CN205941683U - High accuracy voltage current sample system - Google Patents

Abstract

The utility model discloses a high accuracy voltage current sample system, this system include voltage sample module, current sample module, processing module and power module, voltage sample module, current sample module and power module respectively with processing module links to each other, wherein, processing module includes the STC12C5A16S2 singlechip, the application provides a high accuracy voltage current sample system adopts the STC12C5A16S2 singlechip as the treater, and it possess higher conversion efficiency and very fast conversion rate, adoption TPS5430 as the power module of main chip can guarantee the STC12C5A16S2 singlechip 5V to the different voltage input between the 20V under, still can normally work. Adopt the MCP6022 chip as the main chip of voltage sample module and current sample module in addition, voltage and the electric current of having guaranteed the sampling have and have certain precision and stability. Realized that the precision is high, stability is high, measured characteristics such as quick to can select different display mode according to user's demand.

Description

A kind of high-accuracy voltage current sampling system

Technical field

This utility model is related to voltage x current and adopts equipment technical field, and more particularly to one kind can directly be monitored The voltage x current value of operating electrical equipment or certain circuit node is it is ensured that the voltage and current being currently running is in normal model High-accuracy voltage current sampling system within enclosing.

Background technology

DC voltage and current sampling system of the prior art is typically all to be based on simple Ohm's law.I.e. voltage is straight Connect the two ends being connected in parallel on circuit under test, measure running voltage；Electric current is then to flow through, by measurement, the voltage determining resistive element end, So that it is determined that corresponding electric current.Finally carry out A/D conversion, analog quantity is converted to digital quantity, directly displays on the lcd screen.But It is in place of the thinking of traditional design comes with some shortcomings：One is the mutation not considering voltage x current, if a voltage will be sampled The electric current moment change electrical equipment or circuit node it would be possible to unstable data can be produced, thus causing error；Two are the absence of Requirement to conversion speed, part A/D conversion chip operating rate is slower, and work efficiency is low；Three is that display mode is single, leads to Often simply show corresponding data on the lcd screen, lack other display modes.

Utility model content

This utility model provides a kind of high-accuracy voltage current sampling system.

This utility model provides following scheme：

A kind of high-accuracy voltage current sampling system, this system includes voltage sample module, current sample module, processes mould Block and supply module；Described voltage sample module, current sample module and supply module respectively with described processing module phase Even；

Wherein, described processing module includes STC12C5A16S2 single-chip microcomputer；Described current sample module includes the first impedance Unit；Described voltage sample module includes the second impedance unit；Described supply module includes DC voltage converting unit；

Described first impedance unit and described second impedance unit are used to guarantee to input described STC12C5A16S2 mono- The sampled voltage of piece machine is between 0～5 volt；Described DC voltage converting unit is used for guaranteeing to be supplied to described STC12C5A16S2 The running voltage of single-chip microcomputer is stable 5 volt voltage.

Preferably：Described first impedance unit includes the first resistor element being serially connected and second resistance element；Institute State 3rd resistor element and the 4th resistive element that the second impedance unit includes being serially connected.

Preferably：The resistance value of described first resistor element and described second resistance element and the electric current of circuit to be sampled Numerical value is related；The resistance value of described 3rd resistor element and described 4th resistive element and the voltage range phase of circuit to be sampled Close.

Preferably：Described second resistance element is in series with amplifier differential amplifier circuit, and described 4th resistance components in series has Track to track operational amplification circuit；Described track to track operational amplification circuit and described amplifier differential amplifier circuit respectively with described STC12C5A16S2 single-chip microcomputer is connected.

Preferably：Described track to track operational amplification circuit and described amplifier differential amplifier circuit are integrated in same jointly In MCP6022 chip.

Preferably：TPS5430 chip that described DC voltage converting unit includes being sequentially connected, feedback circuit and passive Filter circuit；Described passive filter circuit is connected with described STC12C5A16S2 single-chip microcomputer.

Preferably：Described passive filter circuit is LC filter circuit.

Preferably：Also include the display module being connected with described STC12C5A16S2 single-chip microcomputer；Described display module is used for Show that the transmission signal pin of described STC12C5A16S2 single-chip microcomputer transmits voltage and/or current sample number by communication protocol According to.

Preferably：Described display module includes LCD display.

The specific embodiment being provided according to this utility model, the utility model discloses following technique effect：

By this utility model, it is possible to achieve a kind of high-accuracy voltage current sampling system, under a kind of implementation, should System can include voltage sample module, current sample module, processing module and supply module；Described voltage sample module, Current sample module and supply module are connected with described processing module respectively；Wherein, described processing module includes STC12C5A16S2 single-chip microcomputer；Described current sample module includes the first impedance unit；Described voltage sample module includes second Impedance unit；Described supply module includes DC voltage converting unit；Described first impedance unit and described second impedance list Unit is used to guarantee the sampled voltage inputting described STC12C5A16S2 single-chip microcomputer between 0～5 volt；Described DC voltage conversion Unit is used for guaranteeing that the running voltage being supplied to described STC12C5A16S2 single-chip microcomputer is stable 5 volt voltage.The application provides High-accuracy voltage current sampling system, using STC12C5A16S2 single-chip microcomputer as processor, it has higher conversion effect Rate and faster conversion speed, can ensure that STC12C5A16S2 single-chip microcomputer using TPS5430 as the supply module of master chip Under different control sources between 5V to 20V, remain to normal work.In addition adopt MCP6022 chip as voltage sample mould The master chip of block and current sample module has certain precision and stability it is ensured that the voltage and current of sampling has.Realize The features such as high precision, stability are high, measurement is quick, and different display modes can be selected according to the demand of user.

Certainly, implement arbitrary product of the present utility model to it is not absolutely required to reach all the above advantage simultaneously.

Brief description

In order to be illustrated more clearly that this utility model embodiment or technical scheme of the prior art, below will be to embodiment In required use accompanying drawing be briefly described it should be apparent that, drawings in the following description are only of the present utility model Some embodiments, for those of ordinary skill in the art, on the premise of not paying creative work, can also be according to this A little accompanying drawings obtain other accompanying drawings.

Fig. 1 is a kind of structured flowchart of high-accuracy voltage current sampling system that this utility model embodiment provides；

Fig. 2 is a kind of circuit theory diagrams of high-accuracy voltage current sampling system that this utility model embodiment provides；

Fig. 3 is the supply module circuit theory diagrams that this utility model embodiment provides.

Specific embodiment

Below in conjunction with the accompanying drawing in this utility model embodiment, the technical scheme in this utility model embodiment is carried out Clearly and completely description is it is clear that described embodiment is only a part of embodiment of this utility model rather than whole Embodiment.Based on the embodiment in this utility model, the every other embodiment that those of ordinary skill in the art are obtained, all belong to Scope in this utility model protection.

Embodiment

Referring to Fig. 1, Fig. 2, a kind of high-accuracy voltage current sampling system of providing for this utility model embodiment, such as Fig. 1, Shown in Fig. 2, this system includes voltage sample module, current sample module, processing module and supply module；Described voltage sample Module, current sample module and supply module are connected with described processing module respectively；Wherein, described processing module includes STC12C5A16S2 single-chip microcomputer；Described current sample module includes the first impedance unit；Described voltage sample module includes second Impedance unit；Described supply module includes DC voltage converting unit；Described supply module includes DC voltage converting unit；Institute State the first impedance unit and described second impedance unit is used to the sampling that guarantees to input described STC12C5A16S2 single-chip microcomputer Voltage is between 0～5 volt；Described DC voltage converting unit is used for guaranteeing to be supplied to the work of described STC12C5A16S2 single-chip microcomputer It is stable 5 volt voltage as voltage.In actual applications, described first impedance unit includes the first resistor element being serially connected R1 and second resistance element R2；Described second impedance unit includes the 3rd resistor element R3 being serially connected and the 4th resistance Element R4.Further, the electricity of the resistance value of described first resistor element R1 and second resistance element R2 and circuit to be sampled Fluxion value is related；The resistance value of described 3rd resistor element R3 and the 4th resistive element R4 and the voltage range of circuit to be sampled Related.Further, described second resistance element R2 is in series with amplifier differential amplifier circuit, described 4th resistive element R4 string It is associated with track to track operational amplification circuit；Described track to track operational amplification circuit and described amplifier differential amplifier circuit respectively with institute State STC12C5A16S2 single-chip microcomputer to be connected.In order to simplify the circuit structure of this device, described track to track operation amplifier electricity further Road and described amplifier differential amplifier circuit can be integrated in same MCP6022 chip jointly.

The system that the embodiment of the present application provides, has high accuracy and the voltage sampling circuit of high stability and current sample is electric Sample to corresponding electrical equipment or circuit node in road, and sampled result is input to STC12C5A16S2 single-chip microcomputer, carries out The A/D conversion of fast speed, and output result is shown according to the selection of user.STC12C5A16S2 single-chip microcomputer is a generation New Type of Chip Microcomputer.51 single-chip microcomputers of this new generation have at high speed, and capacity of resisting disturbance is stronger, the advantages of power attenuation is relatively low. Its completely compatible original 51 single-chip microcomputer of program code energy, but speed can be soon between 8 times to 12 times.Have 2 road PWM waveform simultaneously Controlling switch and eight tunnels high speed tens mould ALT-CH alternate channel (250,000 time/second), it is also directed to may produce during controlled motor simultaneously Raw strongly disturbing situation, is made that necessarily jamproof test to single-chip microcomputer.Ensure that monolithic function under stronger interference Can there is reasonable performance.This utility model mainly has the port used to have the VCC port of 41 feet, the GND port of 17 feet, 40 feet P1.0 and 39 feet P1.1 A/D conversion port.The A/D converter of New Type of Chip Microcomputer STC12C5A16S2 is by many parts structure Become.Analogue signal before this by by CHS0/CHS1/CHS2 come the ADC multidiameter option switch of the analog input signal passage of selection, Then the voltage inputting passes through a comparator, then is input to one gradually in comparand register, and the result obtaining is re-fed into turning Change in result register.These depositors all to be controlled by AD_CONTR depositor.Specific workflow is such as among these Under：The analog input analog multiplexer of ADC0 to 7, delivers to comparator.Digital/analog converter (DAC) is converted into mould The comparative result intending inputting and gradually compare will be saved to analog comparater and compare, by the output conversion of successive approximation register Result.Through A/D conversion, the result of conversion is saved in transformation result depositor ADC_RES and ADC_RESL of ADC, arranges ADC The depositor ADC_CONTR mark ADC_FLAG of the A/D converter of control end, inquires about or sends interrupted application program.Simulation is logical Road selects to control control register ADC_CONTR CHS2 to CHS0 to be determined by ADC.It is arranged on ADC control register ASC_ The position of POWER, the conversion speed of ADC is determined by SPEED1 and SPEED0 of the control register of ADC.Before the use should To ADC power supply.The embodiment of the present application can also include the display module being connected with described STC12C5A16S2 single-chip microcomputer；Described aobvious Show that module is used for showing that the transmission signal pin of described STC12C5A16S2 single-chip microcomputer transmits voltage and/or electricity by communication protocol Stream sampled data.Further, described display module includes LCD display.

The result of AD conversion：

$10-bitA/DConverion\mathrm{Re}solt(ADC\_RES\[7:0\],ADC\_RESL\[1:0\])=1024\×\frac{Vin}{Vcc}$

I.e. input voltage is multiplied by 1024 divided by the result that 5V draws, then total is converted into binary representation, wherein high by eight Position is left in ADC_RES, and low two leave in ADC_RESL.Finally there will be data in ADC depositor according to user Selection, program display is received by lcd screen or PC, embodies the multiformity of display.

In concrete making, this current sample modular circuit principle can be is 500 Ω resistance R1 by resistance and resistance is The resistance R2 of 10 Ω is connected, and according to different circuital current numerical value, can determine the numerical value of series circuit.The application is implemented Example is using the resistance of 500 Ω and 10 Ω.Measure the voltage at 10 Ω resistance two ends, the voltage now measuring should be electricity to be sampled 10 times of stream.Likewise, for the stability of sample rate current, output voltage is accessed an amplifier differential amplifier circuit, according to The computing formula of calculus of differences amplifying circuit, the amplification of this circuit is 1 times, if different amplifications will be selected, can To select different resistance.The resistance R3 for 15K Ω for the resistance and resistance can be the big electricity of 3K Ω by this pressure sampling module Resistance R4 carries out series connection and realizes partial pressure, and voltage is controlled between 0-5V.Partial pressure can be determined according to different circuit voltage scopes The numerical value of resistance.The embodiment of the present application adopts the resistance of 15K Ω and 3K Ω.But in practice, output voltage is not necessarily strict and divides Piezoresistance is proportional, and reason is there is possible voltage pulsation, causes output result unstable.So should be by the voltage of output By the high precision operating amplifier of a track to track, the principle according to concomitant circuit is it is ensured that the stablizing of output voltage.Can think To, voltage sample module and current sample wired in parallel, the difference inside same MCP6022 chip can be used in conjunction with Operational amplifier.

In this supply module of specific design, as shown in figure 3, what described DC voltage converting unit included being sequentially connected TPS5430 chip, feedback circuit and passive filter circuit；Described passive filter circuit and described STC12C5A16S2 single-chip microcomputer It is connected.Further, described passive filter circuit is LC filter circuit.This supply module adopts TPS5430 as master chip；From The fixing magnitude of voltage of the VSNS pin output of TPS5430, this pin and external feedback circuit connect, by feedback circuit by electricity Pressure is amplified to 5V.The outfan of feedback circuit passes through LC low-pass filter circuit, filters off ripple it is ensured that the stability of output voltage. So this supply module can provide stable 5V direct voltage output it is ensured that the normal work of single-chip microcomputer.TPS5430 conduct A member of DC/DC manostat series, is the PWM converter of a High Output Current, is integrated with low resistance high side N-channel MOSFET.Substrate includes an efficient voltage error amplifier in the function of listing, there is provided strict voltage-regulation Under precision transient condition, undervoltage lockout circuit, to prevent error starting, until input voltage reaches the 5.5V slow turn-on of internal setting Circuit limit inrush currents and electric voltage feed forward circuit, to improve transient response.Using ENA pin power cutoff current reduction to allusion quotation 18 μ A of type.Other functions also include a high level and effectively enable, excessively stream restriction, overvoltage protection and Thermal shutdown.In order to reduce Design complexity and outer member quantity, TPS5430 carries out internal compensation using feedback circuit.TPS5430 can adjust multiple Power supply, including 24V bus.TPS5430 device has thermal-enhanced, generally 8 hem facing piece encapsulation.Simultaneously TI provide evaluation module with Help quickly realize high-performance power supply design, and meet the strict equipment development cycle.The input voltage of this supply module Scope, because the output voltage of lead battery that the mode that the present embodiment provides is adopted is 6V, but in order to make Circuit board can have and compares being widely applied property, can will be adjustable for the scope of input voltage wider, so can With set input voltage scope as 5V-22V.Output voltage, the output voltage of the embodiment of the present application is 5V.Input voltage stricture of vagina Ripple, output voltage ripple, because the circuit of this Shen embodiment is mainly used in DC/DC blood pressure lowering it is possible to design one is less Ripple, i.e. 40mV.Output rated current, is 1A.Input capacitance, TPS5430 as the master chip of DC/DC reduction voltage circuit, it Input capacitance Cin is necessarily required to a larger decoupling capacitor.The specific value of electric capacity depends on our design requirement, typically It is to take 10uF.If not having so big electric capacity it is also possible to be substituted with a less electric capacity, but it is intended to meet the function of filtering.

Outputting inductance, outputting inductance is to filter the ripple of output voltage.Because there being a compensation inside TPS5430 Circuit, so the outputting inductance that we select determines output current, and the tolerant electric current of outputting inductance institute have to be larger than defeated Go out the maximum of electric current.Therefore we select the inductance of 47uH as outputting inductance.

Output capacitance, output capacitance and and outputting inductance constitute LC filter circuit altogether, by the filter of the ripple of output voltage Fall, to ensure the stability of output voltage.We can select the frequency of LC filter circuit, thus being assured that output capacitance The value of Cout.

$Cout=\frac{1}{3357\×Lout\×Fco\×Vout}=\frac{1}{3357\×8.45KHz\×47uH\×5V}=150uF$

As shown from the above formula, if the frequency of filter circuit is taken as 8.45KHz, output capacitance Cout=150uF.

Bootstrap capacitor, each TPS54331 circuit requires one bootstrap capacitor of design, and bootstrap capacitor is attached to PH An electric capacity between pin and BOOT pin, the value of bootstrap capacitor is necessary for the ceramic mould electric capacity of the high-quality of 0.01uF.

So Rfbt can be taken to be 10K, Rfbb is 3.24K.

Store stream diode：One must be connect between PH and ground and store stream diode, storage stream diode is one and replys Xiao Ji soon Special diode.The alternative condition of this diode is the pressure condition of the maximum low pressure must being fulfilled for circuit, and its backward voltage is necessary Higher than the maximum voltage that can be generated by PH pin.Therefore this store stream diode we can select Ti company produce model For 40V, operating current is the diode of 1A for pressure for B140-13-F.

The determination of Rfbt and Rfbb resistance, the output resistance of TPS54331 is adjustable.Exporting comparison voltage Vref is 1.221V, in order to ensure that output voltage is 5V, we can first set Rfbt as 10K.

$Rfbb=\frac{Rfbt\×1.221}{Vout-1.221}=\frac{10\×1.221}{5-1.221}=3.24K$

In a word, the high-accuracy voltage current sampling system that the application provides, using STC12C5A16S2 single-chip microcomputer as place Reason device, it has higher conversion efficiency and conversion speed faster, permissible as the supply module of master chip using TPS5430 Ensure, under different control sources between 5V to 20V for the STC12C5A16S2 single-chip microcomputer, to remain to normal work.In addition adopt MCP6022 chip as voltage sample module and current sample module master chip it is ensured that sampling voltage and current have tool There is certain precision and stability.The features such as achieve high precision, stability height, measure quick, and can be according to the demand of user Select different display modes.

It should be noted that herein, such as first and second or the like relational terms are used merely to a reality Body or operation are made a distinction with another entity or operation, and not necessarily require or imply these entities or deposit between operating In any this actual relation or order.And, term " inclusion ", "comprising" or its any other variant are intended to Comprising of nonexcludability, wants so that including a series of process of key elements, method, article or equipment and not only including those Element, but also include other key elements being not expressly set out, or also include for this process, method, article or equipment Intrinsic key element.In the absence of more restrictions, the key element that limited by sentence "including a ..." it is not excluded that Also there is other identical element including in the process of described key element, method, article or equipment.

The foregoing is only preferred embodiment of the present utility model, be not intended to limit protection model of the present utility model Enclose.All any modification, equivalent substitution and improvement made within spirit of the present utility model and principle etc., are all contained in this reality With in new protection domain.

Claims (9)

1. a kind of high-accuracy voltage current sampling system is it is characterised in that described system includes voltage sample module, current sample Module, processing module and supply module；Described voltage sample module, current sample module and supply module respectively with described Processing module is connected；

Wherein, described processing module includes STC12C5A16S2 single-chip microcomputer；Described current sample module includes the first impedance unit； Described voltage sample module includes the second impedance unit；Described supply module includes DC voltage converting unit；

Described first impedance unit and described second impedance unit are used to guarantee to input described STC12C5A16S2 single-chip microcomputer Sampled voltage between 0～5 volt；Described DC voltage converting unit is used for guaranteeing to be supplied to described STC12C5A16S2 monolithic The running voltage of machine is stable 5 volt voltage.

2. system according to claim 1 is it is characterised in that described first impedance unit includes the first electricity being serially connected Resistance element and second resistance element；Described second impedance unit includes the 3rd resistor element being serially connected and the 4th resistance Element.

3. system according to claim 2 is it is characterised in that described first resistor element and described second resistance element Resistance value related to the current values of circuit to be sampled；Described 3rd resistor element and the resistance of described 4th resistive element Value is related to the voltage range of circuit to be sampled.

4. system according to claim 3 is it is characterised in that described second resistance element is in series with amplifier differential amplification electricity Road, described 4th resistance components in series has track to track operational amplification circuit；Described track to track operational amplification circuit and described fortune Put differential amplifier circuit to be connected with described STC12C5A16S2 single-chip microcomputer respectively.

5. system according to claim 4 is it is characterised in that described track to track operational amplification circuit and described amplifier are poor Amplifying circuit is divided jointly to be integrated in same MCP6022 chip.

6. system according to claim 1 is it is characterised in that what described DC voltage converting unit included being sequentially connected TPS5430 chip, feedback circuit and passive filter circuit；Described passive filter circuit and described STC12C5A16S2 single-chip microcomputer It is connected.

7. system according to claim 6 is it is characterised in that described passive filter circuit is LC filter circuit.

8. the system according to claim 1 to 7 any one is it is characterised in that also include and described STC12C5A16S2 The display module that single-chip microcomputer is connected；Described display module is used for showing the transmission signal pin of described STC12C5A16S2 single-chip microcomputer Voltage and/or current sampling data are transmitted by communication protocol.

9. system according to claim 8 is it is characterised in that described display module includes LCD display.