LT1513-2IT7 Linear Technology, LT1513-2IT7 Datasheet - Page 14

• Manufacturer Part Number: LT1513-2IT7
• Description: IC BATT CHG CNST/PROG I/V TO2207
• Manufacturer: Linear Technology

Specifications of LT1513-2IT7

• Function: Charge Management
• Battery Type: All Battery Types
• Voltage - Supply: 2.7 V ~ 25 V
• Operating Temperature: -40°C ~ 125°C
• Mounting Type: Through Hole
• Package / Case: TO-220-7 Formed Leads
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

LT1513/LT1513-2
This Cold Cathode Fluorescent Lamp driver uses a Royer
class self-oscillating sine wave converter to driver a high
voltage lamp with an AC waveform. CCFL Royer converters
have significantly degraded efficiency if they must operate at
low input voltages, and this circuit was designed to handle
input voltages as low as 2.7V. Therefore, the LT1513 is
connected to generate a negative current through L2 that
allows the Royer to operate as if it were connected to a
constant higher voltage input.
TYPICAL APPLICATIONS
14
10nF
C10
C2: TOKIN MULTILAYER CERAMIC
C3: MUST BE A LOW LOSS CAPACITOR, WIMA MKP-20 OR EQUIVALENT
L1, L2: COILTRONICS CTX20-4 (MUST BE SEPARATE INDUCTORS)
Q1, Q2: ZETEX ZTX849 OR FZT849
T1: COILTRONICS CTX110605 (67:1)
ELECT
47 F
C1
6
2
+
S/S
V
TO 20V
FB
2.7V
V
V
IN
C
1
7
R7
2k
C9
1 F
15V
D2
Figure 9. CCFL Power Supply for Floaing Lamp Configuration Operates on 2.7V
LT1513-2
20 H
L1
20k
C5
4.7nF
R4
GND
V
SW
U
5
4, TAB
I
FB
3
C6
0.1 F
PWM DIMMING
( 1kHz)
R5
330k
10k
R3
The Royer output winding and the bulb are allowed to float in
this circuit. This can yield significantly higher efficiency in
situations where the stray bulb capacitance to surrounding
enclosure is high. To regulate bulb current in Figure 9, Royer
input current is sensed with R2 and filtered with R3 and C6.
This negative feedback signal is applied to the I
LT1513. For more information on this circuit contact the LTC
Applications Department and see Design Note 133. Consid-
erable written application literature on Royer CCFL circuits is
also available from other LTC Application and Design Notes.
D1
3A
C2
4.7 F
CERAMIC
20 H
L2
Q2
0.082 F
WIMA
C3
3
R1
470
•
4
2
5
•
0.25
NEGATIVE VOLTAGE
IS GENERATED HERE
R2
1
Q1
LAMP CURRENT
10
C4
27pF
3kV
5.6mA
CCFL
1513 F09
•
6
T1
FB
sn1513 1513fas
pin of the