Other Parts Discussed in Thread: UC3854A , UC3854B , UC2854A Reference spec page 2 And spec page 8 :
Q: Why setting 250uA Limit for AC high line ?
If over 250uA can influence which function ?
Which tolerance for this 250uA test plan in TI mass product…
Hello Supardi,
Thank you for using the UCC28019 PFC controller and UCC256404 LLC controller in your charger design.
The conducted EMI signature shows very low low-frequency noise, which represents the converters fundamentals and low harmonics, but…
Hello,
You have a low frequency instability in your power supply. You should re-calculate the compensation network component values in the feed back circuit. The first sample shows an instability at 0.3Hz and the second is unstable at 0.6Hz. When your…
TI released a brand new PFC controller UCC28180, which is functionally simlar to UC3854B, but it has a lower pin-count, it reduces system BoM cost, it helps to reduce shunt power resistor power dissipation and it features programmable switching frequency…
Hello,
I am answering my own question. I am using UC3854B and the voltage feedback reference is changed with UC3854A&B versions. It's not 7.5V its 3V. So my Rvi and Rvd is wrong. I changed my Rvd to 4K7 and now its working.
Now, should I use Rb1 or…
Hi Navneet,
1, The threshold for PKLMT is 0.0 V. Connect this input to the negative voltage on the current sense resistor. Use a resistor to REF to offset the negative current sense signal up to GND. However, In your circuit, PKLMT is connected to…
Other Parts Discussed in Thread: UC3854B , UCC28070 , UCC28051 Hello,
I have an application where I need an ultrawide range pfc at about 10W (not a typical application).
We have experience using uc3854b, ucc385xx, ucc28070 over typical wide range…
Hello Rahamadullah,
To use the UCC2818-EP controller at 400Hz (or higher) the design work is similar to that for 50Hz applications, except that items involving the line frequency are scaled to the higher frequency. These items include Vff filtering…
Hello,
I looked at the waveforms and there are flats spots in the sine wave near cross over. Even these waveforms would pass EN61000-3-2 harmonic content.
I have to be honest that all of my PFC designs have been to meet EN61000-3-2 and were designed…
Hi Stuart,
Leading/lagging power factor is primarily the result of the influence of the input filtering (usually "too much" filtering), not the PFC controller itself. The controller is always trying to achieve PF=1, neither leading nor lagging. The…
