Help required connecting sg3525 to synchro

Thread Starter

MATT838383

Joined Jul 31, 2019
123
Hello everybody! i am trying to connect a synchro of 100KHZ 2,5v on pin 3 of the sg3525, there is problems that i have, when the synchro is connected on pin 3 i have no periodic cycles (0% to 49% )and when i disconnect pin 3 i have the frequency controlled by ct ans rt that is ok! and the pwm vary from (0 to 49%)!
i post my chematic:
best regards!
 

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MisterBill2

Joined Jan 23, 2018
8,214
You need to look at the data sheet and learn what the synchronizing signal must be.
Is this a real circuit or just a simulator circuit? That matters a whole lot.
 
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Thread Starter

MATT838383

Joined Jul 31, 2019
123
ITs a simulation circuit! on the datasheet: (A sync input to the oscillator allows multiple units to be slaved or a single unit to be synchronized to an external system clock .A single resistor between CT and the discharge terminals provides a wide range of dead-time adjustment. ) It is mentionned upper on the schematic! still havent find a solution for this problem!
 

MisterBill2

Joined Jan 23, 2018
8,214
What does the data sheet specify tor that synch input? And for future reference, a "synchro" is an electromechanical device that is used to sense a rotation position, which is what the initial request had me a bit confused when I saw the circuit.
What frequency do you have the circuit generating when it is running? the 100 Khz seems a bit different from what it would be otherwise. Generally a synchronizing signal is used to provide phase lock, and not change the frequency very much at all. So that may be the problem.
 

Thread Starter

MATT838383

Joined Jul 31, 2019
123
The simulation upper is a design founded on the net! i have ltspice 4 and havent found any 3525 or3524! if someone could give me an example to test it!
thanks
regard
 

MisterBill2

Joined Jan 23, 2018
8,214
One more consideration is that the "synch" pin is normally used to synchronize multiple ICs of the same type in a supply application where more than one is used. That is the only intended use, and so it will probably not be useful for any other purpose. You need to read the manufacturers application information to understand what it does, and thatwill never be found on you-tube, which I do not trust for any technical information.
 
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