Overview
The IS32LT3126 is a dual linear programmable current
regulator consisting of 2 independently controlled
output channels; each channel is capable of sourcing
150mA. Both channels can be combined to provide a
total of 300mA. It supports PWM dimming of both
channels via power supply modulation (PSM). It also
features ENx pins to individually PWM dim and
independently adjust the average output current for
each channel. The max current for each channel is set
with its corresponding external resistor.
The UVx pins set the VCC under voltage lockout of
each channel to match the LED stack for high side
PWM dimming operation. In addition, the IC integrates
fault protection for LED open/short, ISETx pin
open/short and over temperature condition for robust
operation. Detection of these failures is reported by
FAULTB pin. When a fault is detected the device will
disable itself and output an open drain low signal.
Multiple devices can have their FAULTB pins
connected to create a “one-fail-all-fail” condition. For
multiple LED string applications, the device can detect
a single LED short. The single LED short detection is
set by a resistor divider on the STx pins. A single LED
short failure is reported by the separate FAULTB_S
pin.
The IS32LT3126 is targeted at the automotive market
with end applications to include interior and exterior
lighting. For 12V automotive applications the low
dropout driver can support one to several LEDs on the
output channels. It is offered in a small thermally
enhanced eTSSOP-16 package.