Voltage sampling circuit, voltage sampling device and electronic equipment

Abstract

The utility model provides a voltage sampling circuit, a voltage sampling device and electronic equipment, and relates to the technical field of power electronics. The circuit comprises a first voltage division unit, a first amplification unit, a second voltage division unit, a second amplification unit and a voltage division output unit, the input end of the first voltage division unit is electrically connected with a voltage source, and the output end of the first voltage division unit is electrically connected with the input end of the first amplification unit; the output end of the first amplification unit is electrically connected with the input end of the second voltage division unit; the output end of the second voltage division unit is electrically connected with the input end of the second amplification unit; the output end of the second amplification unit is electrically connected with the input end of the partial pressure output unit, and the output end of the partial pressure output unit is electrically connected with the load. The precision of voltage sampling and the stability of the circuit can be improved.

Description

Technical Field

[0001] The utility model relates to the technical field of power electronics, and in particular to a voltage sampling circuit, a voltage sampling device and an electronic device. Background Art

[0002] Traditional voltage sampling generally involves directly transmitting the collected DC voltage to the load after it is divided by two resistors with a precision of 1%. However, when the load is powered by a low voltage, such as MCU (Microcontroller Unit) which is mostly powered by 3.3V, the voltage that can be recognized is relatively low. Therefore, when sampling a large voltage of tens of volts, it is necessary to divide the sampled voltage based on a larger resistor. The 1% precision error of the large resistor may be close to the resistance value of the other resistor in the voltage division, which causes a large error in the voltage sampling value input to the MCU, which in turn leads to low control accuracy of the entire control system, affecting the use effect. Utility Model Content

[0003] In order to solve the above technical problems, the embodiments of the present application provide a voltage sampling circuit, a voltage sampling device and an electronic device.

[0004] In a first aspect, an embodiment of the present application provides a voltage sampling circuit, the circuit comprising a first voltage dividing unit, a first amplifying unit, a second voltage dividing unit, a second amplifying unit and a voltage dividing output unit;

[0005] The input end of the first voltage dividing unit is electrically connected to a voltage source, and the output end of the first voltage dividing unit is electrically connected to the input end of the first amplifying unit;

[0006] The output end of the first amplifying unit is electrically connected to the input end of the second voltage dividing unit;

[0007] The output end of the second voltage dividing unit is electrically connected to the input end of the second amplifying unit;

[0008] The output end of the second amplifying unit is electrically connected to the input end of the voltage-dividing output unit, and the output end of the voltage-dividing output unit is electrically connected to a load.

[0009] In one embodiment, the first voltage dividing unit includes a first sampling resistor and a second sampling resistor;

[0010] The first end of the first sampling resistor serves as the input end of the first voltage dividing unit, and the second end of the first sampling resistor is electrically connected to the first end of the second sampling resistor;

[0011] The first end of the second sampling resistor serves as the output end of the first voltage dividing unit, and the second end of the second sampling resistor is grounded.

[0012] In one embodiment, the first voltage dividing unit further includes a first filter capacitor;

[0013] The first end of the first filter capacitor is electrically connected to the second end of the first sampling resistor, and the second end of the first filter capacitor is electrically connected to the second end of the second sampling resistor.

[0014] In one embodiment, the first amplification unit includes a first operational amplifier;

[0015] The non-inverting input terminal of the first operational amplifier serves as the input terminal of the first amplifying unit;

[0016] The inverting input terminal of the first operational amplifier is electrically connected to the output terminal of the first operational amplifier;

[0017] The output end of the first operational amplifier serves as the output end of the first amplifying unit.

[0018] In one embodiment, the second voltage dividing unit includes a third sampling resistor and a fourth sampling resistor;

[0019] The first end of the third sampling resistor serves as the input end of the second voltage dividing unit, and the second end of the third sampling resistor is electrically connected to the first end of the fourth sampling resistor;

[0020] A first end of the fourth sampling resistor serves as an output end of the second voltage dividing unit, and a second end of the fourth sampling resistor is grounded.

[0021] In one embodiment, the first voltage dividing unit further includes a second filter capacitor;

[0022] The first end of the second filter capacitor is electrically connected to the second end of the third sampling resistor, and the second end of the second filter capacitor is electrically connected to the second end of the fourth sampling resistor.

[0023] In one embodiment, the second amplification unit includes a second operational amplifier;

[0024] The non-inverting input terminal of the second operational amplifier serves as the input terminal of the second amplifying unit;

[0025] The inverting input terminal of the second operational amplifier is electrically connected to the output terminal of the second operational amplifier;

[0026] The output end of the second operational amplifier serves as the output end of the second amplifying unit.

[0027] In one implementation, the voltage division output unit includes a fifth sampling resistor, a sixth sampling resistor and a third filter capacitor;

[0028] The first end of the fifth sampling resistor serves as the input end of the voltage division output unit, and the second end of the fifth sampling resistor is electrically connected to the first end of the sixth sampling resistor;

[0029] The second end of the sixth sampling resistor is grounded;

[0030] The first end of the third filter capacitor is electrically connected to the first end of the sixth sampling resistor, and the second end of the third filter capacitor is electrically connected to the second end of the sixth sampling resistor.

[0031] In a second aspect, an embodiment of the present application provides a voltage sampling device, which is applied to an electronic device. The device includes the voltage sampling circuit as described in the first aspect.

[0032] In a third aspect, an embodiment of the present application provides an electronic device, wherein the electronic device includes the voltage sampling device as described in the second aspect.

[0033] The beneficial effects of the voltage sampling circuit provided by the utility model include:

[0034] The present application can ensure accurate sampling accuracy for large voltages without affecting the sampling accuracy due to the voltage division of the sampling resistor. It can also perform filtering and improve the driving capability of the signal, thereby ensuring the stability of the circuit and the accuracy of voltage sampling. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic diagram of a module of a voltage sampling circuit provided by an embodiment of the utility model;

[0037] Figure 2 A circuit diagram of a voltage sampling circuit provided in an embodiment of the utility model.

[0038] Explanation of main component symbols: 110-first voltage divider unit; 120-first amplifying unit; 130-second voltage divider unit; 140-second amplifying unit; 150-voltage divider output unit; 200-voltage source; 300-load; R1-first sampling resistor; R2-second sampling resistor; R3-third sampling resistor; R4-fourth sampling resistor; R5-fifth sampling resistor; R6-sixth sampling resistor; C1-first filter capacitor; C2-second filter capacitor; C3-third filter capacitor; U1-first operational amplifier; U2-second operational amplifier. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0040] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0042] In the description of the present utility model, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present utility model.

[0043] Furthermore, the terms “first”, “second”, “third”, etc. are merely used for distinguishing descriptions and are not to be understood as indicating or implying relative importance.

[0044] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0045] Example 1

[0046] Voltage sampling is a technology that enables the change of one signal to be captured, stored, processed and displayed by another signal. It can convert DC voltage into analog current or digital signal, thus realizing voltage measurement and control applications. It is widely used in industrial automation, computer systems, engineering measurement, home appliances and other products.

[0047] Traditional voltage sampling generally involves dividing the collected DC voltage through two resistors with a precision of 1% and then directly transmitting it to the MCU (Microcontroller Unit). However, since many MCUs are powered by 3.3V and can recognize relatively low voltages, a large voltage divider is required when sampling large voltages of tens of volts. The precision of the resistor is 1%, and the 1% resistance of the large resistor reaches a large part of the resistance of the other resistor in the voltage divider. This results in a large error in the voltage sampling value input to the MCU, which will cause the entire control system to have low control accuracy and affect the use effect.

[0048] See also Figure 1 , this embodiment provides a voltage sampling circuit, the circuit includes a first voltage dividing unit 110, a first amplifying unit 120, a second voltage dividing unit 130, a second amplifying unit 140 and a voltage dividing output unit 150;

[0049] The input end of the first voltage dividing unit 110 is electrically connected to the voltage source 200 , and the output end of the first voltage dividing unit 110 is electrically connected to the input end of the first amplifying unit 120 ;

[0050] The output end of the first amplifying unit 120 is electrically connected to the input end of the second voltage dividing unit 130;

[0051] The output end of the second voltage dividing unit 130 is electrically connected to the input end of the second amplifying unit 140;

[0052] The output end of the second amplifying unit 140 is electrically connected to the input end of the voltage-dividing output unit 150 , and the output end of the voltage-dividing output unit 150 is electrically connected to the load 300 .

[0053] In order to improve the problem that when the input sampling voltage is large and the working voltage of the load is small, the traditional voltage sampling method has a large error in the sampling value, this embodiment proposes a circuit structure with a simple structure and common circuit elements, but can ensure that the voltage sampling signal is accurate and the circuit works stably.

[0054] Specifically, the first voltage divider unit 110 performs a first voltage division on the DC voltage ADC_U provided by the voltage source 200, and the voltage-divided signal ADC_U1 enters the first amplification unit 120 and outputs ADC_U2; the second voltage divider unit 130 performs a second voltage division on ADC_U2, and the voltage-divided signal ADC_U3 enters the second amplification unit 140; finally, through the voltage division output unit 150, the final voltage-divided signal ADC_IN is input into the load.

[0055] In the present application, after the multi-level voltage division by the first voltage division unit 110 and the second voltage division unit 130, the voltage has been reduced to a certain extent. Finally, after the voltage division by the voltage division output unit 150, the voltage accuracy requirement of the load can be met.

[0056] Specific, combined Figure 2 , the circuit structure of the voltage sampling circuit provided in the present application is described in detail. In one embodiment, the first voltage dividing unit 110 includes a first sampling resistor R1 and a second sampling resistor R2;

[0057] The first end of the first sampling resistor R1 serves as the input end of the first voltage dividing unit 110, and the second end of the first sampling resistor R1 is electrically connected to the first end of the second sampling resistor R2;

[0058] A first end of the second sampling resistor R2 serves as an output end of the first voltage dividing unit 110 , and a second end of the second sampling resistor R2 is grounded.

[0059] For example, in order to avoid the precision loss caused by the resistance difference between the sampling resistors, the first sampling resistor R1 and the second sampling resistor R2 should use resistors of the same specification, so as to achieve the voltage reduction effect without causing a large precision error.

[0060] In one implementation, the first voltage dividing unit 110 further includes a first filter capacitor C1;

[0061] The first end of the first filter capacitor C1 is electrically connected to the second end of the first sampling resistor R1 , and the second end of the first filter capacitor C1 is electrically connected to the second end of the second sampling resistor R2 .

[0062] In one embodiment, the first amplification unit 120 includes a first operational amplifier U1;

[0063] The non-inverting input terminal of the first operational amplifier U1 serves as the input terminal of the first amplifying unit 120;

[0064] The inverting input terminal of the first operational amplifier U1 is electrically connected to the output terminal of the first operational amplifier U1;

[0065] The output end of the first operational amplifier U1 serves as the output end of the first amplifying unit 120 .

[0066] Exemplarily, the low voltage power supply VCC is used to power the first operational amplifier U1, and the operational amplifier circuit is a voltage follower, that is, the value of ADC_U2 is equal to the value of ADC_U1. The first filter capacitor C1 is used to reduce the noise in the circuit. In addition, the operational amplifier output signal has a strong driving ability and strong anti-interference ability, and the operational amplifier itself also has a certain filtering effect, which can work together with the filter capacitor to ensure the stability of the transmission signal.

[0067] In one implementation, the second voltage dividing unit 130 includes a third sampling resistor R3 and a fourth sampling resistor R4;

[0068] The first end of the third sampling resistor R3 serves as the input end of the second voltage dividing unit 130, and the second end of the third sampling resistor R3 is electrically connected to the first end of the fourth sampling resistor R4;

[0069] A first end of the fourth sampling resistor R4 serves as an output end of the second voltage dividing unit 130 , and a second end of the fourth sampling resistor R4 is grounded.

[0070] In one implementation, the first voltage dividing unit 110 further includes a second filter capacitor C2;

[0071] The first end of the second filter capacitor C2 is electrically connected to the second end of the third sampling resistor R3 , and the second end of the second filter capacitor C2 is electrically connected to the second end of the fourth sampling resistor R4 .

[0072] In one embodiment, the second amplifying unit 140 includes a second operational amplifier U2;

[0073] The non-inverting input terminal of the second operational amplifier U2 serves as the input terminal of the second amplifying unit 140;

[0074] The inverting input terminal of the second operational amplifier U2 is electrically connected to the output terminal of the second operational amplifier U2;

[0075] The output end of the second operational amplifier U2 serves as the output end of the second amplifying unit 140 .

[0076] As above, illustratively, the third sampling resistor R3 and the fourth sampling resistor R4 should use resistors of the same specification. The low voltage power supply VCC is used to power the second operational amplifier U2, the operational amplifier circuit is a voltage follower, and the value of ADC_U4 is equal to the value of ADC_U3. The second filter capacitor C2 is used to reduce noise in the circuit.

[0077] In one implementation, the voltage division output unit 150 includes a fifth sampling resistor R5, a sixth sampling resistor R6 and a third filter capacitor C3;

[0078] The first end of the fifth sampling resistor R5 serves as the input end of the voltage division output unit 150, and the second end of the fifth sampling resistor R5 is electrically connected to the first end of the sixth sampling resistor R6;

[0079] The second end of the sixth sampling resistor R6 is grounded;

[0080] A first end of the third filter capacitor C3 is electrically connected to a first end of the sixth sampling resistor R6 , and a second end of the third filter capacitor C3 is electrically connected to a second end of the sixth sampling resistor R6 .

[0081] According to the different supply voltages of the load, the resistance values ​​of the fifth sampling resistor R5 and the sixth sampling resistor R6 are not limited, and are determined according to the ADC_U4 and the load requirements at this time. Specifically, the maximum ADC_IN value obtained after the fifth sampling resistor R5 and the sixth sampling resistor R6 are divided should meet the precise recognition voltage range of the MCU.

[0082] In a specific embodiment, taking the power supply to MCU (microcontroller) as an example, the working voltage of MCU is 3.3V. Then, the first sampling resistor R1 and the second sampling resistor R2 perform the first voltage division on the DC voltage ADC_U, the resistance values ​​of R1 and R2 are equal, and the signal ADC_U1 after voltage division enters the first operational amplifier U1. Because the operational amplifier circuit is a voltage follower at this time, the value of ADC_U2 is equal to the value of ADC_U1. Similarly, the resistance values ​​of R3 and R4 are equal. After voltage division, the signal ADC_U3 is obtained, and the value of ADC_U3 is equal to the value of ADC_U4. Finally, after configuring the resistance values ​​of R5 and R6, the signal ADC_IN after voltage division meets the precise identification voltage range of MCU.

[0083] In this embodiment, after the voltage is divided by the resistance values ​​of R1, R2 and R3, R4, the voltage has been reduced to 1 / 4 of the original voltage, and after the reasonable distribution of the resistance values ​​of R5 and R6, the voltage accuracy requirement can be met. At the same time, because the operational amplifiers U1 and U2 can improve the driving ability of the input signal, and the operational amplifiers themselves also have a certain filtering effect, the capacitors C1, C2, and C3 also play a filtering role, jointly ensuring the stability of the transmission signal.

[0084] A voltage sampling circuit provided in the present application can achieve accurate sampling accuracy for large voltages without affecting the sampling accuracy due to the voltage division of the sampling resistor. At the same time, the use of operational amplifiers and filter capacitors can also perform filtering to enhance the signal driving capability, thereby ensuring the stability of the circuit and the accuracy of voltage sampling.

[0085] Example 2

[0086] An embodiment of the present application further provides a voltage sampling device, which includes the voltage sampling circuit as described in any of the above embodiments.

[0087] Example 3

[0088] An embodiment of the present application further provides an electronic device, which includes the voltage sampling device as described in any of the above embodiments.

[0089] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. A voltage sampling circuit, characterized in that: The circuit comprises a first voltage dividing unit, a first amplifying unit, a second voltage dividing unit, a second amplifying unit and a voltage dividing output unit; The input end of the first voltage dividing unit is electrically connected to a voltage source, and the output end of the first voltage dividing unit is electrically connected to the input end of the first amplifying unit; The output end of the first amplifying unit is electrically connected to the input end of the second voltage dividing unit; The output end of the second voltage dividing unit is electrically connected to the input end of the second amplifying unit; The output end of the second amplifying unit is electrically connected to the input end of the voltage-dividing output unit, and the output end of the voltage-dividing output unit is electrically connected to a load.

2. The voltage sampling circuit according to claim 1, characterized in that: The first voltage dividing unit includes a first sampling resistor and a second sampling resistor; The first end of the first sampling resistor serves as the input end of the first voltage dividing unit, and the second end of the first sampling resistor is electrically connected to the first end of the second sampling resistor; The first end of the second sampling resistor serves as the output end of the first voltage dividing unit, and the second end of the second sampling resistor is grounded.

3. The voltage sampling circuit according to claim 2, characterized in that: The first voltage dividing unit further includes a first filter capacitor; The first end of the first filter capacitor is electrically connected to the second end of the first sampling resistor, and the second end of the first filter capacitor is electrically connected to the second end of the second sampling resistor.

4. The voltage sampling circuit according to claim 1, characterized in that: The first amplification unit includes a first operational amplifier; The non-inverting input terminal of the first operational amplifier serves as the input terminal of the first amplifying unit; The inverting input terminal of the first operational amplifier is electrically connected to the output terminal of the first operational amplifier; The output end of the first operational amplifier serves as the output end of the first amplifying unit.

5. The voltage sampling circuit according to claim 1, characterized in that: The second voltage dividing unit includes a third sampling resistor and a fourth sampling resistor; The first end of the third sampling resistor serves as the input end of the second voltage dividing unit, and the second end of the third sampling resistor is electrically connected to the first end of the fourth sampling resistor; A first end of the fourth sampling resistor serves as an output end of the second voltage dividing unit, and a second end of the fourth sampling resistor is grounded.

6. The voltage sampling circuit according to claim 5, characterized in that: The first voltage dividing unit further includes a second filter capacitor; The first end of the second filter capacitor is electrically connected to the second end of the third sampling resistor, and the second end of the second filter capacitor is electrically connected to the second end of the fourth sampling resistor.

7. The voltage sampling circuit according to claim 1, characterized in that: The second amplification unit includes a second operational amplifier; The non-inverting input terminal of the second operational amplifier serves as the input terminal of the second amplifying unit; The inverting input terminal of the second operational amplifier is electrically connected to the output terminal of the second operational amplifier; The output end of the second operational amplifier serves as the output end of the second amplifying unit.

8. The voltage sampling circuit according to claim 1, characterized in that: The voltage division output unit includes a fifth sampling resistor, a sixth sampling resistor and a third filtering capacitor; The first end of the fifth sampling resistor serves as the input end of the voltage division output unit, and the second end of the fifth sampling resistor is electrically connected to the first end of the sixth sampling resistor; The second end of the sixth sampling resistor is grounded; The first end of the third filter capacitor is electrically connected to the first end of the sixth sampling resistor, and the second end of the third filter capacitor is electrically connected to the second end of the sixth sampling resistor.

9. A voltage sampling device, characterized in that: The device comprises the voltage sampling circuit as described in any one of claims 1-8.

10. An electronic device, characterized in that: The electronic device comprises the voltage sampling device as claimed in claim 9.

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