Showing posts with label Oscillators. Show all posts
Showing posts with label Oscillators. Show all posts

Thursday, May 05, 2016

Long Duration Linear Sweep or Ramp Generator

I hope you can help me with a circuit. Its a voltage sweep circuit that will sweep from 0v to10v in a 45 min time period, I'm using it for an input on a signal generator to control the output frequency.

I have tried a constant current source charging a capacitor but it just didn't seem to be solid. If It can be done digitally would be great! I have been struggling to do this and its the last part of the piece for my project.

Mail from CB in NA

I have once answered a similar question. Ramp Generator Elex Quna.

You need clock pulses driving a counter, which operate a digital potentiometer. Or any D-A convector - or R-2R circuit. Say you need 1-10V in 45 mts. You first figure how fine the ramp needs to be, like resolution of 100mV?

The constant current may not work as the capacitor may leak and it may not be a perfect ramp. The cc ramp is good for 1 second or less.

A staircase ladder ramp is best for you, define every step of ladder as say 10 or 100mV. A clock of 1 Sec is given to a counter, binary counts, and the digital output of counter goes to D/A Convertor.

Another here with LTspice, install and launch  LTC6993-2 Demo Circuit to try.

 Pulse Staircase Ramp Generator
"This design highlights the use of the LTC6993-2 and LT1490 to generate a pulse staircase ramp that is re-triggerable. "

Pulse Staircase Ramp Generator

If you wish to use a PIC, AVR or 8051 uC, then use it to time and control a built in D-A convertor or PWM. This is done in the code or firmware.

So .... clock >> counter >> digital to analog >> Ramp = you got it. You can implement in both software or hardware, it is your choice.

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Wednesday, December 02, 2015

Power Oscillator Circuit Design

I am trying to find a circuit diagram for a long time, which will give me the o/p Characteristics as 12V, 0.5A & 4000 Hz (or variable frequency). Will you please help me in this regard? I will be very very thankful to you.

Mail from PS

First make an Oscillator and then Power Amplify it.

LM675 Power Operational Amplifier

"The LM675 is capable of delivering output currents in excess of 3 amps, operating at supply voltages of up to 60V. The device overload protection consists of both internal current limiting and thermal shutdown. The amplifier is also internally compensated for gains of 10 or greater. "

Op Amp Booster Designs  PDF

"The design of booster stages which achieve power gain while maintaining good dynamic performance is a difficult challenge. The circuitry for boosters will change with the application’s requirements, which can be very diverse. A typical current gain stage is shown in Figure 1."

Op Amp Booster Designs

12V, 0.5A & 4000 Hz (or variable frequency) is possible, very high frequencies difficult, for that you have to study RF behavior. Experiment from DC to 1 M Hz, no more with these circuits. 200/300 K Hz if you manage you learn't something. Study pages, learn and try to build it yourself. These links are for learning.

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I am extremely thankful to you for your precious reply for my mail. I have tried it to complete the circuit as per your suggestion, but the results are not as per the requirements. Here, I tell you the exact situation. Sir, I am working on the efficiency improvement of an alternator. for this reason I need a frequency generator circuit which will give me the o/p characteristics as 12V, 0.5A & variable frequency upto 4000Hz. The signal must be AC sine waveform. It can be applicable to inductive load. The i/p will be simply 230V AC. Will you please design a circuit for such requirements?

I am in great need of this. Please, I request you to design it. I will be very very thankful to you.

Reply from from PS IN

For professional service, there will be design charge. Your reply will be posted. Anyone who can design this can comment here.

Unique IC Buffer Enhances Op Amp Designs, Tames Fast Amplifiers

A unity gain IC power buffer that uses NPN output transistors while avoiding the usual problems of quasi-complementary designs is described. F


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Wednesday, October 25, 2006

Ramp Generator

Two questions on Ramp Generators -  I need a circuit design for a ramp generator. The ramp generator circuit that I'm looking for is a 1khz ramp generator capable of + to -50 v at 50m using a microprocessor with digital to analogue converter and output reconstruction filter followed by a high voltage operational amplifier.

The generator is going to be used for RFA (retarding field analysers) on plasmas.

Mail from MF of UK

I need a circuit design for a ramp generator. The ramp generator circuit that I'm looking for has put out a linear time varying positive voltage from 0 to +10 volts and needs a ramp time of 45 minutes. So from 0-10 volts in a 45 minute time frame. Maybe also a reset switch to reset the timer again. Can this be done? Please advise. Thank You

Mail from JA

Can you tell me in what application or how you plan to use it. Then i can probably help you better or make a circuit for you. there are many ways to do it. one is a constant current source charging a capacitor. or a staircase generator with a D-A and counter. send me more details.

4QD-TEC: Waveform generator circuits
Triangle Wave Generator Electronic Circuits

See this note from maxim too

"This application note outlines the implementation of a single-supply, triangular wave oscillator using the MAX9000 and some passive components. The application circuit uses an op amp, comparator, and a voltage reference as active building blocks. The MAX9000 is chosen because it integrates these three components. "

 Precision Triangular-Wave Generator Uses a Single IC

Precision Triangular-Wave Generator Uses a Single IC

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