CN205265663U

CN205265663U - Acquisition circuit is kept apart to high accuracy analog quantity

Info

Publication number: CN205265663U
Application number: CN201521009329.0U
Authority: CN
Inventors: 张坤; 吴翼虎; 陈川; 景德胜; 刘小剑; 吕浩
Original assignee: Xian Aeronautics Computing Technique Research Institute of AVIC
Current assignee: Xian Aeronautics Computing Technique Research Institute of AVIC
Priority date: 2015-12-08
Filing date: 2015-12-08
Publication date: 2016-05-25
Anticipated expiration: 2025-12-08

Abstract

The utility model provides an acquisition circuit is kept apart to the analog quantity, gathers the rear end at AD and passes through digital interface part realization isolation. Among this acquisition circuit is kept apart to high accuracy analog quantity, set up the opto -coupler to realize keeping apart between AD switching device and digital interface, outside DC power supply passes through the DCDC converter and forms the isolator power, does for analog power supply through low voltage difference linear power switching over again the power supply of analog circuit part. The utility model discloses both guaranteed mutual isolation between the analog quantity, analog quantity isolation is simultaneously gathered passageway NOT AND isolation collection passageway and has been obtained the same collection degree, has realized that the collection is kept apart to the analog quantity of high accuracy.

Description

A kind of high-precision analog amount isolation Acquisition Circuit

Technical field

The utility model relates to a kind of analog quantity isolation Acquisition Circuit.

Background technology

Airborne embedded computer often need to gather the analog signals on different electrical power territory, in order to keepMutual isolation between power supply, just must carry out isolation processing to analog quantity.

Conventional analog quantity buffer circuit is to adopt isolation amplifier at AD front end, analog signals to be carried out at presentIsolation processing, inner photoelectrical coupler or the transformer of adopting of isolation amplifier realized, but uses isolation amplifier meetingHave a strong impact on analog quantity acquisition circuit precision. For example how logical with a slice in the airborne embedded computer of certain typeOn road AD sampler, different passages use respectively isolation amplifier and the input of non-isolation amplifier, isolation amplifierThe analog quantity channel of input than the analog channel signals collecting precision of non-isolation amplifier input low 2～3 (non-Approximately 8 of channel isolation precision, approximately 5～6 of channel isolation precision).

Therefore, need to have a kind of new analog quantity isolation Acquisition Circuit, both ensured between analog quantity mutually everyFrom, meet higher acquisition precision simultaneously.

Utility model content

In order to solve in embedded computer system analog signals insulation request and analog acquisition precisionBetween contradiction, the utility model proposes a kind of new analog quantity isolation Acquisition Circuit, after AD gathersEnd is realized isolation by digital interface part.

Scheme of the present utility model is as follows:

A kind of high-precision analog amount isolation Acquisition Circuit, comprises artificial circuit part and digital interface, whereinIn artificial circuit part, be provided with AD converter part, in order to the analog signals of input is converted to numeral letterNumber export digital interface to; Optocoupler is set between AD converter part and digital interface and realizes isolation, outsideDc source forms isolating switch power by DC/DC converter, then is converted to through low pressure difference linearity power supplyAnalog power is described artificial circuit part power supply.

On the basis of above scheme, the utility model is also further done following optimization:

Above-mentioned artificial circuit part also comprises signal conditioning circuit, and the analog signals of input is to pass through signalAfter modulate circuit, access again AD converter part.

The analog signals of above-mentioned artificial circuit part and input altogether.

Above-mentioned digital interface adopts series interface part.

Above-mentioned series interface part is SPI interface.

The utlity model has following technique effect:

Both ensured isolation mutually between analog quantity, simultaneously analog quantity isolation acquisition channel and non-isolation collectionPassage has obtained identical collection degree, has realized high-precision analog quantity isolation and has gathered.

Brief description of the drawings

Fig. 1 is high-precision analog amount buffer circuit schematic diagram of the present utility model.

Detailed description of the invention

As shown in Figure 1, the utility model is done following design to Acquisition Circuit:

1. the digital interface between digital circuit and analog quantity acquisition circuit realizes signal isolation by optocouplerTransmission, for reducing the semaphore that needs transmission, AD acquisition chip should select series interface part (as SPI connectsMouthful), in order to ensure data signal isolation transfer rate, optocoupler should be selected high speed photo coupling;

2. analog quantity acquisition circuit power supply is realized by isolation DC/DC converter by digital power, for anti-Only the output ripple of DC/DC converter own affects AD acquisition precision, and DC/DC converter is exported again through low pressurePoor linear power supply (LDO) is converted to analog power for AD Acquisition Circuit;

The analog signals of analog quantity acquisition circuit and input altogether, and with missile-borne computer numerical portionIsolation, realizes the isolation collection of missile-borne computer to analog quantity;

4. analog quantity isolation Acquisition Circuit is isolated at numerical portion, and analog acquisition part and non-isolation gather electricityRoad is identical, can realize the acquisition precision identical with non-isolation Acquisition Circuit.

Adopt this analog quantity isolation Acquisition Circuit, analog quantity isolation acquisition channel and non-isolation acquisition channel obtainObtained identical collection degree, and realized high-precision analog quantity isolation and gathered.

Claims

1. a high-precision analog amount isolation Acquisition Circuit, comprises artificial circuit part and digital interface, itsIn middle artificial circuit part, be provided with AD converter part, in order to the analog signals of input is converted to numeralSignal exports digital interface to; It is characterized in that: between AD converter part and digital interface, optocoupler is setRealize isolation, external dc power forms isolating switch power by DC/DC converter, then through low voltage differenceIt is described artificial circuit part power supply that linear power supply is converted to analog power.

2. high-precision analog amount isolation Acquisition Circuit according to claim 1, is characterized in that: instituteState artificial circuit part and also comprise signal conditioning circuit, the analog signals of input is by signal condition electricityLu Houzai access AD converter part.

3. high-precision analog amount isolation Acquisition Circuit according to claim 1 and 2, is characterized in that:The analog signals of described artificial circuit part and input altogether.

4. high-precision analog amount isolation Acquisition Circuit according to claim 1, is characterized in that: instituteState digital interface and adopt series interface part.

5. high-precision analog amount isolation Acquisition Circuit according to claim 4, is characterized in that: instituteStating series interface part is SPI interface.