Electrodeless potentiometer

Abstract

The utility model discloses a stepless potentiometer which comprises a reference voltage source, a stepless regulation switch circuit and a level comparison circuit, the reference voltage source provides a constant voltage source for the stepless regulation switch circuit, and the stepless regulation switch circuit comprises a switch tube circuit and a multi-path optocoupler circuit connected with the switch tube circuit. The light blocking sheet shields and does not shield the optocoupler circuits to realize disconnection and connection of the optocoupler circuits, and the level comparison circuit is a comparator connected with each optocoupler circuit; the utility model has the advantages that the input voltage is stable, the reliability is strong, and the wear resistance is good.

Description

Technical Field

[0001] The utility model relates to the field of stepless sensor design, in particular to a stepless potentiometer. Background Art

[0002] In military inverter systems, in order to adjust the output AC voltage amplitude, the output voltage needs to be adjusted. Usually, the current and voltage passing through the circuit are changed by changing the resistance of the potentiometer. Currently, the best performing potentiometers on the market are metal film potentiometers, which are made by depositing metal alloys or metal oxides on an insulating substrate through a vacuum evaporation process. However, metal film potentiometers have the defects of unstable input voltage, low reliability, and poor wear resistance. Utility Model Content

[0003] The technical problem to be solved by the utility model is that the existing potentiometer has the problems of unstable input voltage, low reliability and poor wear resistance.

[0004] The utility model solves the above technical problems through the following technical means: a stepless potentiometer, including a reference voltage source, a stepless adjustment switch circuit and a level comparison circuit, the reference voltage source provides a constant voltage source for the stepless adjustment switch circuit, the stepless adjustment switch circuit includes a switch tube circuit and a multi-channel optocoupler circuit connected to the switch tube circuit, a light shield blocks and does not block the optocoupler circuit to achieve the disconnection and conduction of the optocoupler circuit, and the level comparison circuit is a comparator connected to each optocoupler circuit.

[0005] Further, the reference voltage source includes a polar capacitor C1, a diode D1, resistors R1 to R6, a capacitor C2, a capacitor C3 and an operational amplifier U1A, wherein the positive electrode of the polar capacitor C1, the cathode of the diode D1, one end of the resistor R1 and one end of the resistor R3 are connected to the power supply VCC1, the other end of the resistor R1, the controllable end of the diode D1 and one end of the resistor R2 are connected, the negative electrode of the polar capacitor C1, the anode of the diode D1 and the other end of the resistor R2 are connected and grounded; the other end of the resistor R3 is connected to the in-phase input end of the operational amplifier U1A, one end of the resistor R4 and one end of the resistor R5 are connected to the inverting input end of the operational amplifier U1A, the voltage positive end of the operational amplifier U1A is connected to the power supply VCC2 and one end of the capacitor C2, the other end of the capacitor C2 is grounded, the voltage negative end of the operational amplifier U1A is grounded, the other end of the resistor R5 and one end of the resistor R6 are both connected to the output end of the operational amplifier U1A, and the other end of the resistor R6 is grounded through the capacitor C3.

[0006] Furthermore, the switching tube circuit includes a transistor Q1, a capacitor C4, a resistor R7 and a resistor R8, the collector of the transistor Q1 is connected to the other end of the resistor R6, the base of the transistor Q1, one end of the capacitor C4, one end of the resistor R7 and one end of the resistor R8 are connected, the other end of the capacitor C4 is grounded, the other end of the resistor R7 receives the PWM signal, and the emitter of the transistor Q1 and the other end of the resistor R8 are connected to each optocoupler circuit.

[0007] Furthermore, the circuit structure of each optocoupler circuit is the same, and one of the optocoupler circuits includes a resistor R10, a diode D10, a capacitor C10, an optocoupler U2, a resistor R11, a resistor R12 and a capacitor C11, one end of the resistor R10 is connected to the emitter of the transistor Q1 and the other end of the resistor R8, the other end of the resistor R10, the cathode of the diode D10, one end of the capacitor C10 and the first end of the optocoupler U2 are connected, the anode of the diode D10, the other end of the capacitor C10 and the second end of the optocoupler U2 are connected and grounded, the third end of the optocoupler U2 is connected to one end of the capacitor C11 and grounded, the other end of the capacitor C11, the fourth end of the optocoupler U2, one end of the resistor R12 and one end of the resistor R11 are connected, the other end of the resistor R11 is connected to the power supply VCC3, and the other end of the resistor R12 is connected to the level comparison circuit.

[0008] Furthermore, the optocouplers in each optocoupler circuit are U-type optocouplers.

[0009] Furthermore, the U-shaped optocoupler includes a light emitter, a light detector and a U-shaped channel, the light emitter is located at one end of the U-shaped channel, the light detector is located at the other end of the U-shaped channel, and when the light baffle is located in the light path between the light emitter and the light detector, the circuit of the U-shaped optocoupler is not conductive, and when the light baffle is removed from the light path between the light emitter and the light detector, the circuit of the U-shaped optocoupler is conductive.

[0010] Furthermore, the number of comparators in the level comparison circuit is the same as the number of optocoupler circuits, wherein the non-inverting input terminal of one comparator is connected to the other end of the resistor R12, the output terminal of the comparator is connected to an IO port of the external microcontroller, and the inverting input terminal of each comparator is connected together and connected to the reference voltage Vref.

[0011] The advantages of the utility model are:

[0012] (1) The utility model is provided with a reference voltage source, which can output a constant voltage, thereby avoiding fluctuations and interferences in the circuit due to voltage instability, further improving the circuit stability, and improving the reliability of the potentiometer. In addition, the utility model only needs to use a light shield to shield the optocoupler circuit or not shield the optocoupler circuit to achieve the disconnection or conduction control of the optocoupler circuit, and then achieve the adjustment of the potentiometer, without mechanically adjusting the potentiometer, and the light shield only has the function of shielding light and will not cause wear to the circuit, so that the entire potentiometer has good wear resistance.

[0013] (2) The utility model is provided with a MOS tube Q1, and the entire circuit is turned off by turning off the MOS tube Q1, thereby avoiding unnecessary energy loss when the circuit is not used and saving resources.

[0014] (3) The utility model is provided with an optical coupling circuit, which can realize electrical isolation between the input end and the output end, isolate the input end from the output end, avoid electrical mutual influence and mutual interference between the circuits, thereby making the potentiometer highly anti-interference and highly reliable.

[0015] (4) The output end of the utility model is provided with a level comparator circuit, in which the comparator input end is connected to an optocoupler circuit and a reference voltage Vref. By comparing the signal transmitted by the optocoupler circuit with the reference voltage Vref, a high level or a low level after adjustment is output, thereby avoiding unstable output signal and improving the reliability of the potentiometer. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A schematic diagram of a stepless potentiometer disclosed in an embodiment of the utility model;

[0017] Figure 2 A schematic diagram of a reference voltage source in a stepless potentiometer disclosed in an embodiment of the utility model;

[0018] Figure 3 It is a schematic diagram of a stepless regulating switch circuit in a stepless potentiometer disclosed in an embodiment of the utility model;

[0019] Figure 4 The present invention is a schematic diagram of a level comparison circuit in a stepless potentiometer disclosed in an embodiment of the present utility model. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in combination with the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0021] like Figure 1 As shown, a stepless potentiometer includes a reference voltage source, a stepless adjustment switch circuit, a level comparison circuit and a single-chip microcomputer (not shown in the figure), wherein the stepless adjustment switch circuit includes a switch tube circuit and a multi-channel optocoupler circuit connected to the switch tube circuit, and a light shield shields and does not shield the optocoupler circuit to realize the disconnection and conduction of the optocoupler circuit, and the level comparison circuit is a comparator connected to each optocoupler circuit, and the output end of each comparator is connected to the IO port of the single-chip microcomputer, and the single-chip microcomputer receives the high and low level signals input by each comparator to form a corresponding code, and outputs a voltage signal or a current signal corresponding to the code according to the relationship between the internally stored code, the resistance value and the output power. The following is a detailed introduction to each circuit and working principle. Figure 1 This is the circuit schematic of the entire potentiometer. In order to show the circuit structure more clearly, Figures 2 to 4 Separately intercept Figure 1 The reference voltage source, stepless adjustment switch circuit and level comparison circuit are included.

[0022] See also Figure 2 , the reference voltage source includes a polar capacitor C1, a diode D1, resistors R1 to R6, a capacitor C2, a capacitor C3 and an operational amplifier U1A, the positive electrode of the polar capacitor C1, the cathode of the diode D1, one end of the resistor R1 and one end of the resistor R3 are connected to the power supply VCC1, the other end of the resistor R1, the controllable end of the diode D1 and one end of the resistor R2 are connected, the negative electrode of the polar capacitor C1, the anode of the diode D1 and the other end of the resistor R2 are connected and grounded; the other end of the resistor R3 is connected to the in-phase input end of the operational amplifier U1A, one end of the resistor R4 and one end of the resistor R5 are connected to the inverting input end of the operational amplifier U1A, the voltage positive end of the operational amplifier U1A is connected to the power supply VCC2 and one end of the capacitor C2, the other end of the capacitor C2 is grounded, the voltage negative end of the operational amplifier U1A is grounded, the other end of the resistor R5 and one end of the resistor R6 are both connected to the output end of the operational amplifier U1A, and the other end of the resistor R6 is grounded through the capacitor C3. The reference voltage source can output a constant voltage, thereby preventing the circuit from fluctuating and interfering due to unstable voltage, and further improving the circuit stability.

[0023] See also Figure 3, the switch tube circuit includes a transistor Q1, a capacitor C4, a resistor R7 and a resistor R8, the collector of the transistor Q1 is connected to the other end of the resistor R6, the base of the transistor Q1, one end of the capacitor C4, one end of the resistor R7 and one end of the resistor R8 are connected, the other end of the capacitor C4 is grounded, the other end of the resistor R7 receives a PWM signal, and the emitter of the transistor Q1 and the other end of the resistor R8 are connected to each optocoupler circuit. By turning off the MOS tube Q1, the entire circuit is turned off, avoiding unnecessary energy loss when the circuit is not used, and saving resources. When the MOS tube Q1 is turned on, the optocoupler circuit is turned on or off by a light shield, thereby forming different output combinations.

[0024] Continue reading Figure 3 , the circuit structure of each optocoupler circuit is the same, and one of the optocoupler circuits includes a resistor R10, a diode D10, a capacitor C10, an optocoupler U2, a resistor R11, a resistor R12 and a capacitor C11, one end of the resistor R10 is connected to the emitter of the transistor Q1 and the other end of the resistor R8, the other end of the resistor R10, the cathode of the diode D10, one end of the capacitor C10 and the first end of the optocoupler U2 are connected, the anode of the diode D10, the other end of the capacitor C10 and the second end of the optocoupler U2 are connected and grounded, the third end of the optocoupler U2 is connected to one end of the capacitor C11 and grounded, the other end of the capacitor C11, the fourth end of the optocoupler U2, one end of the resistor R12 and one end of the resistor R11 are connected, the other end of the resistor R11 is connected to the power supply VCC3, and the other end of the resistor R12 is connected to the level comparison circuit. The optocoupler circuit can achieve electrical isolation between the input and output ends, isolating the input from the output and avoiding electrical interaction and interference between circuits, thereby making the potentiometer highly resistant to interference and highly reliable.

[0025] In this embodiment, the optocouplers in each optocoupler circuit are all U-shaped optocouplers. The U-shaped optocoupler includes a light emitter, a light detector and a U-shaped channel, the light emitter is located at one end of the U-shaped channel, the light detector is located at the other end of the U-shaped channel, when the light baffle is located in the light path between the light emitter and the light detector, the circuit of the U-shaped optocoupler is not conductive, and when the light baffle is removed from the light path between the light emitter and the light detector, the circuit of the U-shaped optocoupler is conductive.

[0026] See also Figure 4, the number of comparators in the level comparison circuit is the same as the number of optocoupler circuits, the in-phase input end of one of the comparators is connected to the other end of the resistor R12, the output end of the comparator is connected to an IO port of the single-chip computer, and the inverting input end of each comparator is connected together and connected to the reference voltage Vref. The comparator input end in the level comparator circuit is connected to the optocoupler circuit and the reference voltage Vref, and the signal transmitted by the optocoupler circuit is compared with the reference voltage Vref, so as to output a high level or a low level after setting, so as to avoid encoding failure caused by unstable output signal and improve the reliability of the potentiometer. In this embodiment, the number of comparators in the level comparison circuit and the number of optocoupler circuits are both 4, which can be expanded to more in practical applications without special limitation.

[0027] The control process of the stepless potentiometer is:

[0028] The optocoupler circuit is turned on or off by the light blocking sheet, so that the comparator outputs a high level or a low level, the high level is 1, and the low level is 0. The single-chip microcomputer receives the high and low level signals input by each comparator to form an n-bit binary code, where n is the number of comparators. The single-chip microcomputer stores the relationship between the n-bit binary code, the resistance value, and the output power. The single-chip microcomputer calculates the resistance value and the output power corresponding to the binary code according to the received binary code, and outputs the analog voltage corresponding to the resistance value and the output power through the internal or external DAC module. The analog voltage is used as the output power command value to adjust the duty cycle of the power device to achieve the purpose of adjusting the output power.

[0029] In this embodiment, the optical coupling circuit has 4 paths, the comparator of the level comparison circuit has 4, and the single chip receives the high and low level signals input by each comparator to form a 4-bit binary code. When the 4 comparators of the level comparison circuit all output a high level, the 4-bit binary code is 1111, when the 4 comparators of the level comparison circuit all output a low level, the 4-bit binary code is 0000, when the 4 comparators of the level comparison circuit output a high level, a low level, a high level and a high level respectively, the 4-bit binary code is 1011, when the 4 comparators of the level comparison circuit output a high level, a high level, a low level and a high level respectively, the 4-bit binary code is 1101, and other codes are similar, and no longer given examples one by one.

[0030] The optocoupler circuit is disconnected and turned on by blocking and unblocking the light-shielding sheet, so that the comparator outputs high and low level signals. The high and low level signals between multiple comparators are combined into a code. The microcontroller outputs a voltage signal or current signal corresponding to the code according to the relationship between the code, the resistance value and the output power, so there is no need to mechanically adjust the potentiometer, and the light-shielding sheet only blocks light and will not cause wear to the circuit, so that the entire potentiometer has good wear resistance. Secondly, the relationship between the code, the resistance value and the output power stored inside the microcontroller is used, and according to the coding principle, it can be known that there are two coding combinations. n Different coding results correspond to different resistance values, which greatly expands the resistance range, achieving stepless adjustment while making the resistance range large enough.

[0031] It should be noted that the above is only for the purpose of more clearly introducing the circuit structure and principle of the utility model, thereby describing the coding control of the single-chip microcomputer, but the utility model does not protect the control content of the single-chip microcomputer, but only protects the entire circuit hardware structure, as well as the good wear resistance and stable input voltage effect brought by the hardware structure.

[0032] Through the above technical solution, the utility model sets a reference voltage source, and the reference voltage source can output a constant voltage, thereby avoiding fluctuations and interference caused by unstable voltage in the circuit, further improving the circuit stability, and improving the reliability of the potentiometer. In addition, the utility model only needs to use a light shield to shield the optocoupler circuit or not shield the optocoupler circuit to achieve the disconnection or conduction control of the optocoupler circuit, and then achieve the adjustment of the potentiometer, without mechanically adjusting the potentiometer, and the light shield only has the function of blocking light, and will not cause wear to the circuit, so that the entire potentiometer has good wear resistance.

[0033] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A stepless potentiometer, characterized in that: It includes a reference voltage source, a stepless adjustment switch circuit and a level comparison circuit. The reference voltage source provides a constant voltage source for the stepless adjustment switch circuit. The stepless adjustment switch circuit includes a switch tube circuit and a multi-channel optocoupler circuit connected to the switch tube circuit. The light shielding sheet blocks and does not block the optocoupler circuit to achieve the disconnection and conduction of the optocoupler circuit. The level comparison circuit is a comparator connected to each optocoupler circuit.

2. A stepless potentiometer according to claim 1, characterized in that: The reference voltage source includes a polar capacitor C1, a diode D1, resistors R1 to R6, a capacitor C2, a capacitor C3 and an operational amplifier U1A. The positive electrode of the polar capacitor C1, the cathode of the diode D1, one end of the resistor R1 and one end of the resistor R3 are connected to the power supply VCC1, the other end of the resistor R1, the controllable end of the diode D1 and one end of the resistor R2 are connected, the negative electrode of the polar capacitor C1, the anode of the diode D1 and the other end of the resistor R2 are connected and grounded; the other end of the resistor R3 is connected to the in-phase input end of the operational amplifier U1A, one end of the resistor R4 and one end of the resistor R5 are connected to the inverting input end of the operational amplifier U1A, the voltage positive end of the operational amplifier U1A is connected to the power supply VCC2 and one end of the capacitor C2, the other end of the capacitor C2 is grounded, the voltage negative end of the operational amplifier U1A is grounded, the other end of the resistor R5 and one end of the resistor R6 are both connected to the output end of the operational amplifier U1A, and the other end of the resistor R6 is grounded through the capacitor C3.

3. A stepless potentiometer according to claim 2, characterized in that: The switching tube circuit includes a transistor Q1, a capacitor C4, a resistor R7 and a resistor R8. The collector of the transistor Q1 is connected to the other end of the resistor R6, the base of the transistor Q1, one end of the capacitor C4, one end of the resistor R7 and one end of the resistor R8 are connected, the other end of the capacitor C4 is grounded, the other end of the resistor R7 receives a PWM signal, and the emitter of the transistor Q1 and the other end of the resistor R8 are connected to each optocoupler circuit.

4. A stepless potentiometer according to claim 3, characterized in that: The circuit structure of each optocoupler circuit is the same, and one of the optocoupler circuits includes a resistor R10, a diode D10, a capacitor C10, an optocoupler U2, a resistor R11, a resistor R12 and a capacitor C11. One end of the resistor R10 is connected to the emitter of the transistor Q1 and the other end of the resistor R8, the other end of the resistor R10, the cathode of the diode D10, one end of the capacitor C10 and the first end of the optocoupler U2 are connected, the anode of the diode D10, the other end of the capacitor C10 and the second end of the optocoupler U2 are connected and grounded, the third end of the optocoupler U2 is connected to one end of the capacitor C11 and grounded, the other end of the capacitor C11, the fourth end of the optocoupler U2, one end of the resistor R12 and one end of the resistor R11 are connected, the other end of the resistor R11 is connected to the power supply VCC3, and the other end of the resistor R12 is connected to the level comparison circuit.

5. A stepless potentiometer according to claim 4, characterized in that: The optocouplers in each optocoupler circuit are all U-type optocouplers.

6. A stepless potentiometer according to claim 5, characterized in that: The U-shaped optocoupler includes a light emitter, a light detector and a U-shaped channel, the light emitter is located at one end of the U-shaped channel, the light detector is located at the other end of the U-shaped channel, when the light baffle is located in the light path between the light emitter and the light detector, the circuit of the U-shaped optocoupler is not conductive, when the light baffle is removed from the light path between the light emitter and the light detector, the circuit of the U-shaped optocoupler is conductive.

7. A stepless potentiometer according to claim 4, characterized in that: The number of comparators in the level comparison circuit is the same as the number of optocoupler circuits, wherein the non-inverting input end of one comparator is connected to the other end of the resistor R12, the output end of the comparator is connected to an IO port of an external single-chip microcomputer, and the inverting input end of each comparator is connected together and connected to a reference voltage Vref.

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