Multi-range voltage measuring circuit, device and method

Abstract

The invention discloses a multi-range voltage measurement circuit, device and method, and the circuit comprises a first resistor unit, the first end of which is connected with a sampling end; the second resistor units are different in resistance value and correspond to different measuring ranges, the first end of each second resistor unit is connected with the second end of the first resistor unit, and the first end of each second resistor unit is connected with the result output end; the plurality of first switch units correspond to the plurality of second resistor units, and the first end of each first switch unit is correspondingly connected with the second end of the second resistor unit; the input end of the negative feedback unit is connected with the second end of each first switch unit, the output end of the negative feedback unit is connected with the first end of each first switch unit, and the negative feedback unit is used for achieving a virtual off state under the condition that the first switch units are switched on, so that no current passes through the first switch units.

Description

Technical Field

[0001] The present application relates to the field of voltage measurement circuits, and in particular to a multi-range voltage measurement circuit, device, and method. Background Art

[0002] With the advancement of measurement and control technology, devices are placing increasingly higher demands on measurement circuits and increasing their precision. In auto-ranging applications, a common method involves using analog switches to perform multi-range sampling. Compared to switching with relays, this method can achieve shorter switching times. However, analog switches have an internal on-resistance, typically ranging from tens to hundreds of ohms, which can reduce the measurement accuracy of the measurement circuit. Summary of the Invention

[0003] The present application aims to provide a multi-range voltage measurement circuit, device and method, which can improve the voltage measurement accuracy.

[0004] The present invention provides a multi-range voltage measurement circuit, including:

[0005] a first resistance unit, wherein a first end of the first resistance unit is connected to the sampling end;

[0006] a plurality of second resistance units with different resistance values, the plurality of second resistance units corresponding to different measurement ranges, the first end of each second resistance unit being connected to the second end of the first resistance unit, and the first end of each second resistance unit being connected to the result output end;

[0007] a plurality of first switch units, the plurality of first switch units corresponding to the plurality of second resistance units, and a first end of each of the first switch units correspondingly connected to a second end of the second resistance unit;

[0008] A negative feedback unit, wherein the input end of the negative feedback unit is connected to the second end of each first switching unit, and the output end of the negative feedback unit is connected to the first end of each first switching unit. The negative feedback unit is used to achieve a virtual-off state when the first switching unit is turned on, so that no current passes through the first switching unit.

[0009] According to some embodiments of the present application, the negative feedback unit includes:

[0010] An operational amplifier, wherein a non-inverting input terminal of the operational amplifier is grounded, an inverting input terminal of the operational amplifier is connected to the second terminal of each first switch unit, and an output terminal of the operational amplifier is connected to the first terminal of each first switch unit.

[0011] According to some embodiments of the present application, the negative feedback unit further includes:

[0012] Multiple second switch units, the multiple second switch units correspond to the multiple first switch units, the first end of each second switch unit is connected to the first end of the corresponding first switch unit, and the second ends of the multiple second switch units are all connected to the output end of the operational amplifier.

[0013] According to some embodiments of the present application, each of the first switch units includes:

[0014] A first analog switch, wherein a first end of the first analog switch is correspondingly connected to the second end of the second resistance unit, and a second end of the first analog switch is connected to the input end of the negative feedback unit.

[0015] In a second aspect, an embodiment of the present application discloses a voltage measurement device, including the multi-range voltage measurement circuit as described above.

[0016] In a third aspect, an embodiment of the present application discloses a voltage measurement method, which is applied to the multi-range voltage measurement circuit as described above, and the method includes:

[0017] Get the target range;

[0018] Controlling a first target switch unit to be turned on, where the first target switch unit is a first switch unit corresponding to a target resistance unit, and the target resistance unit is a second resistance unit corresponding to the target range;

[0019] Obtaining the voltage of the result output terminal, the resistance value of the first resistance unit, and the resistance value of the target resistance unit;

[0020] A voltage measurement result is obtained according to the voltage at the result output terminal, the resistance value of the first resistance unit, and the resistance value of the target resistance unit.

[0021] According to some embodiments of the present application, the first target switch unit and the second target switch unit are synchronously controlled to be turned on, and the second target switch unit is a second switch unit corresponding to the first target switch unit.

[0022] In the embodiment of the present application, the first switch unit corresponding to the target range is controlled to be turned on, thereby turning on the second resistance unit corresponding to the target range to perform voltage measurement. A negative feedback unit is used to achieve a virtual off state when the first switch unit is turned on, so that no current flows through the first switch unit, thereby eliminating the voltage drop across the first switch unit. This prevents the internal resistance of the first switch unit from affecting the voltage measurement and improves measurement accuracy.

[0023] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become obvious from the description below, or will be learned through practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present application is further described below with reference to the accompanying drawings and embodiments, wherein:

[0025] Figure 1 A circuit diagram of an embodiment of a multi-range voltage measurement circuit provided by the present application;

[0026] Figure 2 This is a flow chart of an embodiment of the voltage measurement method provided by this application. DETAILED DESCRIPTION

[0027] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0028] In the description of this application, it should be understood that descriptions involving orientation, such as the orientation or positional relationship indicated by up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0029] In the description of this application, "a plurality" refers to more than two. The use of "first" or "second" is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0030] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0031] The following is based on Figures 1 to 2 The present invention describes a multi-range voltage measurement circuit, device, and method provided by embodiments of the present application.

[0032] The present invention provides a multi-range voltage measurement circuit, including:

[0033] A first resistance unit, wherein a first end of the first resistance unit is connected to the sampling end;

[0034] a plurality of second resistance units with different resistance values, the plurality of second resistance units corresponding to different measurement ranges, the first end of each second resistance unit being connected to the second end of the first resistance unit, and the first end of each second resistance unit being connected to the result output end;

[0035] A plurality of first switch units, the plurality of first switch units corresponding to the plurality of second resistor units, and a first end of each first switch unit correspondingly connected to a second end of a second resistor unit;

[0036] A negative feedback unit, wherein the input end of the negative feedback unit is connected to the second end of each first switch unit, and the output end of the negative feedback unit is connected to the first end of each first switch unit. The negative feedback unit is used to achieve a virtual short and virtual open state when the first switch unit is turned on, so that no current passes through the first switch unit.

[0037] In the embodiment of the present application, a first resistor unit and a second resistor unit are connected in series to perform voltage division. Second resistor units with different resistance values ​​correspond to different measurement ranges. The first switch unit corresponding to the target measurement range is controlled to conduct, thereby conducting the second resistor unit corresponding to the target range to perform voltage measurement. A negative feedback unit is used to achieve a virtual off state when the first switch unit is conducting, so that no current flows through the first switch unit, thereby eliminating the voltage drop across the first switch unit. This prevents the internal resistance of the first switch unit from affecting the voltage measurement and improves measurement accuracy.

[0038] Since the first switch unit is located in the voltage divider loop, one of the first switch units is always kept closed by control. For example, when voltage measurement is performed, the corresponding first switch unit is kept closed. When voltage measurement is not performed, any first switch unit is kept closed. This enables the first-end voltage of other disconnected first switch units to be pulled down by the conduction loop. Even if the sampling end has a high input voltage, multiple first switch units always operate within the safe voltage range after voltage division. Therefore, the device can be widely used in low-voltage and high-voltage measurement environments.

[0039] In some embodiments of the present application, the number of resistors in the first resistor unit is not limited. The first resistor unit may include multiple resistors or one resistor (for example, Figure 1 R in ).

[0040] In some embodiments of the present application, the number of second resistance units and the number of resistors in the second resistance unit are not limited. The second resistance unit may include multiple resistors or one resistor. For example, the number of second resistance units is 3, and each second resistance unit includes one resistor (for example, Figure 1 R1, R2, R3 in ).

[0041] In some embodiments of the present application, the voltage measurement signal outputted from the result output terminal is fed back through a high input impedance circuit.

[0042] In some embodiments of the present application, the negative feedback unit includes:

[0043] An operational amplifier, wherein a non-inverting input terminal of the operational amplifier is grounded, an inverting input terminal of the operational amplifier is connected to the second terminal of each first switch unit, and an output terminal of the operational amplifier is connected to the first terminal of each first switch unit.

[0044] In this embodiment, an operational amplifier (e.g., Figure 1 U) in the negative feedback is configured. Due to the virtual short and virtual open characteristics of the operational amplifier in the negative feedback state, no current flows through the first switching unit.

[0045] In some embodiments of the present application, the negative feedback unit further includes:

[0046] A plurality of second switch units are provided, the plurality of second switch units correspond to the plurality of first switch units, a first end of each second switch unit is connected to a first end of a corresponding first switch unit, and second ends of the plurality of second switch units are all connected to an output end of the operational amplifier.

[0047] In this embodiment, the target range is selected by synchronously controlling the first switch unit and the second switch unit corresponding to the target range to be turned on, thereby turning on the corresponding second resistance unit.

[0048] In some embodiments of the present application, each first switch unit includes:

[0049] The first analog switch has a first end connected to the second end of the second resistor unit, and a second end connected to the input end of the negative feedback unit.

[0050] In this embodiment, the first analog switch (eg, Figure 1 The switching rate of S1, S2, and S3 in the range is fast, and range selection and switching can be performed quickly.

[0051] In some embodiments of the present application, each second switch unit includes:

[0052] The second analog switch is connected to the first end of the corresponding first switch unit, and the second end of the second analog switch is connected to the output end of the operational amplifier.

[0053] In this embodiment, the second analog switch (eg, Figure 1 The switching rate of S4, S5, and S6 is fast, and range selection and switching can be performed quickly.

[0054] In addition, an embodiment of the present application discloses a voltage measurement device, including the multi-range voltage measurement circuit as described above.

[0055] In the embodiment of the present application, the first switch unit corresponding to the target range is controlled to be turned on, thereby turning on the second resistance unit corresponding to the target range to perform voltage measurement. A negative feedback unit is used to achieve a virtual off state when the first switch unit is turned on, so that no current flows through the first switch unit, thereby eliminating the voltage drop across the first switch unit. This prevents the internal resistance of the first switch unit from affecting the voltage measurement and improves measurement accuracy.

[0056] In addition, the embodiment of the present application discloses a voltage measurement method, which is applied to the multi-range voltage measurement circuit as described above. Figure 2 As shown, the method includes:

[0057] Step S100: obtaining a target range;

[0058] Step S200: controlling a first target switch unit to be turned on, where the first target switch unit is a first switch unit corresponding to a target resistance unit, and the target resistance unit is a second resistance unit corresponding to a target range;

[0059] Step S300: obtaining the voltage of the result output terminal, the resistance value of the first resistance unit, and the resistance value of the target resistance unit;

[0060] Step S400: obtaining a voltage measurement result according to the voltage at the result output terminal, the resistance value of the first resistance unit, and the resistance value of the target resistance unit.

[0061] In the embodiment of the present application, the first switch unit corresponding to the target range is controlled to be turned on, thereby turning on the second resistance unit corresponding to the target range to perform voltage measurement. A negative feedback unit is used to achieve a virtual off state when the first switch unit is turned on, so that no current flows through the first switch unit, thereby eliminating the voltage drop across the first switch unit. This prevents the internal resistance of the first switch unit from affecting the voltage measurement and improves measurement accuracy.

[0062] In step S200 , when the first target switch unit is controlled to be turned on, the other first switch units are all turned off.

[0063] In step S400, the voltage measurement result is calculated using the following formula:

[0064]

[0065] Wherein, Vout is the voltage of the result output terminal, Vin is the voltage of the sampling terminal, that is, the voltage measurement result, R11 is the resistance value of the target resistance unit, and R12 is the resistance value of the first resistance unit.

[0066] In some embodiments of the present application, the first target switch unit and the second target switch unit are synchronously controlled to be turned on, and the second target switch unit is a second switch unit corresponding to the first target switch unit.

[0067] In this embodiment, the target range is selected by synchronously controlling the first switch unit and the second switch unit corresponding to the target range to be turned on, thereby turning on the corresponding second resistance unit, that is, turning on the target resistance unit.

[0068] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. A multi-range voltage measurement circuit, characterized in that: include: a first resistance unit, wherein a first end of the first resistance unit is connected to the sampling end; a plurality of second resistance units with different resistance values, the plurality of second resistance units corresponding to different measurement ranges, the first end of each second resistance unit being connected to the second end of the first resistance unit, and the first end of each second resistance unit being connected to the result output end; a plurality of first switch units, the plurality of first switch units corresponding to the plurality of second resistance units, and a first end of each of the first switch units correspondingly connected to a second end of the second resistance unit; A negative feedback unit, wherein the input end of the negative feedback unit is connected to the second end of each first switching unit, and the output end of the negative feedback unit is connected to the first end of each first switching unit. The negative feedback unit is used to achieve a virtual-off state when the first switching unit is turned on, so that no current passes through the first switching unit.

2. The multi-range voltage measurement circuit according to claim 1, characterized in that: The negative feedback unit comprises: An operational amplifier, wherein a non-inverting input terminal of the operational amplifier is grounded, an inverting input terminal of the operational amplifier is connected to the second terminal of each first switch unit, and an output terminal of the operational amplifier is connected to the first terminal of each first switch unit.

3. The multi-range voltage measurement circuit according to claim 2, characterized in that: The negative feedback unit also includes: Multiple second switch units, the multiple second switch units correspond to the multiple first switch units, the first end of each second switch unit is connected to the first end of the corresponding first switch unit, and the second ends of the multiple second switch units are all connected to the output end of the operational amplifier.

4. The multi-range voltage measurement circuit according to claim 1, characterized in that: Each of the first switch units includes: A first analog switch, wherein a first end of the first analog switch is correspondingly connected to the second end of the second resistance unit, and a second end of the first analog switch is connected to the input end of the negative feedback unit.

5. A voltage measuring device, characterized in that: The multi-range voltage measurement circuit comprises the multi-range voltage measurement circuit according to any one of claims 1 to 4.

6. A voltage measurement method, characterized in that: Applied to the multi-range voltage measurement circuit according to any one of claims 1 to 4, the method comprising: Get the target range; Controlling a first target switch unit to be turned on, where the first target switch unit is a first switch unit corresponding to a target resistance unit, and the target resistance unit is a second resistance unit corresponding to the target range; Obtaining the voltage of the result output terminal, the resistance value of the first resistance unit, and the resistance value of the target resistance unit; A voltage measurement result is obtained according to the voltage at the result output terminal, the resistance value of the first resistance unit, and the resistance value of the target resistance unit.

7. The voltage measurement method according to claim 6, characterized in that: The first target switch unit and the second target switch unit are synchronously controlled to be turned on, where the second target switch unit is a second switch unit corresponding to the first target switch unit.

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