Help understanding the sg3526 chip

[chrisgraca]

sg 3526

I am having a bit of trouble understanding the pinout of the sg3526 chip. Specifically, what exactly do Reset, Shutdown, and Reset do?

What exactly does Vref get hooked to? Is it the voltage you are trying to operate your circuit at?

I am trying to implement an inverter at 60Hz with a pseudo sine wave.

 

[Awarapunshee]

Vref is the +5V regulated voltage generated internally and also for use for reference reference voltage out side the chip (its an output). Shutdown pin is ofcourse for the shutdown of output PWM.

 

[chrisgraca]

Thank you for your help.

I always forget with chips with inverted inputs for shutdown and resets, but...

Would the !shutdown input need a high input to remain operating?
Also, would the !reset need to be high as well to make sure that I am not constantly resetting? I guess, in addition to that. What exactly does a reset do on a PWM? What is being stored that would need to be reset?

Thanks again

 

[Awarapunshee]

You can study the data sheet attached for your answers.

 

[chrisgraca]

I've been looking at the data sheet, but it's not really helping me out a whole lot.

From what I gather, the shutdown and reset just cause the output to go to zero. By setting the (not shutdown) and the (not reset) inputs to high, the output should be driven by the oscillator alone since I also have the error amplifier inputs hooked up to the same voltage level (ground).

I checked the oscillator and I am getting the frequency that I am expecting. (I'm using a variable resistor at Rt and a 3.3uF capacitor at Ct). The dead time also appears to be working (I'm using a a variable resistor at Rd).

I have Vc hooked up to Vcc through a 330ohm resistor. I tried with and without the resistor but there was no difference.

I still am not getting output at A or B. I'm not quite sure what I'm missing here. Anymore help would be appreciated.