VCA2612 DUAL VGA AMP

Hi,

We have received your inquiry regarding the VCA2612 and hope to have some answers back to you shortly.

Thanks.

Willie,

Is it possible to get a block diagram of what you are trying to do?

hello

i will try to send you a hand drawing tomorrow so you can get a better idea of what iam trying to do please let me no by email are phone 561-853-4160 call me anytime i need to no if the part will work

I FOUND A BETTER PART TO USE THE THS7530 TAKE A LOOK AT THE DRAWING ATTACHED WHAT I WONT TO DO IS TO APPLY A CONTROL VOLTAGE THAT WILL MAKE THE OUTPUT DECREASE AS I INCREASE THE CONTROL VOLTAGE AND INCREASE AS I DECREASE THE CONTROL VOLTAGE LET ME NO

THANKS6116.VCA CONTROL.pdf

OKAY HERE IS THE DRAWING ON TOP OF THE DATA SHEET I JUST DRAW OUT WHAT I THINK IS CORRECT PLEASE LET ME NO IF IT IS CORRECT AND SEND A NOTE BACK ON WHAT NEEDS TO BE CHANGED

SO NOW WHAT IAM DOING WITH THE PART IS USING IT IN A FEED BACK NETWORK AS GAIN CONTROL OF THE SINE REF. IN , SO WITH NO FEEDBACK THE OUTPUT SHOULD BE AT MAX GAIN WITH NO CLIPPING THE INPUT SIGNAL IS AT 1.5V PK-PK AT 400HZ, SO NOW AS I START TO INCREASE THE FEEDBACK SIGNAL INTO THE OP AMP THE OUTPUT OF THE OF-AMP SHOULD START TO GO DOWN THIS WILL DECREASE THE AMPLTLD. OF THE SINE OUT ANND AS THE FEEDBACK TRYS TO DROP THE OUTPUT SIGNAL WILL INCREASE TO COMPENSTAE NOW WE HAVE REGULATION OF THE MAIN OUTPUT SIGNAL

LET ME NO ASAP IAM GETTING A LITTLE BEHIND HERE

THANKS,

WILLIE L. MCCAIN

561-853-41603162.VCA CONTROL VCA2612.pdf

I FORGOT TO ADD SOME PINS JUST TO MAKE THING MORE CLEARER

PIN'S

1,17 TO + 5.0VDC

18,19  A .1 MFD CAP TO GROUND

20 TO GROUND

48 TO GROUND

13,14,15 ALL TIED TOGETHER ( ARE I WILL SELECT LATER )

Willie,

Your VCA circuity looks correct. However, I do have a few questions. Is the other amplifier the THS7530? Is your input frequency set at 400Hz? That is way below our typical -3dB bandwidth, which is 40MHz.

HELLO MS BALL

YES THE INPUT SINEWAVE TO THE PART IS AT 400HZ AND IF I CAN USE THE VCA2612 THE SINEWAVE WILL BE THE SAME 

NOW I LOOKED AT THE THS DEVICE AND IT LOOKS LIKE A WIDE BAND VCA THATS WHY I SELECTED IT BECAUSE IT LOOKS EASIER TO USE AS A CONTROL VCA AMP 

NOW WILL I HAVE THE SAME PROBLEM FOR THE VCA 2612 ARE IS THE VCA2612 A BETTER PART TO USE

HELLO AMY,ITS BEEN A WHILE SINCE I WROTE BUT THE PROJECT IS COMING UP NOW AND I JUST NEED TO CLEAR UP SOME POINTS ABOUT THE VGA'S THAT AIM TRYING TO USE IN THE FEEDBACK LOOP TO CONTROL THE OUTPUT VOLTAGE.

WE HAD TALKED ABOUT THE THS 7530 AND THE VCA 2612, THIS TIME AIM SENDING YOU A SIMPLE LAYOUT OF THE LOOP SO YOU CAN SEE WHAT AIM TRYING TO DO WITH THE PART, THE DRAWING SHOW THE VCA 810 NOW AS I HAD SAID THAT THE MAIN GOAL HERE IS REGULATION CONTROL OF THE POWER CONTROLLER .

SO NOW IF YOU WILL LOOK AT THE LEFT SIDE OF THE DRAWING YOU SEE THE + 9 VDC SENSE VOLTAGE THIS VOLTAGE IS DIVIDED DOWN TO THE LEVEL OF THE PART ( VCA 810 )SO I SET THE REF. POINT OF THE VCA 810 TO +2.50 VDC YOU WILL SEE ON THE FRONT SHEET OF THE PART THEY HAVE / ARE USE +5 VDC FOR THE SUPPLY AND THEY USE TWO 1 K RESISTOR'S TO TO DIVIDE IT DOWN TO +2.50 VDC THIS SETS THE POINT WHERE THE INPUT SIGNAL IS RIDING ON SO IAM GOING TO PUT THE SINE WAVE SIGNAL ON THE + INPUT AND I WILL SET THE - INPUT WITH THE CAPACITOR TO GROUND SO NOW I HAVE A SINGLE END INPUT MY SINE WAVE IS SET AT 1VOLT ARE 2 VOLTS PK-PK.  NOW WITH NO INPUT ON THE VCL - PIN #13 I SHOULD HAVE THE SINE WAVE OUT AT PIN # 11 AND 10 AT 2VOLT'S PK-PK SO ONE SIDE OF THE OUT PUT IS INVERTED. SO I WILL USE THE V OUT + SIGNAL TO THE INPUT OF THE CONTROLLER .

SO NOW AS I APPLY THE FEEDBACK DC VOLTAGE TO THE - IN PUT , BUT NOT GREATER THAN +1.00 VDC. SO AS I GO ARE BECOME CLOSE TO THE ONE VOLT LEVEL THE OUT PUT SINE WAVE WILL START TO DECREASE IN AMPLTD.

TO SET THE OUT PUT VOLTAGE OF THE SYSTEM . SO FROM HERE AS I START TO LOAD THE OUT PUT OF THE POWER STAGE THE OUT PUT SIGNAL WILL TRY TO DRCREASE SO THE VCA 810 OUTPUT WILL GO UP IN AMPLTED. TO MAINTAIN THE OUT PUT SET POINT. AND AS I DECREASE THE LOAD THE  OUT PUT OF THE VCA810 WILL DECREASE IN AMPLTD. TO KEEP THE OUT PUT VOLTAGE AT THE ADJUSTED SET POINT SO NOW WE HAVE REGULATION CONTROL OF THE OUTPUT SINE WAVE.

I THINK THE ( THS7530 ) WILL BE A GOOD PART TO USE AND IT COST LESSER THAN THE VCA2612 BUT THE VAC 2612 HAVE OTHER SECTIONS THA I CAN ALSO ADD THE DC VOLTAGE OF THE CURRENT SENSE AS WELL SO NOW IF THE CURRENT GO OVER THE SET POINT IT WILL OVER RIDE THE VOLTAGE SETTING AND CAUSE THE OUT PUT SINE WAVE TO DECREASE AND NOW WE HAVE POWER LIMIT AS WELL LET ME NO IF  YOU THINK THIS IS A GOOD PART

THE SINE WAVE REF WILL VARY FROM 50 HZ TO APPROX. 2 KHZ

SO GET BACK PLEASE AND LET ME NO SO I CAN START TO DO A FINAL CONTROL SECTION AND SEND IT TO YOU TO VIEW.

IAM TRYING TO USE A PART LIKE THIS THIS WILL ALLOW ME TO SET THE FEEDBACK SECTION IN MANY WAYS AND IT WILL PROVIDE SO TYPE OF ISOLATION FROM THE LOOP FEEDBACK VOLTAGE

PLEASE CALL ME IF YOU CAN TO TALK OVER THE APPLICATION ,I THINK THIS WOULD WORK THE VCA810 WILL BE USED FOR SMALL SYSTEMS AND THE VCA 2612 WILL BE USE FOR A MORE HI-POWER APPLICATION BECAUSE IT HAS MANY OPEN INPUT'S THAT I CAN ADD OTHER CONTROL VOLTAGES IN THE FEEDBACK LOOP.

THANKS ,

WILLIE L. MCCAIN ( 954-606-5886 )FEEDBACK CONTROL.pdf

AMY AIM SORRY THE UNIT IS THE THS7530 THIS UNIT IS THE ONE I THINK WOULD BE BEST TO USE I SENT A DRAWING USING THE VCA 810 JUST TO KEEP IT SIMPLE AS I EXPLAIN WHAT AIM TRYING TO DO .
BUT THE END UNIT WILL BE THE THS7530 BECAUSE IT HAS A POS. AND NEG. CONTROL VOLTAGE INPUT .
I JUST WONT YOU TO NO AGAIN I JUST USE THE VCA810 BECAUSE ITS SIMPLER UNIT TO EXPLAIN, BUT AGAIN I WILL USE THE /ARE I WOULD LIKE TO USE THE THS7530 FOR LOW POWER SYSTEMS AND THE VCA2612 FOR HI POWER SYSTEMS DUE TO IT HAS OTHER INPU POINTS I CAN ADD THING TO FOR DIFFERENT FUNCTIONS

THANKS ,

WILLIE L. MCCAIN ( 954-606-5886 )

Willie,

OK. Thanks for the update.