ISL78171 Datasheet, PDF (18/29 Pages) Intersil Corporation – 6-Channel, 50mA Automotive LED Driver with Ultra-high Dimming Ratio and Phase Shift Control

ISL78171
CASE FAILURE MODE
8 Channel-to-Channel
VF too high
9 Channel-to-Channel
VF too high
10 Output LED stack
voltage too high
11 V_OUT/LX shorted to
GND at start-up or
V_OUT shorted in
operation
TABLE 2. PROTECTIONS TABLE (Continued)
DETECTION MODE
FAILED CHANNEL ACTION
GOOD CHANNELS ACTION
V_OUT REGULATED
BY
Lower OTP triggered but
CHx < 7.5V
Any channel below the target current will fault out after 6 PWM cycles.
Remaining channels driven with normal current.
Highest VF of
remaining
channels
Upper OTP triggered but
CHx < 7.5V
V_OUT > VOVP
All channels go off until chip cools and then come back on with current Boost switch OFF
reduced to 76%. Subsequent OTP triggers will reduce I_OUT further.
Any channel that is below the target current will time-out after 6 PWM Highest VF of
cycles, and V_OUT will return to the normal regulation voltage required for remaining
other channels.
channels
LX current and timing are
monitored.
OVP pins monitored for
excursions below 20% of
OVP threshold.
The chip is permanently shutdown 31ms after power-up if V_OUT/Lx is
shorted to GND.
SMBCLK
V_IH
V_IL
SMBDAT
V_IH
V_IL
P ^tBUF S
t_LOW
t_HD:STA
t_R
t_F
t_HD:DAT
t_HIGH
t_SU:DAT
t_SU:STA
S
NOTES:
SMBus/I²C Description
S = start condition
P = stop condition
A = acknowledge
A = not acknowledge
R/W = read enable at high; write enable at low
FIGURE 30. SMBUS/I²C INTERFACE
t_SU:STO
P
1
7
S
SLAVE ADDRESS
Master to Slave
Slave to Master
1
1
8
1
W
A
COMMAND CODE
A
FIGURE 31. WRITE BYTE PROTOCOL
8
DATA BYTE
1
1
A
P
1
7
1
1
8
1
1
8
1
1
S SLAVE ADDRESS W
A COMMAND CODE A
S SLAVE ADDRESS R
A
Master to Slave
Slave to Master
FIGURE 32. READ BYTE PROTOCOL
8
DATA BYTE
1
1
A
P
Submit Document Feedback ₁₈
FN8602.0
June 15, 2015