The SN3352 is a continuous mode inductive step-down
converter, designed for driving a single LED or multiple
series connected LEDs efficiently from a voltage source
higher than the required LED voltage. The chip operates
from an input supply between 6V and 40V and provides an
externally adjustable output current of up to 750mA.
Depending upon supply voltage and external components,
this can provide up to 30 watts of output power.
The SN3352 includes an integrated output switch and a
high-side output current sensing circuit, which uses an
external resistor to set the nominal average output current.
The SN3352 integrates temperature compensation function
in order to maintain LEDs’ stable and reliable operation.
The SN3352 measures the thermistance mounted close to
LEDs. When ambient temperature near LEDs goes too high
and the Negative Temperature Coefficient thermistors reach
the value of threshold resistance connected at RTH pin,
output current starts to reduce automatically. And after the
ambient temperature fall down to safe temperature，the
current will return to the set value.
The SN3352 can be connected as LED drivers’ chain with
the same temperature compensation percentage. In this
chain, every SN3352’s ADJO output pin drives next stage’s
SN3352 ADJI input pin with temperature compensation
information. So only one thermistor is needed in the whole SN3352 system.