein the controller unit determines the state based on the electrical information.

9. The external antenna status diagnostic circuit as described in claim 1, characterized in that: It also includes a clamping circuit, which includes a second power supply unit and a dual diode connected in series between the second power supply unit and a ground terminal, wherein the clamping circuit is located where the ADC unit is connected to the diagnostic circuit to limit the potential within the range of the power supply voltage from the ground terminal U to the second power supply unit.

10. The external antenna status diagnostic circuit as described in claim 1, characterized in that: It also includes an impedance matching circuit, and the interface unit also connects the vehicle's network access device (NAD) unit to the external antenna via the impedance matching circuit.

Images