LT1158CS LINER [Linear Technology], LT1158CS Datasheet - Page 15

• Manufacturer Part Number: LT1158CS
• Description: Half Bridge N-Channel Power MOSFET Driver
• Manufacturer: LINER [Linear Technology]

APPLICATIONS
from a true short. This is done by using the current limit to
control cold filament current in conjunction with the self-
protection circuit of Figure 9. The reduced cold filament
current also extends the life of the filament.
A good guideline is to choose R
mately twice the steady state “on” current of the lamp(s).
t
lamp filaments heat and drop out of current limit before the
enable capacitor discharges to the enable low threshold.
For a short circuit, the enable capacitor will continue to
discharge below the threshold, shutting down the top
TYPICAL APPLICATIONS
SHUTDOWN
Q1, Q2: IRLZ44 (LOGIC-LEVEL)
L1: HURRICANE LAB
R
CONSTANT OFF TIME CURRENT MODE CONTROL LOOP
FREQUENCY =
VISHAY/ULTRONIX RCS01, SM1
S
CMOS
ON/OFF
: VISHAY/DALE TYPE LVR-3
HL-KK122T/BB
ISOTEK CORP. ISA-PLAN SMR
100k
IRFZ44 (STANDARD)
100k
is then made long enough to guarantee that the
t
OFF
1
2N2222
VP0300
INSERT FOR
ZERO POWER
SHUTDOWN
(
1 –
U
V
Figure 10. High Efficiency 3.3V Step-Down Switching Regulator (Requires No Heatsinks)
V
OUT
IN
)
WHERE t
INFORMATION
U
+
OFF
SENSE
24k
10 s
10 F
U
W
0.01 F
to set I
1000pF
1
2
3
4
5
6
7
8
BOOST DR
V
BIAS
ENABLE
FAULT
INPUT
GND
B GATE FB
SC
+
at approxi-
U
LT1158
1N4148
T GATE DR
B GATE DR
T GATE FB
T SOURCE
SENSE
SENSE
BOOST
V
+
–
+
MOSFET. The LT1158 will then go into the automatic
restart mode described in Self-Protection with Automatic
Restart above.
The time constant for an incandescent filament is tens of
milliseconds, which means that t
longer than in most other applications. This places in-
creased SOA demands on the MOSFET during a short
circuit, requiring that a larger than normal device be used.
A protected high current lamp driver application is shown
in Figure 18.
16
15
14
13
12
11
10
9
0.1 F
510
100
100
0.05 F 1k
680k
1N4148
Q1
Q2
1
2
3
4
5V TO 10V INPUT (USE LOGIC-LEVEL Q1, Q2)
8V TO 20V INPUT (USE STANDARD Q1, Q2
AND CONNECT BOOST DIODE TO PIN 1)
+
22 H
L1
LT1431
500 F
LOW ESR
+
0.015
R
SHUTDOWN
S
8
7
6
5
SHORT-CIRCUIT
CURRENT = 8A
–
4.99k
1%
1.62k
1%
+
will have to be
LT1158
1000 F
LOW ESR
+3.3V/6A
OUTPUT
LT1158 F10
200pF
15