Power Supply Solutions
for small/medium/big size
LCD-PDP/TV
Content
¾ Classical Approach:
¾ 60W SMPS (<20”)
¾ 200W SMPS (up to 30-32”)
¾ Resonant Approach:
¾ 70W SMPS (<20”)
¾ 180W SMPS (up to 30”)
¾ 500W SMPS (up to 50”
LCD-TV, 42” PDP-TV
60W LCD-TV Power Supply:
Block Diagram
•Operation close to
the boundary
between CCM and
DCM: variable
operating frequency
•Zero Voltage/Zero
Current Switching at
turn-on achievable
•Less EMI generated
•Variable frequency
spreads spectrum
Power Supply Unit
EMI filter&
Vac
Bridge
Rectifier
Advanced
PWM
Controller
+12V
•Stand-By function
put into optional
Feedback
60W LCD-TV Power Supply:
Specifications
Wide Input Voltage Range: 90-265VAC
Single Output Voltage (Vout):
Vout
5A12V
Total Output Power: 60W
RemarksCurrent
Accurate OCP and OVP circuit are
building in the simple can be optional.
60W LCD-TV Power Supply: Schematic
L6565
60W LCD-TV Power Supply:
Testing Report
Loading efficiency
Test Loading
12VOuput
5AFull Load (FL)
0.0416A (0.5W)Stand By
0ANo Load
Testing Results
Input PowerFL Eff.Input Voltage
No LoadStand By
81.7%90V
83.2%100V
87.0%240V
87.4%264V
A 60W LCD-TV Power Supply
L6565: Quasi-Resonant SMPS
• Current Mode Quasi-Resonant PWM
controller
• Micropower Start-up Current (40µA
typ.)
• Low Quiescent Current (3mA typ.)
• ZCD input for QR operation/external
synchronization
• Frequency Foldback function
• Line Voltage Feedforward function
• Pulse-by-pulse overcurrent
controller
protection
• 2nd overcurrent level with Hiccupmode operation
• Disable function
• Internal RC filter on Current Sense
• Package: Minidip and SO8
QR Conversion:
Quasi-Resonant Concept
z Llk &Cd
Vin
Cin
Lp
Lm
Llk
Ls
Cd
VDS
Vout
¾ Operation close to the boundary between CCM
and DCM: variable operating frequency
¾ Zero Voltage/Zero Current Switching at turn-
on achievable
¾ Less EMI generated
¾ Variable frequency spreads spectrum
z VDS
z Vin
z Ip
z IPKs
z IPKp
z VR
z Pri z Sec
z TON
z T = 1/ fsw
z TFW
z Tv
z Lp &Cd
z VDS @ Vin2 >Vin
z NO ZVS!
z Vin2
z ZVS
z t
z Is @ Vin2 >Vin
z Ip @ Vin2 >Vin
¾ZVS condition: Vin ≤ VR
200W LCD-TV Power Supply:
Block Diagram
•PFC
200W critical control
mode with ZCD
function for a costeffective application
•Main Converter
200W Flyback
Converter for middle
size LCD-PDP/TV
application
•Standby
10W Flyback
converter with buildin mosfet PWM
controller and circuit
Power Supply Unit
EMC filter
Vac
&Bridge
Rectifier
PFC+PWM+Aux
L6562+L5991
+L6590
Feedback
+24V
+12V
DC DC
conv.
+5V
standby
+5V
to switch off
200W LCD-TV Power Supply:
Specifications
Wide Input voltage range: 90-265VAC
Multi Output Voltages (Vout):
Vout
24V
12V
5V
5Vsb
6A
3A
2A
2A
Total output Power : 200W
RemarksCurrent
5V output use DC-DC converter which
can be put in optional.
200W LCD-TV Power Supply: Schematic
Advanced PWM Controller
L6562+L5991+L6590
L5973D
200W LCD-TV Power Supply:
Testing Report
Loading efficiency
Test Loading
Testing result
5VSB5V12V24VOutputs
2236Full load (FL)
0.1000Stand by
0000No Load
FL Eff.Input voltage
81.6%90V
84.3%120V
86.8%220V
87.5%264V
Input Power
No LoadStand by
200W LCD-TV Power Supply
L6562 - Power Factor Corrector
• TRANSITION-MODE
• PROPRIETARY MULTIPLIER
DESIGN FOR MINIMUM THD
OF AC INPUT CURRENT
• LOW (<4 mA) QUIESCENT
CURRENT
• ON-CHIP FILTER ON
CURRENT SENSE
•1% (@ Tj= 25 °C)
INTERNAL REFERENCE
VOLTAGE
• -600/+800mA TOTEM POLE
GATE DRIVER WITH UVLO
PULL-DOWN AND VOLTAGE
CLAMP
L5991/A Primary PWM
•CM 1MHz PWM Controller
•Low Start-Up Current (<150 µA)
•Low Quiescent Current (7mA typ.)
•Standby function
•Programmable 'Hiccup‘ Mode
Overcurrent Protection
•IN/OUT Synchronization
•Precise Duty Cycle Control
Latched
Controller
•Shutdown/Overvoltage Protection
•Programmable Soft-Start
•Internal 100 ns Leading Edge
Blanking on Current Sense
•Package: DIP-16/SO-16
L6590/A Fully Integrated Power Supply
L6590 - Standby Function
Contact Persons in Shenzhen
MMX Technical Center
NAME
BANGHG
ChenRoy
GuoSam
GuoTom
CHINESE
NAME
A&P Lab, Industrial and Power Team
方弘均
陈治国
郭青山
郭加总
TELEPHONE
NO.
23118601彭超PengChao
23278601
13692 222 12823348601
23318601
CHINA
Fax number:8601-2300Operator: 8601-2000
MOBILE
HONG
KONG
9752 127513602 616 66223068601
FUNCTION /
REMARKS
T/C Deputy Manager
Application Engineer
Senior Application
Engineer
Senior Application
Engineer
Application Engineer
A new approach:
Half Bridge Resonant topology
in LCD TV with ST L6598
controller
L
N
LCD TV power supply
AC Filter +
Rectifier
configuration
Main Power
400Vdc
PFC stage DC-DC stage
Auxiliary Power
24V
18V
9V
5V,3.3V
Inverter
Audio
Tuner
Logic IC
DC-DC stage
5V
uP
PFC stage in Main Power
Po of PFC
23” LCD
120W
TV
160W
26” LCD
TV
30” LCD
TV
180W 220W 300W 460W 600W
250W
150W
250W
L6561 or L6562 in Transition Mode
L6562 with Fixed Off-Time Control
40” LCD
TV
400W
50” LCD
TV
42” PDP
TV
L4981 in Continuous Conduction Mode
DC-DC stage in main power
400Vdc
Half Bridge Resonant Converter
24V
Inverter
Half Bridge
Resonant
Controller
L6598
+
Synchronous
rectification
Step down converter
L6997, L6910
Step down converter
L5973, L4973
Step down converter
18V
Audio
5V,3.3V
Logic IC
9V
Tuner
LM317
Power rating for inverter, audio, tuner,
and logic IC in LCD TV
Inverter : 30” - 12V/10A, 20V/6A, 24V/5A
42” - 24V/10A
50” - 120V/3A
Audio : 12V/2.5A ( class D )
18V/2A ( class AB )
Tuner : 8V, 9V, 30V, 33V
Logic IC : 5V/4A, 3.3V/3A
L6598
Half Bridge Resonant Controller
With high efficiency, low EMI, cost effectiveness
and high power density, it is a good solution for
built-in LCD TV power supplies
L6598 Main Features
• Resonant controller up to 400KHz
• High voltage rail up to 600V
• Low start up current ( < 250uA )
• Low quiescent current ( <2mA )
• Latched / non latched device disable
• 50% duty cycle half bridge driver
• Programmable soft start
• Integrated bootstrap diode
• 350nS dead time
• OP AMP for further protections
( Brown out, OTP …..)
• Package : DIP16 / SO16
L6598 internal block diagram
Internal bootstrap diode
Latch
Non latch
L6598 transformer topologies
For low output voltage
and high output current
For high output voltage
and low output current
Remark : a current doubler circuit can also be used to get a small ripple at the output
Benefits of L6598-based power
supply
• Reduction of switching losses because of zero
voltage switching at turn-on of power MOS
• Reduced current in the half bridge power MOS
• Reduced RMS current in secondary diodes
• Reduced EMI filter dimension and cost
• Reduced core loss
• Reduced size and COST
How to achieve ZVS in series resonant
converter
. Resonant topology
PFC output (+V
Q1
C2
L1
C1
Q2
BUS
)
D
Q1
C
Q1
D1
PFC output (+V
Q1
BUS
T
G G
C
N
N
2
2
L
N
M
1
OUT
D2
D
Q2
C
Q2
C2
C1
L1
I
L1
Q2
)
I
Q1
Q2
Q1
L
M
I
Q2
LOAD
C
PIN
I
Cpin
D
D
Q1
Q2
“G”
I
Q2
I
Q1
I
L1
+V
Diode current
BUS
I
Cpin
V
C1
I
VIN*D
D
D
T
T
T
T
2
1
0
8
2
T3T4T
5
T
6
D
D
1
1
T7T
8
Diagram of 70W demo board with L6598
PFC controller, L6561
Half bridge resonant controller, L6598
Voltage and current controller, TSM`103
Evaluation result of 70W ( 18V/3.8A)
demo board ( L6561 + L6598 )
High
efficiency
Load
Full
Half
Full
Full
Full
Full
Half
Half
Half
EffPoIoVoPiVin
93.9 %67.64W3.8A17.8V72W400Vdc
91.3 %35.6W2A17.8V39W400Vdc
87.3%67.64W3.8A17.8V77.5W88Vac
88.6%67.64W3.8A17.8V76.35W110Vac
90.5%67.64W3.8A17.8V74.7W220Vac
91.%67.64W3.8A17.8V74.4W255Vac
86.93%35.64W2A17.82V41W88Vac
88%35.64W2A17.82V40.5W110Vac
88.4%35.64W2A17.82V40.3W220Vac
Half
88.4%35.64W2A17.82V40.3W255Vac
Diagram of 180W demo board
with L6598
Input Voltage: 370V to 420V (PFC output)
Output : 110V/1.2A, 24V/2A
Output power : 180W
Efficiency of 180W demo board
with L6598
Pout : 180W
Max Efficiency is 95% at the maximum output power of 180W
500W demo board for LCD-PDP/TV power
supplies
L
Universal
( 88 – 264 Vac
N
)
PFC stage
( L4981B )
Brown out
PWM stage
( L6598 )
Aux. stage
( L6590A )
120V/3.5A
12V/7A
5V_aux/2A
Overall Efficiency is estimated at abt. 91%
The demoboard is now under development and
it will be available in Nov 2004
References
• Documents
1. L6598 datasheet , February 2002
2. AN1300, Application Note, L6598 based 12V/3A
resonant application, October 2000
3. AN1660, Application Note, ZVS resonant converter
for consumer application using L6598 IC, March 2003
4. AN1673, Application Note, L6598; off line controller for
resonant converter, June 2003
5. AN 658, Application Note, resonant converter topology
• Hardware
1. 70W ( 18V/3.8A ) demo board with L6561 and L6598
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