Pulsewidth Modulator Controllers for
Off-Line and DC/DC Converters –
InfoCard 6
LT1508/LT1509 Combined Power Factor Correction
Controller/PWM Controller
Universal Input Off-Line PFC and PWM Single Chip Solution
s
Current Mode PWM (LT
®
1509)
s
Voltage Mode PWM (LT1508)
s
Internally Synchronized Operation Up to 300kHz
s
99% Power Factor Over 20:1 Load Current Range
s
Instantaneous Overvoltage Protection
s
PWM Soft Start After PFC Output Reaches Threshold Voltage
s
20-Lead PDIP and Wide SO Packages
s
TOP VIEW
GTDR1 1
GND2 2
GND1 3
C
SET
4
PK
LIM
5
CA
OUT
6
I
SENSE
7
M
OUT
8
I
AC
9
VA
OUT
10
N PACKAGE
20-LEAD PDIP
20 GTDR2
I
(LT1508)
19
LIM
RAMP (LT1509)
18 V
C
17 V
CC
16 SS1
15 R
SET
14 V
SENSE
13 SS2
12 V
REF
11 OVP
SW PACKAGE
20-LEAD PLASTIC SO WIDE
LT1241–LT1246 Series Key Features
Low Start-Up Current (<250µA)
s
50ns Current Sense Delay
s
Current Mode Operation to 1MHz
s
Current Sense Leading Edge Blanking
s
Pin Compatible with UC1842/UC3842 Series
s
No Cross-Conduction Current
s
1A Totem Pole Output
s
s
s
s
s
Trimmed Oscillator Frequency and Sink Current
COMP 1
8 V
REF
Active Pull-Down on Reference and Output
7 V
CC
FB 2
During Undervoltage Lockout
6 OUTPUT
I
SENSE
3
5 GND
R
T
/C
T
4
High Level Output Clamp (18V)
J8 PACKAGE
N8 PACKAGE
Industrial Temperature Range Available
8-LEAD CERAMIC DIP 8-LEAD PLASTIC DIP
S8 PACKAGE
(– 40°C to 85°C)
8-LEAD PLASTIC SOIC
LT1241 IC • 02
TOP VIEW
LTC High Speed
PWM Controller
Family
PART
LT1241
LT1242
LT1243
LT1244
LT1245
LT1246
LT1247
START-UP
THRESHOLD (TYP)
9.6V
16V
8.4V
16V
8.4V
16V
8.4V
OPERATING
V
CC
(TYP)
7.6V
10V
7.6V
10V
7.6V
10V
7.6V
MAX
DUTY CYCLE
50%
100%
100%
50%
50%
100%
100%
MAX
SWITCH FREQ.*
500kHz
500kHz
500kHz
500kHz
500kHz
1MHz
1MHz
BLANKING
TIME (TYP)
100ns
100ns
100ns
100ns
100ns
70ns
70ns
SUPPLY CURRENT
(mA) (MAX)
10
10
10
10
10
20
20
*Recommended Maximum Determined by Rise/Fall Times at 1000pF Loads
LT1241–LT1245
Output Cross-Conduction Current
OUTPUT
OUTPUT CROSS-
CONDUCTION CURRENT VOLTAGE
5V/DIV
20mA/DIV
V
CC
= 15V
C
L
= 15pF
LT1241–LT1245
Current Sense Delay
OUTPUT
CURRENT SENSE
INPUT 1V/DIV VOLTAGE 5V/DIV
V
CC
= 15V
C
L
= 1nF
TIME 50ns/DIV
OUTPUT VOLTAGE
Short Current Sense Delay
means
faster reaction to output overload
conditions. Magnetics and passive
components do not need to be
oversized.
LT1241–LT1245
Output Rise and Fall Time
V
CC
= 15V
C
L
= 1nF
TIME 50ns/DIV
Low Output Cross-Conduction
means
LOWER SUPPLY CURRENT draw at
higher switching frequencies. Switch-
ing at higher than 200kHz is now
practical and more efficient.
TIME 50ns/DIV
Fast Output Rise and Fall Times
with clean edges give better high
frequency switching performance.
FET switches can be turned ON and
OFF efficiently and quickly.
, LTC and LT are registered trademarks of Linear Technology Corporation.
Rev D 0496
Linear Technology Corporation • 1630 McCarthy Blvd. • Milpitas, CA 95035-7417 • (408) 432-1900 • www.linear-tech.com • Literature Only: 1-800-4-LINEAR
Power Factor Correction and
Off-Line Converter Products –
InfoCard 6
LT1248/LT1249 Power Factor Controllers
Features
s
s
s
s
s
s
s
s
s
s
Applications
s
s
High Power Factor Over Wide Load Range
with Line Current Averaging
International Operation Without Switches
Instantaneous Overvoltage Protection
Minimal Line Switching Noise
Typical 250µA Start-Up Supply Current
Rejects Line Switching Noise
Synchronization Capability
Low Quiescent Current: 9mA
Fast 1.5A Peak Current Gate Driver
8-Lead Surface Mount Package: LT1249
Universal Power Factor Corrected Power Supplies
Preregulators
TOP VIEW
TOP VIEW
GND
8
GTDR
V
CC
V
SENSE
VA
OUT
1
2
3
4
5
6
7
8
LT1248CN
LT1248IN
LT1248CS
LT1248IS
16 GTDR
15 V
CC
14 C
SET
13 SS
12 R
SET
11 V
SENSE
10 EN/SYNC
9
V
REF
GND 1
CA
OUT
2
M
OUT
3
I
AC
4
LT1249CN8
LT1249IN8
LT1249CS8
LT1249IS8
PK
LIM
CA
OUT
I
SENSE
M
OUT
I
AC
VA
OUT
OVP
7
6
5
N8 PACKAGE
8-LEAD PLASTIC DIP
S8 PACKAGE
8-LEAD PLASTIC SOIC
N PACKAGE
16-LEAD PLASTIC DIP
S PACKAGE
16-LEAD NARROW PLASTIC SOIC
LT1105/LT1103 Simplified Off-Line Switcher
LT1103
APPLICATION
Universal Off-Line
Battery Charger, Isolated Off-Line
Telecom, – 48V Input Isolated
Low Voltage Isolated DC/DC (≤ 24V)
High Voltage Isolated DC/DC
LT1105
10W to Over 100W
OK
OK
Requires External MOSFET
OK
(INTERNAL SENSE RESISTOR)
10W to 50W
OK
OK
Needs No MOSFET
OK
LT1103 Minimum Parts Count Isolated Off-Line Converter
No Opto-Isolators!
OPTIONAL OUTPUT FILTER
85 - 270V
AC
MBR2045
10µH
5V
10A
+
+
–
BRIDGE
RECTIFIER
+
LINE
FILTER
1000pF
100Ω
BAV21
BAV21
16.2k
1%
39µF
25V
220µF
385V
499Ω
220k
1W
HI
!!
GER E!!
DAN LTAG
O
GH V
1.5KE300A
5W
MUR150
+
35V
3600µF
+
50V
470µF
1N4148
*OUTPUT CAPACITOR IS THREE 1200µF,
50V CAPACITORS IN PARALLEL TO
ACHIEVE REQUIRED RIPPLE CURRENT
RATING AND LOW ESR.
WINDINGS FOR
OPTIONAL
±12V
DC
OUTPUTS
V
IN
V
SW
LT1103
BUK426-800A
+
FB
10Ω
15V
V
C
OSC
390pF
330Ω
0.047µF
0.1µF
5.36k
1%
GND
+
1µF
25V
TRANSFORMER DATA:
COILTRONICS - CTX110228-3
L
(PRI)
= 1.6mH
N
PRI
:N
SEC
= 1:0.05
N
BIAS
:N
SEC
= 1:0.27
LT1103 TA01
Linear Technology Corporation • 1630 McCarthy Blvd. • Milpitas, CA 95035-7417 • (408) 432-1900 • www.linear-tech.com • Literature Only: 1-800-4-LINEAR
©1992 LT/GP 0496 10K
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