With PWM signal in pin 4 Sync can work as MOSFET driver?

I have left the pins 5CT 6RT and 7Disc. unconnected.

In simulation with LTSpice it looks like it does not work and I do not understand the use of that pin.
The oscillator schematic is shown in the datasheet but I still did not understand the use of that pin.

 

That sync pin is to allow more than one 3525 in a circuit to be driven at the same frequency/timing from one oscillator.

The chip it's self is normally used with Nmosfets, used as low side switches. In that configuration no gate driver is needed.

 

That sync pin is to allow more than one 3525 in a circuit to be driven at the same frequency/timing from one oscillator.

I wish to see at least a schema with two SG3525 and a single oscillator.

The chip it's self is normally used with Nmosfets, used as low side switches. In that configuration no gate driver is needed.

Yes, I need 2 LOW Side Driver. But I think to use SG3525 as Low Side MOSFET driver it's not a good idea.

If anyone is interested I have the SG3525 model in LTSpice

 

From STMicro's web site. " A sync input to the oscillator allows multiple units to be slaved or a single unit to be synchronized to an external system clock."

From the same. "The output stages are totem-pole designs capable of sourcing or sinking" This is what a low side driver does.
The web page, http://www.st.com/en/power-management/sg3525.html
The device PDF data sheets will tell you all.

 

Please house am new in the house, and I need some vital information on how to synchronize sg 3525ic. I mean how to use 2 or 3 of the ic together and control it with only 1 friqency

 

Please house am new in the house, and I need some vital information on how to synchronize sg 3525ic. I mean how to use 2 or 3 of the ic together and control it with only 1 friquency.
I will be very happy if I can get some explanation or circuit diagram on it. Thanks in advance.

 

It has been a loooooong time since I last did that, perhaps 35+ years.
If i remember correctly, you have to make the free running frequency lower than the synchronization frequency, as it works by discharging the timing cap earlier.
One side effect is that ramp amplitude will be lower.
The timing pulse also has to be narrow.

 

It has been a loooooong time since I last did that, perhaps 35+ years.
If i remember correctly, you have to make the free running frequency lower than the synchronization frequency, as it works by discharging the timing cap earlier.
One side effect is that ramp amplitude will be lower.
The timing pulse also has to be narrow.

It has been a loooooong time since I last did that, perhaps 35+ years.
If i remember correctly, you have to make the free running frequency lower than the synchronization frequency, as it works by discharging the timing cap earlier.
One side effect is that ramp amplitude will be lower.
The timing pulse also has to be narrow.

Thanks for your quick response schmiyytrigger, but still not understand I need explanation on how to connect the pins together bot the input and output of the ic's

 

There is more info about synchronous operation in SG2524 datasheet,
http://www.ti.com/lit/ds/symlink/sg2524.pdf

From the datasheet:
9.4.1 Synchronous Operation
When an external clock is desired, a clock pulse of approximately 3 V can be applied directly to the oscillator output terminal. The impedance to ground at this point is approximately 2 kΩ. In this configuration, RTCT must be selected for a clock period slightly greater than that of the external clock. If two or more SGx524 regulators are operated synchronously, all oscillator output terminals must be tied together. The oscillator programmed for the minimum clock period is the master from which all the other SGx524s operate. In this application, the CTRT values of the slaved regulators must be set for a period approximately 10% longer than that of the master regulator. In addition, CT (master) = 2 CT (slave) to ensure that the master output pulse, which occurs first, has a longer pulse duration and, subsequently, resets the slave regulators.

 

There is a separate sync pin on SG3525, so outputs are not tied together. Connect oscilloscope output to to the sync pin on the next SG3525 and the oscillators operate in sync. This can be tested on LTspice simulator too.

 

There is a separate sync pin on SG3525, so outputs are not tied together. Connect oscilloscope output to to the sync pin on the next SG3525 and the oscillators operate in sync. This can be tested on LTspice simulator too.

Thanks for the quick response tsan

There is a separate sync pin on SG3525, so outputs are not tied together. Connect oscilloscope output to to the sync pin on the next SG3525 and the oscillators operate in sync. This can be tested on LTspice simulator too.

Thanks for the quick response tsan, God bless you. I will go and try it and give you feedback on it.
Pls can I get your number or your email so that I can be contacting you.

 

But how can the newer IR2153 be synchronized?
I use IR2153 instead of SG3525
Too low a voltage in the CT pin means shutdown.

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I have a PWM given by the microcontroller with which it needs to be in phase.
What if the microcontroller gives an error?
I want it to work on an internal RC in the absence of a external correct PWM.
Does SG3525 do that? to use RC if the sync signal disappears.
Let's say the Sync pin remained High or Low

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Externally synchronized IR2153:
One idea would be:


Is not my scheme, but I still use it at 12V

 

Externally synchronized IR2153:

Doesn't the IR2104 do what you want?

 

Doesn't the IR2104 do what you want?

Yes, he does.
But I am afraid that I will have an error on the PWM signal given by a microcontroller.

In this case a simple circuit must be thought of, as if by mistake the Pwm has a longer period than a predetermined one to operate the SD pin (Shoutdown).

If you know a circuit to give a signal if PWM High or PWN Low takes too long, please let me know.
For too long, if one of the two MOSFETs were left open, it would spark.

 

I will take for a while to discuss the possibility of using synchronized IR2153, but maybe it's a bad idea.

I thought that using this scheme would change the PWM duty cycle.
They say that this way you change the PWM frequency, what do you say?
It seems to me that in this way the caacitor charge faster than it discharge or vice versa....


From:
https://www.infineon.com/dgdl/dt98-1.pdf?fileId=5546d46254e133b401554de8ed5d5e0f

 

I use IR2153 instead of SG3525

The two chips are totally different things. The SG3525, makes its own pulses to drive the mosfets. The IR2153 is a half bridge driver, it needs something else to give it its pulse signal. If driving more than one IR2153 in sync maybe use a buffer chip that works with the pulse voltage output from the microcontroller to the individual half bridge chips.? Just a guess but can't see why it wouldn't work.