Program-controlled capacitor device for automatic matching

Abstract

The utility model relates to the field of capacitor automatic control, in particular to a program-controlled capacitor device for automatic matching, which comprises a capacitor bank and a change-over switch module which are cascaded and connected to a program-controlled amplification and efficacy circuit through conductive wires. The program-controlled amplification and efficacy circuit controls the capacitor bank and the change-over switch module to combine a standard capacitor through the MCU main control circuit, so that the standard capacitor outputs a set capacitance value; the capacitor bank and change-over switch module comprises a capacitor array switch and a capacitor bank electrically connected with the capacitor array switch through a corresponding pointer; the capacitor bank is electrically connected with the program control amplification and efficacy circuit through the capacitor array switch, capacitor program control is achieved through the circuit, the efficiency and stability of capacitor matching are improved, the operation cost and the error rate are reduced, and meanwhile high-precision and high-stability capacitance values are provided.

Description

Technical Field

[0001] This utility model relates to the field of automatic capacitor control, specifically a programmable capacitor device for automatic matching. Background Technology

[0002] A high-precision LCR measuring instrument with a wide bandwidth is used for impedance measurement and testing or debugging. A voltage is applied across the impedance terminals, and an operational amplifier circuit is used to transform and control the input or output current, forming an active equivalent impedance. An impedance transformation circuit is then used to create a simulated inductor / capacitor to simulate a passive large capacitor, facilitating integration. For example, an active simulated capacitor device disclosed in patent application number 201020689996.9 has advantages in practical applications, including a wide measurement range, wide operating bandwidth, small size, simple operation, and portability.

[0003] With the use of programmable test power supplies, while portability is important, matching issues must also be considered. Currently, the matching process mainly relies on the use of power connectors. In low-frequency testing, the connecting cable is inserted into the housing through the connector, which is simple, quick and effective. However, in high-frequency testing, the connection stability between the connecting cable and the connector is easily affected, and operators are prone to operational errors, thereby reducing testing efficiency and resulting in poor flexibility, low efficiency and high cost.

[0004] In view of this, the present invention provides a programmable capacitor device for automatic matching. Utility Model Content

[0005] The purpose of this invention is to provide a programmable capacitor device for automatic matching, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a programmable capacitor device for automatic matching, comprising: cascaded capacitor banks and a switching module, wherein the capacitor banks and the switching module are electrically connected to a programmable amplifier and power circuit via wires, and the programmable amplifier and power circuit controls the capacitor banks and the switching module to combine standard capacitors through an MCU main control circuit to output a set capacitance value; through the programmable amplifier and power circuit and the MCU main control circuit, standard capacitors can be automatically combined, reducing manual operation and improving testing efficiency;

[0007] The capacitor bank and switching module includes a capacitor array switch and capacitor banks electrically connected to the capacitor array switch via corresponding pointers; each capacitor bank is electrically connected to the programmable amplifier and power circuit via the capacitor array switch, and the required capacitance value is matched by automatically controlling the combination of capacitors, thereby improving the degree of automation in matching.

[0008] As a preferred embodiment of this utility model, the capacitor bank includes a capacitor assembly box and a connection slot disposed inside the capacitor assembly box. Each connection slot is connected to a capacitor, which reduces manual operation and can reduce problems caused by operator error.

[0009] As a preferred embodiment of this utility model, the capacitor array switch includes a switch assembly box, and capacitor terminals are provided on both sides of the switch assembly box. The capacitor terminals are connected to the corresponding capacitors in the capacitor group through connection slots.

[0010] As a preferred embodiment of this utility model, the capacitor array switch is provided with a cascaded male terminal and a cascaded female terminal at its upper and lower ends, respectively. The cascaded female terminal is connected to the cascaded male terminal of the external capacitor array switch. The cascaded male terminal corresponding to the bottom capacitor array switch is embedded in the external port. The programmable amplifier and power circuit are connected based on the external port. The frequent plugging and unplugging of the physical connection is avoided by the programmable method, thereby improving the stability of the connection. Especially in high-frequency testing, the traditional connection method is prone to connection stability problems between the connection cable and the connector.

[0011] As a preferred embodiment of this invention, the programmable amplifier and power circuit includes a connection pin for an analog capacitor, a preamplifier connected to the connection pin, a DAC conversion circuit, a power amplifier, and a pair of proportional resistors. The connection pin includes a high-side input pin and a low-side input pin. The input terminal of the preamplifier is connected to a standard capacitor bank and the high-side input pin. The output terminal of the preamplifier is connected to the DAC conversion circuit and the proportional resistors. The output terminal of the DAC conversion circuit is connected to the input terminal of the power amplifier, and the output terminal of the power amplifier is connected to the standard capacitor bank. The output terminal of the proportional resistor is connected to the low-side input pin to simulate a capacitor. Through an impedance transformation circuit, an analog inductor / capacitor is formed, used to simulate a passive large capacitor. It has a wide range of values ​​and operating frequency band, and is suitable for various testing environments.

[0012] As a preferred technical solution of this utility model, the human-machine display component accepts capacitor programmable commands, and the human-machine display component accepts capacitor programmable commands in the form of a display screen, a keyboard, and a host computer interface; the human-machine display component controls the programmable amplification and power circuit combination standard capacitor through the MCU main control circuit.

[0013] In a preferred embodiment of this invention, the power supply circuit is connected to the human-machine display component, the MCU main control circuit, and the programmable amplifier and power circuit, respectively, to supply power to them.

[0014] Compared with the prior art, the beneficial effects of this utility model are: this utility model realizes capacitor programmable control through circuit, which improves the efficiency and stability of capacitor matching, reduces operating costs and error rate, and provides high-precision and high-stability capacitor values, meeting the needs of high-precision LCR measuring instruments. It also has the advantages of wide measurement range, wide operating frequency bandwidth, small size, simple operation and easy portability. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the system structure of this utility model;

[0016] Figure 2 This is a schematic diagram of the capacitor bank and switching module structure of this utility model;

[0017] Figure 3 This is a schematic diagram of the capacitor array switch structure of this utility model;

[0018] Figure 4 This is a schematic diagram of the programmable amplifier and power amplifier circuit of this utility model;

[0019] Figure 5 This is a flowchart of the human-machine interface component testing method of this utility model.

[0020] In the diagram: 1. Capacitor bank and switching module; 11. Capacitor array switch; 1101. Switch assembly box; 1102. Capacitor terminal block; 1103. Cascade male terminal; 1104. Cascade female terminal; 1105. External port; 12. Capacitor bank; 1201. Capacitor assembly box; 1202. Connection slot; 2. Programmable amplifier and power amplifier circuit; 3. MCU main control circuit; 4. Human-machine display component; 5. Power supply circuit. Detailed Implementation

[0021] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0022] In the description of this utility model, it should be noted that the terms "vertical", "up", "down", "horizontal", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0023] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0024] Please see Figure 1-3 This utility model provides a technical solution: a programmable capacitor device for automatic matching, including a cascaded capacitor bank and a switching module 1. The capacitor bank and the switching module 1 are electrically connected to a programmable amplifier and power circuit 2 via wires. The programmable amplifier and power circuit 2 controls the capacitor bank and the switching module 1 to combine standard capacitors through an MCU main control circuit 3, so that it outputs a set capacitance value. For specific capacitance value requirements, the switch relay is driven to operate after calculation, and the combination is selected from a large number of capacitors to realize the capacitance value switching.

[0025] Specifically, the capacitor bank and switching module 1 includes a capacitor array switch 11 and a capacitor bank 12 electrically connected to the capacitor array switch 11 via corresponding pointers. The capacitor bank 12 is selectively activated based on the adaptability of the capacitor array switch 11, providing the capacitor combination required for the current test. The capacitor bank 12 provides a reference standard. The size of the capacitor bank 12 is that of commercially available capacitor banks, and its capacitors use polyphenylene sulfide material, which has a good temperature coefficient and long-term stability. The capacitor bank 12 includes a capacitor assembly box 1201 and connection slots 1202 disposed inside the capacitor assembly box 1201, with each connection slot 1202 corresponding to one capacitor.

[0026] The capacitor array switch 11 uses a Hongfa magnetic latching relay, which has the advantages of low power consumption and low heat generation and is suitable for portable high-precision instruments. The capacitor array switch 11 includes a switch assembly box 1101, and capacitor terminals 1102 are provided on both sides of the switch assembly box 1101. The capacitor terminals 1102 are connected to the corresponding capacitors in the capacitor group 12 through the connection slots 1202.

[0027] A cascaded male terminal 1103 and a cascaded female terminal 1104 are respectively provided at the upper and lower ends of the capacitor array switch 11. The cascaded male terminal 1103 corresponding to the bottom capacitor array switch 11 is embedded in the external port 1105, and the programmable amplifier and power circuit 2 is connected based on the external port 1105.

[0028] It should be noted that the cascaded capacitor bank and switching module 1 enable the capacitor value to range from 10nF to 100uF, with an accuracy of 1%, stability of 0.2% / year time drift, 50PPM temperature drift, and a switching contact resistance of less than 0.05 ohms.

[0029] like Figure 4 As shown, the programmable amplifier and power circuit 2 is used to simulate capacitor characteristics. The programmable amplifier and power circuit 2 includes analog capacitor pins, a preamplifier connected to the pins, a DAC conversion circuit, a power amplifier, and a pair of proportional resistors. The pins include a high-side input pin and a low-side input pin. The input of the preamplifier is connected to a standard capacitor bank and the high-side input pin. The output of the preamplifier is connected to the DAC conversion circuit and the proportional resistors. The output of the DAC conversion circuit is connected to the input of the power amplifier, and the output of the power amplifier is connected to the standard capacitor bank. The output of the proportional resistor is connected to the low-side input pin, thus simulating a capacitor.

[0030] Specifically, when the input port is connected to the measurement circuit and the user interface to input the value of the analog capacitor, the high-side input pin splits the circuit into two paths: one goes to the preamplifier (op-amp) and the other goes to one end of the standard capacitor bank. The current flowing through the preamplifier is negligible due to its high input impedance. The output of the preamplifier supplies the voltage reference to the DAC conversion circuit. The digital conversion value is calculated and supplied by the MCU main control circuit; therefore, the analog voltage output by the DAC conversion circuit is the voltage division ratio of the preamplifier. After voltage division, it supplies the power amplifier, and this output is connected to the other pin of the standard capacitor bank. The analog capacitor is essentially created by changing the voltage across the standard capacitor bank, thereby changing the current across it. The preamplifier provides sufficient input impedance to reduce the impact of bypass current on the analog capacitance. The DAC conversion circuit, with its good linearity, works in conjunction with the preamplifier and power output amplifier for programmable amplification. The power amplifier's role is to improve the circuit's load-carrying capacity and increase its voltage output range. The standard capacitor bank provides a reference for standard capacitors.

[0031] It should be noted that: the programmable amplifier and power amplifier circuit 2 has a passband greater than 20kHz sine wave, an input voltage range of 3p-PV, a programmable resolution better than 0.01%, and an output current range of 150mA. Specifically, the preamplifier uses the AD8629 chip, which has extremely low input offset voltage, typically only 1μV, enabling high-precision signal amplification in the preamplifier. In the programmable amplifier and power amplifier circuit, this chip can accurately amplify even weak input signals, ensuring signal accuracy and integrity. For example, with an input signal of 1mV, after amplification by the AD8629 chip, it can accurately reach the predetermined amplification factor without significant errors due to the chip's own offset voltage. The DAC conversion circuit uses the ADC8811, a 16-bit resolution chip that provides very high precision in converting analog signals to digital signals. In the DAC conversion circuit, it achieves high-precision programmable control of the capacitors. The 16-bit resolution allows for voltage adjustment accuracy within a very small range, meeting the requirement of a programmable resolution better than 0.01%. The power amplifier is an LTC4411, which features high output current and low noise. It can provide sufficient current to ensure that the load is fully driven and achieves the intended function, ensuring the quality of the final output signal. Its high stability characteristics can ensure the reliable operation of the circuit under different environmental conditions, improving the applicability and service life of the circuit.

[0032] MCU main control circuit 3 receives user commands from the user interface, controls the selection of the display module and standard capacitor bank, and is used to control the switching switch and programmable amplifier, adjust the output of the DAC conversion circuit, and coordinate the overall circuit operation. Its operating temperature is industrial grade. It communicates with the main control module via an isolated RS-232C interface. Specifically, it uses the ADI STC89 series, which has high integration and features a 51 core, Flash, AD, DA, PWM, EEPROM, and other functions required by this module.

[0033] Furthermore, the HMI (Human Machine Display) component 4 receives capacitor control commands, which can be achieved through a display screen, keyboard, or host computer interface. The HMI component 4, via the MCU main control circuit 3, controls the programmable amplifier and power circuit 2 to combine standard capacitors, ensuring that the capacitor output parameters are set by the user. Figure 5 As shown, the user operates according to the requirements of the human-machine display component 4. First, the environment is initialized before work to ensure that each working module is in a ready state.

[0034] It should be noted that, since the sampling module is a precision analog module, it is susceptible to interference from other digital modules, which can affect its sampling accuracy. Therefore, isolation measures have been taken for its input / output and power supply sections. The research group adopted a digital input / output mode to avoid the accuracy errors caused by analog isolated input / output.

[0035] Furthermore, the power supply circuit 5 is connected to the human-machine display component 4, the MCU main control circuit 3, and the programmable amplifier and power circuit 2 respectively to supply power to them. The power supply circuit includes two sets of battery power supply, one set of 8V, 8000mAH; and one set of 6V, 4000mAH.

[0036] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A programmable capacitor device for automatic matching, comprising: A cascaded capacitor bank and switching module (1) are connected to a programmable amplifier and power circuit (2) via wires. The programmable amplifier and power circuit (2) controls the capacitor bank and switching module (1) to combine standard capacitors through the MCU main control circuit (3) so that it outputs a set capacitance value. The capacitor bank and switching module (1) includes a capacitor array switch (11) and a capacitor bank (12) electrically connected to the capacitor array switch (11) via a corresponding pointer; the capacitor bank (12) is electrically connected to the programmable amplifier and power circuit (2) via the capacitor array switch (11).

2. A programmable capacitor device for automatic matching according to claim 1, characterized in that: The capacitor bank (12) includes a capacitor assembly box (1201) and a connection slot (1202) disposed inside the capacitor assembly box (1201), and each connection slot (1202) is connected to a capacitor.

3. A programmable capacitor device for automatic matching according to claim 2, characterized in that: The capacitor array switch (11) includes a switch assembly box (1101), and capacitor terminals (1102) are provided on both sides of the switch assembly box (1101). The capacitor terminals (1102) are connected to the corresponding capacitors in the capacitor group (12) through the connection slots (1202).

4. A programmable capacitor device for automatic matching according to claim 3, characterized in that: The capacitor array switch (11) is provided with a cascaded male terminal (1103) and a cascaded female terminal (1104) at its upper and lower ends respectively. The cascaded female terminal (1104) is connected to the cascaded male terminal (1103) of the external capacitor array switch (11). The cascaded male terminal (1103) corresponding to the bottom capacitor array switch (11) is embedded in the external port (1105). The programmable amplifier and power circuit (2) is connected based on the external port (1105).

5. A programmable capacitor device for automatic matching according to claim 4, characterized in that: The programmable amplifier and power circuit (2) includes the wiring pins of the analog capacitor, a preamplifier connected to the wiring pins, a DAC conversion circuit, a power amplifier, and a pair of proportional resistors; the wiring pins include a high-side input pin and a low-side input pin, wherein the input terminal of the preamplifier is connected to a standard capacitor bank and the high-side input pin; the output terminal of the preamplifier is connected to the DAC conversion circuit and the proportional resistors, the output terminal of the DAC conversion circuit is connected to the input terminal of the power amplifier, and the output terminal of the power amplifier is connected to the standard capacitor bank; the output terminal of the proportional resistor is connected to the low-side input pin to realize the analog capacitor.

6. A programmable capacitor device for automatic matching according to claim 1, characterized in that: The human-machine display component (4) receives capacitor program control instructions. The human-machine display component (4) receives capacitor program control instructions through the display screen, keyboard, and host computer interface. The human-machine display component (4) controls the program control amplifier and power circuit (2) to combine standard capacitors through the MCU main control circuit (3).

7. A programmable capacitor device for automatic matching as recited in claim 1, characterized by: The power supply circuit (5) is connected to the human-machine display component (4), the MCU main control circuit (3) and the programmable amplifier and power circuit (2) respectively to supply power to them.

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