® Design Idea DI-33 ® TinySwitch-II Wide Range DVD Supply: <50 mW No-load Consumption Application Device Power Output Input Voltage Output Voltage Topology DVD Player TNY268P 11 W cont. 17 W pk. 85-265 VAC +3.3 V, +5.0 V, +12.0 V, -12 V Flyback Design Highlights • • • • No-load input power <50 mW 700 mW of output power with 1 W input Built-in frequency jitter allows low cost π filter 132 kHz operation minimizes transformer size and turns, providing good cross-regulation • High efficiency – >77% minimum • Meets CISPR22B/EN55022B and FCC B with >10 dB margin • • • • Key Design Points • An optional low voltage bias circuit, D9 and C10, powers U1 via R6, reducing light and zero load power consumption. This provides bias current that would otherwise be provided from the DRAIN by the internal high voltage current source. The current source is disabled when the BP pin is fed externally, an internal clamp limiting the voltage to 6.3 V. The bias supply is designed to produce 7.5 V at no-load. Resistor R6 is chosen to provide approximately 500 µA into the BP pin, the maximum consumption at no-load. • Good cross-regulation on 5 V and 3.3 V outputs is achieved by minimizing secondary leakage through • the use of foil windings and dual sense feedback via R15 and R16. To minimize potential noise coupling to the SOURCE pin during common mode surges, the Y1 capacitor C8 is connected between secondary return and the HV DC rail. Resistors R5 and R7 damp ringing to improve EMI. Optional soft-finish capacitor C7 eliminates output startup overshoot. Optional under-voltage resistor R1 provides clean startup and prevents output glitches on power down. R1 = (VUV-2.5 V)/50 µA. Small loop areas in the secondary layout around D10, C12, D9, C11, D7, C15, D8 and C9 together with postfilters L2/C20, L3/C17 and L4/C18 provide low output ripple, below 50 mV p-p. 12 V, 0.4 A 8 D7 UF4003 D9 1N5822 L2 3.3 uH C15 470 µF 25 V 5 V, 1.6 A 13 L3 3.3 uH D10 1N5822 C8 1 nF Y1 C17 470 µF 10 V C11 1800 µF 25 V 3.3 V, 0.7 A 9 L4 3.3 uH C12 1000 µF 10 V R7 100 Ω D1 & D2 1N4007 VR1 P6KE180 C18 470 µF 10 V RTN 11 C2 0.01 µF 1 kV 1 C9 220 µF 25 V C6 220 µF 25 V D8 UF4003 F1 L 85-265 VAC C20 150 µF 25 V C3 0.047 µF X2 C1 & C4 33 µF 400 V R5 47 Ω R1 2 MΩ (Optional) D5 1N4007 N D D3 & D4 1N4007 4 TinySwitch-II U2 EN U1 S TNY268 C5 0.1 µF 50 V U2 PC817 C7 10 µF 50 V R9 200 Ω R16 6.34 kΩ 1% R10 3.3 kΩ 5,7 BP L1 1.4 mH 0.5 A -12 V, 0.1 A 14 R6 R12 D6 1N4148 3.3 kΩ 1 Ω 1/2 W 6 C10 R8 10 µF 1 kΩ 50 V C14 0.1 µF U3 TL431 R15 20 kΩ 1% R13 10 kΩ 1% PI-3205-091302 Figure 1. TinySwitch-II DVD Player Schematic. DI-33 www.powerint.com September 2002 DI-33 PI-3301-091602 1200 115 VAC 230 VAC 1000 TRANSFORMER PARAMETERS Core Material Himag MZ4 EEL25.4, or equivalent, 2 Gap for AL of 344 nH/T Bobbin EEL25 Vertical 14 Pins Winding Details Shield: 32T, 2 x 32 AWG Primary: 64T, 2 x 32 AWG Bias: 6T, 4 x 32 AWG Shield 2: 4T, 4 x 32 AWG +12 V: 4T, 4 x 32 AWG +5 V: 1T, 14 mm Cu Foil +3.3 V: 2T, 14 mm Cu Foil -12 V: 7T, 4 x 32 AWG Winding Order (Pin Numbers) 3 mm margin tape on both sides of bobbin. Shield (NC-5), tape, Primary (1-4), tape, Bias (7-6), tape, Shield (NC-7), tape, 12 V (13-8), 3.3 V (11-9), 5 V (9-13), tape, -12 V (14-11), tape (NC - no connect) Inductance 1420 µH ±25% Primary Resonant Frequency (Pins 1-4, all other open) 500 kHz (minimum) PIN (mW) 800 600 400 200 0 0 100 200 300 400 500 600 700 800 POUT (mW) Figure 2. PIN vs. POUT Curve. PI-3302-091302 80 70 QP 60 AV 50 dBµV 40 Quasi Peak 30 20 Table 1. Transformer Construction Information. 10 Average 0 -10 -20 0.15 1.0 10.0 -100.0 MHz Figure 3. Conducted EMI with Artificial Hand Connected to Output Return. For the latest updates, visit our Web site: www.powerint.com Power Integrations reserves the right to make changes to its products at any time to improve reliability or manufacturability. Power Integrations does not assume any liability arising from the use of any device or circuit described herein, nor does it convey any license under its patent rights or the rights of others. The products and applications illustrated herein may be covered by one or more U.S. and foreign patents or potentially by pending U.S. and foreign patent applications assigned to Power Integrations. A complete list of Power Integrations’ patents may be found at www.powerint.com. The PI Logo, TOPSwitch, TinySwitch and EcoSmart are registered trademarks of Power Integrations, Inc. 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