PWM with TL494 for MOSFET

[jean12]

Hello ,can any body suggest me a PWM generator circuit with TL494,I am controlling a push pull circuit but with PIC I am having trouble,If I found a TL494 which generates PWM signal it can be good.

Thanks.

 

[--BawA--]

i have found something of your intrest

 

[FvM]

I presume you want to keep the existing gate drivers and supply non-overlapping, noninverted PWM signals from TL494 to the driver. The required TL494 output configuration is shown in the datasheet, it's about connecting pull-down resistors to the E1/2 pins to get a noninverted signal.

 

[jean12]

Hey -BawA-- my rectifier is outputting 420V how do you thing those pin 1 and pin 15 should I connect them so they can sense the output voltage?

Please help.

Thanks.

- - - Updated - - -

Hello FvM I am not getting what you want to talk about when you say non overlapping?

How may I proceed practically?

Thanks.

 

[--BawA--]

suppose u have to keep your output volatge of 311dc constant , you have to design a voltage divider circuit such that, when a 311v is applied to that voltage divider the output should be equal to the the voltage that you are feeding on inverting input. after designing the required voltage divider ,just connect the output of voltage divider to non-inverting input of TL94.

 

[jean12]

Which inverting input are you telling me?Can you explain to me how those values of 1ohm and 240ohm on pin15 has been calculated;I think the values you indicated above are those ones of 22Kohm and 4.7Kohm when I calculated the output voltage on 4.7Kohm I found 4.9V;where is that is referrred to on others pins(An inverting input which has used 4.9V).

Please help.Thanks.

 

[Yosmany325]

Hi everyone, I think you should take a look to the Texas Instruments Application Report (SLVA001D), called Designing Switching Voltage Regulators with the TL494, written by Patrick Griffith. This document contains explanations for all parts inside TL494. Take a look, it's very good starting point.

 

[jean12]

Hello Yosmany325 ,but if you understand the document you can just tell me only how those values could be determined ;me I read but not getting well.

Thanks,please help.!!