TIDA-01421用于無傳感器位置測量的脈沖計數器參考設計

TI公司的TIDA-01421是用于無傳感器位置測量的汽車有刷馬達脈沖計數器參考設計,可配置用于許多DC馬達解決方案,具有共模式輸入范圍寬-14V到80V,工作電壓9-18V電池,工作脈沖頻率范圍100Hz-1.3kHz,馬達最大電流+/-16A,和MSP430? LaunchPad?開發板接口簡單,是高精度測試解決方案.主要用在存儲器座椅,電動車窗,側鏡,電梯門和電源箱.本文介紹了TIDA-01421主要特性,框圖,和MSP-EXP430FR6989 LaunchPad?連接圖以及電路圖,材料清單和PCB設計圖.

The demand to retain memory on the position of theseat, window, sliding door, mirror, lift-gate, and othersdriven by that motor has increased as small motorswithin the modern automotive vehicle continue toevolve. Existing solutions utilize multiple magneticsensors attached to the body of a motor to provide afeedback loop to the motor control module.

A sensorless approach provides redundancy forexisting solutions and, in some cases, removes therequirement for motors with sensors attached. Thesensorless approach has become increasingly popularthrough the implementation of an in-line, current-sense　signal-conditioning circuit. This design provides asolution that is easily modifiable for many automotivemotor systems that control position measurement.

Motor position memory is being applied in more areas of the automotive vehicle including configurationand comfort settings for different driver profiles as well as diagnostics for more efficient and smartercontrol of the motor. The demand for more cost-efficient and easily-configurable solutions for manydifferent motor types has increased. For example, the seats in a vehicle can feature many axes ofmovement and ergonomic adjustment all controlled by individual motors. Existing memory solutions forthese seats require motors with magnetic Hall-effect sensors plus the additional extra wiring for eachsensor. Sensorless position measurement reduces the requirement for this many sensors and wiring bysensing the in-line motor current at the seat control module itself.

A sensorless approach is possible for brushed DC motors due to the effect that the back-electromagneticforce (BEMF) has on the motor current seen entering the motor. As the motor rotates, the impedanceseen by the BEMF periodically changes due to the nature of the DC motor brushes making contact withmultiple poles of the motor and effectively shorting some of the motor windings. This change in impedancechanges the measured current in a very periodic pattern proportional to the actual speed of the motor.

This system provides a way to measure this varying in-line motor current, filter and condition the resultantsignal, then provide a 3.3-V digital logic level series of rising and falling edges for a digital processor tocount and analyze for accuracy and feedback to the main motor controller. With some simple changes incurrent sense resistor values, gain settings, and filter bandwidths, this solution can quickly be modified foruse with many small motor systems.

TIDA-01421主要特性:

? Configurable for Many DC Motor Solutions

? Wide Common Mode Input Range for In-line MotorCurrent Sensing

? Operational for Typical 9-V to 18-V Battery Supply

? Simple Interfacing With MSP430? LaunchPad?Development Kit for Interfacing and Digital Capture

? Highly Accurate Test Solution

TIDA-01421應用:

? Memory Seats

? Power Windows

? Lift Gate and Power Trunk

? Side Mirrors

TIDA-01421系統主要指標: