Analog circuit and device for ECU (Electronic Control Unit) test

Abstract

The embodiment of the utility model provides an analog circuit and device for ECU (Electronic Control Unit) test. The circuit comprises a voltage transmission circuit, a voltage division circuit, a voltage regulation circuit and a negative feedback circuit, the input end of the voltage transmission circuit is used for being connected with an ECU pin, and the output end is connected with the first input end of the negative feedback circuit. One end of the voltage division circuit is connected with the ECU pin, and the other end is connected with the output end of the negative feedback circuit; two input ends of the voltage regulation circuit are respectively connected to two ends of a first resistor on the voltage division circuit, and an output end of the voltage regulation circuit is connected with a second input end of the negative feedback circuit; the output end of the negative feedback circuit is connected with the voltage division circuit. According to the scheme, the problem that the resistance value jumps to one value and then is switched to the target value is solved, the test accuracy of the ECU is not affected, the switching speed is high, and the test efficiency can be improved; in addition, the circuit is simple in structure and does not occupy a large space.

Description

Technical Field

[0001] Embodiments of the present utility model relate to the field of testing technologies, and particularly to an analog circuit and device for ECU testing. Background Art

[0002] An electronic control unit (ECU) is a key component of an automotive electronic control system, responsible for collecting and processing data from various sensors in the vehicle, such as temperature sensors, pressure sensors, etc., and controlling multiple subsystems of the vehicle, thereby ensuring the smooth and efficient operation of the vehicle. In an automotive electronic control system, collecting the analog signal of each sensor is the basis for the ECU to perform control functions. Therefore, the acquisition accuracy of the analog signal of the ECU is particularly important.

[0003] Therefore, when testing the performance of the ECU, one of the test contents is to test the acquisition accuracy of the analog signal of the ECU. When testing the signal acquisition accuracy of the ECU, it is necessary to inject continuously variable resistance values into the ECU to achieve the acquisition test of different signals. To achieve the change of the resistance value, in the prior art, multiple relays are usually used to cut a group of resistors into or out of the circuit respectively, so as to achieve the purpose of changing the resistance. As Figure 1 shown, different combinations of 16 relays are used to achieve the purpose of changing the circuit resistance.

[0004] However, when using the relay control method to change the resistance value, multiple relays need to be set in the circuit, occupying a large space; and there is a millisecond-level response time for relay switching. Therefore, it is difficult to synchronize the responses of each relay, so there is a situation where the resistance first jumps to a value and then jumps to the target resistance value during switching, which may cause the ECU to collect incorrect data and thus affect the test accuracy of the ECU. Content of the Utility Model

[0005] To overcome the problems existing in the related art, embodiments of the present utility model provide an analog circuit and device for ECU testing.

[0006] According to the first aspect of the embodiments of the present utility model, an analog circuit for ECU testing is provided. The analog circuit includes: a voltage transmission circuit, a voltage division circuit, a voltage regulation circuit, and a negative feedback circuit;

[0007] The input end of the voltage transmission circuit is used to connect to the ECU pin, and the output end of the voltage transmission circuit is connected to the first input end of the negative feedback circuit, for transmitting the first voltage signal of the ECU pin to the first input end of the negative feedback circuit;

[0008] One end of the voltage dividing circuit is connected to the ECU pin, and the other end is connected to the output end of the negative feedback circuit; wherein, a first resistor is provided on the voltage dividing circuit;

[0009] Two input ends of the voltage regulating circuit are respectively connected to both ends of the first resistor, and the output end of the voltage regulating circuit is connected to the second input end of the negative feedback circuit, and is used for regulating the received second voltage signal and controlling the third voltage signal transmitted to the second input end of the negative feedback circuit;

[0010] The output end of the negative feedback circuit is connected to the voltage dividing circuit, and is used for regulating the current value flowing through the voltage dividing circuit.

[0011] In an optional implementation manner, the voltage regulating circuit includes a differential amplifier circuit and a digital-to-analog converter DAC;

[0012] Two input ends of the differential amplifier circuit are respectively connected to both ends of the first resistor, and the output end of the differential amplifier circuit is connected to the input end of the DAC, and is used for amplifying the second voltage signal and inputting the amplified fourth voltage signal to the DAC;

[0013] The output end of the DAC is connected to the second input end of the negative feedback circuit, and is used for outputting a preset proportion of the fourth voltage signal as the third voltage signal to the second input end of the negative feedback circuit.

[0014] In an optional implementation manner, the differential amplifier circuit includes a first operational amplifier, a second resistor, a third resistor, a fourth resistor and a fifth resistor;

[0015] The non-inverting input end of the first operational amplifier is connected to the first end of the first resistor through the second resistor and the third resistor, and the inverting input end of the first operational amplifier is connected to the second end of the first resistor through the fourth resistor and the fifth resistor;

[0016] One end of the third resistor is connected to the first end of the first resistor, the other end of the third resistor is respectively connected to the non-inverting input end and one end of the second resistor, and the other end of the second resistor is grounded;

[0017] One end of the fifth resistor is connected to the first end of the first resistor, the other end of the fifth resistor is respectively connected to the inverting input end and one end of the fourth resistor, and the other end of the fourth resistor is connected to the output end of the first operational amplifier;

[0018] Among them, the first end of the first resistor is the end of the voltage dividing circuit close to the ECU pin, and the second end of the first resistor is the end of the voltage dividing circuit close to the output end of the negative feedback circuit.

[0019] In an alternative embodiment, the resistance value of the second resistor is equal to that of the fourth resistor, the resistance value of the third resistor is equal to that of the fifth resistor, and the resistance value of the second resistor is greater than that of the third resistor.

[0020] In an alternative embodiment, the control end of the DAC is further configured to be connected to a controller, receive a digital control signal input by the controller, and convert the digital control signal into an analog control signal to adjust the preset ratio.

[0021] In an alternative embodiment, the negative feedback circuit includes a second operational amplifier and a triode;

[0022] The inverting input end of the second operational amplifier is connected to the output end of the voltage regulating circuit, and the non-inverting input end of the second operational amplifier is connected to the output end of the voltage transmission circuit;

[0023] The base of the triode is connected to the output end of the second operational amplifier, and the collector of the triode is connected to the voltage dividing circuit.

[0024] In an alternative embodiment, the emitter of the triode is configured to be connected to the negative terminal of the target power supply, and the positive terminal of the target power supply is connected to the ECU pin.

[0025] In an alternative embodiment, the voltage transmission circuit includes a third operational amplifier;

[0026] The non-inverting input end of the third operational amplifier is configured to be connected to the ECU pin, and the output end of the third operational amplifier is respectively connected to the inverting input end of the third operational amplifier and the first input end of the negative feedback circuit.

[0027] According to the second aspect of the embodiments of the present invention, there is provided a device for ECU testing, and the device includes the analog circuit for ECU testing as described in the first aspect above.

[0028] In an alternative embodiment, the device includes a printed circuit board PCB, and the analog circuit for ECU testing is disposed on the PCB.

[0029] The technical solutions provided by the embodiments of the present invention may include the following beneficial effects:

[0030] The analog circuit for ECU testing provided by the embodiment of the present utility model includes a voltage transmission circuit, a voltage division circuit, a voltage regulation circuit, and a negative feedback circuit. Two input ends of the negative feedback circuit are respectively connected to the output ends of the voltage transmission circuit and the voltage regulation circuit, and the output end of the negative feedback circuit is connected to the voltage division circuit. By adjusting the proportion of the voltage signal amount input from the voltage regulation circuit to the negative feedback circuit, the voltage signal of the ECU pin can be changed. When the voltage signal of the ECU pin changes and causes the voltage signals input to the two input ends of the negative feedback circuit to be unequal, the negative feedback circuit can adjust the current value flowing through the voltage division circuit, that is, change the current value flowing through the first resistor, and further change the voltage value across the first resistor, so as to change the voltage signal input to the voltage regulation circuit until the input voltage on the negative feedback circuit reaches a steady state, that is, the voltage signals input to the two input ends of the negative feedback circuit are equal, that is, reach a steady state. In the case of reaching a steady state, the current value flowing through the first resistor value no longer changes. At this time, this current value is equal to the ratio of the voltage signal of the ECU pin to the resistance value of the analog resistor, so as to achieve the effect of simulating injecting a corresponding resistance value into the pin of the ECU to be tested; that is, through the analog circuit provided by the embodiment of the present utility model, only by controlling the proportion of the voltage signal amount transmitted from the voltage regulation circuit to the negative feedback circuit, the effect of simulating injecting different resistance values into the ECU pin can be achieved, and there will be no problem that the resistance value first jumps to a value and then switches to the target value, and thus the test accuracy of the ECU will not be affected, and the switching speed between different parameters is fast, so as to improve the test efficiency; in addition, when implementing the embodiment of the present utility model, a large number of relays are not required for control, and it can be achieved only through these simple circuit structures such as the voltage transmission circuit, the voltage division circuit, the voltage regulation circuit, and the negative feedback circuit. The circuit structure is simple and does not occupy a large space.

[0031] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit the present utility model. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required to be used in the embodiments of the present utility model. It should be understood that for those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is a schematic circuit diagram of the prior art for simulating different resistance values provided by the embodiment of the present utility model;

[0034] Figure 2 It is one of the schematic circuit diagrams of the analog circuit for ECU testing provided by the embodiment of the present utility model;

[0035] Figure 3 This is the second schematic diagram of the circuit structure of the analog circuit for ECU testing provided by the embodiments of the present invention;

[0036] Figure 4 This is the schematic diagram of the circuit structure during the ECU testing provided by the embodiments of the present invention. Detailed implementation manners

[0037] Next, in combination with the accompanying drawings in the embodiments of the present invention, the technical solutions in the embodiments of the present invention will be described.

[0038] The terms used in the following embodiments of the present invention are for the purpose of describing specific embodiments, and are not intended to limit the technical solutions of the present invention. As used in the specification and appended claims of the present invention, the singular forms "a", "an", "the", "above-mentioned", "said", and "this" are also intended to include the plural forms, unless clearly indicated to the contrary in the context.

[0039] It should also be understood that although the terms first, second, etc. may be used in the following embodiments to describe a certain type of object, the object should not be limited to these terms. These terms are used to distinguish specific implementation objects of this type of object.

[0040] First, the embodiments of the present invention provide an analog circuit for ECU testing. This analog circuit is applied to ECU testing. Through this analog circuit, the change of the voltage signal of the ECU pin can be adjusted, that is, the effect of simulating the change of the voltage signal brought by injecting different resistance values into the pin of the ECU to be tested is realized, so as to realize the acquisition of the voltage signal of the ECU pin, and thus the test of the acquisition accuracy of the ECU signal can be carried out. Figure 2 This is the schematic diagram of the circuit structure of the analog circuit for ECU testing provided by the embodiments of the present invention. As Figure 2 shown, this analog circuit includes a voltage transmission circuit 210, a voltage division circuit 220, a voltage regulation circuit 230, and a negative feedback circuit 240;

[0041] Among them, the input end of the voltage transmission circuit 210 is used to connect to the ECU pin, and the output end of the voltage transmission circuit is connected to the first input end of the negative feedback circuit 240, for transmitting the voltage signal of the ECU pin to the first input end of the negative feedback circuit;

[0042] One end of the above-mentioned voltage division circuit 220 is connected to the ECU pin, and the other end is connected to the output end of the negative feedback circuit 240; among them, a first resistor 221 is provided on the voltage division circuit 220;

[0043] The input end of the voltage regulation circuit 230 is connected in parallel across both ends of the first resistor 221. The output end of the voltage regulation circuit 230 is connected to the second input end of the negative feedback circuit 240, and is used to adjust the received voltage signal and control the amount of the voltage signal transmitted to the second input end of the negative feedback circuit.

[0044] The output end of the negative feedback circuit 240 is connected to the voltage division circuit 220, and is used to adjust the current value flowing through the voltage division circuit 220.

[0045] Among them, when using the analog circuit provided by the embodiment of the present invention to test the ECU, the input end of the voltage transmission circuit 210 and one end of the voltage division circuit 220 need to be connected to the ECU pin. Both ends of the ECU measurement circuit are respectively connected to the above-mentioned ECU pin and the common ground end of the analog circuit. Through the ECU measurement circuit, the voltage signal of the ECU pin can be collected, and by using the analog circuit provided by the embodiment of the present invention, different resistance values can be simulated to be injected into the ECU pin, thereby causing changes in the voltage signal of the ECU pin. Furthermore, the ECU measurement circuit can collect different voltage signals, so as to perform the test of the signal acquisition accuracy.

[0046] It should be noted that the above-mentioned ECU measurement circuit is arranged inside the ECU and is part of the ECU.

[0047] In a feasible implementation manner, when using the analog circuit provided by the embodiment of the present invention to test the ECU, the input end of the voltage transmission circuit 210 is connected to the ECU pin, and the output end of the voltage transmission circuit 210 is connected to the first input end of the negative feedback circuit 240. In this way, the input end of the voltage transmission circuit 210 can receive the first voltage signal of the ECU pin and transmit the first voltage signal to the first input end of the negative feedback circuit 240.

[0048] In the embodiment of the present invention, one end of the above-mentioned voltage division circuit 220 is connected to the ECU pin. A first resistor 221 is arranged on the voltage division circuit 220, and the two input ends of the voltage regulation circuit are respectively connected across both ends of the first resistor. In this way, the port current of the ECU pin flows through the voltage division circuit 220, that is, through the first resistor. The second voltage signal across both ends of the first resistor is input to the voltage regulation circuit 230 as the input voltage signal of the voltage regulation circuit 230. After receiving the second voltage signal, the two input ends of the voltage regulation circuit 230 adjust the second voltage signal and control the amount of the third voltage signal transmitted to the second input end of the negative feedback circuit 240.

[0049] Among them, in a feasible implementation manner, the resistance value of the above-mentioned first resistor can be 100 Ω. During specific implementation, the specific resistance value of the above-mentioned first resistor can be selected according to actual needs. This is only an exemplary illustration here and does not limit the embodiments of the present invention.

[0050] Exemplarily, the voltage regulation circuit 230 can amplify the received second voltage signal and control the proportion of the third voltage signal amount transmitted to the second input end of the negative feedback circuit 240, so as to realize the change of the ECU pin voltage signal brought by simulating different resistance values. Among them, the above-mentioned proportion refers to the ratio between the third voltage signal amount and the amplified second voltage signal.

[0051] Specifically, the two input ends of the negative feedback circuit 240 are respectively connected to the output end of the voltage transmission circuit and the output end of the voltage regulation circuit. The output end of the negative feedback circuit 240 is connected to the other end of the voltage dividing circuit 220. It is used to receive the first voltage signal transmitted by the voltage transmission circuit and the third voltage signal transmitted by the voltage regulation circuit. When the signal magnitudes of the first voltage signal and the third voltage signal are not equal, the negative feedback circuit 240 adjusts the current value flowing through the voltage dividing circuit, so that the second voltage signal received at the input end of the voltage regulation circuit 230 changes until the values of the third voltage signal and the first voltage signal received at the two input ends of the negative feedback circuit 240 are equal, that is, the negative feedback circuit 240 reaches a steady state; after the negative feedback circuit 240 reaches a steady state, the current value flowing through the first resistor is equal to the ratio of the first voltage signal to the resistance value of the simulated resistor. Therefore, when reaching a steady state, the change of the ECU pin voltage signal brought by simulating the injection of the simulated resistance value into the ECU pin can be realized.

[0052] The analog circuit for ECU testing provided by the embodiments of the present invention can achieve the effect of simulating the injection of different resistance values into the ECU pins only by controlling the proportion of the voltage signal amount transmitted by the voltage regulation circuit to the negative feedback circuit, and there will be no problem that the resistance value first jumps to a value and then switches to the target value, and thus it will not affect the test accuracy of the ECU. Moreover, the switching speed between different parameters is fast, so the test efficiency can be improved; in addition, when implementing the embodiments of the present invention, a large number of relays are not required for control, and it can be realized only by these simple circuit structures such as the voltage transmission circuit, the voltage dividing circuit, the voltage regulation circuit and the negative feedback circuit. The circuit structure is simple and avoids occupying a large space.

[0053] In a feasible implementation manner, as Figure 3 shown, the above-mentioned voltage regulation circuit 230 includes a differential amplifier circuit 231 and a digital-to-analog converter (Digital-Analog Converter, DAC) 232;

[0054] Among them, the two input terminals of the differential amplifier circuit are respectively connected to both ends of the first resistor 221, and the output terminal of the differential amplifier circuit is connected to the input terminal of the DAC 232, which is used to amplify the second voltage signal and input the amplified fourth voltage signal into the DAC 232;

[0055] The output terminal of the above-mentioned DAC 232 is connected to the second input terminal of the negative feedback circuit 240, and is used to output a fourth voltage signal with a preset ratio as a third voltage signal to the second input terminal of the negative feedback circuit 240.

[0056] Specifically, in the embodiment of the present invention, the function of the above-mentioned differential amplifier circuit 231 is to amplify the second voltage signal received by it; the function of the above-mentioned DAC 232 is to transmit a voltage signal with a preset ratio of the fourth voltage signal received by it to the negative feedback circuit 240.

[0057] Among them, in specific implementation, the specific value of the above-mentioned preset ratio can be adjusted. Exemplarily, it can vary between 0 and 1. By adjusting the value of the above-mentioned preset ratio, the voltage change effect generated by injecting different resistance values into the ECU pin can be simulated.

[0058] In an optional implementation manner, the specific value of the above-mentioned preset ratio can be adjusted by the controller. Therefore, in the embodiment of the present invention, the control terminal of the DAC 232 is also used to be connected to the controller, for receiving the digital control signal input by the controller and converting the digital control signal into an analog control signal to adjust the above-mentioned preset ratio.

[0059] Among them, the above-mentioned controller can be the controller in the ECU test device or the controller of the DAC chip. Exemplarily, the controller can be a Microcontroller Unit (MCU).

[0060] When using the analog circuit provided in the embodiment of the present invention for ECU testing, the control terminal of the DAC 232 can be connected to the controller, and a control signal is input to the DAC 232 through the controller to realize the adjustment of the preset ratio, so as to realize the effect generated by simulating the injection of different resistance values into the ECU pin.

[0061] In addition, it should be noted that the fourth voltage signal input to the DAC 232 can be used as the reference voltage of the DAC.

[0062] In an optional implementation manner, as Figure 3As shown, the above differential amplifier circuit 231 includes a first operational amplifier 2311, a second resistor 2312, a third resistor 2313, a fourth resistor 2314, and a fifth resistor 2315;

[0063] Among them, the non-inverting input terminal of the first operational amplifier 2311 is connected to the first end of the first resistor 221 through the second resistor 2312 and the third resistor 2313, and the inverting input terminal of the first operational amplifier 2311 is connected to the second end of the first resistor 221 through the fourth resistor 2314 and the fifth resistor 2315;

[0064] Specifically, one end of the third resistor 2313 is connected to the first end of the first resistor 221, the other end of the third resistor 2313 is respectively connected to the non-inverting input terminal and one end of the second resistor 2312, and the other end of the second resistor 2312 is grounded;

[0065] One end of the fifth resistor 2315 is connected to the first end of the first resistor 221, the other end of the fifth resistor 2315 is respectively connected to the inverting input terminal and one end of the fourth resistor 2314, and the other end of the fourth resistor 2314 is connected to the output terminal of the first operational amplifier 2311;

[0066] The first end of the first resistor 221 is the end of the voltage dividing circuit 220 close to the ECU pin, and the second end of the first resistor 221 is the end of the voltage dividing circuit 220 close to the output terminal of the negative feedback circuit 240.

[0067] The output terminal of the first operational amplifier 2311 is connected to the input terminal of the DAC 232.

[0068] Among them, in the embodiment of the present invention, by adjusting the resistance values of the fourth resistor and the fifth resistor, different multiples of amplification processing can be performed on the second voltage signal input to the first operational amplifier 2311, and the amplification multiple of the differential amplifier circuit can be the ratio between the fourth resistance value and the fifth resistance value.

[0069] In addition, in the embodiment of the present invention, the setting of the second resistor and the third resistor helps to stabilize the static operating point of the differential amplifier circuit; by setting the fourth resistor and the fifth resistor, in addition to being used to achieve voltage signal amplification, common-mode signals can also be suppressed.

[0070] In specific implementation, in order to ensure the impedance balance of the two input terminals of the first operational amplifier, the resistance values of the resistors at the two input terminals of the first operational amplifier can be equal; and when the resistance values of the resistors at the two input terminals of the first operational amplifier are the same, the circuit can be made more symmetrical, thereby improving the common-mode rejection ratio.

[0071] Therefore, in a feasible implementation, the resistance value of the second resistor 2312 is equal to that of the fourth resistor 2314, the resistance value of the third resistor 2313 is equal to that of the fifth resistor 2315, and the resistance value of the fourth resistor 2314 is greater than that of the fifth resistor 2315.

[0072] Specifically, the resistance values of the fourth resistor 2314 and the fifth resistor 2315 can be set according to the amplification factor that the differential amplifier circuit needs to achieve.

[0073] Exemplarily, in a feasible implementation, the resistance values of the second resistor 2312 and the fourth resistor 2314 can be 1 megohm, and the resistance values of the third resistor 2313 and the fifth resistor 2315 can be 10 K ohms. Of course, only a possible specific resistance value of the second resistor 2312, the third resistor 2313, the fourth resistor 2314, and the fifth resistor 2315 is listed here by way of example. In specific implementation, the resistance values of the second resistor 2312, the third resistor 2313, the fourth resistor 2314, and the fifth resistor 2315 can also be set to other values according to actual requirements.

[0074] In a feasible implementation, as Figure 3 shown, the above negative feedback circuit 240 includes a second operational amplifier 241 and a triode 242;

[0075] Among them, the inverting input terminal of the second operational amplifier 241 is connected to the output terminal of the voltage regulation circuit 230, and the non-inverting input terminal of the second operational amplifier 241 is connected to the output terminal of the voltage transmission circuit 210;

[0076] The base of the triode 242 is connected to the output terminal of the second operational amplifier 241, and the collector of the triode is connected to the voltage dividing circuit 220.

[0077] Among them, the current output by the second operational amplifier 241 can be used to control the current between the collector and the emitter of the triode, that is, the current value flowing through the voltage dividing circuit 220.

[0078] Specifically, the inverting input terminal of the second operational amplifier 241 is connected to the output terminal of the DAC. In addition, in the embodiment of the present invention, in addition to being connected to the first operational amplifier and the second operational amplifier, the output terminal of the DAC 232 is also grounded.

[0079] In a feasible implementation, the above voltage transmission circuit 210 includes a third operational amplifier;

[0080] Among them, the non-inverting input terminal of the third operational amplifier is used to be connected to the ECU pin, and the output terminal of the third operational amplifier is respectively connected to the inverting input terminal of the third operational amplifier and the first input terminal of the negative feedback circuit 240.

[0081] Specifically, in the embodiment of the present invention, in the analog circuit for ECU testing, the above-mentioned third operational amplifier is used as a follower, and its output voltage is the same as the input voltage. Therefore, the above-mentioned third operational amplifier is used to transmit the first voltage signal of the ECU pin received to the first input end of the negative feedback circuit 240. In addition, due to the characteristics of the high input resistance and low output resistance of the third operational amplifier, the effective isolation of the front and rear stage circuits can also be achieved by setting the third operational amplifier in this analog circuit.

[0082] Based on the above description, in the embodiment of the present invention, the non-inverting input end of the second operational amplifier is connected to the input end of the third operational amplifier, and is used to receive the first voltage signal output by the third operational amplifier. The inverting input end of the second operational amplifier is connected to the output end of the DAC, and is used to receive the third voltage signal output by the DAC.

[0083] In specific implementation, the third operational amplifier plays a role of negative feedback regulation in the entire analog circuit, and the output signal is returned to the input end to achieve the purpose of changing the input. Exemplarily, when the voltage signal input to the non-inverting input end of the third operational amplifier becomes larger, the output voltage of the second operational amplifier becomes larger, so that the conduction current of the triode becomes larger, and then the current flowing through the first resistor becomes larger, and the second voltage signal between the non-inverting input end and the inverting input end of the first operational amplifier becomes larger, and the fourth voltage signal flowing into the DAC by the first operational amplifier becomes larger, and the third voltage signal divided by the DAC from the fourth voltage signal according to the preset ratio becomes larger until the third voltage signal is equal to the first voltage signal, that is, it reaches a steady state.

[0084] When the voltage signal input to the non-inverting input end of the third operational amplifier becomes smaller, the output voltage of the second operational amplifier becomes smaller, so that the conduction current of the triode becomes smaller, and then the current flowing through the first resistor becomes smaller, and the second voltage signal between the non-inverting input end and the inverting input end of the first operational amplifier becomes smaller, and the fourth voltage signal flowing into the DAC by the first operational amplifier becomes smaller, and the third voltage signal divided by the DAC from the fourth voltage signal according to the preset ratio becomes smaller until the third voltage signal is equal to the first voltage signal, that is, it reaches a steady state.

[0085] Among them, the above-mentioned first voltage signal is the voltage signal of the ECU pin. In an optional implementation manner, this voltage signal is denoted as U0, the current flowing through the first resistor is denoted as I, and the resistor simulated by this analog circuit is denoted as Rx. When the negative feedback circuit reaches a steady state, I = U0 / Rx, that is, the purpose of negative feedback regulation by the third operational amplifier is to achieve I = U0 / Rx, that is, the current I can change proportionally with the value of U0, which is the same as the characteristic of the resistor, so as to achieve the purpose of simulating the resistor.

[0086] In a specific implementation, when the negative feedback circuit reaches a steady state, the magnitude of the first voltage signal input to the non-inverting input terminal of the third operational amplifier circuit is equal to the magnitude of the third voltage signal input to the inverting input terminal. Among them, the first voltage signal is U0, and the third voltage signal is: D*K*(I*R1); where D is the preset ratio preset by the DAC, K is the amplification factor of the first operational amplifier, I is the current value flowing through the first resistor, and R1 is the resistance value of the first resistor.

[0087] Therefore, UO = D*K*(I*R1).

[0088] Considering that when the negative feedback circuit reaches a steady state, I = U0 / Rx, so I*Rx = D*K*(I*R1), that is, Rx = D*K*R1.

[0089] In the embodiment of the present invention, K is a fixed value and R1 is a fixed value. Therefore, by adjusting the value of D, the change of the simulated resistance value Rx can be realized, that is, by adjusting the value of D, different resistance values can be simulated.

[0090] Exemplarily, in one embodiment, when the value of K is 100 and the value of R1 is 100 ohms, and the value of D is 0.2 - 1, the range of the simulated resistance Rx is 2KΩ - 10KΩ.

[0091] Therefore, in the embodiment of the present invention, by adjusting the value of D of the DAC and adjusting the voltage signals at the two input terminals of the third operational amplifier circuit to be equal through the negative feedback circuit, that is, reaching a steady state, in this case, the current flowing through the voltage dividing circuit no longer changes, and this current value is equal to the ratio of the current first voltage signal of the ECU pin to the simulated resistance value, thereby realizing the effect of simulating the voltage signal change brought by injecting this resistance value into the ECU pin.

[0092] In an alternative implementation, the emitter of the triode is used to connect to the negative terminal of the target power supply, and the positive terminal of the target power supply is connected to the ECU pin. During testing, by connecting the emitter of the triode to the negative terminal of the target power supply, the change of the first voltage signal of the ECU pin can be realized, and even the first voltage signal of the ECU pin can be changed to 0.

[0093] Among them, the above-mentioned target power supply can be any power supply. For example, it can be a power supply specifically set for this simulation circuit, or it can be the existing power supply on the ECU test device. The embodiment of the present invention does not limit the specific source of this target power supply, as long as the negative terminal of the target power supply can be connected to the emitter of the triode.

[0094] To facilitate understanding of the analog circuit for ECU testing provided by the embodiments of the present invention, the following will be described in conjunction with specific test scenarios.

[0095] Exemplarily, when using the analog circuit for ECU testing provided by the embodiments of the present invention to perform ECU testing, the analog circuit needs to be connected to the ECU measurement circuit. As Figure 4 shown, one end of the ECU measurement circuit is connected to the ECU pin, and the other end of the ECU measurement circuit is connected to the common ground terminal of the analog circuit. Specifically, the ECU measurement circuit includes resistor 21, resistor 22, and an MCU. The input port (Analog-to-Digital Converter Input, ADC-In) of the analog-to-digital converter of the MCU is connected to one end of resistor 22. The other end of resistor 22 is connected to one end of resistor 21 and the ECU pin. The other end of resistor 21 is connected to a power supply (such as a 5v power supply); another interface of the MCU is connected to the common ground terminal of the analog circuit.

[0096] Of course, Figure 4 only one possible circuit structure of the ECU measurement circuit is exemplarily listed. In specific implementation, other structures can also be adopted. The embodiments of the present invention do not limit the specific circuit structure of the ECU measurement circuit.

[0097] The analog circuit for ECU testing provided by the embodiments of the present invention has at least the following technical effects:

[0098] 1). By controlling only the ratio of the voltage signal amount transmitted by the voltage regulation circuit to the negative feedback circuit, the effect of injecting different resistance values into the ECU pin can be achieved. There will be no problem that the resistance value first jumps to one value and then switches to the target value, thus not affecting the test accuracy of the ECU. Moreover, the switching speed between different parameters is fast, thereby improving the test efficiency.

[0099] 2). It can be achieved only through simple circuit structures such as the voltage transmission circuit, voltage division circuit, voltage regulation circuit, and negative feedback circuit. The circuit structure is simple and does not occupy a large space.

[0100] 3). The power consumption of each component in the analog circuit is small. Therefore, the power consumption of the entire analog circuit is small.

[0101] 4). The resolution of the DAC is high. Therefore, the resolution of the resistance values simulated by the embodiments of the present invention is relatively high.

[0102] Corresponding to Figure 2 and Figure 3The simulation circuit for ECU testing provided by the illustrated embodiment, based on the same concept, the embodiment of the present utility model further provides a device for ECU testing, which device includes Figure 2 and Figure 3 the simulation circuit for ECU testing provided by the illustrated embodiment.

[0103] In a feasible implementation manner, the above device for ECU testing may further include a Printed Circuit Board (PCB) board, and the above simulation circuit for ECU testing is disposed on the PCB board.

[0104] In a feasible implementation manner, the above device for ECU testing may also include at least one of a power supply, a communication device, an MCU, etc. Of course, in a feasible implementation manner, the above device for ECU testing may further include a housing.

[0105] The device for ECU testing provided by the embodiment of the present utility model and the simulation circuit for ECU testing provided by the embodiment of the present utility model are based on the same concept. For the functions and specific implementation manners of each component in the device for ECU testing provided by the embodiment of the present utility model, reference may be made to the foregoing embodiment of the simulation circuit for ECU testing, and details are not described herein again.

[0106] The above is only a preferred specific implementation manner of the present utility model, but the protection scope of the present utility model is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present utility model should be covered within the protection scope of the present utility model. Therefore, the protection scope of the present utility model shall be subject to the protection scope of the claimed rights.

Claims

1. An analog circuit for ECU testing, characterized in that, The analog circuit includes: a voltage transmission circuit, a voltage division circuit, a voltage regulation circuit, and a negative feedback circuit; The input end of the voltage transmission circuit is used to connect to the ECU pin, and the output end of the voltage transmission circuit is connected to the first input end of the negative feedback circuit, for transmitting the first voltage signal of the ECU pin to the first input end of the negative feedback circuit; One end of the voltage division circuit is connected to the ECU pin, and the other end is connected to the output end of the negative feedback circuit; wherein, a first resistor is arranged on the voltage division circuit; The two input ends of the voltage regulation circuit are respectively connected to both ends of the first resistor, and the output end of the voltage regulation circuit is connected to the second input end of the negative feedback circuit, for adjusting the received second voltage signal and controlling the third voltage signal transmitted to the second input end of the negative feedback circuit; The output end of the negative feedback circuit is connected to the voltage division circuit, for adjusting the current value flowing through the voltage division circuit.

2. The analog circuit according to claim 1, wherein The voltage regulation circuit includes a differential amplifier circuit and a digital-to-analog converter DAC; The two input ends of the differential amplifier circuit are respectively connected to both ends of the first resistor, and the output end of the differential amplifier circuit is connected to the input end of the DAC, for amplifying the second voltage signal and inputting the amplified fourth voltage signal into the DAC; The output end of the DAC is connected to the second input end of the negative feedback circuit, for outputting a preset proportion of the fourth voltage signal as the third voltage signal to the second input end of the negative feedback circuit.

3. The analog circuit according to claim 2, wherein The differential amplifier circuit includes a first operational amplifier, a second resistor, a third resistor, a fourth resistor, and a fifth resistor; The non-inverting input end of the first operational amplifier is connected to the first end of the first resistor through the second resistor and the third resistor, and the inverting input end of the first operational amplifier is connected to the second end of the first resistor through the fourth resistor and the fifth resistor; One end of the third resistor is connected to the first end of the first resistor, the other end of the third resistor is respectively connected to the non-inverting input end and one end of the second resistor, and the other end of the second resistor is grounded; One end of the fifth resistor is connected to the first end of the first resistor, the other end of the fifth resistor is respectively connected to the inverting input end and one end of the fourth resistor, and the other end of the fourth resistor is connected to the output end of the first operational amplifier; Wherein, the first end of the first resistor is the end of the voltage division circuit close to the ECU pin, and the second end of the first resistor is the end of the voltage division circuit close to the output end of the negative feedback circuit.

4. The analog circuit according to claim 3, characterized in that, The resistance value of the second resistor is equal to the resistance value of the fourth resistor, the resistance value of the third resistor is equal to the resistance value of the fifth resistor, and the resistance value of the second resistor is greater than the resistance value of the third resistor.

5. The analog circuit according to any one of claims 2-4, characterized in that, The control end of the DAC is also used to connect to the controller, for receiving the digital control signal input by the controller and converting the digital control signal into an analog control signal to adjust the preset proportion.

6. The analog circuit according to any one of claims 1-4, characterized in that, The negative feedback circuit includes a second operational amplifier and a triode; The inverting input terminal of the second operational amplifier is connected to the output terminal of the voltage regulation circuit, and the non-inverting input terminal of the second operational amplifier is connected to the output terminal of the voltage transmission circuit; The base of the triode is connected to the output terminal of the second operational amplifier, and the collector of the triode is connected to the voltage dividing circuit.

7. The analog circuit according to claim 6, characterized in that, The emitter of the triode is used to be connected to the negative terminal of the target power supply, and the positive terminal of the target power supply is connected to the ECU pin.

8. The analog circuit according to any one of claims 1-4, characterized in that, The voltage transmission circuit includes a third operational amplifier; The non-inverting input terminal of the third operational amplifier is used to be connected to the ECU pin, and the output terminal of the third operational amplifier is respectively connected to the inverting input terminal of the third operational amplifier and the first input terminal of the negative feedback circuit.

9. A device for ECU testing, characterized in that, It includes the analog circuit for ECU testing according to any one of claims 1-8.

10. The device according to claim 9, characterized in that, The device includes a printed circuit board (PCB), and the analog circuit for ECU testing is disposed on the PCB.

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