Positive and negative metering voltage sampling circuit

Abstract

The utility model discloses a positive and negative metering voltage sampling circuit, which comprises a resistor R78, a resistor R79, a resistor R80, a resistor R81, a resistor R82, a resistor R86, a resistor R87, a resistor R88 and a resistor R89, the resistor R88, the resistor R87, the resistor R81, the resistor R79, the resistor R78, the resistor R80, the resistor R82, the resistor R86 and the resistor R89 are sequentially connected in series, a first grounding circuit is electrically connected between the resistor R88 and the resistor R87, the two ends of the resistor R88 are connected with a grounding capacitor C80 in parallel, and the two ends of the resistor R88 are connected with a second grounding circuit in parallel. The two ends of the resistor R87 are connected with a grounding capacitor C81 in parallel, and the end, away from the resistor R86, of the resistor R89 is electrically connected with a second grounding circuit. According to the circuit structure provided by the utility model, the metering chip U6 and the metering chip U2 are respectively connected to the UAP point and the V3P point by utilizing the current direction change of alternating current, so that bidirectional voltage metering can be realized in the same circuit, voltage sampling resistors can be saved, the number of the sampling resistors is effectively reduced, the occupied area of a PCB (Printed Circuit Board) is relatively reduced, and the cost is relatively reduced; and the market competitiveness is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of PCB circuits, in particular to a positive and negative metering voltage sampling circuit. Background Art

[0002] With the continuous development and maturity of electronic energy meter technology, the various circuits of the energy meter are also constantly optimized and mature. In the metering circuit module of the foreign trade electronic energy meter, the traditional conventional voltage sampling circuit is as follows Figure 1 As shown, voltage signals are collected separately through two resistor voltage-dividing circuits. This circuit is currently only used in single-phase anti-theft electricity meters, i.e., double manganese copper sampling or double manganese copper dual-metering foreign trade single-phase meters.

[0003] In the metering circuit module of foreign trade electronic watt-hour meters, the traditional conventional voltage sampling circuit uses more sampling resistors, which occupies more PCB board area, resulting in relatively high cost and increased quality risks caused by device cold soldering or damage. More sampling resistors also increase the difficulty of EMC wiring design layout of the voltage sampling circuit and weaken the anti-interference performance of the voltage sampling circuit. Utility Model Content

[0004] The purpose of the utility model is to solve at least one of the technical problems existing in the prior art and to provide a positive and negative metering voltage sampling circuit to solve the above problem.

[0005] To achieve the above purpose, a positive and negative metering voltage sampling circuit is provided, including a resistor R78, a resistor R79, a resistor R80, a resistor R81, a resistor R82, a resistor R86, a resistor R87, a resistor R88 and a resistor R89, characterized in that: the resistor R88, the resistor R87, the resistor R81, the resistor R79, the resistor R78, the resistor R80, the resistor R82, the resistor R86 and the resistor R89 ​​are connected in series in sequence, a first grounding circuit is electrically connected between the resistor R88 and the resistor R87, and the resistor R88 A grounding capacitor C80 is connected in parallel at both ends of the resistor R87, a grounding capacitor C81 is connected in parallel at both ends of the resistor R87, an end of the resistor R89 ​​away from the resistor R86 is electrically connected to a second grounding circuit, and a grounding capacitor C79 is connected in parallel at both ends of the resistor R89. An access point UAP is provided at the connection between the resistor R86 and the resistor R89, and an access point V3P is provided at the connection between the resistor R87 and the resistor R81. The access point UAP is electrically connected to the metering chip U6, and the access point V3P is electrically connected to the metering chip U2.

[0006] According to the positive and negative metering voltage sampling circuit, the resistor R78, the resistor R79, the resistor R80, the resistor R81, the resistor R82 and the resistor R86 are all high-precision resistors of ten KΩ level.

[0007] According to the positive and negative metering voltage sampling circuit, the resistor R87, the resistor R88 and the resistor R89 ​​are all high-precision resistors of the hundred Ω level.

[0008] According to the positive and negative metering voltage sampling circuit, the voltage division ratio (at least two orders of magnitude) of the 10KΩ class high-precision resistor and the 100Ω class high-precision resistor corresponds to the safe sampling range of the metering chip U6 and the metering chip U2.

[0009] The above solution has at least one of the following beneficial effects:

[0010] 1. The circuit structure of the utility model utilizes the change in the current direction of the alternating current. By connecting the metering chip U6 and the metering chip U2 at the UAP point and the V3P point respectively, bidirectional voltage metering can be realized in the same circuit, which can save voltage sampling resistors, effectively reduce the number of sampling resistors, and relatively reduce the area occupied by the PCB board, and relatively reduce the cost, thereby improving market competitiveness and enhancing the practicality of the circuit.

[0011] 2. The utility model effectively reduces the sampling resistance, effectively reduces the quality risk caused by device cold soldering or damage, and improves the product quality of the electric energy meter.

[0012] 3. The utility model reduces the difficulty of the wiring design layout of the voltage sampling circuit for EMC by effectively reducing the sampling resistance, which not only effectively enhances the anti-interference performance of the voltage sampling circuit, but also improves the measurement accuracy of the electric energy meter by enhancing the anti-interference ability of the electric energy meter, thereby effectively improving the stability and reliability of the operation of the electric energy meter and ensuring the service life requirements.

[0013] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The utility model is further described below in conjunction with the accompanying drawings and embodiments;

[0015] Figure 1 It is a conventional voltage sampling circuit in the metering circuit module of the existing foreign trade electronic electric energy meter;

[0016] Figure 2 This is a circuit diagram of a positive and negative metering voltage sampling circuit of the utility model;

[0017] Figure 3 This is the access circuit diagram of the metering chip U2 of the utility model;

[0018] Figure 4 This is the access circuit diagram of the metering chip U6 of the utility model;

[0019] Legend: Figure 3 In the measurement chip U2, pin 13 is connected to Figure 2 The middle access point V3P is connected;

[0020] Figure 4 Pin 2 of the metering chip U6 is connected to Figure 2 The access point UAP is connected. DETAILED DESCRIPTION

[0021] This section will describe in detail the specific embodiments of the utility model. The preferred embodiments of the utility model are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the utility model, but it cannot be understood as a limitation on the protection scope of the utility model.

[0022] Reference Figure 1-4 The embodiment of the utility model provides a positive and negative metering voltage sampling circuit, including a resistor R78, a resistor R79, a resistor R80, a resistor R81, a resistor R82, a resistor R86, a resistor R87, a resistor R88 and a resistor R89, wherein the resistors R88, R87, R81, R79, R78, R80, R82, R86 and R89 are connected in series in sequence, and the resistors R78, R79, R80, R81, R82 and R86 are all high-precision resistors of ten KΩ level, and the resistors R87, R88 and R89 are connected in series in sequence. 9 are all high-precision resistors of the 100Ω class. The voltage division ratio of the 10KΩ class high-precision resistor to the 100Ω class high-precision resistor corresponds to the safe sampling range of the metering chip U6 and the metering chip U2. By adopting high-precision resistors above 10k class, a voltage sampling analog signal with an order of magnitude equivalent to the potential of the main weak current circuit on the PCB printed circuit board can be formed through voltage division, ensuring that the sampling signal of the metering chip U6 / U2 corresponding to the UAP / V3P point meets the most reasonable sampling range of the metering chip, thereby ensuring the insulation safety of the voltage sampling circuit and improving the anti-interference performance of the voltage sampling circuit;

[0023] A first grounding circuit is electrically connected between the resistor R88 and the resistor R87, a grounding capacitor C80 is connected in parallel at both ends of the resistor R88, a grounding capacitor C81 is connected in parallel at both ends of the resistor R87, a second grounding circuit is electrically connected to one end of the resistor R89 ​​away from the resistor R86, a grounding capacitor C79 is connected in parallel at both ends of the resistor R89, an access point UAP is provided at the connection between the resistor R86 and the resistor R89, an access point V3P is provided at the connection between the resistor R87 and the resistor R81, and the access point UAP is electrically connected There is a metering chip U6, and the access point V3P is electrically connected to the metering chip U2. The current direction change of the alternating current is utilized. Since the potential of the ground terminal is constant at zero, when the input terminal is the positive half axis of the alternating current, the current scheme connects the metering chip U6 from R88-R89, UAP as a voltage sampling signal; when the input terminal is the negative half axis of the alternating current, the current scheme connects the metering chip U2 from R89-R88, V3P as a voltage sampling signal. In this way, two metering bidirectional voltage samplings are realized, and the same circuit realizes bidirectional voltage metering.

[0024] Working principle: The circuit of the utility model utilizes the change of current direction of alternating current. Since the potential of the ground terminal is constant at zero, when the input terminal is the positive half axis of alternating current, the current scheme connects the metering chip U6 from R88-R89, UAP side as a voltage sampling signal; when the input terminal is the negative half axis of alternating current, the current scheme connects the metering chip U2 from R89-R88, V3P side as a voltage sampling signal, thus realizing two metering bidirectional voltage samplings, and realizing bidirectional voltage metering in the same circuit; and by adopting high-precision resistors of 10k level or above, through the form of voltage division, a voltage sampling analog signal of a certain order of magnitude equivalent to the potential of the main weak current circuit on the PCB printed circuit board can be formed, ensuring that the sampling signal of the metering chip U6 / U2 corresponding to the UAP / V3P point meets the most reasonable sampling range of the metering chip, thereby ensuring the insulation safety of the voltage sampling circuit and improving the anti-interference performance of the voltage sampling circuit.

[0025] The embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge scope of ordinary technicians in the technical field without departing from the purpose of the present invention.

Claims

1. A positive and negative metering voltage sampling circuit, comprising a resistor R78, a resistor R79, a resistor R80, a resistor R81, a resistor R82, a resistor R86, a resistor R87, a resistor R88 and a resistor R89, characterized in that: The resistor R88, the resistor R87, the resistor R81, the resistor R79, the resistor R78, the resistor R80, the resistor R82, the resistor R86 and the resistor R89 ​​are connected in series in sequence, a first grounding circuit is electrically connected between the resistor R88 and the resistor R87, a grounding capacitor C80 is connected in parallel at both ends of the resistor R88, a grounding capacitor C81 is connected in parallel at both ends of the resistor R87, an end of the resistor R89 ​​away from the resistor R86 is electrically connected to a second grounding circuit, a grounding capacitor C79 is connected in parallel at both ends of the resistor R89, an access point UAP is provided at the connection between the resistor R86 and the resistor R89, an access point V3P is provided at the connection between the resistor R87 and the resistor R81, the access point UAP is electrically connected to the metering chip U6, and the access point V3P is electrically connected to the metering chip U2.

2. A positive and negative measurement voltage sampling circuit according to claim 1, characterized in that: The resistor R78 , the resistor R79 , the resistor R80 , the resistor R81 , the resistor R82 and the resistor R86 are all high-precision resistors of the 10 KΩ level.

3. A positive and negative measurement voltage sampling circuit according to claim 2, characterized in that: The resistor R87, the resistor R88 and the resistor R89 ​​are all high-precision resistors of the 100Ω level.

4. A positive and negative measurement voltage sampling circuit according to claim 3, characterized in that: The voltage division ratio of the 10KΩ class high-precision resistor and the 100Ω class high-precision resistor corresponds to the safe sampling range of the metering chip U6 and the metering chip U2.

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