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124 Threads found on edaboard.com: Pwm Controlling
You should know how you are controlling the stepper motor differently in both modes. We can't. A possible reason for device overheating might be an inappropriate high pwm frequency in combination with a high MOSFET gate capacitance.
Hi, it seems if you just make a simple example, you find out what happens.... (This should be your part... at least to give some data or other informations... now we just can assume what you want to do..) Imagine you want to charge a Pb battery. When the battery is empty you will see maybe 10.5V When it is slowly full charged you will see
Hello all, I'm using LPC1115 controller and getting pwm signal at PIO1_9 by varying prescaler register and keeping the values constant of MR3, so I had set a time and pulses generated continuously and stopped within that time, and for this I used a delay loop within this loop the pulses generated randomly. But the problem is, I need to
As Klaus says, Burst mode is often seen in pwm controllers which are controlling a power supply which has gone into light load?(often called ?low power burst mode?)?in light load, you don?t want to keep switching the fet on and off, as it results in too-large switching losses, so what you do instead , is you just have the controller pulsing the fe
Hi! I have a fairly simple motor controller controlling a DC motor. It's just a MCU feeding a pwm signal through a transistor, much like this one: However, I need the motor to keep running when the pwm signal is zeroed. What I have now is roughly 0-5v amplified to 0-Nv, but what I nee
pwm is good for controlling motor speed. But why do you want to change the frequency?
Not an op-amp. You could use them but the circuitry would be fairly complicated. The pwm signals are logic signals - only two states, low and high, what you need is a level converter that makes the high 5V instead of 3.3V. Do a search for logic level converters and it should come up with many solutions. Brian.
Hey,can any body provide to me the advises on how the IR2110 can be used for driving the six MOSFET making up a full bridge,for controlling an asynchronous three phase machine,my PIC is generating the highly active pwm pulses on its three CCPX Modules. I have a problem on how I can connect the input pin LOW and HIGH of the Driver from the PIC,I
Irrespective of the bad EMC predicates of the circuit shown on post #14, it sounds like redundant. There is no reason to split each half cycle of the wave among two pwm switches. Once the input voltage is pre-rectified, just one bridge/Mosfet suffice.
if counter < 10000 then pwm <= '1'; else pwm <= '0'; end if; Change 10000 to 500000. Did you check the pinout? Are you sure that the output levels of your board are set to 3.3V ?
hi guys, i would require to control a 3 phase pwm signal using dsp from ti, f28335. i would like to bulid a circuit that could control the duty cycle. meaning to put a potentiometer in its analog control a0 to vary the reference voltage to output the frequency. by controlling the reference voltage. the output duty cycle will change hence the
I can help with mikroC code because it has pwm library.
This might help you. Also why are you not using mikroC pwm library and vary the duty of the pwm at required intervals using a Timer ?
hi guys, I just got the datasheet and it says the current for the output voltage 0-10Vdc is 0-20mA and Maximum current is 100mA. Makes no sense, actually. 0-20 mA can be if the control input is designed to work also for a current loop signal without modifications (500 ohm shunt). But what is 100 mA? I don't believe that your cir
Dear all; In my circuit I want to operate 6 IR Emitters (all cathodes are common) using pwm of PIC. I came with idea to use analog deux/demux ic to sequentially operate each IR Emitters but it requires some current drivers since required current is >70mA for each IR emitter. I came up with idea to use npn transistor with each IR Emitter bu
Hello Friends, I am trying to control duty cycle of my pwm wave using at89c51rd2 & ADC0804. I am attaching my code and proteus simulation file here. However I need to clear some of my doubts , please be nice as always. 1.I have seen sample code on internet for this application and constructed my own code following the same. But why I cant us
Hello Friends, I am trying to control duty cycle of my pwm wave using at89c51rd2 & ADC0804. I am attaching my code and proteus simulation file here. However I need to clear some of my doubts , please be nice as always. 1.I have seen sample code on internet for this application and constructed my own code following the same. But why I cant us
Are you talking about using the chip's pwm module or a completely software driven pwm? If the former, then this link may help: Try some numbers in it, and you will see that to get the low frequencies you apparently want, you will have to run the PIC at a fairly low c
No, you can't "use pwm generator to control rotation speed". Since pwm is a CONSTANT FREQUENCY, if you use the pwm output you will get a CONSTANT SPEED. That's not what you want. Remember, pwm varies the duty cycle, not the frequency. As far as the rest of your questions, there no way to answer them-it all depends on the (...)
You might run into problems trying to dim a flourescent tube light but you should research phase control dimmers for more information. You can use pwm but only if you are very careful to use the same pwm rate and phase as the AC power, a triac and standard phase control solution would be far simpler to build. Brian.
A DC motor draws a high current when its is not turning which happens when it starts and when it is overloaded. The current increases as it is loaded. If you simply reduce the voltage to it then it will probably not start running and it will slow down or stop when loaded. Pulse-Width-Modulation (pwm) is used to feed full-voltage pulses to control
Damage to the MOSFET without a snubber is possible but far less likely than in a situation where it is used as a driver. In this schematic the voltage across the MOSFET is simply the rectified AC less any voltage dropped across the load. Essentially, it is being used as a variable resistor to set the current flowing through the bridge rectifier.
That's the complicated way. Use the transistor a Bradthe Rad suggests and use a pwm output from the PIC but forget the AND gate, just enable or disable the pwm output to turn it on and off. It will work better if you can use a logic level MOSFET instead of a bipolar transistor. I control lighting using pwm from a PIC through a 2SK2989 (...)
I doubt there can be significant intensity modulation of an incandescent lamp at 500 Hz pwm, and it's about to impossible at kHz frequency. More likely, there's some kind of electrical crosstalk in your circuit. Nevertheless, if you want clean DC current, you can go either for linear regulator (requires a certain heatsink size) or a buck convert
Hi In those days i am planing to design a digital power supply almost work done but i have problem with current controlling through pwm here i have share to type of design one is based on POT working fine as required. but the other design which i have modded to work as digital power control and current in this design voltage control working fi
Hello. I wanted to make a led design with controllable brightness. The controlling would work via usart ('0' = darkest --- '9' = brightest, simple) It works good, BUT it doesn't receive every command. If I press a button, sometimes it takes 4-5 presses to receive the data, no idea why. Could you please point out what I did wrong in my code? [CO
Hi everybody, i am working on a boost converter using a P&O MPPT algorithm my problem is how to reduce the step size of control to get an accurate value of maximum power point (MPP) i mean which block is controlling the step size is it the integrator, the pwm or other block? waiting your replay Thanks in advance
Triac must use phase angle control rather than pwm, variable delay with respect to mains voltage zero crossing. There are pretty much hard- and software examples at edaboard
I wanna build a ROV which has two separate microcontroller unit to conduct whole operation. One MCU is in the remote module and another is in the host module . those 2 mcu?s are meant to be operated using RS-232 protocol connected through two wire serial connection. Two motors speed are controlled by pwm from remote module and motors are connecte
As u are controlling variable resistor with mcu so make it independent from other system,use a heat shrink sleave of 2inch length, a multiturn variable and small dc motor. connect dc motor with variable resistor with sleeve and control dc motor with pwm.
Hi All, Im using small ebmpast 24V small BLDC motor to write test code for motor speed control. I found that controlling the commutation speed affects the motor speed as well (well thats obvious). So, my question is, when i change the pwm duty cycle, the speed does not change at all but speed is solely controlled by commutation speed. is (...)
The nicest way would be to modify the pwm generating circuit, so the on/off period changes on switch on and off but in the absence of a circuit diagram this is not possible. If you put a series control transistor in series with the motor feed, the controlling the base current, you can control the supply to the motor. As the motor takes 1A, the
Hey guys, i am a beginner in micro-controller, i want to know how to use Pic 18f4431 to generate pwm on six pins to control the switching on and off the 6 mosfets of my 3Ph inverter. I use pic c compiler and i couldn't understand so much the help -> directory file in the pic c. so i would be thankful if anyone could help me with a code that gene
Hi I wanted to control the servo motor according to the accelerometer value ,i developed the code using Arm wizard tool ,the code works well in Proteus tool but in hardware it fails , i checked the pwm output using the Oscilloscope can you help me to rectify the problem in the code #include #include #include
hai,I am new to Pic it possible to use the 2 pwm channls in PIC 16f877A simultaneously?i have a code for pwm in ccp1 module.I want two pwm for controlling two motors.How can i use ccp2 in pwm mode?I use MPLAB IDE,HI TECH C complier....pls anyone provide me the code Yes it's possible to use
Hello, I was thinking can i control the Voltage Regulators Like L200 or LM317 using pic microcontroller ? Can we use pwm Signal to control the reference voltage provide to the voltage regulator ? OR any other idea, Because i need to make one digital power supply which will increment and decrement voltage according to our n
Hi, Think you are using Mikroe C, there should be plenty of examples /tutorials around on pwm. The 877A has an inbuilt hardware pwm module so its easy enough to initiate. To contol the motor you have two common ways of controlling it, a single transistor to drive the motor, using another pic output to turn a double pole relay on /off (...)
i am generating pwm signals in 18f4431. duty of those signals are controlled by an analog input. but when lcd display is included in to the program, the controlling task is not performed correctly. what can be the reasons??
If dont need to control position, then controlling speed of dc motor by pwm is so easy, you can use it. Here a project I did.
Hello Guys, I need help about this curiosity i had in mind. I am controlling a servo motor via CCP of the PIC. The servo is rated to work at maximum stall torque @ 6v. We know the PIC produces 5v out. So I was thinking to connect the supply of the servo externally while the pwm is coming from the CCP pin of the microcontroller. Is this
in my project i want to interface with pwm with pic16f877a for controlling the brightness of the light....anybody help me.... thanks in advance.....
For controlling the speed, use pwm. The microcontroller will generate the pwm signal and the voltage will be 0V or 5V (depending on, if the output is high or low at that moment). Use a MOSFET driver to drive a high voltage Power MOSFET which will drive the motor. Use a freewheel diode across the motor (it will be antiparallel to the (...)
All you would need to do is use the pwm module and adjust the duty cycle as required. This requirement will vary according to your specific circuit. A schematic of the completed hardware will help us help you better. Let's start with one topology. Let's take buck for example. Vout = DC * Vin So, you'd need to adjust DC using the pwm module duty cy
You are changing the width (the duration) of the pulse on-time. Let's say you have a signal with frequency of 50Hz, upon which you will carry out pwm. Then time period is 20ms. If you provide power to the motor for 15ms and keep power off for 5ms, you are controlling the power to the motor and restricting it to (15/20)*100% = 75%. The longer the pu
Hai, I am using pwm for Iris control. Now I am controlling it at a frequency of 15KHz and by varying the dutycycle. Is controlling the motor by changing the dutycycle (with fixed frequency) or by changing the frequency only is better? Is there any difference between these two? And can I increase the speed of opening and closing iris ? (...)
Unfortunately your code is unreadable, can you format it? Otherwise we have to follow every curly bracket and count them up and down. Also, pwm with relays is not really a good idea, and may be causing the issues. You should switch to some semiconductor method (e.g. MOSFETs).
i am using the BLDC motor fan and controlling the speed of the fan using pwm i want to know some basic theory about the motors i taken the 12V motor ,i connected the power supply and increasing the supply voltage by using the power supply form 0 t0 12V when i given the supply from 0 to 3.3 volts the fan it taking the huge current of 460mA and
Hi all, I am doing an exciting project and now I really need a help. I am trying to control the Pulse width and the Period of a pwm (PIC24FJ128GA010) module through serial port. Here I am having the following configuration Explorer 16 Development Board- PC. PC is connected through serial port of micro-controller. I have a python interface i
Dear Samson Hi Of course we can't give AC voltage as input . and about current controlling , yes it is possible and pretty simple with creating a hiccup in pwm . ( don't forget that a boost converter is just an Step up converter , and nothing else !) Best Wishes Goldsmith
The best proceidure to control an AC load is to trigger the switch (Triac) at every zero crossings and vary the angle of the phase to control the brightness or the speed. pwm is best suited for DC load controlling. Cheers