Low Standby Power AC Adapter L6562 L6668

1
Low Standby Power AC Adapter L6562 L6668

• 90W 19V/4.7A AC-DC Converter Reference Design

2
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 lt 0.4W at no load condition
• High Efficiency, typical 82 at low line full
  load
• Latched OVP

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L6562 - Power Factor Correction

• Transition Mode Control
• Very Precise Adjustable Output Over Voltage
  Protection
• Ultra-Low Startup Current (lt70mA)
• ON-CHIP Filter ON Current Sense
• Disable Function
• 1 internal reference voltage
• -600mA/800mA Totem Pole Gate Driver

4
L6668 - PWM Controller

• Current Mode Controller with sophisticated
  standby feature
• On board high voltage startup
• Low quiescent current (lt2mA)
• 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

5
L6668 Standby Operation

• The device operates in different modes depending
  on the converters load condition
• 1.) Fixed Frequency at heavy load
• 2.) Frequency-foldback at medium load
• 3.) Burst Mode Control with no or very light
  load.

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L6668 L6562 Operation

• 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!
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L6668 -- Programmable Frequency Foldback
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L6668 -- Load Dependent Operating Mode
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L6668 -- Interface with PFC Controller
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L6668 -- Converter Output in Short Circuit
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90W Demoboard Schematic
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Demoboard Layout
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PFC Inductor
Inductance 0.7mH
14
Main Transformer
Inductance 0.7mH
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Demoboard Test Result Power Factor
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Demoboard Test Result Standby power loss
No Load Power (mW)
Input Voltage (Vac)
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Demoboard Test Result Load Regulation
220Vac 100Vac
Output Voltage
Output Current
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Demoboard Test Result -- Line Regulation
0A output current 5A output current
Output Voltage
Input AC Voltage
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PFC Waveforms
At 110Vac Ch.1 Current Waveform Ch2. Bridge
Rectifier output waveform
At 220Vac Ch.1 Current Waveform Ch2. Bridge
Rectifier output waveform
20
Main Converter Vdrain Normal Operating Waveform
At 220Vac
At 110Vac
21
Main Converter Vdrain during Short Circuit
Condition
At 220Vac
At 110Vac
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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 resistor
9 R104 75K resistor
10 R105 20ohm resistor
11 R106,R107 750K resistor
12 R108,R121 9.1K resistor
13 R109 470ohm resistor
14 R111 68K 3W resistor
15 R112 0ohm resistor
16 R113,R123 1K resistor
17 R114 4K resistor
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Demoboard BOM
18 R115 2.2K resistor
19 R116 150K resistor
20 R117,R120 47K resistor
21 R118 6.2K resistor
22 R119 82.5K resistor
23 R122 10ohm resistor
24 R124,R125,R126 2M resistor
25 R127 12K resistor
26 R128 5.6K resistor
27 R201 30ohm 3W resistor
28 R202 0ohm resistor
29 R203 2.4K resistor
30 R204 15K resistor
31 R205,R206,R207 1K resistor
32 R208 5.6K resistor
33 CX101 0.22uF/275V X2 capacitor
34 CY 2.2nF/400V Murata DE1E3KX222M
35 C101 0.47uF/400V Capacitor
24
Demoboard BOM
36 C102,C109,C113 10nF/50V Capacitor
37 C103 680nF/50V Capacitor
38 C104,C116 1uF/50V Capacitor
39 C105,C110,C111 100nF/50V Capacitor
40 C112 3.3nF/50V Capacitor
41 C107 82uF/450V ????
42 C108 100uF/35V ????
43 C115 56nF/50V Capacitor
44 C117 22uF/35V ????
45 C201 1nF/1KV Capacitor
46 C202,C203,C204 1000uF/35V ????
47 C205 220uF/35V ????
48 C206 330nF/50V Capacitor
49 BR101 KBL810G bridge rectifier
50 D101 STTH310S rectifier
51 D102 P6KE250 rectifier
52 D104 FR107 rectifier
53 D201,D202 STPS20150CT rectifier
25
Demoboard BOM
54 Z101 20V zener diode
55 Z102 13V zener diode
56 Q101 STP12NM50 MOSFET
57 Q102 STP10NK70Z MOSFET
58 Q103 3904 transistor
59 Q104 3906 transistor
60 Q201 ST TL431 voltage reference
61 COM101 400uH ??
62 COM102 22mH ??
63 COM201 360uH ??
64 L101 22uH ??????
65 L201 10uH ????
66 OPT K817P6 opto-coupler
67 IC101 L6562D PFC IC
68 IC102 L6668 PWM IC
69 TR1 PQ32/20 Transformer
70 TR2 PQ32/20 Transformer