Texas Instruments System Power Solutions
-High efficiency LLC resonant controller and
synchronous rectifier
Texas Instruments
Power Management
AGENDA
1. UCC25710 Multi-strings LLC LED driver
1. Features and Application
2. Block Diagram
3. Operating descriptions and evaluation results:
2. UCC25600 LLC controller
1. LLC operating descriptions
2. Block diagram and features:
3. UCC24610 Synchronous driver:
1. Features and Application
2. EVM and test results:
Typical High Watt (>100W) LED Lighting
Driver Topology
2. Constant Current Driver Stage
1. AC/DC Power Stage
AC
PFC
UCC28061( Inter TM PFC)
UCC28810/1(TM PFC)
LLC Converter
~54Vdc Bus
UCC25600
(LLC)
BUCK
Control
+
TPS4021
1
TPS4020
0
TPS5416
0
BUCK
Control
TPS4021
1
TPS4020
0
TPS5416
0
~15pcs LEDs
in Series
High Watt (>100W) LED Lighting Efficiency
Budget
Outdoor and Industrial >100W
400V
EMI
PFC
Control
Q
1
LLC
Control
Q
2
L
r
L
m
C
Buck
Control
Buck
Control
r
97%
96%
95%
<88% (Traditional solution)
Conventional Topology Issues:
 High cost: PFC+LLC+CC BUCK (multi-chips!!)
 Low efficiency (<~88%)
 Low reliability (many components’ counts)
 EMI issues
TI UCC28810EVM-003 - SIMPLEDrive™
Series Input, Multiple Parallel Equivalent LED Drive (SIMPLEDrive )
3rd stage:
2nd stage:
1st stage:
TM Buck for LED current Resonant Current Half Bridge
TM Boost for PFC
97%
98%
98%
>93% (Three stages multi-string transformer solution)
Innovative two stages multi-string LLC
topology
for LED lighting
EMI
Input Bridge
BUCK
PFC
Control
PWM
Control
UCC28810
HV Gate Driver
Outdoor and Infrastructure >100W
UCC2881
1
UCC25600
new
Outdoor and Infrastructure >100W
400Vdc
EMI
Input Bridge
PFC
Control
UCC28810
☺ High efficiency ~92%
☺ Low cost (no need CC DC/DC driver)
☺ High reliability
☺ Easy EMI
☺ PWM or analog dimming compatible
Ga
Gb
Gate Driver
Benefits for the proposed topology:
CS
UV
OV
PWM
Control
UCC25710
Why Transformer Can Balance Current
1
Ip
T1
4
Np
Ns
2
3
•
Is1
•
•
Ip
1
Np
2
T2
•
4
Ns
3
Is2
•
Transformer current is in
reverse proportion to turn
ratio
Ip/Np = Is/Ns; Is=Ns*Ip/Np
When transformer primary is
connected together, their
primary current must be the
same
When T1 is the same as T2
because of transformer
operation principle their
secondary current is the
same
Is1=Ns*Ip/Np=Is2
Multi-Transformer Architecture
(TI Patented)
AC input
PWN
dimming
One transformer control two LED strings!
UCC25710: LED driver Controller IC













Industry first single chip LLC controller for
driving multiple LED strings directly from PFC
output
Adjustable Fmin (3% accuracy), and Fmax 6%
(accuracy)
Closed Loop LED String Current Control
PWM Dimming Input
LLC and Series LED Switch Control for Dimming
Programmable Dimming LLC ON/OFF Ramp for
Elimination of Audible Noise
Closed Loop Current Control at Low Dimming
Duty-Cycles
Programmable Soft Start
Accurate VREF for Tight Output Regulation
Over-voltage and Under-voltage and Input Overcurrent Protection with Auto-restart Response
Second Over-current threshold with Latch-off
Response
+400-mA/-800mA Gate Drive Current
Low Start-Up and Operating Currents
20 pin SO Lead (Pb)-Free Package
General LED Lighting
LED TV Backlighting


T1
VIN
–
+
LED
String 1
T2
–
+
LED
String 2
TN
ON / OFF
–
+
LED
String N
20V-9.5V
VCC
DTY
BLON
DADJ
GD1
GD2
GND
CL
CREF
VREF
DSR
UCC25710

DIM
DIM PWM Input
FMIN
FMAX
SS
ICOMP
CS
LEDSW
OV
UV
VCC 1
UVLO
+
VVCCON/VCCOFF
9.3V/8.9V
S* Q
ENBL
VVREF
BLON 10
FAULT
5V
Ref
VREF 5
VVREF
RST Gen
R
delay
Supply Control
2.5uA
RESET
H
Q
L
ENBL
TRSTDLY
10ms
~4V
200K
IDADJCH
20uA
+
SS-END
7
DTY
8
DADJ
LED Switch and
DIM
Dimming Control
VVREF
GD Enable
9
OFF
H
UCC25710
Block
Diagram
GD1 2
200K
LLC-OFF
Dead Time
GD2 3
Dimming PWM
Edge Sync
D
ON
80K
Q
2*F
GND 4
FSW
FMIN
20
LLC Control
VCO
FMAX
CLR
GD Toggle
D
80K
Q
SS-END
RESET
Q
LED-ON
FMAX
19
FMIN
VVCO
1V
0.9V
CLR
+
+
+
ICOMP 17
2.4us
S
FAULT
Q
R
+
TSD
Control
Clamp
GND
I DSRCH
44uA
SS Clamp
L
+
le
ab
Dis
SS-END
H
13
Fault Control OV
12
VOVTH
2.6V/2.4V
I DSRDC
44uA
+
VUVTH
2.4V/2.6V
11
Soft Start
VSSTH
4.2V
S
Q
*
Q
R
RESET
CL
VCLTH
1V/0.5V
+
LLC -OFF
14
SS 18
+
VVREF
Current Regulation and
DSR
VCO Slew Control
VVREF
ISS
2.5uA
UVLO
VVREF
H
Dimming Slew
Control
ICOMP
4K
Q
LED-ON
delay
VCLLTH
1.9V
Latch-Off
LATCH-OFF
Low ICC
Current
Amplifier
GM ICOMP
510uS
LEDSW
Zero Frequency Command
VCLREFCLO, 0.5V
VCLREFCHI, 2.8V
CS 16
6
4V
VVCO
CREF 15
Q
UCC25710
UV
UCC25710: DIMMING – LLC ON/OFF
TRANSITION & CURRENT CONTROL
• The DIM input controls the ILED-ON
an ILED-ON` signals.
VREF
VVCO
5
• DSR capacitor C2 and internal 44uA
currents control the slew rate of VVCO
during dimming off and on transitions.
– Turn-off: DSR is discharged to GND
by 44uA
– Turn-on: DSR is charged to ICOMP
by 44uA. Charge level is clamped to
1Vbe above ICOMP
LED
RETURN
R1
CREF
R2
+
+
+
CS
16
Current
Amplifier
+
17
C1
ICOMP
VVREF
H
GMICOMP
510uS
R3
• Control Clamp output, VVCO, tracks
the lower of ICOMP and DSR
Control
Clamp
VVREF
Dimming Slew
Control
ICOMP
4K
IDSRCH
44uA
ILED-ON
GND
H
14
VVREF
C2
VCC
LEDSW
• During LED-OFF times the ICOMP
voltage is held by C1
VCLREFCLO, 0.5V
VCLREFCHI, 2.8V
15
DSR
• ICOMP is only driven by GM amp
during LED-ON times.
VVCO
6
L
delay
2.4us
ILED-ON
IDSRDC
44uA
UCC25710: START-UP & DIM WAVEFORMS
• 10ms RESET initiates SoftStart (SS)
• LLC Soft-Start, VCO
control is clamped to SS
until SS > ICOMP
VCC
9.3V
VREF
UVLO
RESET
Controller
Enabled
9.0V
10ms
Dimming
Enabled
• Dimming is disabled during
SS
• DSR cap is used to limit
LLC control slew rate
during dimming
• ICOMP voltage is
maintained during dimming
Soft-Start
Over
SS
ICOMP
DSR
GD1,2
LEDSW
DIM
Soft-Start
Operation
Disabled
UCC25710: DIMMING – WAVEFORMS
• DIM input controls LEDSW
• DIM input triggers soft turn-on
and turn-off of LLC converter
• LLC on-time is extended
• On-time extension is
proportional to 1-D, D is
dimming duty-cycle
• Extended on-time allows
ICOMP to maintain current
regulation at low D
Dimming
DIM
DTY = 0.1V + 2.5V*(1-D)
DTY
DADJ
Added
LLC On-Time
SS (VVCO)
ICOMP
LLC On/Off
Slew Rate
LEDSW
50% Dimming
10% Dimming
UCC25710: LOW DUTY-CYLE ILLUSTRATION
1.
LLC reaches power level equal to
pedestal LED current in region B.
Power is under delivered in region
A, but is compensated for in
region C
2.
Region B is zero, but sum of A+C
still deliveries correct energy.
3.
Energy delivered in region A + C
is too low, loop is open and
realized peak LED current will
drop
4.
On-time is extended. A + C
energy/pulse is correct to maintain
same peak LED current
LLC POWER
RAMP
DIMMING
PWM SIGNAL
D
A
B
C D
(1)
B=0
LLC POWER
RAMP
DIMMING
PWM SIGNAL
D
C D
A
(2)
A C
LLC POWER
RAMP
D
D
(3)
DIMMING
PWM SIGNAL
LLC POWER
RAMP
DIMMING
PWM SIGNAL
D AC D
(4)
UCC25710: FAULT MANAGEMENT
•
Faults
–
–
–
–
–
•
OV – highest LED string voltage
UV – lowest LED string voltage
CL(1V) – input current signal over-current
CL(2V) – input current signal latch-off
TSD – Chip thermal shutdown
Response
– OV, CL(1V) & TSD: The LLC converter and LEDSW are turned off. When
the fault clears a RESET and SS are initiated.
– UV: The LLC converter and LEDSW are turned off. A RESET and SS are
immediately initiated, repeatedly, until fault clears.
– CL(2V): The LLC and LEDSW are latched off until UVLO recycles.
– During RESET the LLC converter and LEDSW are OFF
– During SS the LLC converter and LEDSW are ON, i.e. no DIMMING
PMP4302: Multi-string LLC AC/DC Driver
for general LED lighting
TI Parts
Reference Design
PMP4302:
AC input Multi-string LLC
converter for general
LED lighting
UCC28810
(TM PFC)
UCC25710
(Multi-string LLC)
UCC28610
(Aux Flyback)
Vin
Output
90V~2
64V
54V@500mA
with 4 string
Topology
TM PFC+Multistring LLC
converter
Eff.
Dimming
92%
PWM
dimming
Features
•
•
•
•
Outdoor and Infrastructure >100W
400Vdc
PFC
Control
UCC28810
Ga Gb
CS
UV
OV
Gate Driver
EMI
Input Bridge
PWM
Control
UCC25710
Lowest cost than AC/DC + DC/DC
Highest efficiency to 92%
PWM dimming compatible
Integrate LED open/short protection and over current
protection
Applications
•
General LED lighting and LED backlight TV
PMP4302 demo board
Aux Power
Input EMI
LED light bar
4x15LEDs
PFC
Stage
Multi-string LLC Stage
PMP4302: Schematics for UCC25710
after PFC stage
Multi-string transformer
LLC topology
PWM dimming
&
Total current
sensing
feedback
PMP4302: LED current output tolerance
LED output current Vs Input
voltage
w/ 100% dimming
0.515
230V ac input
Io1
Io2
Io3
Io4
%
1%
4.9
4.8
5
5.1
3.030
2%
10
9.8
10.4
10.3
2.962
5%
25.2
24.1
25.2
25.1
2.208
10%
50.4
49.7
51.5
51.3
1.774
20%
100.9
100.1
102.7
102.5
1.280
30%
151.4
150.4
154.1
153.6
1.214
40%
201.9
200.9
205.1
204.9
1.033
50%
252.4
251.1
256.4
255.8
1.043
60%
302.9
301.4
307.7
307
1.033
70%
353.5
351.8
358.6
357.8
0.956
80%
403.9
402.2
409.7
408.8
0.923
90%
454.3
452.2
461.1
460.1
0.973
99%
499.3
496.7
507.2
506.2
1.045
100%
503.9
501.4
512.4
511.7
1.084
0.513
Output C urrent (A)
PWM
Dimming
0.511
0.509
0.507
0.505
90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260
Input Voltage(V)
Current tolerance can
achieve <+-3% with dimming
range from 1% to 100%
0.9
0.92
0.89
0.91
0.88
0.9
Efficiency
Efficiency
PMP4302: Efficiency
(TM PFC + Multi-string LLC + Aux power)
0.87
0.86
0.89
0.88
0.85
0.87
90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260
Input Voltage(V)
Dimming version
90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260
Input Voltage(V)
Non-Dimming version
PMP4302: waveforms
1% dimming
50% dimming
5% dimming
90% dimming
CH1: LEDSW
MOSFET Vgs
5V/Div
CH2: LED
Output Current
1A/Div
CH3: DSR
2V/Div
CH4: Primary
Current 1A/Div
PMP4302: waveforms
2
1.8
1.6
1.4
1.2
M
Full Load
1
Half Load
0.8
20% Load
0.6
0.4
0.2
90Vac input
0
0
CCM to get
better
current
tolerance
230Vac input
CH1: Primary MOSFET Vds 100V/Div
CH2: LED Output Current 200mA/Div
CH4: Primary Current 1A/Div
0.5
1
1.5
2
Wn
Lm/Lk=6
Fs=100KHz
Q=0.7
Lm1+Lm2=640uH
Lr=100uH
Cr=30nF
PMP4302: Thermal and Bode Plot
PMP6251: LED Backlighting for EdgeLite/ Group Dimming Digital TV
Application
Reference design Features

Support to universal 90~264Vac range
LED 4 outputs @120mA, 63V, 5Vsb@1A, 5V@3A,
13V@3A


Eff 83.7%@110Vac, 85.2%@240Vac

Secondary side 120Hz blanking control for dimming
8mm height and 6mmheight for LED magnetic
component


Board dimension 300mm(L) * 200mm(W) * 8mm(H)

LED output common + and LED OVP and UVP
Integrated the protection ckt to reduce the solution
part count.

Utility
Dedicated controller for edge-lit/ group dimming base(90~265VAC)
on the LLC topology – UCC25710

Providing design package – Schematic, Gerbo file,
PCB file, Magnetic components…

TM PFC
UCC28051
Multi-Transformer
UCC25710
LLC PWM
UCC25600
GM PWM
UCC28610
4 Channels/ 63V/120mA
Audio 12.7V/3A
AD Board 5V/3A
System- MCU
(+5VSB/2A)
PMP6251: PFC+ Multi-string LLC
Efficiency
Efficiency Data of PFC+LLC Power Stage from 1% - 100% Dimming
92.00%
Eff%(PFC+LLC)
Rate of Dimming
90.00%
88.00%
86.00%
84.00%
82.00%
80.00%
0%
20%
40%
60%
80%
100%
Eff% of (PFC+LLC)
Efficiency exclude standby Power Converter at full load condition ~ 90%
Summary
•
UCC25710 with multi-transformer LLC topology can achieve:
☺High efficiency
☺Low total BOM cost with high reliability
☺PWM or analog dimming compatible
☺Output LED strings open/short protection
☺Input over current protection
☺Support 1%~100% dimming range
☺Easy EMI
Summary
• LED backlight becomes a trend for flat screen TVs
• TI proposed multi-transformer backlight solution
– Simple current matching method
– Single stage power processing
– Fault tolerant capability
• UCC25710 provides the IC solution for multitransformer architecture
•
•
•
•
•
Multi-Transformer LLC + LED switch control
Precision LED current control
Soft ramping of LLC for audible noise reduction
Extended PWM dimming dynamic range
Complete protection features
TI UCC25600
8 Pin Resonant Half Bridge Controller
Features
ƒ Adjustable Soft start (1ms to 500ms)
ƒ Adjustable dead time
Td
ƒ Adjustable Fswmax & Fswmin (3% accuracy)
RT
ƒ Io = +1A /-1.5A
OC
ƒ Enable (ON/OFF control)
SS
Protection functions
ƒ Two levels over current protection
ƒ auto recovery
ƒ latch
ƒ Bias voltage UV and OV protection
ƒ Over temperature protection
ƒ Soft start after all fault conditions
SOT 8 pin package= Easy design and layout
1
8
GATE1
2
7
VCC
3
6
GND
4
5
GATE2
Ready
to Order
Application Circuit
360~400V
Vcc
DC_OUT
Td
Gate1
RT
Vcc
OC
GND
SS
Gate2
1
1
1
1
Programmable dead time
Frequency control with minimum/maximum frequency limiting
Programmable soft start with on/off control
Two level over current protection, auto-recovery and latch up
Matching output with 50ns tolerance
LLC Resonant Converter with Wide
Operation Range
4
Q=0.1
Q=0.2
Q=0.5
Q=0.8
3.5
Cr
n:1:1
Lr
Vin
Vo
M=Vo/V in
3
2.5
2
ZVS Region
1.5
Q=1
Q=2
Q=5
Q=8
Q=10
ZCS Region
1
Lm
RL
0.5
0
0.4
Resonant
frequency
f0 =
1
2π Lr Cr
Transformer
turns-ratio
0.6
n=
Vin / 2
Vo
At 400V input, switching frequency is resonant frequency
During holdup time, switching frequency is reduced
0.8
fn
1
1.2
Operation Principles
At Resonant Frequency
Vg_Q1
t
Vg_Q2
t
Vp
Q1
Cr
Vin
t
ir
D1
n:1:1
Lr
Vo
*
Q2
Lm
*
RL
*
im
D2
t
is
t
t0
t1
t2
t3
t4
At resonant frequency,
maximum efficiency is expected
Operation Principle
Below Resonant Frequency
Vg_Q1
Vg_Q2
Q1
Vp
Cr
Vin
Vo
*
Q2
ir
D1
n:1:1
Lr
Lm
*
RL
*
D2
im
When switching frequency is below
resonant frequency, magnetizing inductor
begins to participate in resonant and
increase voltage gain
Secondary diode becomes discontinuous
is
t0
t1 t2 t3
Operation Principle
Above Resonant Frequency
Vg_Q1
Vg_Q2
Q1
Vp
Cr
Vin
Vo
*
Q2
ir
D1
n:1:1
Lr
Lm
*
RL
*
D2
im
When switching frequency is above
resonant frequency, circuit behaves as SRC
Secondary current becomes CCM, reverse
recovery loss increases
is
t0
t1 t2 t3
Benefits of LLC Resonant Converter
Cr
1:n:n
Lr
Lm





ZVS can be achieved by utilizing transformer magnetizing inductor
Capacitor filter, less voltage stress on rectifiers
Smaller switching loss due to small turn off current
Variable switching frequency control, not sensitive to load change
Wide operation range without reducing normal operation efficiency
UCC24610
Green Rectifier Controller
• Secondary Side Synchronous Rectifier
Controller for Flyback and LLC Converters
• Operates in Continuous and Discontinuous
Mode Flybacks and LLC Resonant
• Automatic Light Load Management
• Highly Integrated Control
• Micro Power Sleep Current at light/No load
• Enables 90%+ efficiency at full load and Optimized
Efficiency Over Entire Load Range
• Zero Glitch Transition between CCM and DCM
Operation for varying Line or Load Changes
• Turns MOSFETS Off to Maximize Light
Load Efficiency
• Reduces External Components with up to
5% Reduction in Power Supply Costs
• Dissipates less than 1mW in Sleep Mode
Making Energy Star Goals easily Achievable
+
•
•
•
•
•
AC/DC Adaptors
Mobile Chargers – Cell Phone, IPod
Set Top Box
Appliance Power Supplies
Bias Supplies
+
VD
GATE
VCC
VS
TON
EN/TOFF
iSYNC_RESET
CSYNC
RSYNC
iSYNC
EVM
Available
+5V
OUT
C CM
SYNC
C PIN
GND
VCC
rSYNC
To Control Logic
UCC24610
Adding Green Solutions to the Portfolio
Green Rectifier
UCC24610
LLC
Or
Flyback
MOSFET
Drivers
Sync Rectifier
Driver
Isolated
Feedback
Green PWM Controllers
UCC28610 Green Mode PWM
UCC28600 Green Mode QR PWM
UCC25600 Green Mode Resonant LLC
Expand the Operation Range of
UCC24610
• With 50V maximum rating, UCC24610 has trouble to use in 19V output LLC
• LLC converter with voltage doubler can be used to extend the operation range of
UCC24610
• No center tap, simpler transformer structure
• Less voltage drop on the SR, better devices can be used
• UCC24610 can be powered up using on aux power source with boots trap diode
UCC24610 Competitive Analysis
TI
IR
NXP
(8)
NXP
ST
ON
ON
Gren
(9)
Zerex
Parameter/Device: UCC24610
IR1166S
TEA1761T
TEA1791T
STSR30
NCP4302
NCP4303B
GR8387
ZXGD3101T8
50
200
120
120
(ext. clamp)
95
200
200
180
Vdrain (V)
DCM, QR
DCM, QR, CCM DCM, QR, CCM DCM, QR, CCM DCM, QR, CCM DCM, QR, CCM
Conduction Modes DCM, QR, CCM DCM, QR, CCM DCM, QR
-1
-0.25
-0.25
-1.5
2.5
2.5
1
2.5
GATE Ion (Apk)
-3
4
2.7
2.7
1.5
-2.5
-5
-4
-2.5
GATE Ioff (Apk)
3
600
500
?
?
500
250
500
500
n/a
Max Freq (kHz)
SO-8
SO-8
SO-8
SO-8
SO-8
SO-8
SO-8
SO-8
Packages PwrQFN-8, SO-8
67, 147
128
150
150
160
178
180
128
250
Rthja (C/W)
(5)
(5)
Unknown
Unknown
-40 to +125
-25 to +125
-20 to +128
-20 to +128
-40 to +125
-40 to +125
-40 to +125
Tj Range (C)
Special Features:
No
No
No
No
Enable function
Yes
Yes
Yes
Yes
Yes
No
No
No
No
No
No
Auto Light-Load Mode
Yes
Yes
Yes
No
No
No
No
No
No
No
No
Inductance Compensation
Yes
None Indicated None Indicated None Indicated None Indicated None Indicated None Indicated None Indicated None Indicated
Open/Short Protections
Yes
No
No
No
No
No
No
No
Regulated Opto-drive
Yes
Yes
No
No
No
No
No
Gate Voltage Reduction
Yes
Yes
Yes
Yes
No
No
No
No
No
No
No
No
Over-temp Protection
Yes
Key Differentiators
• High Gate Drive current
• Auto Light Load Mode
• Open/Short Protection
5.6V/3A AC Adapter:
12V/40A Server Application:
95%
94%
93%
Efficiency
92%
91%
90%
89%
88%
87%
86%
85%
0
4
8
12
16
20
24
Load Current (Amps)
28
32
36
40
UCC24610 in 19.5V LLC
AC Adapter Application
Synchronous rectifier in LLC converter
System implementation
Test Results
•
•
•
Waveforms
– YEL (Primary current)
A/Div
– BLU (Lower SR VDS)
V/Div
– GRN (Upper SR VGS)
V/Div
– RED (Lower SR VGS)
V/Div
Horizontal scale
– 2 µs/Div
Operating conditions
– VI =320 V
– IO =1.0 Adc (20 W)
– fSW below resonance
1
10
10
10
Test Results
•
•
•
Waveforms
– YEL (Primary current)
A/Div
– BLU (Lower SR VDS)
V/Div
– GRN (Upper SR VGS)
V/Div
– RED (Lower SR VGS)
V/Div
Horizontal scale
– 2 µs/Div
Operating conditions
– VI =390 V
– IO =1.0 Adc (20 W)
– fSW close to resonance
1
10
10
10
Test Results
•
•
•
Waveforms
– YEL (Primary current)
A/Div
– BLU (Lower SR VDS)
V/Div
– GRN (Upper SR VGS)
V/Div
– RED (Lower SR VGS)
V/Div
Horizontal scale
– 1 µs/Div
Operating conditions
– VI =420 V
– IO =1.0 Adc (20 W)
– fSW above resonance
1
10
10
10
Test Results
•
•
•
Waveforms
– YEL (Primary current)
A/Div
– BLU (Lower SR VDS)
V/Div
– GRN (Upper SR VGS)
V/Div
– RED (Lower SR VGS)
V/Div
Horizontal scale
– 2 µs/Div
Operating conditions
– VI =320 V
– IO =2.3 Adc (45 W)
– fSW below resonance
1
10
10
10
Test Results
•
•
•
Waveforms
– YEL (Primary current)
A/Div
– BLU (Lower SR VDS)
V/Div
– GRN (Upper SR VGS)
V/Div
– RED (Lower SR VGS)
V/Div
Horizontal scale
– 2 µs/Div
Operating conditions
– VI =390 V
– IO =2.3 Adc (45 W)
– fSW close to resonance
1
10
10
10
Test Results
•
•
•
Waveforms
– YEL (Primary current)
A/Div
– BLU (Lower SR VDS)
V/Div
– GRN (Upper SR VGS)
V/Div
– RED (Lower SR VGS)
V/Div
Horizontal scale
– 1 µs/Div
Operating conditions
– VI =420 V
– IO =2.3 Adc (45 W)
– fSW above resonance
1
10
10
10
Test Results
•
•
•
Waveforms
– YEL (Primary current)
A/Div
– BLU (Lower SR VDS)
V/Div
– GRN (Upper SR VGS)
V/Div
– RED (Lower SR VGS)
V/Div
Horizontal scale
– 2 µs/Div
Operating conditions
– VI =320 V
– IO =4.6 Adc (90 W)
– fSW below resonance
1
10
10
10
Test Results
•
•
•
Waveforms
– YEL (Primary current)
A/Div
– BLU (Lower SR VDS)
V/Div
– GRN (Upper SR VGS)
V/Div
– RED (Lower SR VGS)
V/Div
Horizontal scale
– 2 µs/Div
Operating conditions
– VI =390 V
– IO =4.6 Adc (90 W)
– fSW close to resonance
1
10
10
10
Test Results
•
•
•
Waveforms
– YEL (Primary current)
1 A/Div
– BLU (Lower SR VDS)
10 V/Div
– GRN (Upper SR VGS)
10V/Div
– RED (Lower SR VGS)
10V/Div
Horizontal scale: 2 µs/Div
Operating conditions
– VI =420 V
– IO =4.6 Adc (90 W)
– fSW above resonance
Operating Efficiency with UCC24610
90-W LLC Laptop Adapter (UCC24610) - Efficiency
95
90
Efficiency (%)
VI (V)
85
SR
Diode
80
75
70
1.0
1.5
2.0
2.5
3.0
3.5
4.0
4.5
IO (A)
More than 6% efficiency improvement is achieved by using UCC24610
with Synchronous rectifier
Thank You!