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121 Threads found on edaboard.com: Voltage Controlled Pwm
hello friend thank you i came to know about a good pulse width modulator with your post. you have to use two pots one for varying duty cycle and other for varying frequency. you didnt told at what voltage you want to operate. i suppose it as 3V and you have to connect 2K ohm resistor plus 1k ohm potentiometer and 100 ohm resistor in series between
Hi, Anyone who has experience with that how to get a pwm signal whose Puls should be controlled based one the I/P voltage ?5V Using simple OP-Amp ? Thanks in advance
The LM321 can work with the input voltage of 0V. What is the maximum voltage of your pwm I/P? I thiank this maybe not a safe salution.
Hi to control the brighness you need to conrol current passing in the led. To do this you can either coontrol the current itself or to control the resistor through which the current is passing. To control current itself, you will use a voltage controlled current source where the voltage control signal is a low pass filtered version of (...)
i am fibished with ths job.. i did it using a voltage controlled oscilator integrated circuit called 8038. i amplified the output of the microcontroller using an octocoupler. i obtained the DC value of the pwm pulses using an R-C circuit.. then i fed this DC value to the 8038 integrated circuit. now by changing the duty cycle of the (...)
Hi everyone, I design a Boost circuit with specification: Input: 3.3v Output: 5v, 50mA After soft-start, the output voltage increases very high: around 18v. Then it decreases to 10v, but very slowly. How can I control the output voltage? Best Regard! Thanks
In the first step convert 4-20mA to 1.0-to-5.0V using 250Ω resistor .. In the second step, apply this 1-5V control voltage to voltage controlled P(ulse) W(idth) M(odulator) = pwm .. Here are details of the voltage controlled pwm:
Hi all... can any one tell me how to do "Average Modeling BUCK pwm voltage Mode Control.." I mean i need to do state space average modeling for complete BUck converter which includes pwm also... Thanks a lot...
yes you use the following circuits thanks, i think it may helpful voltage controlled AC Light Dimmer
looks like voltage controlled pwm to me. PIC reading voltage value through ADC and feed it to pwm, so its duty cycle varies proportional to voltage.
Hi; I have no application experience but just have an idea. Mosfets can behave like a resistor in a limited range, that is called linear region or ohmic mode. May be you can use a mosfet in this mode, and you can use it in parallel to gain resistor in an op-amp aplifier application. To adjust resistance of fet, you can generate dc voltage usi
I'm looking for a simple pwm low voltage (6/12V 50W) lamp controller, using PIC 16F84/F628 or 12C509 and a power MOSFET. It should provide "soft start" and regulate the lamp voltage from a battery V greater or equal the nominal Vlamp. Does anyone has already it or I have start this design from scratch ? T.I.A.
Does anybody have a simple solution? i wish to control a camera mount, with two steppers, from a analog joystik im thinking to use a simple comparator compuling to determine "up / down" and somehow rig up a voltage controlled oscilator to make a frequency depending on the stick position.. so i can "pan" the camera slowly, or fast when the s
Another famous and versalite Switching Regulator IC is National Semiconductor LM1578A / LM2578A / LM3578A. It may be operated in either the continuous or the discontinuous conduction mode. It can be used as either Flyback-, Inverting-, Step-Up- or Step-Down converter. Functional Description The
Feedback loop will regulate the o/p voltage and also stabilize the ckt. bimbla.
Is You inverter contain degenerative feedback circuit? Are You use special h-bridge mosfet drive to control power mosfet (undervoltage protection & etc...)?
These switching methods are much more efficient that putting a drop in series with the motor. This is sort of like the difference between a switching and an analog regulated power supply. The other advantage of pwm is at the low end of the motor speed. The mechanical rotation speed is more linearly related to the width than the motor speed w
Without going into details, you will need a small microcontroller that will take signal from IR sensor and a digital potentiometer (od D/A converter) that will, together with output voltage (an op-amp in SUM configuration) generate a signal for the error amplifier of the 3524. By doing this your circuit will slow down the fan when the IR detedct so
Hi everybody, My target is to have different voltage levels like 3V, 4V, 7V, 15V etc etc.. I want to know whether there is any variable voltage regulator that can digitally controlled using this micontroller in order to get varying voltages from +3 to +15 V. For example in my software routine I give any specific (...)
Hi, pwm is fairly complicated, although, with a 555 timer (NE555?) you could use FM. just set it up to oscillate at, say, 200Khz, then connect your audio input to pin 5. This will pull the frequency off a bit. AM (amplitude modulation) is probably the easiest. But...if you directly modulate an IR led with audio, and demodulate it at the r
Hey there guys, So I have a new water cooled computer with three very big 12" fans. I want these to be temperature controlled, so I figgured the best way was off the motherboard fan header (since this can be set of the CPU temp). The problem is that the output off the motherboard is pwm (pulse width modulated) and these big slow RPM (but ver
Hey there guys, So I have a new water cooled computer with three very big 12" fans. I want these to be temperature controlled, so I figgured the best way was off the motherboard fan header (since this can be set of the CPU temp). The problem is that the output off the motherboard is pwm (pulse width modulated) and these big slow RPM (but ver
I have the feeling that to have a small microcontroller connected to the serial port (simple commands from PC keyboard in Hyperterminal) is just more user-friendly approach .. no software for PC required .. All what you need is to type, say, 001 for 10mV, or 010 for 100mV and so on .. When you type a command like 010 in Hyperterminal it sends o
One good way of controlling motor's speed is to use a rotary encoder attached the the motor's shaft . Alternatively you can use a disk with several holes, install LED(s) on one side and photoelement(s) on the other side, and using PIC microcontroller measure pulses' duration which is direct proportional to the motors' speed .. In both cases volta
Hi I used AVR pwm for DAC later, therefor cause LCD contrast adjust with a voltage from 0 to about 5 v , you can use this dac for do this. the frequency is not important but use fast pwm mode. for covert the pulse to analog voltage, use low past filter. for better result use more than 3 LPF.
Hey everyone.... Im working on a new one now and I just wanted to get some input.... Ive been thinking of building a "dummy" load for test. I am thinking of using a PIC16F676 to read and display voltage and current... I was thinking of using the pic to limit the current by using pwm and shunting a MOSFET through a limit resistor to ground. But I do
So i'm in the process of converting a voltage controlled device into a current controlled device which utilizes the PIC16C54C microcontroller. The original voltage controlled schematic involved using multiple ZVN3306FCT-ND MOSFET transistors which were controlled by the PIC. These MOSFETs (...)
Hello Everyone, this is my first post! I am presently trying to design a voltage controlled light source. Basically I have a supply that has a 0 to 5 volt swing, I need to convert that swing to 0 - 24 volt to power my light source. I tried with a current sense amplifier but it was capping my output at 12v although the swing there was working
No the HV9910B operates in open loop current mode control.There is no closed voltage loop,no voltage feedback,So no voltage loop compensation need. But if HV9910B is in Peak current mode control,the inner slope-cpmpensation must add when duty>50% in CCM. PFM SMPS need no loop co
Hi, This might be a out of way question, but still...... Actually few days back I saw a project which was a "Variable Constant Current Source" & the designer had controlled the Output Current value through PIC16F877A. The analog circuit is connected with uC through three pins AN0, AN1 & RC1/T1OSI/CCP2. The system also detects shortciruiting of th
what factors effect the voltage drop on pwm dc-dc converter?
Analog voltage/current signals...
Dear All, I need to control the speed of common ceiling fan using a Triac/dimmer I know about a dimmer circuit but it uses a POT. I want to design a digital dimmer which get some Analog voltage/or pwm from MCU and control the speed or please tell me any other way i can do this.
hi everyone recently i have a project regarding controlling the rectified o/p voltage of an 3 phage alternator with varying load and rpm. the system parameters are as follows controlled o/p = 130V max o/p current = 0-200A rpm = 0-2500 (0 - 500hz) field current vary frm 0-10A to provide the desired o/p power. i have to do this by varying t
I'm an amateur in electronics and am trying to teach my self by building some circuits for a human-powered music project that I've been involved in recently. I'm looking for some guidance and advice from those of you who have more experience and skills on a good approach to a few issues. I have a pedal power system composed of 4 bicycles with 3
How output of an inverter can be controlled? What is the need of voltage control of full bridge inverters? It all depend on your desinge of the inverter and the type of oscilator used,some of the ic's used as oscilators has an in buid pwm control by feeding in feed back loop to the pwm control pin,eg SG3524.352
Did you think about available methods to "control" an AC voltage? What are the intended output voltage properties?
Hi, I am thinking to do a very simple high side p-mosfet power switch. Let say Vcc 5V to source, gate voltage controlled by FPGA output, and the load current is about 0.5A at the the drain, parallel with filtering capacitor. What specific precautions will need to take care? How to determine MOSFET parameters in order to get fast turn on/off t
Digital potentiometer in picture has value for max. current <2.5mA & max. voltage 5V I thought that might be a problem. Also, getting a pot with a low enough value could be difficult as well. I still think the constant-current source would work well; a cheap transistor and 2 resistors and the digital pot. Still, if y
If you expect bad control system behaviour with a continuous PI or PID controller, you should expect nothing but worse results with on-off control, I think. In my opinion, the best method to achieve good dynamic load regulation is a feedforward structure, that directly translates output load changes into primary control action, without waiting f
Pulse-width modulation (pwm), or pulse-duration modulation (PDM), is a commonly used technique for controlling power to inertial electrical devices, made practical by modern electronic power switches. The average value of voltage (and current) fed to the load is controlled by turning the switch between supply and load on and off at a (...)
If you have to use low voltage rattings, reduse attack and decay time (response) of automatic pwm adjustment. There is no offset voltages in normal operation, it developes only during adjusting. In a similar case, i had used 1/3 voltage rating to bus. which was available. Still in use for many months without a problem.
The easiest is to have the microcontroller vary the voltage feedback loop of the 3844 using a digital potentiometer. Does the microcontroller also need to be isolated or can it run off the same supply as the 3844 (still requires regulator to microcontroller's Vdd)? In any case the digital pot is not, and its SPI data lines could be driven via opt
voltage controlled oscillators based on the 555 series are well known. One way to do that with your MCU would be to generate a pwm output, then pass that through a low-pass D/A filter, say 10K and 10 uF (just a guess). Use that voltage output at the Control voltage pin (pin5) of the 555. Why would you (...)
Take a step back and ask what attribute of the solenoid you are trying to control. Current? voltage? Position? Flow? Get your mind right about feedback. There's plenty of options for power switches, drivers and so on. But these are only the nuts and bolts, and I don't see a plan.
Not quite sure I understand. Is your gate drive 7.4V or is that your supply? You say you've got 7.4V at 8A. The graph is for 15V. Maybe you've got some reverse EMF issue (as the motor spins faster, it generates a higher reverse voltage)
If you are trying to control a normal CPU fan, designed to connect to a PC motherboard, then that circuit won't work. The fan is not voltage controlled, it is pwm (pulse-width modulated) controlled. You need to make a pwm controller - there are many examples if you search google, here is one that's (...)
Alien, the only thing magical about 50% I recall in RF days was I tune the slicer to exactly 50% using the relative 2nd harmonic content level in the days when 2% loss of window margin for dat recovery was too much. But for spectral content in dB the duty cycle does not affect the harmonics generated by the edges much, just the repetitive stuff
Hello, I am wondering how to make a good pwm controlled heater output. I am using a N FET that is controlled by a push-pull configuration (12V/0V) and the N FET has a 100 Ohm resistor connected to the gate. The pwm is a CTOUT output from the State Configurable Timer of the LPC controller (pwm output is (...)
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 (...)