TL494 pulse width modulable?

[boram69]

DEAR!
I am desining a power supply with TL494,but pulse width could not be changed.
When Pin1>Pin2, Pin3->5v,and P1<P2,Pin3->0.1v. How change duty cycle.
A cap 10n and resistor(47k)series P2 and P3.
Thanks!

 

[Aoxomox]

Hi boram69,

the input OPAMPs are configured as comparators, which gives the behavior you describe on Pin3.

Maybe you should read this abstract first, a detailed desciption of the TL494.
**broken link removed**

In principle for static operation you tie IN+ to GND and IN- to VCC and apply a voltage to the DTC pin. This is how just to generate a PWM.

But for regulation of a power supply you should use the Error OPAMPs.

-aOxOmOx

 

[haywire]

DEAR!
I am desining a power supply with TL494,but pulse width could not be changed.
When Pin1>Pin2, Pin3->5v,and P1<P2,Pin3->0.1v. How change duty cycle.
A cap 10n and resistor(47k)series P2 and P3.
Thanks!

Hi,
i'm having the same problem. i was searching for a solution and i stumbled upon your post.

have you solved this problem?

thanks.