概觀
The IS31BL3228A (IS31BL3228B) is a low noise,
constant frequency charge pump DC/DC converter
for white LED applications. The IS31BL3228A
(IS31BL3228B) is capable of driving up to four (six)
channels of LEDs at preset 20mA per channel from a
2.8V to 5.5V input. The current sinks may be operated
individually or in parallel for driving higher current
LEDs. Only one 1μF small capacitor (at C+ thru C-)
and two small 2.2μF capacitors (at VCC and VOUT) are
needed, it makes this part ideally suited for small,
battery-powered applications.
The serial digital input is used to enable, disable, and
set current for each LED with 14 settings down to
1.8mA. Each output of the
IS31BL3228A/IS31BL3228B is equipped with built-in
soft-start circuitry prevents excessive inrush current
during start-up. A low-current shutdown feature
disconnects the load from the input and reduces
quiescent current to less than 3μA.
The IS31BL3228A and IS31BL3228B are available in
a Pb-free, space-saving UTQFN-12 (2mm×2mm)
package.