I have a question about UCC 2819A.
For details, please see the attached document.
Thank you.UCC2819A-1.pdf
This thread has been locked.
If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.
Hello Masazumi Ishii,
The error amplifier output voltage (VAOUT) varies with load. At high load and low line it is a maximum and at light load and high line it is a minimum.
The lower the value of EAOUT means the lower the duty cycle required by the pfc controller. The UCC2819A monitors the value of EAOUT.
When this voltage falls below a nominal 0.33V the gate drive output signal (DRVOUT) is disabled. When EAOUT rises above the zero power comparator threshold then DRVOUT is re-enabled.
So instead of using a series of very narrow pulses to control the output, the UCC2819A uses a burst type of mode at low power.
That is the function of the zero power comparator.
The threshold listed on the parametric section of the data sheet for the zero power comparator
is measured at ATE before the part is acceptable.
Regards
John