Hi Ankit,
Having received and run your simulation file (as modified from the original UCC28780 SIMPLIS file), I've found two main issues: that the output cap still had 20V as its initial condition, and the VS-pin resistor-divider set the VS signal…
Part Number: UCC28780 Hello,
I work for a new design with UCC28780, and I have an error for Current sense resistor Rcs (sheet calculation D89, D90) , and Rtz Setting (D107, D108).
The cause of this error seems to be secondary power and voltage, but I…
Part Number: UCC28780EVM-021 Other Parts Discussed in Thread: UCC28781 , UCC28780 Q2 (P/N BSS126H6327XTSA2) of UCC28780EVM-021 has drain-source on-state resistance around 300 ohms (maximum 700 ohms). Could use use CPC3960 which has maximum on-state resistance…
Part Number: UCC28780EVM-021 Other Parts Discussed in Thread: UCC28780
Above screenshot is the startup test waveform on Q2' Source and Gate in UCC28780EVM-02 . The ramp-up time is around 50ms.
We prototyped the circuit with Q2 replaced by BSP135 and…
Part Number: UCC28780 Other Parts Discussed in Thread: UCC24612 , UCC24650 , UCC2897A Hi team,
My customer has following questions on this chip:
1.Is UC28780 suitable to control the active dual-position flyback chip to be used in a 70W 24/24V isolated dcdc…
Part Number: UCC28780EVM-021 Other Parts Discussed in Thread: UCC28780 We isolated the current to other extra circuits, VDD waveform became
However, failed to get output voltage and tried to measure VREF pin of UCC28780. VDD and VREF became
VDD changed…
Part Number: UCC28780EVM-021 Other Parts Discussed in Thread: UCC28780 The measure resistance on VREF pin is 28 ohms. We think UCC282780's VREF was damaged internally as all other external components connected to VREF are OK.. What condition would cause…
Part Number: UCC28780 Other Parts Discussed in Thread: UCC2897A , LM5025 , LM5026 Hello There,
Please let me understand UCC28780 application.
(1) Can this device be designed for DC/DC? If it's recommended for offline ACDC, what's the reason?
(2…
Hello,
Actually, the Tz time is fixed once Rrtz and input voltage are fixed. the sequence of ZVS and ZCD will decide the tuning direction of PWMH, then impact the negative current . too large negative current requires higher peak current even output load…
