LT8312IMS#PBF [Linear]
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| 型号： | LT8312IMS#PBF |
| 厂家： | 
Linear |
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LT8312
Boost Controller with
Power Factor Correction
FeaTures
DescripTion
The LT®8312 is a power factor correction (PFC) boost
controller. A LT8312-based design can achieve a power
factorofgreaterthan0.99byactivelymodulatingtheinput
current,allowingcompliancewithmostHarmonicCurrent
Emission requirements.
n
PFC Boost with Minimum Number of External Com-
ponents
V and V
IN
n
Limited Only by External Components
OUT
n
n
n
n
n
Active Power Factor Correction
Low Harmonic Distortion
Overvoltage Protection
Energy Star Compliant (<0.5W No-Load Operation)
16-Lead MSOP Package
The LT8312 is well suited for a wide variety of off-line
applications. The input range can be scaled up or down,
depending mainly on the choice of external components.
Efficiencies higher than 95% can be achieved with output
power levels up to 250W.
applicaTions
L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear
Technology Corporation. All other trademarks are the property of their respective owners.
n
Industrial
Aviation
n
Typical applicaTion
Universal Input 200W PFC Boost Converter
B1
GBU404
D4
CMR5H-06
V
400V
0.5A
OUT
4:1
•
D2
20Ω
560µF
×2
90V
TO 265V
AC
0.1µF
499k 100k
•
10µF
4.7pF
2k
Efficiency
499k 100k
D3
99
98
97
96
95
94
93
92
91
1M
1M
V
DCM
FB
IN
115VAC
1M
V
IN_SENSE
EN/UVLO
9.53k
95.3k
LT8312
230VAC 50Hz
20Ω
GATE
V
SENSE
REF
INTV
CC
100k
221k
4.7µF
0.01Ω
GND
2.2µF
OVP
V
C
0
40 60 80 100 120 140 160
20
POWER (W)
8312 G01
8312 TA01a
8312fa
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For more information www.linear.com/LT8312
LT8312
absoluTe MaxiMuM raTings
pin conFiguraTion
(Note 1)
EN/UVLO...................................................................30V
IN
TOP VIEW
V ............................................................................42V
V
16
1
2
3
4
5
6
7
8
GND
GND
GND
IN_SENSE
15 SENSE
14 GATE
INTV ......................................................................18V
CC
FB ...............................................................................3V
V
13 INTV
CC
REF
OVP
12 EN/UVLO
V ...............................................................................5V
V
C
11
V
IN
C
GND
GND
10 DCM
V
................................................................1mA
9
FB
IN(SENSE)
OVP.............................................................................4V
SENSE......................................................................0.4V
DCM....................................................................... 3mA
Operating Temperature Range (Note 2)....–40°C to 125°C
Storage Temperature Range .................. –65°C to 150°C
MS PACKAGE
16-LEAD PLASTIC MSOP
θ
= 125°C/W
JA
orDer inForMaTion
(http://www.linear.com/product/LT8312#orderinfo)
LEAD FREE FINISH
LT8312EMS#PBF
LT8312IMS#PBF
LT8312HMS#PBF
LT8312MPMS#PBF
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
16-Lead Plastic MSOP
16-Lead Plastic MSOP
16-Lead Plastic MSOP
16-Lead Plastic MSOP
TEMPERATURE RANGE
–40°C to 125°C
–40°C to 125°C
–40°C to 150°C
–55°C to 150°C
LT8312EMS#TRPBF
LT8312IMS#TRPBF
LT8312HMS#TRPBF
LT8312MPMS#TRPBF
8312
8312
8312
8312
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on nonstandard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
8312fa
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For more information www.linear.com/LT8312
LT8312
elecTrical characTerisTics The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C.
PARAMETER
CONDITIONS
MIN
10
TYP
MAX
38
UNITS
Input Voltage Range
Quiescent Current
V
V
= 0.2V
45
60
70
70
µA
µA
EN/UVLO
Not Switching
V
IN
V
IN
V
IN
Quiescent Current, INTV Overdriven
V
INTVCC
= 11V
60
40
8
µA
V
CC
Shunt Regulator Voltage
I = 1mA
Shunt Regulator Current Limit
mA
INTV Quiescent Current
V
V
= 0.2V
= 1.5V, Not Switching
12.5
1.8
15.5
2.2
17.5
2.7
µA
mA
CC
EN/UVLO
EN/UVLO
l
EN/UVLO Pin Threshold
EN/UVLO Pin Voltage Rising
EN/UVLO = 1V
1.21
8
1.25
10
1.29
12
V
EN/UVLO Pin Hysteresis Current
μA
l
l
V
Voltage
0µA Load
200µA Load
1.97
1.95
2.0
1.98
2.03
2.03
V
V
REF
SENSE Current Limit Threshold
Minimum SENSE Current Limit
SENSE Input Bias Current
Current Sense Blanking Time
FB Voltage
96
102
3
107
mV
mV
µA
Current Out of Pin
15
90
130
1.25
0.01
100
180
170
0.1
80
170
1.28
0.03
600
ns
l
1.22
V
FB Voltage Line Regulation
FB Pin Bias Current
10V < V < 35V
%/V
nA
IN
(Note 3), FB = 1.25V, OVP = 1.35V
FB Error Amplifier Voltage Gain
FB Error Amplifier Transconductance
FB Low Detection Voltage
DCM Current Turn-On Threshold
Maximum Oscillator Frequency
Linear Regulator
ΔV /ΔV
V/V
µmhos
V
VC
FB
ΔI = 5µA
Current Out of Pin
µA
400
kHz
INTV Regulation Voltage
9.8
10
10.4
900
V
CC
Dropout (V -INTV
)
I
= –10mA, V = 10V
500
mV
IN
CC
INTVCC
IN
Current Limit
INTV < 9.5V
12
80
25
120
mA
mA
CC
INTV > 9.5V
CC
Gate Driver
t GATE Driver Output Rise Time
C = 3300pF
18
18
ns
ns
V
r
L
t GATE Driver Output Fall Time
f
C = 3300pF
L
GATE Output Low (V
)
OL
0.01
GATE Output High (V
)
OH
INTV
–
V
CC
50mV
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The LT8312E is guaranteed to meet specified performance from
0°C to 125°C junction temperature. Specification over the –40°C and
125°C operating junction temperature range are assured by design,
characterization and correlation with statistical process controls. The
LT8312I is guaranteed to meet specified performance from –40°C to
125°C operating junction temperature range. The LT8312H is guaranteed
to meet performance specifications over the –40°C to 150°C operating
junction temperature range. The LT8312MP is guaranteed to meet
performance specifications over the –55°C to 150°C operating junction
temperature range. High junction temperatures degrade operating
lifetimes. Operating lifetime is derated for junction temperatures greater
than 125°C.
Note 3: Current flows out of the FB pin.
8312fa
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For more information www.linear.com/LT8312
LT8312
Typical perForMance characTerisTics
EN/UVLO Threshold
vs Temperature
Input Voltage Hysteresis Current
vs Temperature
VIN IQ vs Temperature
1.3
1.28
1.26
1.24
1.22
1.2
12
11.5
11
100
90
80
70
60
50
40
30
20
10
0
V
= 24V
IN
V
IN
= 12V
RISING
FALLING
10.5
10
–50
0
25 50 75 100 125 150
–50
0
25 50 75 100 125 150
–50
–25
0
25 50 75 100 125 150
–25
–25
TEMPERATURE (°C)
TEMPERATURE (°C)
TEMPERATURE (°C)
8312 G01
8312 G02
8312 G03
SENSE Pin Threshold Current
vs Temperature
VREF vs Temperature
VREF vs VIN
2.100
2.075
2.050
2.025
2.000
1.975
1.950
1.925
1.900
2.05
2.04
2.03
2.02
2.01
2
120
100
80
60
40
20
0
MAX I
LIM
V
IN
= 24V WITH NO LOAD
NO LOAD
1.99
1.98
1.97
1.96
1.95
200µA LOAD
V
= 24V WITH 200µA LOAD
IN
–50
0
25 50 75 100 125 150
10
20
25
(V)
30
35
40
–50
–25
0
25 50 75 100 125 150
–25
15
TEMPERATURE (°C)
V
TEMPERATURE (°C)
IN
8312 G04
8312 G05
8312 G06
INTVCC vs Temperature
INTVCC vs VIN
VIN Shunt Voltage vs Temperature
10.5
10.25
10
42
41.5
41
10.2
10
I
= 1mA
NO LOAD
10mA LOAD
25mA LOAD
SHUNT
9.8
9.6
9.4
9.2
9
40.5
40
9.75
9.5
39.5
39
–50
0
25 50 75 100
150
125
–50 –25
0
25 50 75 100 125 150
–25
5
15
20
V
25
(V)
30
35
40
10
TEMPERATURE (°C)
TEMPERATURE (°C)
8312 G07
8312 G09
IN
8312 G08
8312fa
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For more information www.linear.com/LT8312
LT8312
Typical perForMance characTerisTics
Maximum VIN Shunt Current
vs Temperature
THD vs Output Power
Power Factor vs Output Power
60
50
40
30
20
10
0
1.00
0.95
0.90
0.85
0.80
0.75
0.70
0.65
0.60
10
9
115VAC
230VAC 50Hz
8
230VAC 50Hz
7
6
115VAC
5
0
20 40 60 80 100 120 140 160
0
20 40 60 80 100 120 140 160
–50
0
25 50 75 100 125 150
–25
POWER (W)
POWER (W)
TEMPERATURE (°C)
8312 G11
8312 G12
8312 G10
pin FuncTions
GND (Pins 1, 2, 3, 7, 8): Ground.
EN/UVLO(Pin12):Enable/UndervoltageLockout.Aresis-
tor divider connected to V is tied to this pin to program
IN
V
(Pin 4): Voltage Reference Output Pin, Typically
REF
the minimum input voltage at which the LT8312 will turn
on. When below 1.25V, the part will draw 60μA with most
of the internal circuitry disabled and a 10μA hysteresis
current will be pulled out of the EN/UVLO pin. When above
1.25V, the part will be enabled and begin to switch and
the 10μA hysteresis current is turned off.
2V. This pin drives a resistor divider for the OVP pin. Can
supply up to 200μA.
OVP (Pin 5): Overvoltage Protection. This pin accepts a
DC voltage to compare to the voltage output information.
When FB pin voltage is above the OVP, the part stops
switching. This protects devices connected to the output.
INTV (Pin 13): Regulated Supply for Internal Loads
CC
V (Pin 6): Compensation Pin for Internal Error Amplifier.
and GATE Driver. Supplied from V and regulates to 10V
C
IN
Connect a series RC from this pin to ground to compen-
sate the switching regulator. A 100pF capacitor in parallel
helps eliminate noise.
(typical). INTV must be bypassed with a 4.7μF capacitor
CC
placed close to the pin.
GATE(Pin14):N-ChannelFETGateDriverOutput.Switches
FB (Pin 9): Voltage Loop Feedback Pin. FB is used to
regulate the output voltage.
betweenINTV andGND.DriventoGNDduringshutdown
CC
state and stays high during low voltage states.
DCM(Pin10):DiscontinuousConductionModeDetection
Pin. Connect a capacitor and resistor in series with this
pin to the auxiliary winding.
SENSE (Pin 15): The Current Sense Input for the Control
Loop. Kelvinconnectthispintothepositiveterminalofthe
switch current sense resistor, R , in the source of the
SENSE
NFET. The negative terminal of the current sense resistor
should be connected to the GND plane close to the IC.
V (Pin 11): Input Voltage. This pin supplies current to
IN
the internal start-up circuitry and to the INTV LDO. This
CC
pinmustbelocallybypassedwithacapacitor. A42Vshunt
regulator is internally connected to this pin.
V
(Pin 16): Line Voltage Sense Pin. The pin is
IN(SENSE)
used for sensing the AC line voltage to perform power
factor correction. Connect a resistor in series with the
line voltage to this pin.
8312fa
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For more information www.linear.com/LT8312
LT8312
block DiagraM
D2
R2
V
IN
C3
C2
R13
R14
R1
L2
C1
L1
D1
R5
V
10
DCM
12
EN/UVLO
START-UP
INTERNAL REG
16
11
OUT
V
C6
R3
R4
V
IN
IN(SENSE)
R8
V
REF
4
5
OVP
–
1.22V
R9
A7
M2
+
–
INTV
CC
+
ONE
SHOT
13
A2
Q1
C5
R10
R11
CURRENT
COMPARATOR
–
V
+
–
600MV
A1
A3
+
R
S
S
GATE
Q
DRIVER
14
15
M1
MASTER
LATCH
–
+
SENSE
FB
9
6
R6
A6
A4
A8
GND
1, 2, 3, 7, 8
MULTIPLIER
1.22V
VC
OSCILLATOR
C4
8312 BD
8312fa
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For more information www.linear.com/LT8312
LT8312
operaTion
The LT8312 is a power factor correction boost controller
IC. It provides high power factor and low harmonic distor-
tion in applications with current mode control and critical
conduction mode.
a rate proportional to the difference between the output
voltage and the input voltage. When the current decreases
to zero, the output diode turns off and the voltage on the
drain of the MOSFET starts to oscillate from the parasitic
capacitance and the inductor. The auxiliary winding has
the same voltage across it as the main inductor and rings
too. The capacitor connected to the DCM pin, C1, trips the
comparator A2, which serves as a dv/dt detector, when
the ringing occurs. The dv/dt detector waits for the ringing
waveform to reach its minimum value and then the switch
turns back on. This switching behavior is similar to zero
volt switching and minimizes the amount of energy lost
whentheswitchisturnedbackonandimprovesefficiency
as much as 5%. Since this part operates on the edge of
continuous conduction mode and discontinuous conduc-
tionmode,theoperatingmodeiscalledcriticalconduction
mode (or boundary conduction mode).
Active power factor correction is becoming a require-
ment for offline power supplies. A power factor of one is
achieved if the current drawn is proportional to the input
voltage. TheLT8312modulatesthepeakcurrentlimitwith
a scaled version of the input voltage. This technique can
provide power factors of 0.97 or greater.
The Block Diagram shows an overall view of the system.
The external components are in a boost topology configu-
ration. The auxiliary winding supplies power to the part in
steady-state operation. The V pin supplies power to an
internal LDO that generates 10V at the INTV pin. The
controlcircuitryconsistsofanerroramplifier,amultiplier,
a current comparator, and a master latch, which will be
explained in the following sections. A comparator is used
to detect discontinuous conduction mode (DCM) with a
cap connected to the auxiliary winding. The part features
a 1.9A gate driver.
IN
CC
The output voltage is regulated with a resistor divider
connected to the FB pin. The output of the error amplifier
is the VC pin. This node needs a capacitor to compensate
the control loop.
The LT8312 is designed for off-line applications. The
EN/UVLO and a resistor divider are configured for a
micropower hysteretic start-up. In the Block Diagram, R2
is used to stand off the high voltage supply voltage. The
Power Factor Correction
When the V
pin is connected to the supply volt-
IN(SENSE)
age with a resistor, the current limit is proportional to the
supply voltage. If the LT8312 is configured with a fast
control loop, the VC pin would adjust to the changes of the
internal LDO starts to supply current to the INTV pin
CC
when V is above 2.5V. The V and INTV capacitor
IN
IN
CC
V
. The only way for the multiplier to function is
IN(SENSE)
are charged by the current from R2. When V exceeds
IN
to set the control loop to be an order of magnitude slower
than the fundamental frequency of the V signal.
the turn-on threshold and INTV is in regulation at 10V,
CC
IN(SENSE)
the part begins to switch. The V hysteresis is set by the
IN
In an offline application, the fundamental frequency of
the supply voltage is 120Hz so the control loop unity gain
frequency needs to be set less than approximately 12Hz.
EN/UVLO resistor divider. The auxiliary winding provides
power to V when its voltage is higher than the V volt-
IN
IN
age. A voltage shunt is provided for fault protection and
can sink 8mA of current when V is over 40V.
IN
Start-Up
During a typical cycle, the gate driver turns the external
MOSFET on and a current flows through the inductor.
This current increases at a rate proportional to the input
voltage.Thecontrolloopdeterminesthemaximumcurrent
and the current comparator turns the switch off when the
current level is reached. When the switch turns off, the
inductor current begins to flow through the diode con-
nected to the output capacitor. This current decreases at
The LT8312 uses a hysteretic start-up to operate from
high offline voltages. A resistor connected to the supply
voltage protects the part from high voltages. This resistor
is connected to the V pin on the part and bypassed with
IN
a capacitor. When the resistor charges the V pin to a
IN
turn-on voltage set with the EN/UVLO resistor divider and
the INTV pin is at its regulation point, the part begins to
CC
switch. The resistor cannot provide power for the part in
8312fa
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For more information www.linear.com/LT8312
LT8312
operaTion
steadystate, butreliesonthecapacitortostartupthepart,
Programming Output Voltage
then the auxiliary winding begins to provide power to the
The output voltage is set using a resistor divider from the
output capacitor to the FB pin. From the Block Diagram
the resistors R3 and R4 form a resistor divider from the
output capacitor. The output voltage equation is:
V pin along with the resistor. An internal voltage clamp
IN
is attached to the V pin to prevent the resistor current
IN
from allowing V to go above the absolute maximum
IN
voltage of the pin. The internal clamp is set at 40V and is
R3+R4
capable of 8mA (typical) of current at room temperature.
VOUT = VBG •
R5
Setting the V Turn-On and Turn-Off Voltages
IN
The V voltage is equal to FB Voltage in Electrical Speci-
BG
A large voltage difference between the V turn-on voltage
IN
fication Table.
and the V turn-off voltage is preferred to allow time for
IN
the auxiliary winding to power the part. The EN/UVLO
sets these two voltages. The pin has a 10μA current sink
when the pins voltage is below 1.25V and 0μA when
Setting V
Resistor
IN(SENSE)
TheV
resistorsetsthecurrentfeedingtheinternal
IN(SENSE)
multiplierthatmodulatesthecurrentlimitforpowerfactor
correction.Atthemaximumlinevoltage,V ,thecurrent
above 1.25V. The V pin connects to a resistor divider
IN
MAX
as shown in Figure 1.
is set to 360µA. Under this condition, the resistor value is
equal to (V /360µA).
The UVLO threshold for V rising is:
IN
MAX
R1+R2
R2
VIN(UVLO,RISING) =1.25V •
+10µA •R1
Critical Conduction Mode Operation
Criticalconductionmodeisavariablefrequencyswitching
scheme that always returns the inductor current to zero
with every cycle. The DCM pin uses a fast current input
comparatorincombinationwithasmallcapacitortodetect
dv/dt on the auxiliary winding. To eliminate false tripping,
a blanking time of 200ns is applied after the switch turns
off. The detector looks for 80μA of current through the
DCM pin due to falling voltage on the auxiliary winding
when the output diode turns off. This is not the optimal
timetoturntheswitchonbecausetheswitchvoltageisstill
The UVLO Threshold for V Falling is :
IN
R1+R2
R2
VIN(UVLO,FALLING) =1.25V •
V
IN
R1
R2
EN/UVLO
LT8312
GND
close to V
and would waste all the energy stored in the
OUT
8312 F01
parasitic capacitance on the switch node. Discontinuous
ringingbeginswhentheoutputdiodecurrentreacheszero
Figure 1. Undervoltage Lockout (UVLO)
8312fa
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LT8312
operaTion
and the energy in the parasitic capacitance on the switch
node transfers to the input capacitor. This is a second-
order network composed of the parasitic capacitance on
the switch node and the main inductor. The minimum
voltage of the switch node during this discontinuous
Loop Compensation
The feedback loop is a traditional g error amplifier. The
m
loop crossover frequency is set much lower than twice
the line frequency for PFC to work properly. In a typical
application, the compensation capacitor is 1µF.
ring is 2V -V . The LT8312 turns the switch back on
IN OUT
at this time, during the discontinuous switch waveform,
by sensing when the slope of the switch waveform goes
from negative to positive using the dv/dt detector. This
switching technique may increase efficiency by 5%.
MOSFET and Diode Selection
With a strong 1.9A gate driver, the LT8312 can effectively
drive most high voltage MOSFETs. A low Q MOSFET is
G
recommendedtomaximizeefficiency.Inmostapplications,
At low current limits, the frequency of critical conduc-
tion mode can become very high. The LT8312 features a
maximum frequency clamp of 400kHz. The part operates
in discontinuous conduction mode when the natural criti-
cal conduction mode frequency is higher than 400kHz.
the R
should be chosen to limit the temperature rise
DS(ON)
of the MOSFET. The drain of the MOSFET is stressed to
V
OUT
during the time the MOSFET is off and the diode is
conducting current.
The diode is stressed to V
when the switch is on. The
OUT
average current through the diode is equal to the load
Sense Resistor Selection
current.
The resistor, R
, between the source of the external
SENSE
N-channelMOSFETandGNDshouldbeselectedtoprovide
anadequateswitchcurrenttodrivetheapplicationwithout
exceeding the current limit threshold.
Discontinuous Mode Detection
The discontinuous mode detector uses AC-coupling to
detect the ringing on the auxiliary winding. A 22pF ca-
pacitor with a 30k resistor in series is recommended in
most designs.
Minimum Current Limit
The LT8312 features a minimum current limit of approxi-
mately 3% of the peak current limit. This helps improve
the harmonic distortion during the input supplies off-line
crossover period.
Power Factor Correction/Harmonic Content
The LT8312 attains high power factor and low harmonic
content by making the peak current of the main power
switchproportionaltothelinevoltagebyusingandinternal
multiplier. A power factor of >0.97 is easily attainable for
most applications by following the design equations in
this data sheet. With proper design, LT8312 applications
can easily meet most harmonic standards.
Universal Input
The LT8312 operates over the universal input voltage
range of 90V AC to 265V AC.
8312fa
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LT8312
Typical applicaTions
8312fa
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LT8312
Typical applicaTions
8312fa
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LT8312
package DescripTion
Please refer to http://www.linear.com/product/LT8312#packaging for the most recent package drawings.
MS Package
16-Lead Plastic MSOP
(Reference LTC DWG # 05-08-1669 Rev A)
0.889 ±0.127
(.035 ±.005)
5.10
3.20 – 3.45
(.201)
(.126 – .136)
MIN
4.039 ±0.102
(.159 ±.004)
(NOTE 3)
0.50
(.0197)
BSC
0.305 ±0.038
(.0120 ±.0015)
TYP
0.280 ±0.076
(.011 ±.003)
REF
16151413121110
9
RECOMMENDED SOLDER PAD LAYOUT
3.00 ±0.102
(.118 ±.004)
(NOTE 4)
DETAIL “A”
0.254
4.90 ±0.152
(.193 ±.006)
(.010)
0° – 6° TYP
GAUGE PLANE
0.53 ±0.152
(.021 ±.006)
1 2 3 4 5 6 7 8
0.86
(.034)
REF
1.10
(.043)
MAX
DETAIL “A”
0.18
(.007)
SEATING
PLANE
0.17 – 0.27
(.007 – .011)
TYP
0.1016 ±0.0508
(.004 ±.002)
MSOP (MS16) 0213 REV A
0.50
(.0197)
BSC
NOTE:
1. DIMENSIONS IN MILLIMETER/(INCH)
2. DRAWING NOT TO SCALE
3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.
MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.
INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE
5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX
8312fa
12
For more information www.linear.com/LT8312
LT8312
revision hisTory
REV
DATE
DESCRIPTION
PAGE NUMBER
A
2/16
Modified schematics.
1, 14
Changed minimum current limit for INTV
Changed OVP pin description.
.
3
6
CC
8312fa
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-
13
tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.
LT8312
Typical applicaTion
Universal Input 200W PFC Boost Converter
D4
V
400V
0.5A
OUT
4:1
•
D2
20Ω
560µF
×2
90V
TO 265V
AC
0.1µF
499k 100k
•
10µF
4.7pF
2k
499k 100k
D3
1M
1M
V
DCM
FB
IN
1M
V
IN_SENSE
EN/UVLO
9.53k
95.3k
LT8312
20Ω
GATE
V
SENSE
REF
INTV
CC
100k
221k
4.7µF
0.01Ω
GND
2.2µF
OVP
V
C
8312 TA04
relaTeD parTs
PART NUMBER DESCRIPTION
COMMENTS
and V Limited Only By External Components
OUT
LT3798
Off-Line Isolated No Opto Flyback Controller with Active PFC
V
IN
LT3752/
LT3752-1
Active Clamp Synchronous Forward Controllers with Internal Input Voltage Range: LT3752: 6.5V to 100V, LT3752-1: Limited Only By
Housekeeping Controller
Eternal Components
LT3753
LT8311
Active Clamp Synchronous Forward Controller
Input Voltage Range: 8.5V to 100V
Synchronous Rectifier Controller with Opto-Coupler Driver
for Forward Converters
Optimized for Use with Primary-Side LT3752/LT3752-1, LT3753 and
LT8310 Controllers
LT3748
100V Isolated Flyback Controller
5V ≤ V ≤ 100V, No Opto Flyback, MSOP-16 with High Voltage Spacing
IN
LTC®3765/
LTC3766
Synchronous No Opto Forward Controller Chip Set with
Active Clamp Reset
Direct Flux Limit, Supports Self Starting Secondary Forward Control
LTC3723-1/
LTC3723-2
Synchronous Push-Pull and Full-Bridge Controllers
High Efficiency with On-Chip MOSFET Drivers, Adjustable Synchronous
Rectification Timing
LTC3722/
LTC3722-2
Synchronous Full Bridge Controllers
Adaptive or Manual Delay Control for Zero Voltage Switching, Adjustable
Synchronous Rectification Timing
8312fa
LT 0216 REV A • PRINTED IN USA
LinearTechnology Corporation
1630 McCarthy Blvd., Milpitas, CA 95035-7417
14
●
●
LINEAR TECHNOLOGY CORPORATION 2015
(408)432-1900 FAX: (408) 434-0507 www.linear.com/LT8312
相关型号：
LT8312MPMS#PBF
LT8312 - Boost Controller with Power Factor Correction; Package: MSOP; Pins: 16; Temperature Range: -55°C to 125°C
Linear
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