The spreader of low cost high accuracy that is based on Microchip detects plan
[introduction] BMS(Battery Management System) is batteries of component of core of car of join new energy resources and truckload bridge. The development of car of new energy resources of benefit from benefit from, the BMS that regards core as the component also got flying development. BMS differs according to pilot structure cent is BMS of type of principal and subordinate and BMS of machine of an organic whole. No matter which kinds control a construction, it is indispensable that total electric current detects. The electric current of BMS detects cent detects for sensor of traditional Huo Er means and spreader detect means. Through the analysis, the cost of voltaic sensor program of the technology of sampling of direct form electric current that is based on spreader is lower, precision is taller, it is car and the first selection that the sources of energy stores systematic BMS applies.
Spreader detects means makes first selection, it is as a result of its taller measurement precision is mixed on one hand relatively inferior cost, because its measurement technique is simple,be on the other hand, use device is little, convenient and quick. Its measure a principle is to measure spreader directly the voltage of two end, according to Ohm’s law, divide the resistance with spreader to be able to get the electric current in circuit is worth with measures voltage. And suddenly Er sensor detects means although the structure is simple, but the change that its measured value follows temperature is bigger. For this, the spreader of the low cost high accuracy that the article is based on the introduction interface of Microchip MCU, CAN and signature manage platform detects plan, for everybody reference and use.
This plan used the CSM2F-8518-L100J32 of spreader of big electric current of Bourns, the MCU SAMC21E18A of Microchip, ADC MCP3421, appearance amplifier MCP6N16, voltage is fiducial the CAN interface ATA6560 of MCP1501 and Microchip. Appearance amplifier MCP6N16 and voltage are fiducial the MCP1501 collection spreader signal magnifies and carry litre, turn the imitate signal of enlarge into digital signal by PGA ΔΣADC MCP3421 of the buy inside 18-bit again, pass Microchip MCU SAMC21E18A through I2C interface, next MCU is read into what linage occupies take, processing and demarcate, the CAN interface ATA6560 of Microchip is used at data news report. This plan besides use at BMS system, still can use at dynamoelectric and mix use a car, bus electric current detects and solder equipment.

The characteristic of this spreader plan: The biggest job keeps apart voltage to be able to achieve 560V. Below room temperature, precision can amount to 2‰ , full range precision is 5‰ , voltage of power source wide range is inputted, the electric current that uses up when 12V is less than 3mA, working temperature limits – 40~125 ℃ , detect continuously voltaic 500A, 1000A of the biggest impulse current (30mins On/off)
For the test of convenient user, demarcate and application, plan also was offerred at the same time go up a machine software. Receive a tool through the bridge, plan undertakes pair of spreader with OK and intuitionistic user demarcate and test application. Support of Flash of the buy inside MCU is read write a function, use the data of the functional memory demarcate of imitate EEPROM. Board go up and stick on spreader have NTC temperature sensor, the user is OK real time read take board the temperature that goes up with spreader.

Understood this electric current to detect after the integral characteristic of plan, we come again the characteristic with the core respective parts of an apparatus that introduction of one by one forms this plan.
First from now on the MCU proceed with of plan, the characteristic of Microchip MCU SAMC21E18A is 32 Bit Cortex M0+ MCU, can 5V power supply, sercom of agile the peripheral that string together a mouth can make up UART neatly arbitrarily, SPI and I2C; Buy CAN controller supports CAN-FD inside, at the same time compatible CAN2.0 A/B.
Its amplifier MCP6N16 is had from corrective framework, can pass super- low maladjusted, low maladjusted drift and exceedingly good in all model and power source restrain a function to come to utmost ground improve DC performance, remove the undesirable effect of 1/f noise at the same time, realize superhigh precision in total temperature limits thereby. While the engineering technology of CMOS of low power comsumption of MCP6N16 is realizing low power comsumption, return the bandwidth that can offer 500 KHz. In addition, it deserves to a hardware makes can bring a foot to be able to reduce power comsumption further. To fixed rate and function, the electric current that this kind of low power comsumption moves and stays machine function need is fewer, can lengthen batteries consequently life and reduce itself to give out heat. The moving report depress of this amplifier comes 1.8V, make the n of two 1.5V dry cell is used up far what fall than typical situation is little, and its course is inputted to course and output an operation even if also can ensure below the condition of low power supply full range is used. This makes the function inside limits of whole moving voltage gets promoting considerably. MCP6N16 appearance amplifier special apply to need high-powered, high accuracy and low power comsumption, low voltage runs the application that have both, recuperation of the sensor port that covers medical treatment, consumption and industrial market to go up, signal and stationary and portable instrument are waited a moment.
Compare with other A/D converter, all sorts of high accuracy patterns that MCP3421 fits to need to design simple, low power comsumption and economic space particularly / several changeover application. Main show is in its characteristic: Complete difference divides an input, 18 resolution, accurate successive from calibration function; Optional choose 3.75, 15, 60 or 240SPS sampling rate has transition; Can work in successive changeover or sheet second changeover mode, in sheet the leisure after second changeover period inside enter automatically bide one’s time mode, huge reduced electric current to use up; Precision of in-house and compositive 2.048V 0.05% , and the fiducial voltage source that temperature drift is 5ppm/ ℃ only, but amplifier of process designing gain (PGA) offer 1/2/4/8 times gain, the signal that allows to measure minimum and have very high resolution, circuit of in-house and compositive oscillator offers I2C serial interface to wait.
Microchip mixes reach Bryan J of vice president of department of linear signal product. Liddiard expresses: The development need of “ADC market and application is higher resolution, taller speed and more high accuracy. In addition, lower power comsumption and smaller it is very important also to enclose, we are new these products that roll out can satisfy above overall demand. ”
Tall voltage inputs MCP16331 of manostat of compositive switch step-down to be able to work to fall in the input voltage source of highest 50V. Compositive character includes to go up to electric current of control of mode of electric current of peak value of bridge arm switch, fixed frequency, in-house compensation, peak value is restricted and cross lukewarm protection. Require the exterior element of least quantity only, can develop complete step-down dc / dc converter power source. Mix through MOSFET of raceway groove of N of component of compositive current limliting, low resistance, high speed relevant drive circuit will achieve tall converter efficiency. Tall switch frequency reduced the size of component of exterior filter wave to the greastest extent, achieve the solution of small size thereby. MCP16331 can be in output voltage stabilized voltage comes 2.0V-24V while, offer the permanent current of 500 MA. Is parts of an apparatus compositive of electric current of high-powered peak value? Mode framework, although be inputted in what middling of power source system sees,twinkling of output electric current changes during the condition, undertake stabilized voltage steadily to outputting voltage. EN input is used at open to mix shut parts of an apparatus. To be restricted report and load assign application, when parts of an apparatus is shut, the input carries the electricity that uses up a few μA only. This cites a base pull on interiorly, accordingly although EN cites a base impending, parts of an apparatus still also can be started. Output voltage can undertake installing through exterior resistor voltage divider.
Car and industrial CAN market ask to provide more high-powered, lower power comsumption and bigger flexibility in order to have the solution of cost effectiveness all the time. Microchip is brand-new CAN of series high speed is sent and receive implement accord with high-powered requirement, those who offerred a trade is low need machine electricity, the parts of an apparatus with a variety of cabinet over all dimension can offer an alternative. Microchip company ATA6560/1 is sent and receive implement standard of supportive CAN FD and the data rate that are as high as 5Mbits/s, offer butt joint port for bus line of CAN agreement controller and physics of CAN crewel type. Accord with ISO11898-2, ISO11898-5 and SAEJ2284 standard, have taller electromagnetism compatibility (EMC) and electrostatic release (ESD) function. When power supply voltage is shut, ATA6560/1 is sent and receive implement the passive performance that can provide ideal for CAN bus line, deserve to voltage of a power supply is 3V to join continuously to the MCU of 5V mouth. To the network of CAN of of all kinds high speed, CAN node that asks low power comsumption needs to be waked up through CAN bus line especially, the ATA6560/1 that has a variety of operation pattern and special fail-safe function is superexcellent choice undoubtedly. CAN of low power comsumption is sent and receive implement be based on advanced technology development, can function of farther compositive imitate and complex digital function.
The ocean of Chou Jia of field application chief inspector of be good at company shows the world: Be good at company regards the world as the technology cent sells business to follow solution business, always pay close attention to trends of market technology demand, through using Microchip company’s high-powered Cortex-M0+ MCU, rich imitate signal catenary, power source and interface product, be united in wedlock with spreader sensor, world be good at company offerred complete spreader electric current to detect for the client solution, can apply extensively at the car to mix store can BMS, dynamoelectric and mix use a car, industrial generatrix electric current detects and solder the application that the big electric current such as equipment detects.