Multi-range current acquisition circuit

Abstract

The utility model discloses a multi-range current acquisition circuit, which comprises a load current acquisition circuit and a current bypass circuit, the load current acquisition circuit is connected in series between a power supply and a load resistor RX, and the current bypass circuit is connected in parallel with one side of the load current acquisition circuit. According to the utility model, the current bypass circuit is designed to be connected in parallel with one side of the load current acquisition circuit, so that current acquisition is not influenced after normal switching of the load current acquisition circuit, and a new current path can be provided when the acquisition circuit is not switched so as to ensure that the load at the output end can work normally.

Description

TECHNICAL FIELD

[0001] The utility model relates to power data monitoring technical field especially relates to a multi-range current acquisition circuit. BACKGROUND

[0002] The most mainstream scheme of current sampling at present is the form of shunt resistance, and the current flows through the sampling resistance to form a voltage difference, and the current value can be measured and calculated by collecting the pressure difference. When the span of the current is extremely large, such as the working current is above 10A, and the static current is in the uA level, it is impossible to use a fixed resistance for acquisition. Because the voltage difference of the large resistance is large when the current is large, it will cause the voltage to be divided in the whole power supply circuit, thereby causing the voltage loss of the power supply end to be too much to reach the load end, and the load end cannot work normally due to insufficient voltage. And the small resistance can collect large current, and the voltage signal is too small to collect or the precision is poor when testing small current. Therefore, multiple sampling resistors need to be switched to realize acquisition.

[0003] The current problem is that when the load current works in the static small current, the current acquisition circuit will switch to work in the small current range of the large resistance, and when the load starts to work, the working current suddenly increases, and the current acquisition circuit fails to switch to the small resistance large current range in time, at this time, the voltage of the load end will rapidly decrease, and even cannot work. UTILITY MODEL CONTENTS

[0004] The utility model mainly aims at providing a multi-range current acquisition circuit, which aims at solving the problem of abnormal power supply caused by the output voltage drop due to the untimely multi-range switching.

[0005] In order to achieve the above-mentioned purpose, the utility model provides a multi-range current acquisition circuit, which comprises: a load current acquisition circuit and a current bypass circuit, the load current acquisition circuit is connected in series between the power supply and the load resistance RX, and the current bypass circuit is connected in parallel on one side of the load current acquisition circuit.

[0006] The further technical scheme of the utility model is that the current bypass circuit comprises diode Q1, diode Q2, diode Q3, diode Q4 and operational amplifier APM1.

[0007] The negative electrode of diode Q1 is connected with the positive electrode of diode Q2, and one end of the load current acquisition circuit is connected, the negative electrode of diode Q3 is connected with the positive electrode of diode Q4, and the other end of the load current acquisition circuit and the pin 1 of the operational amplifier APM1 are connected, and the positive electrode of diode Q1 is connected with the negative electrode of diode Q2, the positive electrode of diode Q3, the negative electrode of diode Q4, the pin 2 and the pin 3 of the operational amplifier APM1.

[0008] The further technical scheme of the utility model discloses, the current bypass circuit still includes resistance R4, one end of resistance R4 is connected with the negative pole of diode Q4, and the other end is connected with pin 2 and pin 3 of operational amplifier APM1.

[0009] The further technical scheme of the utility model discloses, the load current acquisition circuit includes resistance R1, resistance R2, resistance R3, operational amplifier APM2, analog-digital converter ADC and switch, one end of resistance R1, one end of resistance R2, one end of resistance R3 are connected with pin 1 of operational amplifier APM1, pin 2 of operational amplifier APM2 and power supply negative pole, one end of switch is connected with pin 1 of operational amplifier APM2, the negative pole of diode Q1 and one end of load resistance RX, the other end of switch is connected with the other end of resistance R1, or the other end of resistance R2, or the other end of resistance R3, and the other end of load resistance RX is connected with power supply positive pole.

[0010] In summary, the utility model discloses multi-range current acquisition circuit has following technical effect:

[0011] The utility model discloses a technical scheme, designs a current bypass circuit, and is connected in parallel on one side of load current acquisition circuit, can guarantee that load current acquisition circuit normal switching does not cause the influence to current acquisition, and can provide a new current passage when guaranteeing that the load of output end can normally work when acquisition circuit is not switched. ACCURACY

[0012] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, the following will briefly introduce the drawing needed to be used in embodiment or prior art description, and obviously, the drawing in the following description is only some embodiments of the utility model, and for ordinary skilled person in the art, under the premise of not paying creative labor, other drawings can also be obtained according to the structure shown in these drawings.

[0013] Figure 1 It is the circuit structure schematic diagram of the utility model discloses multi-range current acquisition circuit.

[0014] The realization of the utility model, functional characteristics and advantages will be further explained with reference to the drawings by combining with the embodiment. DETAILED DESCRIPTION

[0015] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of the utility model.

[0016] In order to solve the problem that the abnormal current is caused by the failure of high-speed switching of multi-range measurement in the current measurement field, the utility model provides a kind of multi-range current acquisition circuit, the technical scheme mainly adopted by the utility model multi-range current acquisition circuit is to design a current bypass circuit, and it is connected in parallel on one side of load current acquisition circuit, it can not only ensure that load current acquisition circuit is switched normally and does not affect current acquisition, but also provide a new current path to ensure that the load of output end can work normally when acquisition circuit is not switched.

[0017] The utility model discloses a key point is to adopt diode to form current bypass circuit, however, the voltage at the two ends of diode can cause leakage, thereby affecting measurement, the utility model also ingeniously solves the problem of diode leakage, and solves the problem that diode bypass can only flow in one direction, and cannot measure positive and negative current.

[0018] Specifically, please refer to Figure 1 The utility model discloses a kind of multi-range current acquisition circuit, and the preferred embodiment of the utility model multi-range current acquisition circuit includes: load current acquisition circuit and current bypass circuit, load current acquisition circuit is connected between power supply and load resistance RX, current bypass circuit is connected in parallel on one side of load current acquisition circuit.

[0019] More specifically, in the embodiment, the current bypass circuit includes diode Q1, diode Q2, diode Q3, diode Q4 and operational amplifier APM1.

[0020] The negative electrode of diode Q1 is connected to the positive electrode of diode Q2, and one end of load current acquisition circuit is connected, the negative electrode of diode Q3 is connected to the positive electrode of diode Q4, and the other end of load current acquisition circuit and the pin 1 of operational amplifier APM1 are connected, the positive electrode of diode Q1 is connected to the negative electrode of diode Q2, the positive electrode of diode Q3, the negative electrode of diode Q4, the pin 2 and pin 3 of operational amplifier APM1.

[0021] In the embodiment, the current bypass circuit further includes resistance R4, one end of resistance R4 is connected to the negative electrode of diode Q4, and the other end is connected to the pin 2 and pin 3 of operational amplifier APM1.

[0022] The load current acquisition circuit includes resistors R1, R2, and R3, operational amplifier APM2, analog-to-digital converter (ADC), and a switch. One end of resistors R1, R2, and R3 is connected to pin 1 of operational amplifier APM1, pin 2 of operational amplifier APM2, and the negative terminal of the power supply. One end of the switch is connected to pin 1 of operational amplifier APM2, the negative terminal of diode Q1, and one end of the load resistor RX. The other end of the switch is connected to the other end of resistor R1, R2, or R3. The other end of the load resistor RX is connected to the positive terminal of the power supply.

[0023] The following combination Figure 1 The working principle of the multi-range current acquisition circuit of this utility model is explained.

[0024] like Figure 1 As shown, resistor RX is the electrical load. Operational amplifier APM2, analog-to-digital converter (ADC), resistors R1, R2, and R3, and a switch together form a multi-range load current acquisition circuit. When the current is very small, the switch switches the circuit to resistor R3, which has a large current. When the current in resistor RX suddenly increases, the voltage across resistor RX increases. When it increases to 0.6V, diodes Q2 and Q3 will conduct (diodes Q1, Q2, Q3, and Q4 are Schottky diodes, with a typical forward voltage of 0.3V). The large current bypasses through diodes Q2 and Q3, limiting the voltage difference across resistor RX to 0.6V. When the load current acquisition circuit switches the switch to resistors R1 or R2, it ensures that the diodes will not conduct if the voltage difference across resistor RX is less than 0.6V. This solves the problem of excessive voltage drop during switch switching causing the load resistor RX to malfunction. This solution results in a maximum voltage loss of only 0.6V before the switch is complete. When the current is negative, diodes Q1 and Q4 operate, thus achieving bidirectional clamping of the sampling resistor voltage difference. When resistors R1 and R2 are switched to appropriate ranges, and the voltage difference is less than 0.6V, operational amplifier APM1 ensures that the voltage difference across diodes Q3 and Q4 is 0V. With 0V across the diodes, there is no leakage current, ensuring normal sampling. Especially during low-current sampling, all current flows through the sampling resistor, guaranteeing that sampling accuracy is not compromised.

[0025] In summary, the multi-range current acquisition circuit of this utility model has the following technical effects:

[0026] The utility model discloses a current bypass circuit is designed, and is connected in parallel on one side of load current collection circuit, can guarantee that load current collection circuit normal switching does not cause the influence to current collection, and can provide a new current passage when guaranteeing that the load of output end can normally work when collection circuit is not switched.

[0027] The above-mentioned is only the preferred embodiment of the utility model, and does not limit the patent range of the utility model, and the equivalent structure transformation of the utility model specification and the attached drawing contents is made under the concept of the utility model, or direct / indirect application in other related technical fields are included in the patent protection range of the utility model.

Claims

1. A multi-range current harvesting circuit, characterized by, The utility model relates to a load current acquisition circuit and a current bypass circuit, the load current acquisition circuit is connected between the power supply and the load resistance RX, and the current bypass circuit is connected in parallel to one side of the load current acquisition circuit. The current bypass circuit comprises diode Q1, diode Q2, diode Q3, diode Q4 and operational amplifier APM1.

2. The multi-range current harvesting circuit of claim 1, wherein, The negative electrode of diode Q1 is connected to the positive electrode of diode Q2 and one end of the load current acquisition circuit, the negative electrode of diode Q3 is connected to the positive electrode of diode Q4 and the other end of the load current acquisition circuit and pin 1 of the operational amplifier APM1, and the positive electrode of diode Q1 is connected to the negative electrode of diode Q2, the positive electrode of diode Q3, the negative electrode of diode Q4, pin 2 and pin 3 of the operational amplifier APM1. The current bypass circuit further comprises resistance R4, one end of which is connected to the negative electrode of diode Q4, and the other end of which is connected to pin 2 and pin 3 of the operational amplifier APM1.

3. The multi-range current harvesting circuit of claim 2, wherein, The load current acquisition circuit comprises resistance R1, resistance R2, resistance R3, operational amplifier APM2, analog-to-digital converter ADC and a switch, one end of resistance R1, one end of resistance R2 and one end of resistance R3 are connected to pin 1 of the operational amplifier APM1, pin 2 of the operational amplifier APM2 and the negative electrode of the power supply, one end of the switch is connected to pin 1 of the operational amplifier APM2, the negative electrode of diode Q1 and one end of the load resistance RX, the other end of the switch is connected to the other end of resistance R1, or the other end of resistance R2, or the other end of resistance R3, and the other end of the load resistance RX is connected to the positive electrode of the power supply.

4. The multi-range current harvesting circuit of claim 2, wherein, ​

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