PDF《EV020-5-S-00C》

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2018 MPS. All Rights Reserved. EVALUATION BOARD SCHEMATIC Figure 1―Schematic EV020-5-S-00C C UNIVERSAL INPUT, DUAL OUTPUTS FOR SMALL APPLIANCES EV020-5-S-00C Rev.1.0 www.MonolithicPower.com

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2018 MPS. All Rights Reserved. PCB LAYOUT (SINGLE-SIDED) Figure 2―Top Layer Figure 3―Bottom Layer EV020-5-S-00C C UNIVERSAL INPUT, DUAL OUTPUTS FOR SMALL APPLIANCES EV020-5-S-00C Rev.1.0 www.MonolithicPower.com

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2018 MPS. All Rights Reserved. CIRCUIT DESCRIPTION The EV020-5-S-00C is configured in a single-stage Flyback topology, it uses primary-side-control which can mostly simplify the schematic and get a cost effective BOM. It can also achieve accurate constant voltage and acceptable cross regulation. FR1 and CR1 compose the input stage. FR1 is used to protect for the component failure or some excessive short events, also it can restrain the inrush current. C1, L1 and C2 compose π filter to guarantee the conducted EMI meet standard EN55022. R1 paralleled with L1 is used to damp resonant between L1 and C1, C2. R2, R3, D1 and C3 compose the snubber circuit to reduce drain-source voltage spike. R4, C5, C6 and D2 are used as Vcc power supply. C5 is high frequency decoupling capacitor and should be placed with Vcc pin as near as possible. R5 and R6 are resistor divider for detecting output voltage by sampling voltage on primary auxiliary winding. CY1 is Y capacitor lowering common mode noise to make sure there is enough EMI margin. T1 is power transformer, the structure of which is also very important to pass EMI test. D3 is rectifier for 12V output. Schottky diode is recommended for better efficiency and regulation.C7 and R7 are composed snubber for D3, which is to restrain the voltage spike between D3. C8 and C11 are output capacitors for 12V output. C8 should be low ESR electrolytic capacitor for better load regulation. C11 is ceramic capacitor to reduce high frequency voltage ripple. R9 is dummy load to lower the output voltage of 12V rail at no load condition. D4 is rectifier for 5V output. Schottky diode is recommended for better efficiency and regulation. Due to the output current is low at this rail and there is no obvious spike on D4, so no RC snubber is needed. C9 and C10 are output capacitors for 5V output. C9 should be low ESR electrolytic capacitor for better load regulation. C10 is ceramic capacitor to reduce high frequency voltage ripple. R8 is dummy load to lower the output voltage of 5V rail at no load condition. U3 is three terminals voltage regulator for precise 5V output. C12 is output capacitor for U3. EV020-5-S-00C C UNIVERSAL INPUT, DUAL OUTPUTS FOR SMALL APPLIANCES EV020-5-S-00C Rev.1.0 www.MonolithicPower.com

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2018 MPS. All Rights Reserved. EV020-5-S-00C BILL OF MATERIALS Qty Ref Value Description Package Manufacturer Manufacturer_P/N

2 C1, C2 4.7μF Capacitor;

400V;

20% DIP Beryl 4.7μF/400V

1 C3 470pF Ceramic Capacitor;

1000V;

U2J;

1206 muRata GRM31B7U3A471JW31L

1 C4 0Ω Shorted with 0Ω resistor

0603 Yageo RC0603JR-070RL

1 C5 1μF Ceramic Capacitor;

25V;

X7R;

0603 muRata GRM188R71E105KA12D

1 C6 22μF Electrolytic Capacitor;