Tool/software:
Hi Team,
Good Day...
I have started to design the wide range power supply using Flyback converter topology. My design parameter is listed as below,
Input voltage range - 20V to 370V
Output voltage - 24V DC
Output current - 4A
For the above design, I have selected the UCC28C42D switch to generate the PWM pulse. To design Flyback transformer, I have referred the UCC28C42D datasheet for deriving the values of transformer turns ratio, primary inductance, peak current to the transformer & external MOSFET, etc., When i look into the datasheet detailed design procedure, the formulas are given for designing the continuous current mode (CCM).
My question is how to determine my design should be performed for CCM or DCM and is there any formulas for DCM? Since i could see formulas for only CCM operation in the datasheet.
Based on the mode of operation (CCM or DCM), the entire design calculation will be varied? Could you please help me on this?
I have done some calculation using formulas mentioned in the UCC28C42D datasheet and values are below,
| NPS | 4.545513333 | 4.545513333 | Ratio |
| Duty cycle | 0.84560251 | 0.84560251 | % |
| Sw Frequency | 150000 | 250000 | Hz |
| Lp(Max) | 0.001938538 | 0.001163123 | H |
| Vreflected | 109.09232 | 109.09232 | V DC |
| NPA | 9.091026667 | 9.091026667 | Ratio |
Please advise me which mode of operation to be considered for the above design requirement.
