Hi all the team members,
We are using TL494 IC for some specific applications. We need small information about TL494.
The above picture is block diagram of TL494. In that picture i marked 0.7mA with red color.
So i want to know about functionality of that particular amount of current and importance.
will u possible to use TL494 for average current mode controller or not?
But block diagram of TL494 when compare to TL598 then PWM controller block of TL494 seems like positive feedback.
Can u please show me in TL494 block diagram how it is converted to negative feedback.
The below figure represents non-inverting type2 compensator. But Op amp IN+,IN- the R-C circuit represents same, In inverting Type 2 they are not keeping R-C circuit like this
Can u explain why they represent like this for non-inverting Type2 compensator.
Hello,
In Figure 1, the input sensing voltage is collected to inverting INPUT, from the the level of OPAMP, it is negative feedback, and the transfer function output has minus sign;
In Figure 2, the input sensing voltage is collected to non-inverting INPUT, from the the level of OPAMP, it is positive feedback, and the transfer function output has no minus sign;
But from the level of closed loop, the feedback has to be negative feedback. When output is increased, the duty cycle has to deceased. Maybe the OPAMP output is increased, but the PWM COMPARITOR can decrease the duty cycle. Per my understanding, the Figure 2 is used for TL494. When OUTPUT voltage is increased, the OPAMP output is increased, but the PWM COMPARATOR (and NPN Drive output) reduces duty cycle, and hence the output is reduced.
I don't have more detailed internal block diagram than what is provided in D/S.
I hope this helps,
Regards,
