Datasheet DK106 (Dongke Semiconductor) - 8

SHENZHEN DONGKE SEMICONDUCTOR CO., LTD HIGH PERFORMANCE SWITCH MODE POWER CONTROLLER-DK106
(2) Choose the core: Checking via supplier or the correlative chart can know that EE16 or EE19 core is suitable for 15W power supply. Now we choose EE16 for below calculation.
11.2.3 Input voltage setting
Input voltage is AC85V-265V, as to get the MAX. power value according to the lowest voltage and take the voltage loss(from wires and rectification) into consideration, Vs=80*1.3=100V.
11.2.4 Conduction time
Ton=1/F*D=1/65*0.5=7.7μS
11.2.5 Number of the original(input) turns (Np)
PS: ΔBac---Alternating working magnetic flux density (mT), set to be 0.2 Ae--------Core effective area (m m²), EE16’s Ae is 20 m m²
11.2.6 Number of the output turns (Ns)
PS: Vout----Output voltage=12V+1V=13V, take the voltage loss (from wires and rectification) into consideration. Vor-----Flyback voltage=100V, set it lower then 150W for the safety of IC.
11.2.7 Input inductance value (Lp)
PS: Ip----Input peak current (it is set to be 320mA in the IC)
11.2.8 Verification of the design
Because the saturation magnetization of Ferrite material is about 0.4T, the designed Magnetic flux density in transformer should be no more then 0.4T. However, Single-ended Flyback circuits works in the first quadrant of B-H, and residual magnetism of the core is about 0.1T, so the maximum working magnetic flux density should be 0.4-0.1=0.3T. Bmax<0.3, so the design is workable.
11.2.9 Leakage inductance of a transformer
It is suggested to use P/S/P way to wind the transformer so that to reduce the leakage inductance.
12. SPECIAL NOTICE FOR PBC LAYOUT DESIGN 12.1
Heat dissipation: A good estimate is that the controller will dissipate the output power. So enough cooper area connected to the 5, 6, 7, 8 COLLECTED pins and tin-plating are necessary to provide the controller heat sink.
12.2
The 5, 6, 7, 8 COLLECTED pins is high voltage part of the IC, peak voltage is as high as 600V, so it should be at least 1.5mm far away from the low voltage part in the PCB as to avoid circuit breakdown and discharging.
12.3
Pin No.1 is for testing only. It is prohibited to be connected with other circuits when in use. Address: Building 18, Hejing industrial zone, Heping village, Fuyong, Baoan Area, Shenzhen, China. Tel: 86-20-38488121 Email: amy_hsf@yahoo.cn Website: www.yxpower.com