HELLO THIS GOES BACK SOMETIME WHEN I FIRST SENT IN A DESIGN NOTE USING THE PART NUMBER VCA-2612
AS A FEEDBACK LOOP CONTROL ARE TO USE THIS PART IN A FEED BACK CONTROL DESIGN .
OKAY TAKE A LOOK AT THE LAYOUT OF A FDBK. LOOP CONTROL USING THE VCA2612 AMP AS THE MAIN CORE OF THE LOOP
TAKE A LOOK AT THE PINS TO SEE IF THEY ARE CORRECT AS FAR AS THE LAYOUT THAT WILL FOLLOW WHAT IAM TRYING TO DO .
THE VCA2612 WILL BE USED AS THE MAIN DEVICE IN THE FEED BEACK CONTROL SECTION THE PART HAS TWO DEVICES SO I WILL USE ONE FOR THE FEEDBACK VOLTAGE CONTROL AND THE OTHER UNIT IN THE SAME PKG AS THE CURRENT CONTROLLER AND THAN FROM HERE
I WILL USE THE / ARE I WILL USE ONE OF THE INA SERIES OF OP-AMPS TO DO A VOLTAGE AND CURRENT GAIN BLOCK THAT WILL GIVE ME THE TOTAL POWER THE SYSTEM IS PROVIDING .
FOR NO WE WILL JUST FOCUS ON THE FEEDBACK CONTROL SECTION IF YOU WOULD LOOK AT THE DRAWING I'VE ATTACHED
THE SINE WAVE THAT IS GOING INTO PIN 16 OF THE VCA2612 WILL HAVE A BUFFER AT THE INPUT SO AS TO GIVE THE INPUT SIGNAL A OFF SET VOLTAGE OF +2.500 VDC THIS REF VOLTAGE WILL BE COMING FROM A REF-1 DEVICE THE REF O1 IS A +10.000 VDC REF VOLTAGE DEVICE TO I WILL DIVIDE THE SIGNAL DOWN TO WHAT LEVEL I NEED FOR THE DIFFERENT SECTIONS OF THE DESIGN TO GIVE A MORE STABLE SOURCE THE INPUT SIGNAL WILL GO TO THE INPUT OF A 1MFD CAP. AND I WILL BE USING THE LNP SECTION OF THE DEVICE SO I WILL HAVE SOME FORM OF STABILITY AS THE FEEDBACK SECTION SETTING UP THE BW FOR THE FEEDBACK SIGNAL. AND ALSO THIS COULD BE A GOOD POINT TO SAMPLE THE TRU SINE WAVE FROM THE OUT PUT TO COMPENSATE FOR THE ADDED DELAY TRU THE SYSTEM THIS WILL BE A GOOD POINT TO ENTER THE FEEDBACK SIGNAL TO REDUCE POSSIBLE OSCILLATION DUE THE THE TIME DIFF. FROM THE INPUT SIGNAL TO THE OUTPUT SIGNAL. , NOW THE OP-AMP AT THE BOTTOM OF THE DRAWING THIS IS WHERE THE OUTPUT SIGNAL FROM THE POWER STAGE WILL BE INJECTED BACK INTO THE SYSTEM ,AS YOU WILL SEE THE OUTPUT VOLTAGE SENSE WILL BE THRU A SMALL TRANSFORMER THAT WILL PRODUCE ABOUT 5 V PK-PK SINE WAVE AND IT WILL GO THEU A SMALL FULL-BRIDGE RECTIFIER AND DIVIDED DOWN TO A LEVEL THAT WILL BE A DC VOLTAGE AROUND +2.500 VDC TO MATCH THE VOLTAGE REF THAT IS ON THE + INPUT OF THE OP-AMP SO AS THE REF LEVEL BECOMES LARGER THAN THE REF. SIGNAL THE OUTPUT OF THE OP-AMP WILL START TO GO DOWN TND HERE IS WHERE YOU CAN SET THE MAX AMPLTD. OF THE OUTPUT VOLTAGE TO REGULATE THE SYSTEM .
SO AS I LOAD THE OUTPUT VOLTAGE THE SYSTEM WILL REGULATE THE OUTPUT TO MAINTAIN THE SAME LEVEL AS THE REF. VOLTAGE AND AS THE LOAD DECREASS THE ERROR AMP WILL COMPENSATE TO MAINTAIN THE SAME OUTPUT FROM NO LOAD TO FULL LOAD.
AND THAN I WILL USE THE OTHER AMP SECTION OF THE VCA2612 AS THE CURRENT INPOUT SO AS THE CURRENT REACHES THE MAX. LEVEL IT WILL CAUSE THE OUT SIGNAL TO DECREASE AGAIN SO THE SYSTEM IS NOW ALSO POWER LIMITED.
THE SECTION OF THE DRAWING THAT HAS HV.DRV(P) AND HV DR. (N) WILL DRIVE THE SWITCHING SIGNALS FOR THE POS SECTION OF THE SINEWAVE AND THE NEG. SECTION OF THE SINE WAVE TO GET THE SUM AT THE OUTPUT OF THE LOW-PASS FILTER SECTION TO GET THE 115 VRMS SETTING BY THE 2 K OHN POT TO SET THE OUTPUT LEVEL OF THE SYSTEM .
SO WHAT I NEED TO DO WITH THE VCA2612 IS THE REGULATOR ARE THE FEED BACK LOOP SECTION TO MAINTAIN A STABLE OUTPUT VOLTAGE OF 115 VRMS FROM NO LOAD TO FULL LOAD. THE GAIN SELECTS LOCATED AT PINS 40,41 AND 42 CAN BE SET VIA THE DIP SWITCH WHERE YOU CAN SLIDE THE DETERMINED SWITCH HI ARE LOW TO SET THE MAIN OVERALL GAIN OF THE OUT PUT AND I WILL USE A OP-ANP FROM BOTH THE VCAOUT(P) AND VCAOUT (N) THAT WILL GO THO THE DRIVER DEVICE THE THE SWITCH SIGNAL WILL BE SET VIA THE TRIANGLE WAVE TO THE PART SO WHEN I APPLY A SINWAVE THE UNIT WILL MODULATE LIKE A CLASS D AMP AND THE HI-VOLTAGE SIGNAL WILL GO THE THE OUTPUT FILTER SECTION AND THE LOW FREQ. SINEWAVE WILL BE FILTERED OUT TO GET THE SINE WAVE AT 50HZ TO AROUND I KHZ AND THE TRIANGLE WILL BE AT APPROX 50KHZ MIN TO APPROX. 400 KHZ THIS WILL BE TESTED TO SEE APPROX. WHERE I HAVE THE LOWEST SWITCH LOSS THRU THE POWER
STAGE, NOW HERE THE MOST IMPORTANT IDEA IS TO USE THE VCA2612 AS THE FEEDBACK CONTROLLER AND THE SINEWAVE AT THE INPUT INTO PIN 16 WILL BE CONSTANT THIS SIGNAL SETS THE OVERALL OUTPUT LEVEL , SO THE SINE WAVE AT THIS POINT WILL BE CONSTANT AND THE FEEDBACK SIGNAL INTO PIN 43 WILL REGULATE ARE KEEP THE OUTPUT SIGNAL CONSTANT FROM NO LOAD TO FULL LOAD.
SO AGAIN LOOK AT THE PINS TO SEE IF I HAVE THE CORRECT PINS SELECTED AND THEY ARE SELECTED CORRECTLY ARE TO SEE IF SOME PINS WILL ARE SHOULD HAVE PULL UP ARE PULL DOWN RESISTORS PLACED CORRECTLY
AGAIN THANKS SO MUCH FOR YOUR TIME AND IF YOU THINK THE PIN'S ARE CORRECT I WILL DO A MAIN DRAWING SO THE PINS WILL BE LABELED CORRECTLY AND THE DRAWING WILL BE CLEAR.
YOU CAN ALSO CONTACT ME DIRECTLY ANY TIME DAY ARE NIGHT AT 954-606-5886
THANMKS,
WILLIE L. MCCAINFEEDBACK LOOP CONTROL.pdfFEEDBACK LOOP CONTROL.pdf