
8-String WLED Driver with Integrated Step-Up
Regulator and SMBus/PWM Dimming Capability
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1. V IN = 12V, C COMP = 33nF, R COMP = 1k I , R ISET = 50k I , R OSC = 100k I , R DFSET = 250k I , PWMI = SGND,
C PWMO = 1μF, T A = -40 N C to +85 N C , unless otherwise noted. Typical values are at T A = +25 N C.) (Note 2)
PARAMETER
CONDITIONS
MIN
TYP
MAX
UNITS
FAULT PROTECTION
OVP Threshold Voltage
OVP Shutdown Voltage
OVP Global Fail
FB_ UVLO Threshold
FB_ Overvoltage Threshold
FB_ Check LED Source Current
FB_ Overvoltage Fault Timer
Overcurrent FAULT Shutdown Timer
Rising edge, hysteresis = 60mV
Rising edge (tracks with OVP threshold voltage)
FB open
I PEAK > 2.9A at duty = 75% (typical)
1.15
1.25
48
140
7.4
0.4
88
72
1.35
1.45
120
300
8.6
168
168
V
V
mV
mV
V
mA
F s
F s
FAULT High-Level Leakage Current
FAULT Low-Level
Clamp Voltage
FAULT Charge Current
V FAULT = V IN = 28V
V IN -
5.5
45
1
V IN
-4.5
65
F A
V
F A
PWM FILTER
PWM Output Impedance
20
60
k I
DPWM Oscillator Frequency
DFSET Short-Detection
Threshold Voltage
PWMI Input Frequency Range
PWMI Brightness Setting
R DFSET = 250k I
R DFSET = 10k I
DPST/SMBus mode
Direct-PWM mode
SMBus mode, PWMI duty cycle = 98%
SMBus mode, PWMI duty cycle = 50%
SMBus mode, PWMI duty cycle = 0%
190
4.4
9.5
0.1
97.5
48
0.2
210
5.5
300
10.5
30.0
98.5
52
0.6
Hz
kHz
mV
kHz
%
SMBus TIMING SPECIFICATION
SMBus Frequency
Bus Free Time
START Condition Hold Time from SCL
START Condition Setup Time from SCL
STOP Condition Setup Time from SCL
SDA Hold Time from SCL
SDA Setup Time from SCL
SCL Low Period
SCL High Period
f SMB
t BUF
t HD:STA
t SU:STA
t SU:STO
t HD:DAT
t SU:DAT
t LOW
t HIGH
10
4.7
4
4.7
4
300
250
4.7
4
100
kHz
F s
F s
F s
F s
ns
ns
F s
F s
6
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