ISL97672 Intersil, ISL97672 Datasheet - Page 12

• Manufacturer Part Number: ISL97672
• Description: 6-Channel LED Driver
• Manufacturer: Intersil

cooled to approximately +100°C, the device will restart
with the DC LED current level reduced to 75% of the
initial setting. If the dissipation problem persists,
subsequent hitting of the limit will cause identical
behavior, with the current reduced in steps to 50% and
CASE FAILURE MODE
1
2
3
4
/FLAG
CH0 Short Circuit
CH0 Short Circuit
CH0 Short Circuit
CH0 Open Circuit
with infinite
resistance
VIN
IMAX
DRIVER
FAULT FLAG
ILIMIT
Upper
Over-Temperature
Protection limit
(OTP) not triggered
and CH0 < 4V
Upper OTP
triggered but VCH0
< 4V
Upper OTP not
triggered but CH0
> 4V
Upper OTP not
triggered and CH0
< 4V
12
DETECTION
FAULT
MODE
LOGIC
FIGURE 20. SIMPLIFIED FAULT PROTECTIONS
GENERATOR
DETECT
FAULT
LOGIC
PWM
CH0 ON and burns power.
All channels go off until chip
cooled and then comes back on
with current reduced to 76%.
Subsequent OTP triggers will
reduce I
CH1 disabled after 6 PWM cycle
time-out.
V
time-out after 6 PWM cycles and
switch off. V
normal level.
TABLE 1. PROTECTIONS TABLE
OUT
FAILED CHANNEL ACTION
DRIVER
SHORT
THRM
THRM
SHDN
SHDN
FET
O/P
OTP
OTP
will ramp to OVP. CH1 will
PWM/OC0/SC0
OUT
ISL97672
VSET
OUT
further.
will drop to
LX
VSC
VSC
LX
finally 25%. Unless disabled via the EN pin, the device
stays in an active state throughout.
For the extensive fault protection conditions, please refer
to Figure 20 and Table 1 for details.
OVP
T2
T1
SENSOR
TEMP
REF
Same as CH0
CH1 through CH5 Normal
CH1 through CH5 Normal
CH1 through CH5 Normal
GOOD CHANNELS ACTION
VOUT
Q0
PWM/OC5/SC5
CH0
VSET
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REGULATED BY
Highest VF of
CH1 through
CH5
Highest VF of
CH1 through
CH5
Highest VF of
CH1 through
CH5
Highest VF of
CH1 through
CH5
Q5
CH5
June 24, 2010
V
OUT
FN7632.0