Low Standby Power AC Adapter L6562 + L6668 90W 19V/4.7A AC-DC Converter Reference Design

90W Adaptor General Features Input Voltage range: 100 to 240Vac Output Voltage and current: 19V/4.7A Power Factor Correction: Above 0.98 Low Standby < 0.4W at no load condition High Efficiency, typical 82% at low line full load Latched OVP

L6562 - Power Factor Correction Transition Mode Control Very Precise Adjustable Output Over Voltage Protection Ultra-Low Startup Current (<70mA) ON-CHIP Filter ON Current Sense Disable Function 1% internal reference voltage -600mA/+800mA Totem Pole Gate Driver

L6668 - PWM Controller Current Mode Controller with sophisticated standby feature On board high voltage startup Low quiescent current (<2mA) Slope Compensation Pulse-by-pulse & Hiccup-Mode OCP Interface with PFC Controller Disable Function (on/off control) Latched Disable for OVP/OTP Function Programmable soft start

L6668 – Standby Operation The device operates in different modes depending on the converter’s load condition 1.) Fixed Frequency at heavy load 2.) Frequency-foldback at medium load 3.) Burst Mode Control with no or very light load.

L6668 + L6562 Operation This MOSFET has to withstand high stress for short period. Points to note: PWM is powered up before PFC. PFC is switched off during standby mode. PWM MOSFET has to withstand high stress for a short period of time under low line, full load before bulk capacitor voltage build up!

L6668 -- Programmable Frequency Foldback

L6668 -- Load Dependent Operating Mode

L6668 -- Interface with PFC Controller

L6668 -- Converter Output in Short Circuit

90W Demoboard Schematic

Demoboard Layout

PFC Inductor Inductance 0.7mH

Main Transformer Inductance 0.7mH

Demoboard Test Result – Power Factor

Demoboard Test Result – Standby power loss No Load Power (mW) Input Voltage (Vac)

Demoboard Test Result – Load Regulation 220Vac 100Vac Output Voltage Output Current

Demoboard Test Result -- Line Regulation 0A output current 5A output current Output Voltage Input AC Voltage

PFC Waveforms At 110Vac Ch.1 Current Waveform Ch2.: Bridge Rectifier output waveform At 220Vac Ch.1 Current Waveform Ch2.: Bridge Rectifier output waveform

Main Converter Vdrain Normal Operating Waveform At 110Vac At 220Vac

Main Converter Vdrain during Short Circuit Condition At 110Vac At 220Vac

Demoboard BOM Item Reference Part Description 1 Assembly Dwg. 2 Schematic 3 PC Board PC Board,1-Layers,136mm x62mm 4 F101 3.15A/250V fuse 5 RT NTPA78R0LBMB0 Murata NTR 6 RV G471 varistor 7 R101,R102 1.5M resistor 8 R103 22K 9 R104 75K 10 R105 20ohm 11 R106,R107 750K 12 R108,R121 9.1K 13 R109 470ohm 14 R111 68K 3W resistor 15 R112 0ohm 16 R113,R123 1K 17 R114 4K

Demoboard BOM 18 R115 2.2K resistor 19 R116 150K 20 R117,R120 47K 21 22 R119 82.5K 23 R122 10ohm 24 R124,R125,R126 2M 25 R127 12K 26 R128 5.6K 27 R201 30ohm 3W resistor 28 R202 0ohm 29 R203 2.4K 30 R204 15K 31 R205,R206,R207 1K 32 R208 33 CX101 0.22uF/275V X2 capacitor 34 CY 2.2nF/400V Murata DE1E3KX222M 35 C101 0.47uF/400V Capacitor

Demoboard BOM 36 C102,C109,C113 10nF/50V Capacitor 37 C103 680nF/50V 38 C104,C116 1uF/50V 39 C105,C110,C111 100nF/50V 40 C112 3.3nF/50V 41 C107 82uF/450V 电解电容 42 C108 100uF/35V 43 C115 56nF/50V 44 C117 22uF/35V 45 C201 1nF/1KV 46 C202,C203,C204 1000uF/35V 47 C205 220uF/35V 48 C206 330nF/50V 49 BR101 KBL810G bridge rectifier 50 D101 STTH310S rectifier 51 D102 P6KE250 52 D104 FR107 53 D201,D202 STPS20150CT

Demoboard BOM 54 Z101 20V zener diode 55 Z102 13V 56 Q101 STP12NM50 MOSFET 57 Q102 STP10NK70Z 58 Q103 3904 transistor 59 Q104 3906 60 Q201 ST TL431 voltage reference 61 COM101 400uH 共模 62 COM102 22mH 63 COM201 360uH 64 L101 22uH 差模色环电感 65 L201 10uH 差模磁棒 66 OPT K817P6 opto-coupler 67 IC101 L6562D PFC IC 68 IC102 L6668 PWM IC 69 TR1 PQ32/20 Transformer 70 TR2