CCS/TL494: On the role of constant current source in TL494

In the PDF document The amplifier outputs are biased low by a current sink to provide maximum pulse width out when both amplifiers are biased off.Can I interpret this constant current source as a pull-down resistor?When the output of the two error amplifiers is reverse bias,The third pin(FEEDBACK) output voltage is low.The third pin is connected with an 2K resistor to ground, and the pin remains low. How should this be understood? The constant current source of the 0.7mA cannot be output to the third pin?

Jin Chao Yang,

Thank you for your interest in the TL494. I have contacted the systems engineering team for this device so we can get their input to your questions. They will make an effort to address your post promptly, but please allow up to a day or so.

- Daniel

Hi Jin,

The constant current source is indeed a current source, not a resistive pull-down. The error amplifier structure is shown in Figure 9 and 10 from section 3.3.4 in the document "Designing Switching Voltage Regulators with the TL494" found at www.ti.com/.../slva001e.pdf and because of this current sink design Figure 11 shows the best techniques for feedback gain control.

Thank you Brian Johnson96!
When the two error amplifiers do not have high level outputs,The feedback pin can only input current and cannot output current?The current input to the feedback pin must not be greater than the maximum current value of the current absorber?May I think so?