ISL6730AEVAL1Z [INTERSIL]
Power Factor Correction Controllers;型号: | ISL6730AEVAL1Z |
厂家: | Intersil |
描述: | Power Factor Correction Controllers |
文件: | 总19页 (文件大小:420K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
Power Factor Correction Controllers
ISL6730A, ISL6730B, ISL6730C, ISL6730D
The ISL6730A, ISL6730B, ISL6730C, ISL6730D are active
Power Factor Correction (PFC) controller ICs that use a boost
topology. The controllers are suitable for AC/DC power
systems, up to 2kW and over the universal line input.
Features
• Reduce component size requirements
- Enables smaller, thinner AC/DC adapters
- Choke and cap size can be reduced
- Lower cost of materials
The ISL6730A, ISL6730B, ISL6730C, ISL6730D operate in
Continuous Conduction Mode (CCM). Accurate input current
shaping is achieved with a current error amplifier. A patent
pending breakthrough negative capacitance technology
minimizes zero crossing distortion and reduces the magnetic
components size. The small external components result in a
low cost design without sacrificing performance.
• Excellent power factor over line and load regulation
- Internal current compensation
- CCM Mode with Patent pending IP for smaller EMI filter
• Better light load efficiency
- Automatic pulse skipping
The internally clamped 12.5V gate driver delivers 1.5A peak
current to the external power MOSFET. The ISL6730A,
ISL6730B, ISL6730C, ISL6730D provide a highly reliable
system that is fully protected. Protection features include
cycle-by-cycle overcurrent, over power limit, over-temperature,
input brownout, output overvoltage and undervoltage
protection.
- Programmable or automatic shutdown
• High reliable design
- Cycle-by-cycle current limit
- Input average power limit
- OVP and OTP protection
- Input brownout protection
The ISL6730A, ISL6730B provide excellent power efficiency
and transitions into a power saving skip mode during light load
conditions, thus improving efficiency automatically. The
ISL6730A, ISL6730B, ISL6730C, ISL6730D can be shut down
by pulling the FB pin below 0.5V or grounding the BO pin. The
ISL6730C, ISL6730D have no skip mode.
• Small 10 Ld MSOP package
Applications
• Desktop computer AC/DC adaptor
• Laptop computer AC/DC adaptor
• TV AC/DC power supply
Two switching frequency options are provided. The ISL6730B,
ISL6730D switch at 62kHz, and the ISL6730A, ISL6730C
switch at 124kHz.
• AC/DC brick converters
100
95
V
I
+
VLINE
VOUT
90
85
80
75
70
65
60
ISL6730A, SKIP
ISL6730C
VCC
ISEN
GATE
GND
ICOMP
ISL6730
VIN
FB
COMP
BO
VREG
0
20
40
60
80
100
OUTPUT POWER (W)
FIGURE 1. TYPICAL APPLICATION
FIGURE 2. PFC EFFICIENCY
TABLE 1. KEY DIFFERENCES IN FAMILY OF ISL6730
VERSION
Switching Frequency
Skip Mode
ISL6730A
124kHz
ISL6730B
62kHz
ISL6730C
ISL6730D
62kHz
No
124kHz
No
Yes-Fixed
Yes-Fixed
August 8, 2013
FN8258.1
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774 | Copyright Intersil Americas LLC 2013. All Rights Reserved
Intersil (and design) is a trademark owned by Intersil Corporation or one of its subsidiaries.
All other trademarks mentioned are the property of their respective owners.
1
ISL6730A, ISL6730B, ISL6730C, ISL6730D
Pin Configuration
ISL6730A, ISL6730B, ISL6730C, ISL6730D
(10 LD MSOP)
TOP VIEW
1
2
3
4
5
GATE
VCC
GND
ISEN
ICOMP
VIN
10
9
8
VREG
FB
7
BO
6
COMP
Pin Descriptions
PIN # I/O SYMBOL
DESCRIPTION
1
2
3
4
-
GND
ISEN
Ground pin. All voltage levels refer to this pin.
Current sense pin. The current through this pin is proportional to the inductor current.
I
I/O ICOMP Current error amplifier output pin.
I
VIN
BO
Input voltage sense. This pin provides the reference voltage to shape inductor current. Connect this pin to a resistor divider from
the rectified input voltage. The resistor divider ratio is used to adjust the phase lag between input voltage and the input current.
The phase lag is required to compensate the phase lead generated by the EMI filter.
5
I/O
This pin should be decoupled to GND with a minimum 0.1µF ceramic capacitor. The BO pin is a voltage follower, which will follow
the DC voltage of the VIN pin. The BO pin is internally tied to GND through a resistor R . The decoupling capacitor provides ripple
IS
filtering. When the voltage at the BO pin (V ) drops below brownout voltage threshold, the controller enters shutdown mode
BO
and the gate drive is disabled. The BO pin will be disabled when the FB pin drops below the enabling threshold.
6
7
I/O COMP Output of the error amplifier. The voltage of the COMP pin sets the input power. During start-up, a small charge current will slowly
ramp up the voltage of the COMP pin.
I
FB
Voltage feed back pin. Connect this pin to a resistor divider from the output. The resistor divider sets the output voltage. When
the FB pin voltage exceeds 104% of the reference voltage, overvoltage-protection is triggered and gate drive is disabled. When
the FB pin is below 10%, the device is put into shutdown mode. There is an internal pull-down current source for open loop
protection.
8
-
VREG Output of internal regulator. The voltage having a ±2% tolerance over line, load and operating temperature. Bypass to GND with
a 47nF low ESR capacitor. VREG can source up to 10mA. This pin is not recommended for usage other than bypass.
9
I
VCC
Power supply pin. The VCC pin should be decoupled to GND with a minimum 0.1µF ceramic capacitor.
10
O
GATE
Push-pull gate drive for the external MOSFET. Output voltage is clamped at 12.5V. This pin provides typically 2A sink and 1.5A
source capability.
Ordering Information
PART NUMBER
(Notes 1, 2, 3)
PART
MARKING
TEMP.
RANGE (°C)
PACKAGE
(Pb-Free)
PKG.
DWG. #
ISL6730AFUZ
6730A
6730B
6730C
6730D
-40 to +125
-40 to +125
-40 to +125
-40 to +125
10 Ld MSOP
M10.118
M10.118
M10.118
M10.118
ISL6730BFUZ
ISL6730CFUZ
ISL6730DFUZ
ISL6730AEVAL1Z
ISL6730BEVAL1Z
NOTES:
10 Ld MSOP
10 Ld MSOP
10 Ld MSOP
Evaluation Board
Evaluation Board
1. Add “-T*” suffix for tape and reel. Please refer to TB347 for details on reel specifications.
2. These Intersil Pb-free plastic packaged products employ special Pb-free material sets, molding compounds/die attach materials, and 100% matte
tin plate plus anneal (e3 termination finish, which is RoHS compliant and compatible with both SnPb and Pb-free soldering operations). Intersil
Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.
3. For Moisture Sensitivity Level (MSL), please see device information page. For more information on MSL please see techbrief TB363.
FN8258.1
August 8, 2013
2
Block Diagram
V
EMI CHOKE
D
I
V
OUT
L
C
OUT
V
C
Q
1
LINE
F3
C
C
F1
R
F2
L
m
D
F1
CS
D
F2
C
REG
VCC
VREG
LINEAR
REGULATOR
VCC
CURRENT
MIRROR
UVLO
GATE
2:1
I
CONTROL
LOGIC
OC
> -------------
R
SEN
I
CS
I
2
ISEN
GND
OTP
CS
SKIP
PWM
COMP
CEQ GEN.
R
× I
ISEN
2
ICOMP
IS
= ----------------------------------
V
CS
I
REF
RIS
Gmi
SOFT-START
ENABLE
OSCILLATOR
0.25 × VIN
----------------------------- C O M P B
BO
2
2.5V
R
R
IN2
R
FB2
VIN
FB
COMPB
COMP-1V
SKIP
CLAMP
OVER POWER
LIMIT
Gmv
20µA
R
FB1
IN1
I
FB
SKIP
COMP
BO
C
BO
Application Schematics
Typical 300W Application Schematic
D1
1N5406
VOUT
D2
2
1
DC+
L1
0u
TP9
L2
1.5mH
C3D04060
P1
P2
R1
2M
AC1
SPP20N60C3
Q1
F2 8A
DB1
GBU808
TP12
GATE1
C4
DNP
100n
C2
C3
470n
C1
270u
450V
5mH
L3
1
UNIVERSAL INPUT
85~265Vac
390V
C22
R2
2.2
680n
R3
2M
C21 0.1
C19 0.1
R28 0.22
R27 0.22
R5 0.22
R4
51k
P3
AC2
P4
C6
2.2n
TP10
GND
C5
2.2n
C8
C26
DNP
DZ1
3.3V
220n
3.3M
R6
PE
D8
S1M
47n
C20
D7
S1M
P5
C9
1u
R14
8.2k
DNP
VREG
VCC
C11
330p
TP8
U1
R8
470k
C10
1nF
C7
1u
R10
VCC
P6
P7
3.3M
TP7
ICOMP
10
R9
3k
ISEN
GATE
3
2
R11
470k
TP6
ICOMP
1
GND
GATE
DNP
GND
TP5
ISEN
R26
49.9
VIN
4
TP3
VIN
7
FB
C12
DNP
TP1
FB
C13
R13
7.15k
R17
0
VCC
ISL6730B/D
220p
C16
1n
R21
25k
TP4
TP2
R19
42.2k
2N7002
Q2
COMP
BO
DNP
1
DNP
R18
62k
DNP P8
C15
150n
DNP
R20
10k
C14
470n C18
C17
1n
DNP
2.2u
P9
DNP
Application Schematics (Continued)
Typical 85W Application Schematic
S3KB-TP
D1
VOUT
S3KB-TP
S3KB-TP
3
1
D2
DC+
TP9
F1 3.15A
L1 0uH
L2 2.2m
D3
D4
AC1
P1
C3D04060E
P2
R1
2M
IPP60R600C6
Q1
1
390V
C4
DNP
100n
C2
C3
330n
C1
56u
450V
7.5mH
L3
UNIVERSAL INPUT
85~265Vac
R2
2.2
R3
2M
D5
D6
R4
51k
P3
0.22
R5
AC2
P4
C6
470p
TP10
S3KB-TP
S3KB-TP
C5
470p
GND
C8
C26
DNP
DNP
DZ1
3.3V
3.3M
R6
220n
PE
D8
D7
S1M
P5
S1M
R9
2.1k
C9
1u
R14
DNP
5.36k
VCC
C24
47n
C11
R8
470k
C10
6.8n
U1
470p
VCC
GND
P6
P7
10
1
ICOMP
TP6
GATE
GND
TP7
3
2
R11
470k
ICOMP
ISEN
GATE
TP5
ISEN
VIN
R10
VIN
3.3M
4
TP3
7
FB
C12
DNP
TP1
FB
C13
220p
R13
7.15k
R17
1.5k
VCC
ISL6730A/C
C16
1n
R21
25k
DNP
TP4
TP2
R19
COMP
40.2k
2N7002
Q2
VIN
1
DNP
R18
68k
DNP P8
C15
100n
DNP
R20
10k
C14
C17
470n C18
1n
DNP
2.2u
P9
DNP
ISL6730A, ISL6730B, ISL6730C, ISL6730D
Absolute Maximum Ratings
Thermal Information
VCC to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +28V
GATE to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -0.3V to +18V
VIN, BO, ISEN, FB and COMP to GND. . . . . . . . . . . . . . . . . . . . . . . .-0.3V to +6.3V
ESD Rating
Human Body Model (Tested per JESD22-A114) . . . . . . . . . . . . . . .2.5kV
Machine Model (Tested per JESD22-A115). . . . . . . . . . . . . . . . . . . . 200V
Charged Device Model (Tested per JESD-C101E. . . . . . . . . . . . . . . . . 1kV
Latch Up (Tested per JESD-78B; Class 2, Level A) . . . . . . . . . . . . . . 100mA
Thermal Resistance (Typical)
MSOP Package (Notes 4, 5) . . . . . . . . . . . .
θ
(°C/W)
136.9
θ
(°C/W)
39.4
JA
JC
Maximum Junction Temperature (Plastic Package) . . . . . . . . . . . .+150°C
Maximum Storage Temperature Range . . . . . . . . . . . . . .-65°C to +150°C
Ambient Temperature Range . . . . . . . . . . . . . . . . . . . . . . .-40°C to +125°C
Junction Temperature Range . . . . . . . . . . . . . . . . . . . . . . .-40°C to +125°C
Pb-Free Reflow Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . see link below
http://www.intersil.com/pbfree/Pb-FreeReflow.asp
Recommended Operating Conditions
VCC to GND. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15V to + 20V
Ambient Temperature Range . . . . . . . . . . . . . . . . . . . . . . .-40°C to +125°C
CAUTION: Do not operate at or near the maximum ratings listed for extended periods of time. Exposure to such conditions may adversely impact product
reliability and result in failures not covered by warranty.
NOTES:
4. θ is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.
JA
5. For θ , the "case temp" location is taken at the package top center.
JC
Electrical Specifications Operating Conditions: V = 15V, T = +25°C. Boldface limits apply over the operating temperature range,
CC
A
-40°C to +125°C.
MIN
MAX
PARAMETER
SUPPLY CURRENT
SYMBOL
TEST CONDITIONS
(Note 8)
TYP
(Note 8) UNITS
V
CC
Start Up Current
I
V
V
V
= 1V, V < V (ON)
CC CC
73
179
580
3.0
106
237
690
3.7
139
295
800
4.2
µA
µA
µA
mA
START
FB
FB
FB
Standby Current
I
= GND, V > V (ON)
CC CC
STDN
Skip Mode Current
Operating Current (Note 6)
VCC UVLO
I
= 2.5V, COMP = SKIP*0.25 +1V
CCSKIP
I
GATE is floating
CC
UVLO Rising Threshold
UVLO Falling Threshold
UVLO Threshold Hysteresis
REGULATOR VOLTAGE VREG
Overall Accuracy
V
9
6.7
-
10
7.5
2.5
11
8.3
-
V
V
V
CC(ON)
V
CC(OFF)
V
CC(HYS)
V
I
= 0 to -10mA, V = 15V, Load Capacitor = 47nF
5.1
30
5.4
50
5.6
70
V
REG
REG CC
Current Limit
mA
PWM CONVERTERS
Maximum Duty Cycle
f
f
= 124kHz for ISL6730A/C and
= 62kHz for ISL6730B/D
94.8
96.5
-
%
SW
SW
OSCILLATOR
Free Running Frequency, ISL6730A/C
Free Running Frequency, ISL6730A/C
Free Running Frequency, ISL6730B/D
Free Running Frequency, ISL6730B/D
PWM Ramp Amplitude
T
= -40°C to +125°C, V = 0.6V
IN
98
114
47
107
125
54
116
136
61
kHz
kHz
kHz
kHz
V
A
T
= -40°C to +125°C, V = 2.5V
IN
A
T
= -40°C to +125°C, V = 0.6V
IN
A
T
= -40°C to +125°C, V = 2.5V
IN
57
64
71
A
V
1.33
1.46
1.59
m
GATE DRIVER
Gate Drive Pull-Down Resistance
Gate Drive Pull-Up Voltage Drop
V
V
= 15V, I
= 15mA
= 15mA
-
2.33
0.3
4.46
0.45
Ω
CC
GATE
= 9V, I
GATE
0.15
V
CC
FN8258.1
August 8, 2013
6
ISL6730A, ISL6730B, ISL6730C, ISL6730D
Electrical Specifications Operating Conditions: V = 15V, T = +25°C. Boldface limits apply over the operating temperature range,
CC
A
-40°C to +125°C. (Continued)
MIN
MAX
PARAMETER
SYMBOL
TEST CONDITIONS
(Note 8)
TYP
1.5
(Note 8) UNITS
Gate Drive Max. Sourcing/Sinking
Current
-
-
A
ns
ns
V
Rise Time
C
= 2.2nF, V = 15V, Gate Voltage Rise Time from 10%
CC
-
-
34
34
12
62
O
to 90% of V
GC
Fall Time
C
= 2.2nF, V = 15V, Gate Voltage Fall Time from 10%
CC
57
O
to 90% of V
GC
Gate Clamp Voltage
V
10.5
13.5
GC
VOLTAGE REFERENCE
Reference Voltage
V
2.48
2.5
65
2.52
V
REF
Feedback Pin Pull-Down Current
Rising Threshold to Enable Converter
Falling Threshold to Disable Converter
Enable Hysteresis
I
-
-
nA
FB
FB_EN
FB_DIS
FB_Hys
280
190
-
300
202
100
320
214
-
mV
mV
mV
VOLTAGE ERROR AMPLIFIER
Error Amp Transconductance
ISource/Sink
Gmv
50
-
77
13
104
-
µA/V
µA
V
COMP Offset Voltage
V
0.95
0.58
1.01
0.64
1.07
0.75
COMP_OFF
COMP Soft-Start Enable Voltage
INPUT VOLTAGE SENSING
VIN Leakage Current
V
V
COMP_EN
-
9
-
nA
MULTIPLIER GAIN
GMUL
COMP = 2.5V, V = 1.0V, BO = 1.0V, I
IN
= 50µA
0.196
0.25
0.296
V/V
SEN
CURRENT ERROR AMPLIFIER
Current DC Gain
A
ΔI
/ΔI
ISEN
1.6
205
-
1.9
268
60
2
2.2
331
-
A/A
µA/V
µA
iDC
ICOMP
I = ±20µA
ICOMP
Error Amp Transconductance
ICOMP Source/Sink Current (Note 7)
Current Sensing Input Offset
Gmi
-3
7
mV
LIGHT LOAD EFFICIENCY ENHANCEMENT AND OVERPOWER PROTECTION
Skip Mode COMP Threshold
COMP Upper Limit
V
Applied for ISL6730A/B
1.32
3.53
2.5
1.36
3.85
2.83
88
1.4
4.17
3.16
89
V
V
SCMT
V
CUL
COMP Valid Range
V
-1V
V
CUL
FB Exit Threshold Voltage
V
Fraction of the set point (V
), I
REF ISEN
= 0µA, Applied for
87
%
FB_EXIT
ISL6730A/B
ISEN Exit Threshold Current
BROWNOUT DETECTION
Brownout Rising Threshold
Brownout Falling Threshold
OVERVOLTAGE PROTECTION
Overvoltage Protection
I
V
= 2.5V, Applied for ISL6730A/B
FB
-38
-29
-20
µA
SEN_EXIT
V
478
387
494
401
510
415
mV
mV
BO_R
V
BO_F
V
Fraction of the set point (V
); ~1µs noise filter
REF
102.9
104.1
105.3
%
OVP
FN8258.1
August 8, 2013
7
ISL6730A, ISL6730B, ISL6730C, ISL6730D
Electrical Specifications Operating Conditions: V = 15V, T = +25°C. Boldface limits apply over the operating temperature range,
CC
A
-40°C to +125°C. (Continued)
MIN
MAX
PARAMETER
OVERCURRENT PROTECTION
Overcurrent Threshold
SYMBOL
TEST CONDITIONS
(Note 8)
TYP
(Note 8) UNITS
I
-197
-177
-159
µA
OC
THERMAL SHUTDOWN
Shutdown Temperature (Note 7)
Thermal Shutdown Hysteresis (Note 7)
NOTES:
-
-
160
25
-
-
°C
°C
6. This is the V current consumed when the device is active but not switching. Does not include gate drive current.
CC
7. Limits should be considered typical and are not production tested.
8. Parameters with MIN and/or MAX limits are 100% tested at +25°C, unless otherwise specified.
Typical Performance Curves
101.0
100.50
100.25
100.00
100.5
100.0
99.5
V
= 2.5V
IN
99.75
99.50
V
= 0.6V
80
IN
99.0
-40
-20
0
20
40
60
80
100
120 140
-40
-20
0
20
40
60
100
120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
FIGURE 3. FEEDBACK ACCURACY
FIGURE 4. F
vs TEMPERATURE, V = 15V
CC
SW
105
100
95
101
100
99
90
85
98
80
97
75
0
0.5
1.0
1.5
(V)
2.0
2.5
3.0
-40
-20
0
20
40
60
80
100
120 140
V
TEMPERATURE (°C)
IN
FIGURE 5. A
vs TEMPERATURE
FIGURE 6. F
vs V T = +25°C
IN, A
IDC
SW
FN8258.1
August 8, 2013
8
ISL6730A, ISL6730B, ISL6730C, ISL6730D
Typical Performance Curves (Continued)
102
101
100
102
101
100
99
I
START
HYSTERSIS
I
CC
(GATE FLOATING)
UP
THRESHOLD
99
98
DOWN
THRESHOLD
98
-40
-20
0
20
40
60
80
100
120 140
-40
-20
0
20
40
60
80
100
120 140
TEMPERATURE (°C)
TEMPERATURE (°C)
FIGURE 8. V SUPPLY CURRENT vs TEMPERATURE
CC
FIGURE 7. UVLO THRESHOLDS vs TEMPERATURE
112
110
108
106
104
102
100
98
FALL TIME
RISE TIME
96
-40
-20
0
20
40
60
80
100
120 140
TEMPERATURE (°C)
FIGURE 9. GATE DRIVER ABILITY vs TEMPERATURE (LOAD = 2.2nF)
FN8258.1
August 8, 2013
9
ISL6730A, ISL6730B, ISL6730C, ISL6730D
EMI CHOKE
Functional Description
VCC Undervoltage Lockout (UVLO)
The ISL6730A, ISL6730B, ISL6730C, ISL6730D start
automatically once the voltage at VCC exceeds the UVLO
threshold.
V
C
LINE
C
F3
F2
L
m
D
F1
Shutdown
D
F2
When the VFB pin is below 0.2V, the controller is disabled and
the PWM output driver is tri-stated. When disabled, the IC power
will be reduced. During shutdown, the COMP pin is discharged to
GND and the controller is disabled. The Over-Temperature
Protection (OTP) is still alive to prevent the controller from
starting up in a high temperature ambient condition.
R
IN2
VIN
BO
R
C
IN1
BO
In the event that the FB pin is disconnected from the feedback
resistors, the FB pin is pulled to ground by an internal current
FIGURE 10. INPUT VOLTAGE SENSING SCHEMATIC
source I . When the FB pin voltage drops below 0.2V, the gate
driver is disabled. The ISL6730A, ISL6730B, ISL6730C,
ISL6730D enters shutdown mode.
FB
The BO pin also utilizes the VIN resistor divider for voltage
sensing. Set the resistor divider ratio to satisfy the brownout
requirement.
Soft-Start
First, calculate the resistor divider ratio, KBO.
V
The COMP pin is released once the soft-start operation begins. A
13µA current sources out to the RC network connected from the
COMP pin until the FB pin voltage reaches 90% of the reference
voltage.
BORMAX
-------------------------------------------
K
=
(EQ. 1)
BO
V
– 2V
F
RMSmin
Where V is the forward voltage drop of the bridge rectifier and
F
the voltage drop of D
D .
F1; F2
Switching is inhibited when the COMP pin voltage is below 1V.
When the COMP pin reaches 1V, the current error amplifier and
the gate driver are activated and the converter starts switching.
Then, select the R
based on the highest reasonable resistance
IN2
value. Then select the R
based upon the desirable minimum
IN1
RMS value of the line voltage for the PFC operation.
During UVLO, Brownout and Shutdown, the COMP is pulled to the
ground.
K
BO
(EQ. 2)
--------------------
R
=
⋅ R
IN1
IN2
1 – K
BO
Input Voltage Sensing
Inductor Current Sensing
The current sensing of the converter has two purposes. One is to
force the inductor current to track the input semi-sinusoidal
waveform. The other purpose is for overcurrent protection. Refer to
Figure 11 for the current sensing scheme. The sensed current I
is in proportion to the inductor current, I as described in
The VIN pin is needed to sense the rectified input voltage. The
sensed semi-sinusoidal waveform is needed to shape inductor
current, which helps achieves unity power factor. At the same
time, the voltage on the VIN pin is used to generate the negative
capacitive element at the input. This will cancel the input filter
CS
L
capacitor, C . Canceling the effect of C will increase the
F
F
Equation 3.
displacement power factor and alleviate the zero crossing
distortion, which is related to the distortion power factor.
R
1
2
CS
(EQ. 3)
-- ---------------
I
=
⋅
⋅ I
CS
L
R
SEN
where:
is the current sensing resistor with low value in the return
R
CS
path to the bridge rectifier.
R
is the current scaling resistor connected between ISEN to
SEN
the R
.
CS
FN8258.1
August 8, 2013
10
ISL6730A, ISL6730B, ISL6730C, ISL6730D
BRIDGE RECTIFIER
V
L
F
I
EMI CHOKE
VOUT
COUT
L
Q1
V
LINE
C
C
C
F1
F3
F2
CF1
L
m
RCS
FIGURE 12. TYPICAL PFC INPUT FILTER CIRCUIT
CURRENT
MIRROR
BRIDGE RECTIFIER
EMI CHOKE
L
F
2:1
I
RSEN
ISEN
CS
V
LINE
C
F3
C
C
F1
F2
L
m
I
> 0.5 I
CS
OC
FIGURE 13. LOW COST PFC INPUT FILTER CIRCUIT
FIGURE 11. INDUCTOR CURRENT SENSING SCHEME
For applications where the output power is above 500W, the
negative capacitance helps to improve the power factor
dramatically. Please refer to Table 2 for the recommended
A high value R renders more accurate current sensing. It is
CS
recommended to use the R to render 120mV peak voltage at
CS
the maximum line voltage during full load condition.
filtering capacitor to be placed after the bridge rectifier, C
.
F1
120mV ⋅ V
⋅ η
RMSMAX
TABLE 2.
(EQ. 4)
-------------------------------------------------------------
>
R
CS
2 ⋅ P
Omax
C
Po < 100W
0.68
100W < Po < 500W Po > 500W
0.33 0.22
F1
Where η is the efficiency of the converter at the maximum line
Typical
input with full load.
C(µF)/100W
Since the R sees the average input current, high value R
CS CS
Additional C may be used to accommodate the use of small
F1
boost inductor or to eliminate the differential mode filter inductor
as long as the equipment meets the power factor or goal.
generates high power dissipation on the R . Use a reasonable
CS
R
according to the resistor power rating. The worst-case power
CS
dissipation occurs at the input low line when input current is at
its maximum. Power dissipation by the resistor is:
The equivalent negative capacitor is a function of the input
2
(EQ. 5)
P
= (I
)
⋅ R
CS
voltage divider ratio, K , the current sensing gain and current
BO
RCS
RMSMAX
compensation error integration gain.
where:
Adjusting the negative Ceq can be achieved by adjusting the
current compensation network.
I
is the maximum input RMS current at the minimum
RMSMAX
input line voltage, V
.
RMSmin
Frequency Modulation
Select the R
SEN
according to the peak current limit requirement.
The ISL6730A, ISL6730B, ISL6730C, ISL6730D can further
reduce EMI filter size by lowering the differential noise power
density. The reduction is achieved by switching frequency
modulation.
The resistor is sized for an overload current 25% more than the
peak inductor peak current.
Negative Input Capacitor Generation (Patent
Pending)
The patent pending negative capacitor generation capability of
the ISL6730A, ISL6730B, ISL6730C, ISL6730D allows the
The frequency varies with the VIN pin. The switching frequency
reaches the peak value when the VIN pin voltage is 2V as shown
in Figure 6. The peak value of ISL6730A/C is 124kHz, and the
ISL6730B/D is 62kHz.
capacitor C to be moved from before the bridge rectifier
F2
(Figure 12) to after the bridge rectifier (Figure 13). Thus, a
Output Voltage Regulation
smaller lower cost C can be used. The change in topology
F2
reduces the size of the EMI filter. Furthermore, C can be
F1
The output voltage is sensed through a resistor divider. The
middle point of the resistor divider is fed to the FB pin. The
resistor divider ratio sets the output voltage. The
increased thus decreasing the size of L (Figure 13).
F
transconductance error amplifier generates a current in
proportion to the difference between the FB pin and the 2.5V
internal reference. The PFC is stabilized by the compensation
network that is connected from the COMP pin to the ground.
The voltage of the COMP sets the input average power by
determining the amplitude of the current reference. To keep the
FN8258.1
August 8, 2013
11
ISL6730A, ISL6730B, ISL6730C, ISL6730D
harmonic distortion minimum, it is desirable to set the control
bandwidth much lower than twice of the line frequency. The
recommended voltage loop bandwidth is 10Hz.
Overvoltage Protection
If the voltage on the FB pin exceeds the reference voltage by about
4%, the gate driver is turned off. The controller resumes normal
operation after the FB pin drops below reference voltage.
During start-up, the compensation capacitors and the charging
current from the error amplifier sets the input power increase
rate. Thus, soft-start is achieved.
Over-Temperature Protection
The ISL6730A, ISL6730B, ISL6730C, ISL6730D is protected
against over-temperature conditions. When the junction
temperature exceeds +160°C, the PWM shuts down. Normal
operation is resumed when the junction temperature decreases
below +135°C.
The COMP is discharged during shutdown and fault conditions.
Light Load Efficiency Enhancement
For PC, adaptor and TV applications, it is desirable to achieve
high efficiency at light load conditions and low standby current.
The ISL6730A, ISL6730B can enter light load efficiency mode
automatically.
Application Guidelines
Layout Considerations
The voltage error amplifier output, COMP, is an indicator of the
average input power level. The controller compares the V(COMP)
and V(SKIP). If V(COMP)-1V is less than V(SKIP)*0.25, the PFC
controller stops gate switching and the COMP pin voltage is
clamped to V(SKIP)+0.6V. ISL6730A/B use a fixed V(SKIP), which
is 1.4V; for ISL6730C/D, the SKIP function are disabled.
As in any high frequency switching converter, layout is very
important. Switching current from one power device to another
can generate voltage transients across the impedances of the
interconnecting bond wires and circuit traces. These
interconnecting impedances should be minimized by using wide,
short printed circuit traces. The critical components should be
located as close together as possible using ground plane
construction or single point grounding.
The controller exits skip mode when V drops to 88% (typical) of
FB
the reference voltage or when the sensed returned current
exceeds 29µA.
Figure 14 shows the critical power components; Q , D and COUT
.
1
Protection Circuits
Input Brownout, BO Protection
Brownout occurs when there is a drop in the line voltage. The BO
pin is a dual function pin. The BO pin detects the brownout
condition and shuts down the gate driver and controller. During
normal operation, the BO pin is used to compensate the effect of
the input line voltage change on the voltage loop. To keep the
harmonic distortion low, the corner frequency formed by the RBO
and CBO should be lower than 6Hz.
To minimize the voltage overshoot, the interconnecting wires
indicated by heavy lines should be part of the ground or the
power plane in a printed circuit board. The components shown in
Figure 14 should be located as close together as possible. Please
note that the capacitors C
and C each represent numerous
VCC
O
physical capacitors. Locate the ISL6730A, ISL6730B, ISL6730C,
ISL6730D within 2 inches of the MOSFET, Q . The circuit traces
1
for the MOSFETs’ gate and source connections from the
ISL6730A, ISL6730B, ISL6730C, ISL6730D must be sized to
handle up to 1.5A peak current.
D
The BO pin is the output of the average voltage of the rectified
voltage. The PFC controller is turned off when the BO pin drops
below 0.4V. This protects the PFC power stage to enable
operation at or below brownout condition for long periods of
time. The controller resumes operation when the BO pin returns
to 0.5V.
L
C
OUT
Q
1
The BO pin is usually connected to GND through a capacitor, CBO
.
To avoid distortion on the VIN pin, select C so that:
BO
GATE
C
» 0.22μF
(EQ. 6)
BO
VCC
C
Overcurrent Protection
VCC
The peak current limiting function prevents the inductor from
saturation. The gate driver turns off when the current goes above
the current limit.
FIGURE 14. CRITICAL CURRENT POWER COMPONENTS
Overpower Protection
The overpower protection is implemented by limiting the COMP
pin voltage higher than 3.85V (typical).
Component Selection Guidelines
A 300W, universal input, PFC converter design is provided for
demonstration. The design method is for a continuous current
mode power factor correction boost converter with the
ISL6730B/D. The switching frequency is 62kHz.
FN8258.1
August 8, 2013
12
ISL6730A, ISL6730B, ISL6730C, ISL6730D
Table 3 shows the design parameters.
Select the bridge diode using Equation 15 and sufficient reverse
breakdown voltage. Assuming the forward voltage, V , is 1V
across each rectifier diode. The power loss of the rectifier bridge
can be calculated:
F,BR
TABLE 3. CONVERTER DESIGN PARAMETERS
PARAMETER
VLINE
CONDITIONS
MIN
85
TYP MAX UNIT
115 265 VAC
P
= 2 • V
• I
F, BR INAVE(MAX)
(EQ. 15)
BR
FLINE
47
63
Hz
W
(EQ. 16)
P
= 2 • 1V • 3.5A = 7W
BR
P
T
Maximum Output Power
Hold Up Time
300
OMAX
INPUT CAPACITOR SELECTION
20
ms
%
HOLD
Refer to Table 2 for the recommended input filter capacitor value.
Efficiency
VLINE = 115VAC
92
0.33
100
(EQ. 17)
-----------
= 0.99μF
C
= 300W •
F1
BOOST INDUCTOR SELECTION
This is the recommended capacitor used after the diode bridge.
For better power factor, less capacitance can be used. To lower
the input filter inductor size, more capacitance can be used.
First, calculate the maximum input RMS current, I
INMAX.
P
OMAX
(EQ. 7
-----------------------------------
I
=
INMAX
η • V
RMSmin
Two 0.47µF capacitors in parallel are used for C
.
F1
Where η is the converter efficiency at V
. PF is the power
(EQ. 8)
RMSmin
BOOST DIODE SELECTION
factor at V
RMSmin.
The boost diode loss is determined by the diode forward voltage
300W
0.92 • 85V
---------------------------
= 3.84A
I
=
INMAX
drop, V and the output average current. The maximum output
F
current is:
Assuming the current is sinusoidal and the peak to peak ripple at
line is 40%.
P
OMAX
--------------------
I
=
=
(EQ. 18)
(EQ. 19)
OUT(max)
V
OUT
The boost inductor, L , is given by the following equation:
BST
300W
---------------
I
= 0.77A
2 • V
OUT(max)
2V
⎛
⎞
⎟
⎠
390V
RMSmin
RMSmin
(EQ. 9)
---------------------------------------------------------------
---------------------------------------
L
≥
• 1 –
⎜
BST
V
0.4 • F
• 2 • I
⎝
OUT
sw
INMAX
The forward power loss on the diode is:
(EQ. 20)
(EQ. 21)
P
= I
• V
OUT(max) F
FD
85V
-----------------------------------------------------
2 • 85V
390V
⎛
⎞
⎠
-----------------------
L
≥
• 1 –
= 617μH
(EQ. 10)
BST
⎝
0.4 • 62kHz • 3.84A
P
= 0.77A • 1.85V = 1.42W
FD
The peak current of the inductor is the sum of the average peak
inductor current and half of the peak to peak ripple current.
Select and design the boost inductor as given by Equation 11.
The ISL6730A, ISL6730B, ISL6730C, ISL6730D provides peak
current limit function that can prevent the boost inductor
saturation. Assuming 25% margin is given to the OCP threshold,
select and design the boost inductor with saturation current
given by Equation 11 with 25% more.
The IDD03E60 part is selected.
The reverse recovery loss on the diode can be calculated. The
Q
is found from the diode datasheet. Q = 220nC when
RR
RR
I = 3.5A.
F
The reverse recover loss on the diode can be estimated:
1
4
(EQ. 22)
(EQ. 23)
--
P
=
• Q
• V
• F
OUT
RRD
RRD
RR
sw
0.4
⎛
⎞
⎠
(EQ. 11)
-------
I
=
2 • I
• 1 +
INMAX
1
LPeak
⎝
2
--
P
=
• 220nC • 390V • 62kHz = 1.33W
4
0.4
2
The total power loss on the diode is:
⎛
⎞
(EQ. 12)
-------
I
=
2 • 3.88A • 1 +
= 6.5A
LPeak
⎝
⎠
(EQ. 24)
P
= P
+ P
= (1.42 + 1.35)W = 2.75W
RRD
D
FD
INPUT RECTIFIER
The maximum average input current is calculated:
MOSFET POWER DISSIPATION
2 • 2 • I
The power dissipation on the MOSFET is from two different types
of losses; the condition loss and the switching loss.
INMAX
(EQ. 13)
(EQ. 14)
-----------------------------------------
I
I
=
=
INAVE(max)
INAVE(max)
π
For the MOSFET, the worst case is at minimum line input voltage.
2 • 2 • 3.88A
-------------------------------------
= 3.5A
First, the drain to source RMS current is calculated:
π
V
8
3π
2
RMSmin
---------- -------------------------
I
= I
1 –
INMAX
•
(EQ. 25)
(EQ. 26)
DS(max)
V
OUT
8
2
85V
---------- -------------
I
= 3.88A 1 –
•
= 3.3A
DS(max)
3π 390V
FN8258.1
August 8, 2013
13
ISL6730A, ISL6730B, ISL6730C, ISL6730D
The MOSFET, SPP20N60C3 is selected.
2
(4πf
⋅ C
⋅ ESR) + 1
OUT
2
(EQ. 27)
(EQ. 28)
line
(EQ. 38)
(EQ. 39)
P
= I
• R
DS(on)
------------------------------------------------------------------------------
⋅
OUT(max)
V
V
= I
COND
DS(max)
Opp
Opp
(4πf
) ⋅ C
⋅ 0.8
OUT
line
2
P
= 3.3A • 0.3Ω = 3.27W
COND
2
(4π ⋅ 50Hz ⋅ 270μF ⋅ 0.77Ω) + 1
-------------------------------------------------------------------------------------------
= 0.77A ⋅
= 6.6V
The switching loss of the MOSFET consists of three parts: the
turn-on loss, the turn-off loss and the diode reverse recovery loss.
(4π ⋅ 50Hz) ⋅ 270μF ⋅ 0.8
The minimum OVP threshold is 103% of the nominal output
value. The maximum output peak to peak ripple should be less
From the MOSFET datasheet, the typical switching losses curves
are provided.
than 6% of the nominal value, which is 23.4V
.
P-P
When R = 3.6Ω, I = 6A, E = 0.015mJ, E
ON
= 0.007mJ.
G
D
OFF
CURRENT SENSING RESISTORS
The switching loss due to transition is calculated:
Please refer to Equation 4 for calculation of the current sensing
resistor R
(EQ. 29)
(EQ. 30)
P
P
= (E
+ E
) • F
OFF
sw
SW
SW
ON
.
CS
= (0.015mJ + 0.007mJ) • 62kHz = 1.36W
120mV ⋅ 265V ⋅ 0.92
(EQ. 40)
------------------------------------------------------
= 0.069Ω
R
≥
CS
2 ⋅ 300W
The diode reverse recovery incurs additional power loss on the
MOSFET. This loss can be estimated as:
While a large R renders better current sensing accuracy, larger
CS
(EQ. 31)
P
= Q
• V
• F
OUT
sw
R
also incurs higher power dissipation. Select R from
CS
CS
RR
RR
available standard value resistors to determine the sense
resistor.
This loss is also related the di/dt during the MOSFET turn-on. The
di/dt can be found out from the MOSFET datasheet. At
(EQ. 41)
R
= 0.068Ω
CS
R
= 3.6Ω, the turn-on di/dt is 4000A/µs. From the Typical
G
Reverse Recovery Charge curve at T = +125°C, the
The maximum power dissipation on the R occurs at low line
CS
and full load condition. The maximum power dissipation is
J
Q
= 220nC when I = 3.5A.
RR
F
calculated:
(EQ. 32)
(EQ. 33)
P
= 220nC • 390V • 62kHz = 5.32W
RR
2
(EQ. 42)
(EQ. 43)
P
P
= I
• R
CS
RCSMAX
INMAX
2
THE TOTAL LOSS ON THE MOSFET
= 3.88A • 0.068Ω = 1.023W
P
+ P
+ P
SW
= 3.27W + 1.36W + 5.32W = 9.95W
RCSMAX
COND
RR
The resistor, R
Equation 3, R
sets the overcurrent protection limit. From
should be greater than:
SEN
SEN
OUTPUT CAPACITOR SELECTION
The output capacitor, C , is required to hold the output above
OUT
R
• I
• (1 + 0.25)
CS LPeak
(EQ. 44)
300V during one line cycle. For capacitors with 20% tolerance,
the tolerance should be taken into consideration. Thus, the
output capacitance should be greater than:
-------------------------------------------------------------------
≥
R
SEN
2 • 0.5 I
OC
Where |x| stands for the ABS(x) function.
2 ⋅ T
⋅ P
OMAX
HOLD
1
(EQ. 34)
---------------------------------------------------- -----------------
C
≥
⋅
OUT
2
2
1 – 0.2
0.068Ω • 6.6A • 1.25
V
– V
HOLD
(EQ. 45)
OUT
-------------------------------------------------------
≥ = 3.117kΩ
R
SEN
2 • 90μA
2 ⋅ 20ms ⋅ 300W
---------------------------------------------
(EQ. 35)
C
≥
⋅ 1.25 = 242μF
Select R
from available standard value resistors, the selected
OUT
SEN
is 3.16kΩ.
2
2
(390) – (300V)
R
SEN
Calculate the ripple RMS current through the capacitor:
CURRENT LOOP COMPENSATION
V
The input current shaping is achieved by comparing the sensed
current signal to the sensed input voltage signal. The current
error amplifier (Gmi), together with the current compensation
network, adjusts the duty cycle so that the inductor current
traces the sensed rectified voltage. Thus, unity power factor is
achieved.
8 2
3π
OUT
(EQ. 36)
(EQ. 37)
---------- -------------------------
I
= I
•
– 1
CORMS(max)
CORMS(max)
OUT(max)
V
RMSmin
8
2
390V
---------- -------------
– 1 = 1.635A
I
= 0.77A
•
3π
85V
Select the proper capacitor according to the hold time and ripple
RMS current requirement. The actual capacitance is 270µF.
The compensation network consists of the Trans-Conductance
error amplifier (Gmi) and the impedance network (Z
The
ICOMP).
goal of the compensation network is to provide a closed loop
transfer function with the sufficient 0dB crossing frequency
It is important to make sure the output peak-to-peak ripple is
less than the minimum OVP threshold as specified in the
“Electrical Specifications” table on page 6. The ESR at 2 times of
the line frequency of the capacitor is found in the capacitor
datasheet. The ESR of the output capacitor is 770mΩ at 100Hz.
(f
) and adequate phase margin. Phase margin is the
and 180°. The
0dB
difference between the open loop phase at f
0dB
following equations relate the compensation network’s poles,
zeros and gain to the components (R , C and C ) in Figure 15.
ic ic ip
FN8258.1
August 8, 2013
14
ISL6730A, ISL6730B, ISL6730C, ISL6730D
The cross over frequency of the current loop should be set
V
V
I
OUT
between 2kHz to 100kHz. At cross over frequency, the transfer
function from duty cycle to inductor current is well approximated
by Equation 48:
L
Q
C
1
OUT
C
F1
V
OUT
(EQ. 48)
---------------------
G
(s)=
id
L
⋅ s
BST
R
CS
It is recommended to set the cross over frequency from 1/10 to
1/6 of the switching frequency with phase margin of 60°. A high
frequency pole is set at 1/2 of the switching frequency for ripple
CURRENT
MIRROR
2:1
I
R
CS
SEN
filtering. In this example, we set the cross over, F at 1/6 of the
C
switching frequency.
F
C
ISEN
--------------------------------------------------------
F =
Z
(EQ. 49)
F
⎛
⎛
⎜
⎝
⎞
⎟
⎠
⎞
M
C
-------
tan atan
+ Φ
⎜
⎟
F
P
⎝
⎠
ICOMP
Where F = F /6 = 10.3kHz, Φ is the phase margin, which is
C
S
M
I
REF
R
IS
60°. F = F /2 = 31kHz.
P
S
Gmi
R
C
ic
ic
Thus, the current loop compensation zero is:
C
ip
(62KHz) ⁄ 6
------------------------------------------------------------
F =
= 2.12kHz
(EQ. 50)
(EQ. 51)
Z
2
⎝ ⎠
6
⎛
⎛ ⎞
⎞
--
tan atan
+ 60deg
⎝
⎠
FIGURE 15. INDUCTOR CURRENT SENSING SCHEME
The total compensation capacitance is calculated:
2
FROM DUTY TO
⎛
⎜
⎜
⎝
⎞
⎟
⎟
⎠
V
A
R
CS
1 + (f ⁄ f )
⎛
⎜
⎝
⎞
⎟
⎠
OUT
iDC
INDUCTOR CURRENT
c
z
-------------------------------------- ------------- ---------------
L
80
C
+ C
=
ic
⋅
⋅
⋅
------------------------------
ip
2
2
V
R
SEN
1 + (f ⁄ f )
m
⋅ (2πf )
c
p
BST
c
40
20
COMPENSATION
GAIN
(EQ. 52)
(EQ. 53)
C
+ C = (19.8)nF
ip
ic
0
F
P
F
Z
f
-20
-40
-60
-80
-100
z
----
C
= (C + C
)
iC
ip
ip
f
p
OPEN LOOP
GAIN
The value of the noise filtering capacitor is:
2.12kHz
31kHz
(EQ. 54)
(EQ. 55)
(EQ. 56)
CURRENT GAIN
MODULATOR GAIN
----------------------
= 1.35nF
C
= 14.9nF ⋅
ip
The value of C is:
ic
100
1k
10k
100k
C
= 19.8nF – 1.35nF = 18.4nF
FREQUENCY (Hz)
ic
FIGURE 16. ASYMPTOTIC BODE PLOT OF CURRENT LOOP GAIN
The value of R is:
ic
1
1
-----------------------------------
F =
----------------------------------------------------------
R
=
= 4.11kΩ
(EQ. 46)
(EQ. 47)
Z
ic
2π • R • C
2π ⋅ 2.12kHz ⋅ 18.4nF
ic
ic
Select the R value from the standard value, we have:
C
1
---------------------------------------------------
=
F
P
C
• C
ic
+ C
ic
R
= 4.02kΩ, C = 18nF, C = 1.2nF. Figure 17 shows the actual
ic ip
ip
ic
bode plot of current loop gain.
-----------------------
•
2π • R
ic
C
ip
Use the following guidelines for locating the poles and zeros of
the compensation network.
FN8258.1
August 8, 2013
15
ISL6730A, ISL6730B, ISL6730C, ISL6730D
For example, C = 0.68µF, C = 0.94µF, using the low cost EMI
F2 F1
80
60
40
20
0
10.5kHz
filter shown in Figure 13. When V
= 230VAC, f = 50Hz,
LINE
LINE
P
= 60W.
O
Assuming 95% efficiency under the above test condition, the
resistive component, which is in phase to voltage:
P
o
(EQ. 62)
--------------------------------
I =
= 0.275A
a
V
⋅ 0.95
LINE
-20
The reactive current through the input capacitors:
180
10.5kHz
(EQ. 63)
(EQ. 64)
I = V
• (2π ⋅ f
) • (C + C ) = 0.117A
LINE F1 F2
c
LINE
135
90
45
0
Thus, the displacement power factor is:
I
60
45
a
-----------------------------------
PF
=
= 0.92
DIS
2
2
(I ) + (I )
a
c
3
3
3
10
100
1x10
FREQUENCY (Hz)
1x10
1x10
The reactive current generated by the equivalent negative
capacitor is:
FIGURE 17. BODE PLOT OF THE ACTUAL CURRENT LOOP GAIN
(EQ. 65)
I
= V
• (2π ⋅ f
) • (C
) = 0.045A
NEG
cneg
LINE
LINE
INPUT VOLTAGE SETTING
First, set the BO resistor divider gain, K according to
BO
Equations 1 and 2.
With the equivalent negative capacitor, the total reactive current
reduces to:
(EQ. 66)
Assuming the converter starts at V
= 80V
, then the BO
RMS
LINE
I
– I
= 0.072A
cneg
c
resistor divider gain, K should be:
BO
0.5V
80V – 2V
(EQ. 57)
------------------------
K
=
= 0.00641
The displacement power factor increases to:
BO
I
a
(EQ. 67)
-------------------------------------------------------
PF
=
= 0.967
DIS
In this design, two 3.3MΩ resistors in series are used for R
.
2
2
IN2
(I ) + (I – I )
cneg
a
c
So, R
is calculated:
IN1
0.00641
1 – 0.00641
(EQ. 58)
VOLTAGE LOOP COMPENSATION
------------------------------
⋅ (6.6MΩ) = 42.6kΩ
R
=
IN1
The average diode forward current can be approximated by:
P
in
(EQ. 68)
Using resistor from the standard value, R
IN1
= 43kΩ, the actual
---------------
I
=
D(ave)
V
OUT
K
is calculated:
BO
R
IN1
+ R
IN2
(EQ. 59)
Assuming the input current traces the input voltage perfectly. The
--------------------------------
K
=
= 0.00647
BO
R
input power is in proportion to (V
- 1V).
IN1
COMP
⎛
⎜
⎞
⎟
⎟
⎠
R
1
0.25
SEN
NEGATIVE INPUT CAPACITOR GENERATION
-------------------------------------- --------------- -----------------------------------------------
I
=
•
•
• Δ
D(ave)
COMP
⎜
⎝
2
R
⋅ 0.5 ⋅ R
V
OUT
CS
IS
((2 2) ⁄ π) ⋅ K
The ISL6730A, ISL6730B, ISL6730C, ISL6730D generates an
equivalent negative capacitance at the input to cancel the input
filter capacitance. Thus, more input capacitors can be used
without reducing the power factor.
BO
(EQ. 69)
Where Δ
COMP
is the V - 1V. 1V is the offset voltage.
COMP
R
is the internal current scaling resistor. R = 14.2kΩ.
IS
IS
The input equivalent negative capacitance is a function of the
current sensing gain, BO resistor divider gain and the
compensation components.
A
(EQ. 70)
---
I
= 0.598 • Δ
D(ave)
COMP
V
V
R
SEN
⎛
⎜
⎝
⎞
m
(EQ. 60)
--------------- -------------------------
C
=
K
⋅ 0.8 –
(C + C )
ip
⎟
NEG
BO
ic
V
R
A
⎠
OUT
CS iDC
1.5
3.16k
⎛
⎝
⎞
--------- ---------------------------
C
=
0.00647 ⋅ 0.8 –
(18nF + 1.2nF) = 0.62μF
NEG
⎠
390 0.068 ⋅ 1.9
(EQ. 61)
This equivalent negative capacitor cancels the input filter
capacitor required for EMI filtering. Therefore, the displacement
power factor significantly improves.
FN8258.1
August 8, 2013
16
ISL6730A, ISL6730B, ISL6730C, ISL6730D
The zero, F is calculated:
Zv
VOUT
F
CV
2.5V
(EQ. 76)
(EQ. 77)
-----------------------------------------------------------------------------
F
=
Zv
tan(Φ + atan(F
⁄ (F )))
Pv
m
CV
R
FB2
FB
8Hz
------------------------------------------------------------------------------------------------
= 1.15Hz
F
=
Zv
tan(60deg + atan((8Hz) ⁄ (20Hz)))
Gmv
R
Then the total capacitance used for compensation is calculated:
FB1
I
FB
2
G
(i • (2πF )) • G
• Gmv
DIV
(F
⁄ F
)
ZV
+ 1
PS
CV
CV
------------------------------------------------------------------------------------------
• --------------------------------------------
C
+ C
=
vp
vc
2
(2πF
)
CV
(F
⁄ F
) + 1
CV
PV
COMP
(EQ. 78)
(EQ. 79)
Rvc
Cvc
Thus, the total compensation capacitance is:
Cvp
C
+ C
= 1829nF
vp
vc
F
ZV
(EQ. 80)
(EQ. 81)
----------
C
= 1829nF •
= 105nF
FIGURE 18. OUTPUT VOLTAGE SENSING AND COMPENSATION
vp
F
PV
Thus, the transfer function from V
COMP
to V is:
OUT
C
R
= 1829nF – 105nF = 1724nF
vc
V
(s)
I
1
OUT
D(ave)
(EQ. 71)
(EQ. 72)
-----------------------
--------------- --------------------
G
(s)=
=
⋅
PS
Δ
C
⋅ s
Δ
COMP
1
COMP
O
(EQ. 82)
------------------------------------------
=
= 81.2kΩ
vc
2 ⋅ π ⋅ F ⋅ C
ZV
VC
I
⎛
⎜
⎝
⎞
1
0.598
D(ave)
------------------ --------------------
---------------
=
G
(s)=
⋅
⎟
PS
Choose components from the standard values. We have
C
⋅ s
Δ
C ⋅ s
⎠
O
COMP
O
C
= 100nF, C = 1500nF, R = 82.5kΩ. The actual bode plot
VP
VC VC
is shown in Figure 20.
As shown in Figure 18, the voltage loop gain is:
60
40
20
0
(EQ. 73)
(EQ. 74)
G
(s)= G (s) • G
• gmv • Z
(s)
COMP
VLOOP
PS
DIV
The output feedback resistor divider gain, G
is:
DIV
V
REF
---------------
G
=
DIV
V
0
OUT
-20
-40
The compensation gain uses external impedance networks as
shown in Figure 18, Z
(s) is given by:
COMP
R
• C • s + 1
vc
1
vc
90
-------------------------------------- ------------------------------------------------------------
Z
(s)=
•
(EQ. 75)
COMP
(C + C ) ⋅ s
R
• C • C
vc vc vp
vc
vp
75
60
-----------------------------------------
• s + 1
C
+ C
vp
vc
45
30
15
The targeted cross over frequency, F is 8Hz. The high frequency
CV
pole, F is required in order to reject the 2 time line frequency
Pv
component. F = 20Hz. The targeted phase margin is 60°.
Pv
0
1
3
F
1x10
10
100
Zv
100
80
FREQUENCY (Hz)
F
F
Pv
CV
FIGURE 20. BODE PLOT OF THE ACTUAL VOLTAGE LOOP GAIN
60
Gmv*Z
(s)
COMP
40
G
(s)
PS
20
0
G
(s)
VLOOP
-20
-40
-60
G
DIV
1
10
100
FREQUENCY (Hz)
1k
FIGURE 19. ASYMPTOTIC BODE PLOT OF CURRENT LOOP GAIN
FN8258.1
August 8, 2013
17
ISL6730A, ISL6730B, ISL6730C, ISL6730D
Revision History
The revision history provided is for informational purposes only and is believed to be accurate, but not warranted. Please go to the web to make sure that
you have the latest revision.
DATE
REVISION
FN8258.1
FN8258.0
CHANGE
Added electronic specifications to parts ISL6730B/D and made necessary changes throughout document.
Initial Release.
August 8, 2013
February 26, 2013
About Intersil
Intersil Corporation is a leader in the design and manufacture of high-performance analog, mixed-signal and power management
semiconductors. The company's products address some of the largest markets within the industrial and infrastructure, personal
computing and high-end consumer markets. For more information about Intersil, visit our website at www.intersil.com.
For the most updated datasheet, application notes, related documentation and related parts, please see the respective product
information page found at www.intersil.com. You may report errors or suggestions for improving this datasheet by visiting
www.intersil.com/en/support/ask-an-expert.html. Reliability reports are also available from our website at
http://www.intersil.com/en/support/qualandreliability.html#reliability
For additional products, see www.intersil.com/en/products.html
Intersil products are manufactured, assembled and tested utilizing ISO9000 quality systems as noted
in the quality certifications found at www.intersil.com/en/support/qualandreliability.html
Intersil products are sold by description only. Intersil Corporation reserves the right to make changes in circuit design, software and/or specifications at any time
without notice. Accordingly, the reader is cautioned to verify that data sheets are current before placing orders. Information furnished by Intersil is believed to be
accurate and reliable. However, no responsibility is assumed by Intersil or its subsidiaries for its use; nor for any infringements of patents or other rights of third
parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Intersil or its subsidiaries.
For information regarding Intersil Corporation and its products, see www.intersil.com
FN8258.1
August 8, 2013
18
ISL6730A, ISL6730B, ISL6730C, ISL6730D
Package Outline Drawing
M10.118
10 LEAD MINI SMALL OUTLINE PLASTIC PACKAGE
Rev 1, 4/12
5
3.0±0.05
A
DETAIL "X"
D
10
1.10 MAX
SIDE VIEW 2
0.09 - 0.20
4.9±0.15
3.0±0.05
5
0.95 REF
PIN# 1 ID
1
2
0.50 BSC
B
GAUGE
PLANE
TOP VIEW
0.25
3°±3°
0.55 ± 0.15
DETAIL "X"
0.85±010
H
C
SEATING PLANE
0.10 C
0.18 - 0.27
0.10 ± 0.05
0.08 C A-B D
M
SIDE VIEW 1
(5.80)
NOTES:
1. Dimensions are in millimeters.
(4.40)
(3.00)
2. Dimensioning and tolerancing conform to JEDEC MO-187-BA
and AMSEY14.5m-1994.
3. Plastic or metal protrusions of 0.15mm max per side are not
included.
(0.50)
4. Plastic interlead protrusions of 0.15mm max per side are not
included.
5. Dimensions are measured at Datum Plane "H".
6. Dimensions in ( ) are for reference only.
(0.29)
(1.40)
TYPICAL RECOMMENDED LAND PATTERN
FN8258.1
August 8, 2013
19
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