Wish to generate a reference rectified sine

[Flyback]

Hi
We need a unipolar train of half sines.....50Hz sine...so rectified thats 100Hz.
Also 1V pk...but variable to eg 0.9Vpk say.
Also, it doesnt have to supply any current...its just a reference for a switching power supply.
Do you know the best way? Low component count.

 

[ChrisP58]

Is this as an engineering tool for development and test, or will it go into production?

 

[crutschow]

How accurate (distortion level) does the sinewave need to be, and to what frequency accuracy?

A quasi-sinewave can be generated by double-integrating a square-wave.

 

[Flyback]

this is for a production test tool

 

[shortbus=]

Is it too late to get a refund on your EE degree?

 

[JimB]

Several possibilities come to mind:

1 Simply rectify a 50Hz sine wave using a bunch of diodes.

2 Use a op-amp precision rectifier circuit. This will give better shape to the rectified sinewave "zero crossing" null.

3 Use a form of direct digital synthesis.
Store digitised values of a half sine wave into an EPROM (or similar), clock the values into a suitable D to A converter, pass the output of the DtoA through a low pass filter to remove the "steps" in the waveform caused by the digitisation process.

JimB

 

[crutschow]

Can you use a function generator, or do you want it to be a stand-alone circuit?