Datasheet
SLIS094A − MARCH 2000 − REVISED MAY 2005
8
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265
PARAMETER MEASUREMENT INFORMATION
OUTPUT CURRENT
vs
TIME FOR INCREASING LOAD RESISTANCE
O
I − Output Current − A
I − Output Current
Region 1
Region 2
t
1
t
2
First output current pulses after turn-on in chopping mode with
resistive load.
0
1
1.5
O
0
t
1
≈ 40 µs
t
2
≈ 2.5 ms
Time
Time
I
OK
(see
Notes
A
and
B)
REGION 1 CURRENT WAVEFORM
I
OK
t
2
t
1
t
1
1.25
0.75
0.5
0.25
NOTES: A. Figure 3 illustrates the output current characteristics of the device energizing a load having initially low, increasing resistance, e.g.,
an incandescent lamp. In region 1, chopping occurs and the peak current is limited to I
OK
. In region 2, output current is continuous.
The same characteristics occur in reverse order when the device energizes a load having an initially high, decreasing resistance.
B. Region 1 duty cycle is approximately 2%.
Figure 3. Chopping-Mode Characteristics
0.9
0.6
0.3
0
− 50 − 25 0 25 50 75
1.2
OUTPUT CURRENT LIMIT
vs
CASE TEMPERATURE
100
T
C
− Case Temperature − °C
O
I − Output Current Limit − A
1.5
125 150
V
CC
= 5.5 V
V
CC
= 4.5 V
Figure 4