Load excitation device and testing machine

Abstract

The utility model relates to a load excitation device and a testing machine, the load excitation device comprises an operational amplifier module, a power tube, an acquisition module and a control module, the operational amplifier module is connected with the control end and the output end of the power tube, the input end of the power tube is connected with external voltage, the output end of the power tube is connected with the acquisition module and a load, and the acquisition module is connected with the control module. The control module is an operational amplifier module; the control module receives an acquisition signal output by the acquisition module and outputs a corresponding analog signal to the operational amplifier module, and the operational amplifier module performs negative feedback regulation on the power tube based on the analog signal, so that the voltage output to the load is constant, stable output of different loads can be met, the output response is rapid, and the output stability is improved.

Description

Technical Field

[0001] This application relates to the field of semiconductor testing technology, and in particular to a load excitation device and a testing machine. Background Technology

[0002] With the development of the new energy industry, the demand for high-current testing of power semiconductors is expanding. Voltage and current (VI) sources, as an indispensable part of Automatic Test Equipment (ATE) for integrated circuits, are used to provide test excitation to the device under test (DUT). The excitation source needs to provide stable and accurate voltage and current waveforms to meet the performance requirements of the tested products. Traditional load excitation methods involve acquiring the load voltage and using PWM modulation to turn the MOSFET on and off. This approach cannot meet the requirement of rapid output response under different loads within a certain timeframe, resulting in low output stability. Utility Model Content

[0003] Therefore, it is necessary to provide a load excitation device and test machine that can improve output stability in order to address the above problems.

[0004] A first aspect of this application provides a load excitation device, including an operational amplifier module, a power transistor, a data acquisition module, and a control module. The operational amplifier module is connected to the control terminal and the output terminal of the power transistor. The input terminal of the power transistor is connected to an external voltage. The output terminal of the power transistor is connected to the data acquisition module and a load. The data acquisition module is connected to the control module, and the control module is connected to the operational amplifier module. The control module receives the acquisition signal output by the data acquisition module and outputs a corresponding analog signal to the operational amplifier module. The operational amplifier module performs negative feedback regulation on the power transistor based on the analog signal to keep the voltage output to the load constant.

[0005] In one embodiment, the control module includes a controller and a digital-to-analog converter (DAC), the controller being connected to the acquisition module and the DAC, and the DAC being connected to the operational amplifier module.

[0006] In one embodiment, the operational amplifier module includes an operational amplifier, a negative feedback loop, and an operational amplifier attenuation feedback loop. The negative feedback loop is connected to the output terminals of the digital-to-analog converter and the power transistor. The inverting input terminal of the operational amplifier is connected to the negative feedback loop. The output terminal of the operational amplifier is connected to the operational amplifier attenuation feedback loop. The operational amplifier attenuation feedback loop is connected to the control terminal and the output terminal of the power transistor.

[0007] In one embodiment, the negative feedback loop includes resistors R7 and R8. The first end of resistor R7 is connected to the digital-to-analog converter, the second end of resistor R7 is connected to the first end of resistor R8 and the inverting input of the operational amplifier, and the second end of resistor R8 is connected to the output of the power transistor.

[0008] In one embodiment, the operational amplifier attenuation feedback loop includes a DC oscillation component loop and an AC oscillation component loop. The DC oscillation component loop is connected to the output terminal of the operational amplifier and the control terminal of the power transistor, and the AC oscillation component loop is connected to the output terminal of the operational amplifier and the output terminal of the power transistor.

[0009] In one embodiment, the DC oscillation component circuit includes a resistor R10, and the AC oscillation component circuit includes a resistor R3 and a capacitor C1. The first end of the resistor R10 is connected to the output terminal of the operational amplifier, and the second end of the resistor R10 is connected to the control terminal of the power transistor. The first end of the capacitor C1 is connected to the output terminal of the operational amplifier, and the second end of the capacitor C1 is connected to the first end of the resistor R3. The second end of the resistor R3 is connected to the output terminal of the power transistor.

[0010] In one embodiment, the operational amplifier module further includes a capacitor C2, the first end of which is connected to the inverting input terminal of the operational amplifier, and the second end of which is connected to the output terminal of the operational amplifier.

[0011] In one embodiment, the voltage connected to the power supply terminal of the operational amplifier is greater than or equal to the external voltage connected to the input terminal of the power transistor.

[0012] In one embodiment, the acquisition module is a voltage / current acquisition module.

[0013] In one embodiment, the power transistor is a MOSFET.

[0014] In one embodiment, the controller is an FPGA, MCU, or CPU.

[0015] A second aspect of this application provides a test machine including the aforementioned load excitation device.

[0016] The aforementioned load excitation device and tester have a control module that receives the acquisition signal from the acquisition module and outputs a corresponding analog signal to the operational amplifier module. The operational amplifier module performs negative feedback adjustment on the power transistor based on the analog signal to keep the voltage output to the load constant, which can meet the stable output of different loads and has a rapid output response, thus improving output stability. Attached Figure Description

[0017] Figure 1 This is a structural block diagram of the load excitation device in one embodiment;

[0018] Figure 2 This is a schematic diagram of the load excitation device in one embodiment. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0021] It is understood that the term "connection" in the following embodiments should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have electrical signal or data transmission with each other.

[0022] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, operations, components, parts, or combinations thereof.

[0023] In one embodiment, such as Figure 1 As shown, a load excitation device is provided, including an operational amplifier module 110, a power transistor 120, a data acquisition module 130, and a control module 140. The operational amplifier module 110 is connected to the control terminal and the output terminal of the power transistor 120. The input terminal of the power transistor 120 is connected to an external voltage, and the output terminal of the power transistor 120 is connected to the data acquisition module 130 and the load. The data acquisition module 130 is connected to the control module 140, and the control module 140 is connected to the operational amplifier module 110. The control module 140 receives the acquisition signal output by the data acquisition module 130 and outputs a corresponding analog signal to the operational amplifier module 110. The operational amplifier module 110 performs negative feedback regulation on the power transistor 120 based on the analog signal to keep the voltage output to the load constant.

[0024] The load can be resistive, capacitive, or other types of loads, such as semiconductor chips and other devices that need to be tested. Figure 2As shown, the control module 140 specifically includes a controller 142 and a digital-to-analog converter (DAC). The controller 142 is connected to the acquisition module 130 and the DAC. The DAC is connected to the operational amplifier module 110. The controller 142 receives the acquisition signal output by the acquisition module 130 and controls the DAC to output the corresponding analog signal to the operational amplifier module 110. The controller 142 can be an FPGA, MCU, or CPU, etc. It is understood that in other embodiments, the control module 140 can also use analog circuits, as long as it can output analog signals.

[0025] Depending on the actual testing requirements, the acquisition module 130 can be a voltage / current acquisition module to acquire the voltage / current supplied to the load. The controller 142 compares the acquired signal output by the acquisition module 130 with the set output value, accumulates it through an internal algorithm, and controls the digital-to-analog converter (DAC) to output an analog signal of rated amplitude to the operational amplifier module 110 based on the calculation result, so that the voltage output to the load is constant, achieving constant voltage output from the load. Here, constant voltage means that the error between the actual voltage output to the load and the set output value is within the allowable range.

[0026] In one embodiment, such as Figure 2 As shown, the operational amplifier module 110 includes an operational amplifier U1, a negative feedback loop 112, and an operational amplifier attenuation feedback loop 114. The negative feedback loop 112 is connected to the digital-to-analog converter (DAC) and the output of the power transistor 120. The inverting input of the operational amplifier U1 is connected to the negative feedback loop 112, and the output of the operational amplifier U1 is connected to the operational amplifier attenuation feedback loop 114. The operational amplifier attenuation feedback loop 114 is connected to the control terminal and the output terminal of the power transistor 120. R6 is the load, and the power transistor 120 can be a MOSFET or other controlled switching transistor. In this embodiment, the power transistor 120 is a MOSFET Q1. The voltage V+ connected to the power supply terminal of the operational amplifier U1 is greater than or equal to the external voltage V connected to the input terminal of the power transistor 120. Taking the MOSFET Q1 as an example of sampling an NMOS transistor, the gate is used as the control terminal, the drain as the input terminal, and the source as the output terminal. Since the gate-source voltage V of the MOSFET Q1 needs to be driven... GS The circuit is conducting under positive voltage, therefore the voltage V at point A of the output terminal of operational amplifier U1 is... A It must be greater than the voltage V at the source B point of MOSFET Q1. B Therefore, the supply voltage V+ of operational amplifier U1 must be greater than or equal to the supply voltage V of MOSFET Q1.

[0027] In addition, the operational amplifier module 110 may also include capacitor C2, specifically an inner-loop hysteresis capacitor used for loop compensation. The first terminal of capacitor C2 is connected to the inverting input of operational amplifier U1, and the second terminal of capacitor C2 is connected to the output of operational amplifier U1. The function of capacitor C2 is to reduce the overall link bandwidth, filter out high-frequency spurious interference, and improve loop stability. The capacitance value of capacitor C2 can be selected according to actual needs; for example, a smaller capacitance value can be selected to avoid the capacitance value being too large and affecting the output signal settling time.

[0028] Specifically, the negative feedback loop 112 includes resistors R7 and R8. The first end of resistor R7 is connected to the digital-to-analog converter (DAC), the second end of resistor R7 is connected to the first end of resistor R8 and the inverting input of operational amplifier U1, and the second end of resistor R8 is connected to the output of power transistor 120.

[0029] Furthermore, the operational amplifier attenuation feedback loop 114 includes a DC oscillation component loop 1142 and an AC oscillation component loop 1144. The DC oscillation component loop 1142 is connected to the output terminal of the operational amplifier U1 and the control terminal of the power transistor 120, and the AC oscillation component loop 1144 is also connected to the output terminal of the operational amplifier U1 and the output terminal of the power transistor 120. The DC oscillation component loop 1142 includes a resistor R10, and the AC oscillation component loop 1144 includes a resistor R3 and a capacitor C1. The first end of the resistor R10 is connected to the output terminal of the operational amplifier U1, and the second end of the resistor R10 is connected to the control terminal of the power transistor 120. The first end of the capacitor C1 is connected to the output terminal of the operational amplifier U1, and the second end of the capacitor C1 is connected to the first end of the resistor R3. The second end of the resistor R3 is connected to the output terminal of the power transistor 120. The operational amplifier attenuation feedback loop 114, composed of resistor R3, resistor R10, and capacitor C1, is used to form the corresponding operational amplifier attenuation feedback component, thereby controlling the operational amplifier adjustment speed.

[0030] Reference Figure 2 If the op-amp module 110 does not have an op-amp attenuation feedback loop 114, and the output of operational amplifier U1 is directly connected to the gate of MOSFET Q1, when point B oscillates violently and the oscillation frequency falls within the frequency band controlled by capacitor C2, the voltage at point B will be fed back to the inverting input C of operational amplifier U1 through resistor R8, causing the output at point A to change drastically with the oscillation amplitude. When the output at point A suddenly becomes too low, the voltage V across MOSFET Q1 will decrease. AB The voltage decreases instantaneously, causing the impedance of MOSFET Q1 to increase excessively, which in turn causes the output at point B to decrease instantaneously. At this time, the voltage fed back to point C is too small, causing the output at point A to increase again. This results in the output oscillating continuously, with the waveform always containing a high-frequency AC component with a certain amplitude on top of the DC voltage.

[0031] Based on this, by setting an op-amp attenuation feedback loop 114 in the op-amp module 110, when the output at point B oscillates, capacitor C1, resistor R3, and op-amp output impedance Z0 form the path for the AC (oscillation) component, while resistor R10 and op-amp output impedance Z0 form the path for the DC component. Therefore, the output at point A is the sum of the AC and DC components at point B, and we assume its voltage is V0. Since a certain amount of AC component already exists at point A, when point B oscillates violently, the operational amplifier U1 adjusts the output at point A based on the voltage at point B, resulting in only a small change in the voltage V0 at point A. This adjusts the MOSFET Q1 until the voltage at point B stabilizes, making the DC component at point A greater than the AC component, or in other words, the oscillation at point B does not significantly affect the DC component at point A.

[0032] C2 is the internal hysteresis capacitor of the loop. From an analog perspective, it can be regarded as an RC filter. From a control perspective, it can be regarded as adding a dominant pole, improving the overall phase margin of the loop and enhancing stability. The selection of this capacitor is generally related to the design link bandwidth.

[0033] In one embodiment, a test machine is also provided, including the load excitation device described above.

[0034] The aforementioned load excitation device and tester, controlled by a negative feedback loop, ensure stable and reliable operation and are adaptable to loads with varying resistance values. Through the design of the feedback loop and operational amplifier AC feedback link, stable output can be achieved for different product testing specifications, with short rise times, rapid system response, and strong robustness.

[0035] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0036] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A load excitation device, characterized in that, The system includes an operational amplifier module, a power transistor, a data acquisition module, and a control module. The operational amplifier module is connected to the control terminal and the output terminal of the power transistor. The input terminal of the power transistor is connected to an external voltage. The output terminal of the power transistor is connected to the data acquisition module and a load. The data acquisition module is connected to the control module, and the control module is connected to the operational amplifier module. The control module receives the acquisition signal output by the data acquisition module and outputs a corresponding analog signal to the operational amplifier module. The operational amplifier module performs negative feedback regulation on the power transistor based on the analog signal to keep the voltage output to the load constant.

2. The apparatus according to claim 1, characterized in that, The control module includes a controller and a digital-to-analog converter. The controller is connected to the acquisition module and the digital-to-analog converter, and the digital-to-analog converter is connected to the operational amplifier module.

3. The apparatus according to claim 2, characterized in that, The operational amplifier module includes an operational amplifier, a negative feedback loop, and an operational amplifier attenuation feedback loop. The negative feedback loop is connected to the output terminals of the digital-to-analog converter and the power transistor. The inverting input terminal of the operational amplifier is connected to the negative feedback loop. The output terminal of the operational amplifier is connected to the operational amplifier attenuation feedback loop. The operational amplifier attenuation feedback loop is connected to the control terminal and the output terminal of the power transistor.

4. The apparatus according to claim 3, characterized in that, The negative feedback loop includes resistors R7 and R8. The first end of resistor R7 is connected to the digital-to-analog converter, the second end of resistor R7 is connected to the first end of resistor R8 and the inverting input of the operational amplifier, and the second end of resistor R8 is connected to the output of the power transistor.

5. The apparatus according to claim 3, characterized in that, The operational amplifier attenuation feedback loop includes a DC oscillation component loop and an AC oscillation component loop. The DC oscillation component loop is connected to the output terminal of the operational amplifier and the control terminal of the power transistor, and the AC oscillation component loop is connected to the output terminal of the operational amplifier and the output terminal of the power transistor.

6. The apparatus according to claim 5, characterized in that, The DC oscillation component circuit includes a resistor R10, and the AC oscillation component circuit includes a resistor R3 and a capacitor C1. The first end of the resistor R10 is connected to the output terminal of the operational amplifier, and the second end of the resistor R10 is connected to the control terminal of the power transistor. The first end of the capacitor C1 is connected to the output terminal of the operational amplifier, and the second end of the capacitor C1 is connected to the first end of the resistor R3. The second end of the resistor R3 is connected to the output terminal of the power transistor.

7. The apparatus according to claim 3, characterized in that, The operational amplifier module also includes a capacitor C2, the first end of which is connected to the inverting input terminal of the operational amplifier, and the second end of which is connected to the output terminal of the operational amplifier.

8. The apparatus according to claim 3, characterized in that, The voltage connected to the power supply terminal of the operational amplifier is greater than or equal to the external voltage connected to the input terminal of the power transistor.

9. The apparatus according to any one of claims 1-8, characterized in that, The acquisition module is a voltage / current acquisition module.

10. A testing machine, characterized in that, Includes the load excitation device according to any one of claims 1-9.

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