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135 Threads found on edaboard.com: Pwm And Switch
1. Enable clock for timer 2. Setup the timer as timebase for pwm 3. Enable clock for GPIO and AFIO 4. Set IO as AFIO output push-pull 5. Setup pwm 6. Enable timer 7. switch on pwm pins Not really simple, but it is STM32))
Hello I am working on 3 phase motor control by V/F control. my circuit consist microcontroller > IR2110> IRF640. pwm freqency is 1KHZ Design is non isolated my problem that while MOSFET switch on and switch off it create posivite and negative spikes upto +/- 25volts resultant +5v and (...)
An IRF640 is Quite Common. But it would be better if you stated the Purpose. pwm Circuit, Power Amplifier, switch mode Circuit, ETC. Also How Many Amps and What Voltage.
What if both the switch and the pwm are ON?
If you can it might be a good idea to add some filtering to remove the pwm components if it is an old motor to remove the effects that have been highlighted.
0000 = ECCP OFF Klaus CCPxM<3:0> = 0000 //Capture/Compare/pwm off (resets the module) what is meant by Resets the module? Can I apply low and high signals on these pins as digital outputs? Actually I want to assign all of them as Port Pins
then what should i do for generating complementary pwm signals? As already mentioned above, there is no need to generate complementaru pwm signals. The upper side of the leg can switch at low frequency, and the high side of the leg can switch at low frequency. Once you are driving a 3-phase BLDC motor, it i
Hi guys, I want to use the ITS724G "intelligent FET" to do some high-side pwm switching (1khz max) at 12V. I need to isolate this pa
No way. You can't use triacs with pwm. You need zero crossing circuit to sync with AC phase and switch triac every 10ms after curresponding delay, which will adjust the power.
Hi, this is my first post here, feeling nervous. I want to design a pwm switch for general purpose loads, meaning I don't know if it is used with a 12V pump, a fan or LED lights. I want to pack 4 of these as tightly as possible and each has to provide at least 3A. What would be the best way to go about this? I have been looking (...)
There is the resistive drop method. Turn on a transistor to varying degrees, to make the LED brighter or dimmer. Or, you can switch the power to the LED on and off, at varying duty cycle (pwm). This is more efficient than the resistive drop method. There are many ways to achieve pwm.
Load regulation is purely impedance ratio of source impedance to step load change, during any flow of current. Since pwm modulates switch RdsOn average impedance by duty cycle where 0% =∞, 50% = 2x and 100%=1x you can estimate load regulation and ripple due to RdsOn and impedance of coil with average (...)
?COMP? is the result of comparing the pwm On current sense after a 1us RC filter. But you are modulating using a 332 KHz switch or a 3us cycle, so your filter is 3T which does not reach 100% of Isense within one switch cycle and will be affected by boost duty cycle. Since 1T response is 63% of a step (=1/(1-e)) I am (...)
Hello, Have just been running switch mode LED driver demo boards from and linear.com. I usually do Analog Dimming, so am not used to listening out for ?whining? during pwm dimming. However, all of these boards ?whine? when pwm dimmed?.the whining sound varies as the pwm dimming frequency is varied (kind (...)
In case where no volume control is required it can be done by connecting Gate of MOSFET to pwm o/p pin through resistor, Source to speaker and Drain to Vcc. Really? Looks like a very limited audio DAC and amplifier design. Does your speaker tolerate DC current? Which pwm frequency? How many bits resolution? You can of (...)
If you consider a pwm driver like DRV10x , you can simply drive a transistor switch directly from MCU and get rid of the redundant D/A/D conversion. DRV10x or a direct processor controlled pwm don't provide constant current control, there should be a current feedback. I don't get the particular purpose of the (...)
I can't agree to your assumption that unipolar pwm scheme doesn't need deadtime. It also involves synchronous commutation between high- and low-side of each bridge leg, but with different timing for both bridge legs. MOSFET and IGBT bridges incoprorate diodes, in so far there's no need to place separate diodes. Driving a bridge into (...)
If the LEDs are in series and use 48V at 1A then a transistor cannot be used because it will need 100mA at its base to fully saturate. The Arduino can supply only 25mA. Use a logic-level Mosfet to switch the power supply to the LEDs modulated by the pwm.
Darlington's have the disadvantage of almost 2 diode drops initially ( actually 1 diode drop & 1 saturation drop) but when conducting heavy currents with fast pulses in pwm due to low input capacitance compared to MOSFETS will have better current gain( ~100) . When the transistor is used as a switch and saturates, the hFE typically (...)
pwm Chopper Controlled DC Motor Driver OBJECTIVES: To design, build, test and demonstrate a pwm chopper controlled DC motor driver based on IC UC3524 - the building blocks of this pwm IC. - the application of this IC in DC motor speed control. - the interface of this IC to the DC motor via power electronic (...)
Your circuit description sounds like an old fashioned sinewave analog inverter. It probably wastes as much power making heat as its output power. A modern sinewave inverter uses Pulse-Width-Modulation (pwm) at a high frequency so that the output devices switch completely on and off (then there is very little heat produced) (...)
why not use a simple pwm switch for each table from a central DC source such as battery & charger. The regulator would cost same or less than one 4W LED. A Master brightness could then be used with a central power source with voltage from 11 to 14V. Each table should have PTC protection and EMI filter. Then you can use my design for outd
Please I need your help here. I apologise that this thread might be seen as question that one or more members have already asked but bear with me because this one is unique with many reasons. I'm working on a 48v Inverter system, using MOSFETs as the switch. The switching topology is push-pull, 12 pcs of IRFP260N on each side. Each MOSFET has 12k o
For the isolation sake, you could build the simplest flyback/forward converter with two (identical?) secondary windings. All you need is a cheap MOSFET switch, a small ferrite core and a LM555 as a pwm generator. Of course, you also need two rectification diodes and capacitors but it's an economical solution anyway.
pwm is so trivial with analog threshold and triangle wave ( LPF after Pulse ) into a comparator or gate, why in software? unless going for <5% extreme ends of range or wishing to use programmable current levels.
Hi everyone . I have been recently logging in using facebook and have decided to join this board witch i find pretty interesting . So my problem is with an old hung chang 5502 oscilloscope that was still unused though , i have used it mainly for monitoring some high frequency signals coming from switch mode power supplies pwm ICs . (...)
I use pwm port that connection to DIGITAL input and from digital input (with interrupt-B5) I take another digital output controller (C0), it's because I need to switch fourth transistors and this technique should work for me. (Attached picture of the connection) in duty Cycle I see that I flip between the (...)
The circuit is generating a return-to-zero code to transmit the data across a coil. Although it implements a H-bridge topology, the switch control scheme is different from usual pwm.
I need pwm driving linear Ramp circuit, output is 1 to 5VDC . Component count is critical fpr the place. Thank you very much
guys i have designed switch mode power supply by using Fly-back topology for 12 volt DC and in this design i have used SG6858 pwm IC. i have a little bit confusion about the explanation of this design and i have to present it tomorrow. I am attaching my full design and kindly do give me its detailed (...)
Since the intensity of a LED is controlled by current and not voltage, the best way to dim it is to use pwm and a variable duty cycle. You set the max current by the output voltage and a resistor to generate the current through the LED, or you can use a special switch mode driver that generates a specified (...)
Hi, Not sure about your method of using comparators and op amps ? simply use an voltage selector switch to change the Pics pwm output driving a power transistor or mosfet would be simpler. Unlike a proper voltage regulator you would have little true control of the output voltage and current unless you added lots of (...)
According to block diagram pwm pulses are used to control the switch while analog DC determines the amplitude of pwm pulses on output.
1. Consider a Boost converter, ( switch and inductor ) To charge the battery in the DC rated inductor at high freq. regulated by impedance of 48V battery and filter average battery voltage to control pwm ratio ( regulator). Voltage drop ratio depends on the resistance ratio of the switch to the equivalent (...)
...such 2 pwm, if we starting with a period of (say 100us), and we start module, we can see the wave foam both are starting together...here i want to start the second ch pwm little time later.. Depending on what IC driver for switch device is employed at circuit, you don´t need take care, due such delay feature is a
Sir I had an doubt that it is act as a normal 3 phase diode bridge rectifier(for ac to dc side) and igbt inverter(for dc to ac) is it right sir? It's definitely not right. Or let's say, it's right in so far that the circuit acts as a rectifier when all IGBTs are off. But that's not the intended circuit operation. Consider that t
The tl494 is a veritable chip. If you need switchable output voltages then you could use transistors to switch in and out resistors to ground on the feedback loop, or if your using the chip as a pwm generator switch resistors to ground from pin 3. Or if you want to be clever you might be able to use the (...)
Hello, I am on my new school project - aquarium controling device. I will be measuring ph of water with temperature compensation and I will regulate water temperature with pwm on microcontroller. Here comes the problem of me, not knowing much about triacs. I newer worked with pwm before and I don't have basic idea, how (...)
An adjustable current source is a linear circuit that produces a lot of heat. Instead, Pulse-Width-Modulation (pwm) is used at a fairly high frequency that produces only a little amount of heat because the output devices switch completely on and off. The width of the pulses determines the brightness of the light bulb.
I am trying to drive a 24 volt dc 300 watt dc motor. Using a pwm frequency of 1 kHz. I have tried multiple designs of mosfets, and transistors but they keep blowing up due to the inrush current 20 amps. Or maybe something going on with the micro-controller. But I found a design that worked for a while but was not large enough(4transistors). So I ex
Guys, I need to pass current to a battery from a PV. Now, I'm intended to use n-FET. the pic tells my connection, where the battery is missing... now, I have connected the drain to PV and source to battery (infact an inductance first). Is that okey??? or I have to flip the drain to source??? But FET have to be at high side, and n-FET, no alte
Hi friends, I have designed boost converter (10W) with input side uncontrolled recitfier. My aim is to maintain power factor near to unity. in that while switch ON the power supply, immediatly MOSFET(IRF840) getting more heat and later damage. Can any one help and tell me the procedure how to design inductor,capacitor etc.which type of induc
Hi all, I need to design Current Mode Class-D (CMCD) PA with modulated pwm signal as an input and encounter these problems. I describe step by step the design I done and the problems I encounter in the pdf file below. Hope any of you can show me which part I did wrong. Thanks a lot.
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 (...)
Use a timer to generate a 5ms interrupt and switch the pwm frequency in the interrupt routine. Keith
Anybody know how this circuit works with pwm in pic 18F4520
I assume you are using pwm to switch a fixed voltage to the motor. The torque is mostly a function of the current through the motor. So what is the current when the voltage is fixed? Well, when the motor is held stopped then the current is just the voltage divided by the motor resistance. In that case the torque would be linearly proportional t
Hello Everyone, I am trying to build a Step-Up Converter and have a few questions. I basically have a 3v supply voltage and want to step up to 5 volts @800mA 1) Can the pwm be substituted with a momentary switch? 2) How does one calculate Ripple Voltage? 3) How do u calculate the frequency? 4) What should be the Voltage
As far as I understand, the problem is that you are not performing true synchronous pwm, alternating between high and low side switch as required for 4-quadrant H-bridge operation.