Applying a voltage across the terminals of the motor causes the motor to move to one direction. To be precise, it pushes or pulls on the mass, the mass then moves as a result of this force. The drv201a device is an advanced voice coil motor driver for camera auto focus. The question is how is the voice coil controlled, using a scope on an old drive you can see there is obviously ac present, so i put a circuit togther that reverses the polarity acrross the coil controlled by a pwm output from a pic, it works but the coil gets to its full movement within a small deviation from 50% symmetry, and its just as good. I also have your resistor and capacitor snubber circuit in parallel with the coil in my diy driver to. The lv8498ct is a constant current driver ic for voice coil motors that supports i 2 c control integrating a digitalanalog converter dac. I also have your resistor and capacitor snubber circuit in parallel with the coil in my diy driver to try to prevent damage to the mosfet. Thus a voice coil does not primarily move the mass, motion is a consequence of the force the voice coil applies to it. Such hard drive will probably be hard to fine, the diy is probably the best option to make the ideal forcestroke at a low price. Flexible circuit termination of the coil provides reliable electrical connection with. Its well within the capabilities of an arduino to drive one of these. It uses an ultraminiature wlp package and includes a current detection resistor for constant current control, which makes the ic ideal for. A block diagram of the vcm control system with the sfopid controller. Voice coil motors are widely used in the industry owing to their advantages of light weight, lowest price and good repeatability as digital camera and mobile phone camera.
Drv201 voice coil motor driver for camera auto focus rev. The brushless dc motor driver circuit described here uses a drv10866 driver ic to drive a small bldc fan, without using any position sensors. The fixed part of the voice coil motor is a permanent magnet and the moving part is the coil. Long travel and high torque rotary voice coil actuators the model twr0348001rc was designed to allow for a relatively low moving mass and inertia, as well as a long rotary stroke of 34 degrees 0. Builtin voltage drop protection circuit vcc 2v output off. Current command of the voice coil motor vcm has been preferred so far, due to its good performance in terms of robustness. The pendulum and driver circuit shown were made with parts on hand.
The max14570 utilizes a switching output topology to provide high efficiency over the entire input supply voltage range. The coil and permanent magnet on the bob must repel each other when the coil is energized. Brushless dc motor driver full project with circuit. Pdf application of voice coil motors in active dynamic. As snoopen says you want a voice coil driver or actuator. The si9961a contains all of the power and control circuitry necessary to drive the vcm that is typically found in 31 2 inch hard disk drives and optical disk drives.
Vcm current is controlled with a fixed frequency pwm controller or a linear mode driver. Jun 18, 2018 the voicecoil actuator is a linear motor which can provide precise force and positioning over a modest distance, and is easy to control. Supplied with mounting card for easy wire connection and mounting. Drv201evm the drv201evm is an evaluation board to assist in evaluating the drv201 ic as a voice coil motor vcm driver for camera auto focus. Since the voice coil driver doesnt need to be particularly fast, but should run off a single 5v supply, were using a linear technology lt1006 here.
Originally used in radio loud speakers, voice coil actuators are gaining popularity in. Linear motors voice coils voice coils motion control. The voice coil motor driver 310 includes a current sense amplifier 320 that senses current through the voice coil motor 315, and also includes a voltage sense amplifier 325 that senses voltage across the voice coil motor 315. Voice coils motion control linear motors voice coils. A tutorial on control design of hard disk drive selfservo. If you cant get the pendulum to run, flip the driver coil over or reverse the leads to the coil. Its also possible to use the driver chips from the original hard disk pcb to get an idea of the sort of chips used, this site has a listing of various driver chips with links to datasheets, but they are usually much more complicated since they often combine both the spindle motor driver and the voice coil driver readwrite head into one package. Vdrops imotor 1a ileaks voice coil motor circuit vcm pwm inputs pwmhpwml high input, combination chip consisting of spindle motor spm and voice coil motor vcm circuit for hdd applications. The voice coil motor driver 310 is coupled to a voice coil motor 315 for driving it at desired levels. A hard disk voice coil assembly, also called actuator, is a linear control device within a hard drive responsible for positioning the read write heads. Description smp circuit the ka2811c is a monolithic onechip ic which includes spm spindle motor driver, vcm voice coil motor driver and peripheral driver, designed for driving hdd motor. As you can see from the schematic, vcc will be a 5v supply and vin sets the laser. There are a number of people offering onweb examples of hdd voice coil drivers used for other purposes.
The max14570 is a highefficiency voice coil motor vcm driver ideal for use in powersensitive autofocus camera applications. Driving a linear voice coil motor arduino forum index. The amplitude of the frequency determines the displacement of the voice coil motor. Voice coil motor driver with pwm input, 800 series moticont.
Undervoltage lockout uvlo the drv201 device is an advanced voice coil motor thermal shutdown driver for camera auto focus. The lv8498ct is a constant current driver ic for voice coil motors that supports i2c control integrating a digitalanalog converter dac. It is sometimes said that voice coils are intended for fast. Optional output slewrate control and spreadspectrum oscillator reduce conducted noise and radiated. Assuming that the primary coil would act as a pull up resistor, i expected to see ov while the ignition module car or irf740 my coil driver circuit is closed, and 12v when it is open. I am able to drive a lvcm02503801 linear voice coil using a cytron 10a motor driver shield and a spwm sinewave pwm signal but when i add an rc filter i get response in the motor. It consists of a copper coil wound around a former and a permanent magnet. Vcm current is internal current limit for vcm driver controlled with a fixed frequency pwm controller or a 4kv esdhbm linear mode driver. A bldc fans speed can be varied smoothly, without the usual steps associated with a normal ac fan.
Drv201 voice coil motor driver for camera auto focus 1 features 2 applications. C logic thresholds 10bit dtoa converter 100 a resolution low voltage i. Linear dc motors, voice coil motors vcm or voice coil actuators vca are the simplest type of electric motors. It uses an ultraminiature wlp package and includes a current detection resistor for constant current control, which makes the ic ideal for miniaturization of camera modules intended for use in cameraequipped mobile phones. It is particularly indicated for driving inductive loads as linear motor, and finds. Just a prototype, and at the beginning a unique voice coil motor would be fine, to setup and refine parameters. The device is an advanced voice coil motor driver for camera auto focus.
The voicecoil actuator is a linear motor which can provide precise force and positioning over a modest distance, and is easy to control. Voice coil motors are highly controllable electrical actuators suitable for. Pdf halbach magnetic circuit for voice coil motor in hard disk. According to the features of accessing data on disk, hdd servo systems mainly involve three kinds of control tasks 3. Yes, i do think that there is a driver in the pcb of the hdd, but i am not using it. It has an integrated da converter for setting the vcm current. As the shield comes with two l293d motor driver chipsets, that means it can individually drive up to four dc motors making it ideal for building fourwheel robot platforms. The si9961a is a linear actuator voice coil motor driver suitable for use in disk drive head positioning systems.
A current sensing resistor is coupled in series with the voice coil motor. Current recycling voicecoilmotor vcm driver circuit. The control circuit includes a sense amplifier having inputs that couple to the current sensing resistor and includes a feedback circuit that includes an input and also includes an. Moticont provides designs and manufactures linear motors, positioning stages, and fully integrated singlemultiaxis positioning systems including voice coil. But a voice coil doesnt primarily move things, it is a consequence of the force it applies. The a schematic and b cross section moving magnet vca shows how it is the physical complement of the movingcoil arrangement. Thus a voice coil does not primarily move the mass, motion is a. Linear voice coil motors actuators and micro voice coil. Simulations and experimental results proved effectiveness of the proposed magnet array in the voice coil motor for a commercial hard disk drive. A voice coil is a linear actuator, that moves a mass along a line. I am using a direct connection to the head there are 2 wires on the top. Both the device itself, and the associated controller can be very simple and robust.
With this solution, in fact, the characteristics of the system to be controlled by the servocontroller are rather independent from all possible variations of electrical impedance of the vcm and power supply voltage. The voice coil motor will oscillate at the desired frequency and displacement. The l293d is a dualchannel hbridge motor driver capable of driving a pair of dc motors or single stepper motor. Parallel wiring means a dual voice coil subwoofer has a 4ohm coil subwoofer. Providing control and drive of the voicecoil motor used for head positioning in 5 v disk drive. The so called motor turned out to be a voice coil, which is a thing that i have never dealed with before. The coils are wired parallel to each other giving only a 2ohm load to your amplifier. Vcm current is open and shortcircuit protection on vcm controlled with a fixed frequency pwm controller or a output linear mode driver. Voice coil motor driver, 950 series a high performance, dual channel, cost effective dc motor driver to implement intelligent motion control with analog inputs. Undervoltage lockout uvlo the drv201a is an advanced voice coil motor driver thermal shutdown for camera auto focus.
A voice coil is a kind of linear actuator, it moves a given mass along a line. Us6373650b1 voice coil motor control circuit having. The linear voice coil motor vcm is a direct drive and hysteresisfree. The following file outline detail information regarding dual voice coil wiring. Drv201 voice coil motor driver for camera auto focus. Design and implementation of a voicecoil motor servo. Designed for camera autofocus and zoom applications, this high accuracy digital ic is provided in a wlcsp package ideal for portable devices. Voice coil positioners always need feedback, and carefully designed loop filters. The compact 5 phase stepper driver project can handle motor up to 3. Hi, i am new to electronics and am making a simple mistake but do not see it. Fan8621b 12v spindle motor and voice coil motor driver ic features, voltage drop, and increasing drive capability up. Voice coil motor vcm is widely used in high precision position servo control for its merits of high linearity and no coggingtorque. Precision position control of a voice coil motor using self.
Open and short circuit detection 3 description undervoltage lockout uvlo the drv201a is an advanced voice coil motor driver thermal shutdown for camera auto focus. The a3904 is a voice coil motor vcm driver, with an i2ccompatible serial interface. Drv201a voice coil motor driver for camera auto focus. Us5838515a pwmlinear driver for disk drive voice coil actuator. There are two basic means of connecting a dvc driver. Positioning control of voice coil motor with shorted turn. A voice coil motor control circuit provides control signals to a voice coil motor circuit drivel that is coupled to a voice coil motor. Linear voice coil motors linear dc motors, voice coil motors vcm or voice coil actuators vca are the simplest type of electric motors. This study aims to fast move the coil so that the move time can be shortened. If the disk drive sort of works and has an interface you know, then you can try the controlling as you would control the disk drive stepper motor easy with st506412 interface. Vcm current is open and short circuit protection on vcm controlled with a fixed frequency pwm controller or a output linear mode driver.
For high starting torque and high speed, spm circuit employes wss waltz step start method for starting the motor and can drive up to 2a. Vcm current is internal current limit for vcm driver controlled with a fixed frequency pwm. The lv8498ct is a constant current driver ic for voice coil motors that supports i2c control. Voice coil motor driver for cameras eeweb community. This provides a general view of an hdd voice coil actuator. To be precise, it pushes and pulls a mass wherever it is along a line. C serial interface lowcurrentdrawsleepmodeactivelow 2. Reversing the polarity of the applied voltage will move.
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