Part Number: UC3879 Cannot identify best method to correctly value/size of the series capacitor for the primary winding in voltage control mode. We are seeing failures when load is close to short with a series film capacitor rated at 470nF but see significant…
Part Number: UC3879
We are experiencing high failure rates for our Q17 (low side FET on the right leg) under close to short circuit conditions. We are observing the cycle-by-cycle current limit phase shifts Q15 (left leg) and begins conflicting…
Part Number: UC2879 Other Parts Discussed in Thread: UC3879 Hi Team,
I understand UC2879 is rated for operating ambient temperature of -40°C to 85°C. and UC3879 is rated for operating ambient temperature of 0°C to 70°C. when I look at the junction…
Part Number: UC3879 Other Parts Discussed in Thread: UCC3895 , UCC28950 Dear all,
I am redesigning a full bridge converter as a Phase shifted full bridge converter using UC 3879.
I have a series capacitor in series with primary of the transformer…
Other Parts Discussed in Thread: UC3879 Hello,
I want to sync UC3879 with an external clock pulse. In the application note( U-154) i saw that, the ic locks with the fastest clock pulse. I also saw that, to provide an external clock-pulse, i need to…
The start-up behavior of this controller is critical in our application. I have three questions that are not addressed by the datasheet:
1) The capacitor on the SS (soft-start) pin is charged from approximately 300mV to at least 4.3V with a 9uA (typical…
Hi Bliss Zhou,
Thank you very much for quick response, but I am afraid I still didn't get it. In UC3875 generator has a little bit different configuration compare to UCC2843 (BTW can't find chapter 8.3.9 in DS). Both, Rt and Ct goes to ground according…
Other Parts Discussed in Thread: UCC3895 , UC3879 , TINA-TI Hi
I'm familiar with the old UC3879 but need some help wiht the UCC3895. I'm using peak-current control.
With 3879 you can't limit the maximum duty cycle. The linear part can be set but the…
Hi John,
Thanks for the schematic attached.
Can you help on my previous posted question as below without associated waveform?
For the full bridge or phase shift full bridge, is the demagnetizing current flowing through the primary winding of…
Hello,
The UCC3806 is a dual output controller though it can be used in a flyback where only one of the outputs are used to drive the switch it might be better to choose a single output controller. Look at page 46 of the attached under General Purpose…
