Application Note

CM6900 Application Note A-002A
Design a High Efficiency LED Power
Supply Use CM6900+CM6807
Michael Lee
Introduction
Recently, energy saving is becoming a very important topic due to the increasing
seriousness of energy shortage problem and the rising demand for energy in developing
industrial countries. Because of this, every country is paying close attention to new
power source for lighting.
Since existing lighting method mainly uses low illuminant
CFL fluorescent tube, high illuminant LED became the spot of attention these few years.
Applications for LED power supply differ from what were used traditionally.
LED power
supply is required to have high efficiency (greater than 88%) due to its high illuminant
characteristic. In addition, LED lighting needs constant current mode control lighting;
all LED lighting power applications require current mode control function to be added.
Therefore, highly efficient power supply is very important when it comes to using LED
lighting. Traditional PWM which uses switching power supply is no longer sufficient
when such high efficiency is required.
Champion Microelectronic combines CM6900 resonant controller and CM6805/07 PFC
series to provide a complete LED lighting power supply solution that is highly efficient
(>88%), standby power (<0.5W), and constant voltage / constant current available.
This solution targets to 100W – 1KW power supply, and can be used on LED lighting,
street lamps, large LED display, and high voltage lighting for gym…etc.
Because this
solution provides high efficiency >88%, it can provide stable power source to the
customers and cut down the maintenance cost.
Also, the high efficiency can decrease
the product temperature and prolongs the life of the lighting system.
2007/10/31 Preliminary
Champion Microelectronic Corporation
Page 1
CM6900 Application Note A-002A
LED 350W Lighting System Specification
Input Spec
1. Vin: 85Vac~264Vac
2. Iin: 5A MAX.
3. PF>[email protected] Full Load
4. Power Frequency 47-63Hz
5. Working Temperature 50℃
Output Spec
1. Vout: 39~44V
2. Iout: 4A~8A
3. Voltage Ripple Noise: 300mV
4. Current Ripple <0.1A
5. Control mode: constant voltage /
constant current
6. Efficiency >91% @230Vac Full Load
>90% @115Vac Full Load
7. Stand-by <0.5W
<1W @0.35W Load
8. Heat Sink: no heat sink required
9. Working environment: airtight
1. LED Lighting 350W Power Supply Block Diagram (with STANDBY):
DC bus
385V
EMI
Filter
Half
Bridge
PFC
AC LINE
PWM
Start-up
Circuit
CM6807
PWM
40V
Synchronous
Rectifier
PWM
Resonant
Controller
(CM6900)
Stand-by
Power
2007/10/31 Preliminary
ENABLE
PWM
12VP
12Vs
Champion Microelectronic Corporation
Page 2
CM6900 Application Note A-002A
2. LED Lighting 350W Power Supply Block Diagram (without
STANDBY):
DC bus
385V
EMI
Filter
AC LINE
Half
Bridge
PFC
Start-up
Circuit
PWM
CM6807
12VP
12Vs
40V
Synchronous
Rectifier
PWM
PWM
Resonant
Controller
(CM6900)
ENABLE
Above two block diagrams are for applications that require / does not
require Green Power. Designer can use according to its product spec.
Below are more details on these two applications.
2007/10/31 Preliminary
Champion Microelectronic Corporation
Page 3
CM6900 Application Note A-002A
一、 Circuit Diagram(With STANDBY Function)
1. PFC+AUX POWER
MA070-22-14-8S
(1.1mmX12)--T6,T1
L1
F1 Fuse/250V/7A
+VDC
D1
T2--(N.C)
2
SF20L60U
C1
C9--(N.C)
0.47uF/250VAC
4
Vin
L2
1
+14VP
PQ-3230
Q1
BC817
PFCDRV
D10XB60
C4
3
R1 10Ω
C6
2.5Ω/5A
C7
0.47uF/400V
C9
2.2nF/250VAC
STP20NM50/STP20NM50FD
3
2
+
40uH
0.47uF/250VAC
3
0.47uF/250VAC
-
2
BD1
4
C3
t
T POINT S
1
2
RT1
TP2
CM1
C2
1
T2
CM1
1
1
T POINT S
1
4
T1
TP1
C10
2.2nF/250VAC
C8
1uF/400V
0.1uF/25VY
C11
C12
1nF/250VAC1nF/250VAC
C5
220uF/450V
Q3
BC807
R4
+VDC
47nF/630V
Q2
R2 10Ω
R3
47KΩ
0.05Ω
Vin
R5
2MΩ
R6
5KΩ 1/4W
R7
2MΩ
R8
2MΩ
R9
5KΩ 14W
R10
2MΩ
Q4
MMBTA44
R12
390KΩ
R13
100KΩ
R11
47Ω
D2
+14VP
C13
100pF/25V
U1
1
1N4148
2
3
4
5
CM6807
GND
PWMOUT
IAC
PFC OUT
Isense
VCC
VEAO PWMtrif ault
FB
DCLIMIT
10
PFCDRV
9
Q5
PFCDRV
8
+14VP
7
6
R15
100KΩ
C15
C17
C18
0.1uF/25VN
47KΩ/1K
C16
+ C14
0.1uF/25VY 100uF/25V
1uF/25VN
R16
27KΩ
+15VPS
BC817
R14
C19
0.1uF/25VN
R17
0.15uF/25VN
ZD1
ZMM(14V)
56KΩ
+12VP
R18
R19
47KΩ
+VDC
T3
2
R24
+12VPS
D5 SS100
C21
1nF/500V
680K 1/4W
R25
D6
+ C22
100uF/25V
L3
5
7
8
PQ-20/20
220uF/25V
+VDC
C27
0.1uF/63V
1N4148
47KΩ
SD
20A/30V
C26
+ C24
4
R22
470Ω
3
C20
LTV817B
4
U3
3
ENABLE
High active
0.1uF/63V 220uF/25V
0.1uF/25VY
R23
1KΩ
1
0.1uF/25VY
2N7002/SOT
2N7002/SOT
14VS
R21
56KΩ
Q7
C28
C29 222M/250V Y1
U2
2
Q6
+ C23
D7
US1J
5uH
R20
1KΩ
1
14VS
10
9
6
4.7KΩ
D4
D3 1N4148
1
R26
1KΩ
2
C25
LTV817B
DCFB
R27
0.1uF/25V
10KΩ
R28
47KΩ
U4
CM431BCM233
STP8NM70
R30
Q8
DCDRV
10Ω
R31 1KΩ
DCFB
R32
47KΩ
R33
2Ω 1/4W
Circuit Explanation:
In the above diagram, PFC and auxiliary power uses CM6807.
consumption <0.5W.
2007/10/31 Preliminary
CM6807 can achieve no load
This structure can be used for low no load consumption application.
Champion Microelectronic Corporation
Page 4
R29
1KΩ
CM6900 Application Note A-002A
2. HB POWER STAGE
+VDC
C30
D8 SCD14
R34
47Ω
Q9
STP10NM50
2.2nF/250VAC
DRVH
SSYNDRVL
R35
47KΩ
C31
T4
L4
3
DRVHGND
Lp(1.5mH) IRF3710
10
9
100nF/400V 150uh/PQ-20/20
C32
47nF/630V
R36 47KΩ
Q10
L5
D9 SCD14
Q11
STP10NM50
R37
47Ω
7
6
8
+ C33
DRVL
R39
47KΩ
40V
PQ-32/30
0.8uH/20A
1000uF/50V 1000uF/50V
R38 0.005Ω /2W
Q12
11
12
+ C34
+ C35
+ C36
1000uF/50V 1000uF/50V
IRF3710
R40 47KΩ
SSYNDRVH
Circuit Explanation:
Above diagram is the main structure of DC/DC power supply for LED lighting.
This is a
SRC structure which uses synchronize rectifier to increase the efficiency of DC/DC.
This structure can increase DC/DC efficiency to over 96%, which solves the industry
problem of using LLC structure that only has efficiency lower than 92% and can not
easily achieve synchronize rectification.
After adopting SRC structure, synchronize
rectification is easy to achieve and the main transformer efficiency gets better. By
using CM6900, the original disadvantage of SRC is solved; therefore, SRC structure is
the best choice for high efficiency requirements.
2007/10/31 Preliminary
Champion Microelectronic Corporation
Page 5
CM6900 Application Note A-002A
3. CM6900 CV/CC MODE CONTROLLER
+14VS
40V
Q13
BC817
T5
C38
5
R41
300KΩ
U5
1
2
3
VREF
4
C39
10nF/25V
R42
18KΩ
5
R43
6
10KΩ
7
R44
100KΩ
C40
1nF/25V
R49
5KΩ
R50
150K
R51
20KΩ
R46
R48
45KΩ
240KΩ
8
R47
24KΩ
C45
0.1uF/25V
C46
+14VS
Rset
VREF
VFB
VCC
FEAO
PRIDRV
NC/D_IN- PRIDRVB
D_IN+/VREF1SRDRV
DEAO
SRDRVB
CSS
GND
Ilim
RT/CT
16
Q14
VREF
15
R53
24KΩ
1KΩ
C42
CM6900
6
3
13
2
Q15
BC817
12
7
11
8
10
R45
9
+14VS
VREF
C43
680pF/25VN
0.1uF/25V
EE-19
Q16
C44
0.1uF/25V
BC807
C41 +
100uF/25V
0.1uF/25V
+14VS
Q17
BC817
C47 0.1uF/25V
R54
4.7Ω 1/4W
SSYNDRVH
VREF
R57 10KΩ
R55
BC807
LM358/SO
4
3
5.1KΩ
7
R59
8
+
U6A
-
1
1N4148
2
5.1KΩ
R61
U6B
6
5
R58
1KΩ
R62 1KΩ
LOAD SWITCH
2N7002/SOT_0
Q19
BC817
1Ω
IO+
+14VS
5.1KΩ
Q20
+14VS
R60
8
4
D10
Q18
R56
15KΩ
+
LM358/SO
-
+14VS
C48
R64
0.1uF/25V 10KΩ
R63
4.7Ω 1/4W
SSYNDRVL
Q21
BC807
Circuit Explanation
Because of the high efficiency requirement of LED lighting power supply, there must be
an appropriate controller IC for DC/DC that uses SRC structure.
Champion
Microelectronic CM6900 is the best choice as it has synchronize rectifier built internally.
In addition, it has OVP/OCP soft start function and FM+PWM operating mode, it is very
easy to use in applications requiring constant current / constant voltage mode.
The LM358 OPA is used for constant current mode feedback amplifier circuit.
Adding
this circuit allows CM6900 to be used in constant current mode.
2007/10/31 Preliminary
DRVHGND
+14VS
14
50KΩ
R52
1uF/63V
BC807
DRVH
Champion Microelectronic Corporation
Page 6
DRVL
CM6900 Application Note A-002A
二、 Application Circuit Diagram (Without STANDBY Function)
1. PFC+AUXPOWER Circuit
+15VPS
1A/100V
D1
+ C1
10uF/25V
+ C2
AUX2
3
D2
1A/100V
MA070-22-14-8S
(1.1mmX12)--T6,T1
4
AUX1
L1
10uF/25V
F1 Fuse/250V/7A
+VDC
D3
T2--(N.C)
2
SF20L60U
C3
C4
C9--(N.C)
0.47uF/250VAC
T POINT S
0.47uF/250VAC
-
+
2
PQ-3230
1
L2
1
+14VP
40uH
0.47uF/250VAC
PFCDRV
D10XB60
Q1
BC817
C8
2.5Ω/5A
C11
2.2nF/250VAC
STP20NM50/STP20NM50FD
C6
R1 10Ω
3
3
Vin
4
C5
t
1
2
RT1
TP2
CM1
4
CM1
BD1
3
T POINT S
2
1
1
1
TP1
T2
4
T1
C12
2.2nF/250VAC
C9
0.47uF/400V
C13
C14
1nF/250VAC1nF/250VAC
C7
220uF/450V
47nF/630V
Q3
BC807
R4
+VDC
Q2
R2 10Ω
0.1uF/25VY
C10
1uF/400V
0.05Ω
R3
47KΩ
Vin
R5
2MΩ
R6
5KΩ 1/4W
R7
2MΩ
R8
2MΩ
R10
2MΩ
R9
5KΩ 14W
Q4
MMBTA44
R12
390KΩ
R13
100KΩ
R11
47Ω
D4
+14VP
C15
100pF/25V
U1
1
1N4148
2
3
4
5
CM6807
GND
PWMOUT
IAC
PFC OUT
Isense
VCC
VEAO PWMtrif ault
FB
DCLIMIT
10
9
8
7
6
Q5
PFCDRV
+14VP
R14
R15
100KΩ
47KΩ/1K
C18
C17
C19
R16
27KΩ
0.15uF/25VN
C21
0.1uF/25VN
+ C16
0.1uF/25VY 100uF/25V
1uF/25VN
C20
0.1uF/25VN
+15VPS
BC817
R17
200KΩ
R18
ZD1
ZMM(14V)
56KΩ
Circuit Explanation:
In the above diagram, PFC is achieved by using CM6807 and auxiliary power is
achieved by using auxiliary winding on PFC Choke.
The auxiliary power’s voltage
output is determined by the turns on the PFC Choke. The voltage is calculated to be
(15VP=PFC Vdc / Nratio).
2007/10/31 Preliminary
Champion Microelectronic Corporation
Page 7
CM6900 Application Note A-002A
2. Half Bridge Efficiency
+VDC
C22
D5 SCD14
R19
47Ω
Q6
STP20NM50
2.2nF/250VAC
DRVH
SSYNDRVL
R20
47KΩ
C23
T3
L3
3
DRVHGND
Lp(1.5mH) IRF3710
10
9
100nF/400V 150uh/PQ-20/20
C24
47nF/630V
R21 47KΩ
Q7
R22
47Ω
40V
L4
D6 SCD14
Q8
STP20NM50
7
6
8
+ C25
DRVL
R24
47KΩ
PQ-32/30
0.8uH/20A
1000uF/50V 1000uF/50V
R23 0.005Ω /2W
Q9
11
12
+ C26
+ C27
+ C28
1000uF/50V 1000uF/50V
IRF3710
R25 47KΩ
SSYNDRVH
Circuit Explanation:
Above diagram shows the main structure of DC/DC power supply for LED lighting.
This is a half bridge SRC structure, and it uses synchronize rectifier to improve the
efficiency of DC/DC. This structure can increase DC/DC efficiency to over 96%, which
solves the industry problem of using LLC structure that only has efficiency lower than
92% and can not easily achieve synchronize rectification.
After adopting SRC
structure, synchronize rectification is easily achieved and the main transformer
efficiency gets better. By using CM6900, the original disadvantage of SRC is solved;
therefore, SRC structure is the best choice for high efficiency requirements.
2007/10/31 Preliminary
Champion Microelectronic Corporation
Page 8
CM6900 Application Note A-002A
3. Control Circuit
+12VS
40V
Q10
BC817
C31
T4
Q11
R26
300KΩ
6
1
+15VS
2
+12VS
3
BC817
D7
+ C32
1A/100V
VREF
R27
4
C33
47KΩ/1K
aux2
C34 +
R28
18KΩ
5
R29
10nF/25V
6
10KΩ
R31
100KΩ
220uF/25V
D8
1A/100V
ZD2
C36
ZMM(14V)
1nF/25V
R36
5KΩ
R37
150K
R38
20KΩ
R33
R35
45KΩ
240KΩ
8
R34
24KΩ
C40
C41
0.1uF/25V
3
+12VS
Rset
VREF
VFB
VCC
FEAO
PRIDRV
NC/D_IN- PRIDRVB
D_IN+/VREF1SRDRV
DEAO
SRDRVB
CSS
GND
Ilim
RT/CT
16
VREF
14
2
12
8
11
R32
9
EE-19
+12VS
Q13
VREF
BC807
50KΩ
R39
R40
24KΩ
1KΩ
C37
CM6900
C38
680pF/25VN
0.1uF/25V
C39
0.1uF/25V
+12VS
Q15
BC817
R30
C42 0.1uF/25V
U3A
5.1KΩ
LM358/SO
+12VS
4
4
3
7
R46
R48
5.1KΩ
U3B
6
5
R45
1KΩ
R49 1KΩ
LOAD SWITCH
2N7002/SOT_0
R41
1Ω
4.7Ω 1/4W
12VSYNDRVL
IO+
+12VS
5.1KΩ
Q19
Q17
BC817
R47
8
1N4148
2
8
1
BC807
R43
15KΩ
+
D9
12VSYNDRVH
R44 10KΩ
R42
LM358/SO
4.7Ω 1/4W
Q16
VREF
+12VS
7
Q12
BC817
13
10
Q18
BC807
C43
R50
0.1uF/25V 10KΩ
Circuit Explanation:
Because of the high efficiency requirement of LED lighting power supply, there must be
an appropriate controller IC for DC/DC that uses SRC structure.
Champion
Microelectronic CM6900 is the best choice as it has synchronized rectifier built internally.
In addition, it has OVP/OCP soft start function and FM+PWM operating mode, it is very
easy to use in applications requiring constant current / constant voltage mode.
The LM358 OPA shown above uses constant current mode feedback amplifier circuit.
Adding this circuit allows CM6900 to be used in constant current mode.
The auxiliary winding's power output of 15V from the PFC choke controls the circuit
power, it then support CM6900 via circuit regulator.
2007/10/31 Preliminary
DRVHGND
+12VS
15
0.1uF/25V
-
10uF/25V
+
+ C35
7
-
10uF/25Vaux1
DRVH
BC807
U2
Q14
5
2.2uF/63V
Champion Microelectronic Corporation
Page 9
DRVL
CM6900 Application Note A-002A
Conclusion:
LED lighting application is increasing, and it is a trend to provide high efficiency power
supply > 90%. To meet the new LED market demand, Champion already has the
complete solution to provide the best design and application for its customers.
For further information on LED lighting and IC application, please feel free to contact us
for details.
Contact Person:
Kathy Chen
Tel: 886-2-2788-0558 # 605
Fax: 886-2-2788-2985
E-mail: [email protected]
HsinChu Headquarter
Sales & Marketing
5F, No. 11, Park Avenue II,
Science-Based Industrial Park,
HsinChu City, Taiwan
T E L : +886-3-567 9979
F A X : +886-3-567 9909
7F-6, No.32, Sec. 1, Chenggong Rd.,
Nangang District, Taipei City 115,
Taiwan, R.O.C.
2007/10/31 Preliminary
T E L : +886-2-2788 0558
F A X : +886-2-2788 2985
Champion Microelectronic Corporation
Page 10