LT3798_15,LT3798_15 pdf中文资料,LT3798_15引脚图,LT3798

FEATURES

n

LT3798

Isolated No Opto-Coupler

Flyback Controller

with Active PFC

DESCRIPTION

The LT

®

3798 is a constant-voltage/constant-current iso-

lated flyback controller that combines active power factor

correction (PFC) with no opto-coupler required for output

voltage feedback into a single-stage converter. A LT3798

based design can achieve a power factor of greater than 0.97

by actively modulating the input current, allowing compli-

ance with most Harmonic Current Emission requirements.

The LT3798 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 86% can be achieved with output

power levels up to 100W. In addition, the LT3798 can easily

be designed into high DC input 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.

Protected by U.S. Patents, including 5438499 and 7471522.

Isolated PFC Flyback with Minimum Number of

External Components

V

IN

and V

OUT

Limited Only by External Components

Active Power Factor Correction

Low Harmonic Distortion

No Opto-Coupler Required

Constant-Current and Constant-Voltage Regulation

Accurate Regulated Voltage and Current (±5% Typical)

Energy Star Compliant (<0.5W No Load Operation)

Thermally Enhanced 16-lead MSOP Package

APPLICATIONS

n

Offline 5W to 100W+ Applications

High DC V

IN

Isolated Applications

Offline Bus Converter (12V, 24V or 48V Outputs)

TYPICAL APPLICATION

Universal Input 24W PFC Bus Converter

24.50

V

OUT

vs I

OUT

90V

TO 265V

AC

499k

0.1µF

499k

100k

D3

1M

95.3k

V

IN

D2 20

4.7pF

10µF

V

OUT

(V)

24.25

4:1:1

24.00

2k

DCM

FB

4.99k

22pF

D1

90.9k

Z1

560µF

×2

23.75

D4

V

IN_SENSE

EN/UVLO

LT3798

V

REF

24V

1A

23.50

VAC = 90V

VAC = 120V

VAC = 220V

VAC = 265V

0

0.2

0.4

0.6

I

OUT

(A)

0.8

1

3798 TA01b

100k

40.2k

CTRL3

CTRL2

CTRL1

OVP

GATE

SENSE

INTV

CC

20

Z2

0.05

4.7µF

GND

COMP

+

2.2µF

COMP

–

2.2nF

221k

16.5k

V

C

0.1µF

3798 TA01a

3798fa

1

LT3798

ABSOLUTE MAXIMUM RATINGS

(Note 1)

PIN CONFIGURATION

TOP VIEW

CTRL1

CTRL2

CTRL3

V

REF

OVP

V

C

COMP

+

COMP

–

1

2

3

4

5

6

7

8

16

15

14

13

12

11

10

9

V

IN_SENSE

SENSE

GATE

INTV

CC

EN/UVLO

V

IN

DCM

FB

EN/UVLO ...................................................................30V

V

IN

............................................................................42V

INTV

CC

......................................................................12V

CTRL1, CTRL2, CTRL3 ................................................4V

FB, V

REF

, COMP

+

........................................................3V

V

C

, OVP, COMP

–

.........................................................4V

SENSE ......................................................................0.4V

V

IN_SENSE

.................................................................1mA

DCM .......................................................................±3mA

Operating Temperature Range (Note 2)

LT3798E/LT3798I................................... –40°C to 125°C

Storage Temperature Range .................. –65°C to 150°C

17

GND

MSE PACKAGE

16-LEAD PLASTIC MSOP

θ

JA

= 50°C/W,

θ

JC

= 10°C/W

EXPOSED PAD (PIN 17) IS GND, MUST BE SOLDERED TO PCB

ORDER INFORMATION

LEAD FREE FINISH

LT3798EMSE#PBF

LT3798IMSE#PBF

LT3798HMSE#PBF

LT3798MPMSE#PBF

TAPE AND REEL

LT3798EMSE#TRPBF

LT3798IMSE#TRPBF

LT3798HMSE#TRPBF

LT3798MPMSE#TRPBF

PART MARKING*

3798

PACKAGE DESCRIPTION

16-Lead Plastic MSOP

TEMPERATURE RANGE

–40°C to 125°C

–40°C to 150°C

–55°C to 150°C

Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.

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/

ELECTRICAL CHARACTERISTICS

PARAMETER

Input Voltage Range

V

IN

Quiescent Current

V

IN

Quiescent Current, INTV

CC

Overdriven

V

IN

Shunt Regulator Voltage

V

IN

Shunt Regulator Current Limit

INTV

CC

Quiescent Current

EN/UVLO Pin Threshold

EN/UVLO Pin Hysteresis Current

V

IN_SENSE

Threshold

V

REF

Voltage

CTRL1/CTRL2/CTRL3 Pin Bias Current

CONDITIONS

The

l

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

A

= 25°C. V

IN

= 18V, INTV

CC

= 11V, unless otherwise noted.

MIN

10

V

EN/UVLO

= 0.2V

V

EN/UVLO

= 1.5V, Not Switching

V

INTVCC

= 11V

I = 1mA

V

EN/UVLO

= 0.2V

V

EN/UVLO

= 1.5V, Not Switching

EN/UVLO Pin Voltage Rising

EN/UVLO=1V

Turn Off

0µA Load

200µA Load

CTLR1/CTRL2/CTRL3 = 1V

l

TYP

60

70

60

40

8

MAX

38

70

UNITS

V

µA

V

mA

45

12.5

1.8

1.21

8

1.97

1.95

15.5

2.2

1.25

10

27

2.0

1.98

17.5

2.7

1.29

12

2.03

±30

µA

mA

V

µA

V

nA

3798fa

2

LT3798

ELECTRICAL CHARACTERISTICS

PARAMETER

SENSE Current Limit Threshold

Minimum SENSE Current Limit Threshold

SENSE Input Bias Current

FB Voltage

FB voltage Line Regulation

FB Pin Bias Current

FB Error Amplifier Voltage Gain

FB Error Amplifier Transconductance

Current Error Amplifier Voltage Gain

Current Error Amplifier Transconductance

Current Loop Voltage Gain

DCM Current Turn-On Threshold

Maximum Oscillator Frequency

Minimum Oscillator Frequency

Backup Oscillator Frequency

Linear Regulator

INTV

CC

Regulation Voltage

Dropout (V

IN

-INTV

CC

)

Current Limit

Gate Driver

t

r

GATE Driver Output Rise Time

t

f

GATE Driver Output Fall Time

GATE Output Low (V

OL

)

GATE Output High (V

OH

)

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 LT3798E 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

INTV

CC

-

50mV

C

L

= 3300pF 10% to 90%

,

C

L

= 3300pF 90% to 10%

,

18

0.01

ns

V

No Load

I

INTVCC

= –10mA, V

IN

= 10V

Below Undervoltage Threshold

Above Undervoltage Threshold

12

80

9.8

10

500

25

120

10.4

900

V

mV

mA

10V < V

IN

< 35V

(Note 3), FB = 1V

ΔV

VC

/ΔV

FB

, CTRL1=1V, CTRL2=2V, CTRL3=2V

ΔI = 5µA

ΔV

COMP

+/ΔV

COMP

–, CTRL1 = 1V, CTRL2 = 2V, CTRL3 = 2V

ΔI = 5µA

ΔV

CTRL

/ΔV

SENSE

,1000pF Cap from COMP

+

to COMP

–

Current Out of Pin

COMP

+

= 0.95V, V

IN_SENSE

= 150µA

COMP

+

= 0V, V

FB

<V

OVP

COMP

+

= 0V, V

FB

>V

OVP

4.05

CONDITIONS

V

IN_SENSE

= 150µA

V

IN_SENSE

= 34µA

V

IN_SENSE

= 21µA

Current Out of Pin, SENSE = 0V

l

The

l

denotes the specifications which apply over the full operating

temperature range, otherwise specifications are at T

A

= 25°C. V

IN

= 18V, INTV

CC

= 11V, unless otherwise noted.

MIN

96

TYP

102

14

4

15

1.22

1.25

0.01

4.25

180

170

100

50

21

80

150

4

0.5

20

1.28

0.03

4.4

MAX

107

UNITS

mV

µA

V

%/V

µA

V/V

UMHOS

V/V

UMHOS

V/V

µA

kHz

LT3798I is guaranteed to meet specified performance from –40°C to 125°C

operating junction temperature range. The LT3798H is guaranteed to meet

performance specifications over the –40°C to 150°C operating junction

temperature range. The LT3798MP 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.

3798fa

3

LT3798

TYPICAL PERFORMANCE CHARACTERISTICS

EN/UVLO Threshold

vs Temperature

1.3

EN/UVLO HYSTERESIS CURRENT (µA)

12

T

A

= 25°C, unless otherwise noted.

EN/UVLO Hysteresis Current

vs Temperature

100

90

11.5

80

70

I

Q

(µA)

60

50

40

30

20

10

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G02

V

IN

I

Q

vs Temperature

V

IN

= 24V

V

IN

= 12V

1.28

RISING

EN/UVLO (V)

1.26

11

1.24

FALLING

1.22

10.5

1.2

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G01

0

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G03

2.100

2.075

2.050

V

REF

vs Temperature

2.05

2.04

2.03

2.02

V

REF

(V)

V

REF

vs V

IN

SENSE Current Limit Threshold

vs Temperature

120

100

CURRENT LIMIT (mA)

80

60

40

20

0

–50 –25

MIN I

LIM

V

IN_SENSE

= 34µA

MIN I

LIM

V

IN_SENSE

= 21µA

MAX I

LIM

2.025

V

REF

(V)

2.000

1.975

1.950

1.925

1.900

–50 –25

0

V

IN

= 24V WITH NO LOAD

2.01

2

1.99

1.98

1.97

1.96

NO LOAD

V

IN

= 24V WITH 200µA LOAD

200µA LOAD

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G05

1.95

10

15

20

25

V

IN

(V)

30

35

40

3798 G05

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G06

Maximum Oscillator Frequency

vs Temperature

220

5

Minimum Oscillator Frequency

vs Temperature

25

Backup Oscillator Frequency

vs Temperature

195

FREQUENCY (kHz)

4

V

FB

< V

OVP

FREQUENCY (kHz)

V

OVP

> V

FB

0

25 50 75 100 125 150

TEMPERATURE (°C)

3799 G07

20

3

15

170

2

10

145

1

5

120

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G06a

0

–50 –25

0

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G07a

3798fa

4

LT3798

TYPICAL PERFORMANCE CHARACTERISTICS

10.5

T

A

= 25°C, unless otherwise noted.

INTV

CC

vs Temperature

NO LOAD

10mA LOAD

25mA LOAD

10.2

10

9.8

INTV

CC

vs V

IN

42

41.5

V

IN

SHUNT VOLTAGE (V)

41

V

IN

Shunt Voltage vs Temperature

I

SHUNT

= 1mA

10.25

INTV

CC

(V)

INTV

CC

(V)

10

9.6

9.4

40.5

40

9.75

9.2

9.5

–50 –25

9

39.5

39

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G08

5

10

15

25

20

V

IN

(V)

30

35

40

3798 G09

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G10

Maximum Shunt Current

vs Temperature

LEAKAGE INDUCTANCE BLANKING TIME (µs)

10

2

1.8

1.6

1.4

Leakage Inductance Blanking Time

vs SENSE Current Limit Threshold

25

V

OUT

vs Temperature

PAGE 17 SCHEMATIC:

UNIVERSAL

9

SHUNT CURRENT (mA)

24.5

V

OUT

(V)

8

1.2

1

0.8

0.6

0.4

0.2

0

120

60

40

80

100

20

SENSE CURRENT LIMIT THRESHOLD (mV)

3798 G12

24

VAC = 120V

7

VAC = 220V

23.5

6

5

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G11

23

–50 –25

0

25 50 75 100 125 150

TEMPERATURE (°C)

3798 G012a

Output Voltage

vs Input Voltage

24.6

PAGE 17 SCHEMATIC:

UNIVERSAL

OUTPUT CURRENT (A)

1.10

Output Current

vs Input Voltage

PAGE 17 SCHEMATIC:

UNIVERSAL

V

OUT

= 22V

24.4

1.05

V

OUT

(V)

24.2

1.00

24

23.8

0.95

23.6

90 110 130 150 170 190 210 230 250 270

V

IN

(VAC)

3798 G13

0.90

90 110 130 150 170 190 210 230 250 270

V

IN

(VAC)

3798 G14

3798fa

5

LT3798_15

LT3798_15概述

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