The IS32LT3181 is a six channel linear current
regulator for automotive rear tail light applications such
as RCL (Rear Combination Lamps) and CHMSL
(Center High Mounted Stop Lamps). It is fully
programmable with two LED brightness levels for the
different intensity requirements of “stop” bright (DC
mode) and “tail” dim (PWM mode).
A logic level at the PWM pin is used to select between
the tail and stop output conditions. The stop condition
provides the highest intensity output, while the tail
condition utilizes an internally generated PWM signal
to reduce the intensity of the LEDs’ light output.
An active low fault output signal reports a device error
condition. The FAULTB pin of several devices can be
tied together to disable all the output stages when a
fault is detected by any one of the devices.
The sink current at the OUTx pins is easily set with a
single resistor at the STOP pin. The constant-current
sink outputs can be combined in parallel to create
higher current-driving capability on a single string. A
second resistor at the TAIL pin sets the duty cycle of
the internal PWM oscillator for dimming the LED output
when operating in the tail condition.
An external FET (optional) can be implemented for
operation with wide varying supply voltages to
minimize device thermal dissipation.
The IS32LT3181 is offered in an eTSSOP-16 package.