The PCU9655 is a UFm I²C-bus controlled 16-channel LED driver optimized for voltage
switch dimming and blinking 100 mA Red/Green/Blue/Amber (RGBA) LEDs. Each LED
output has its own 8-bit resolution (256 steps) fixed frequency individual PWM controller
that operates at approximately 31.25 kHz with a duty cycle that is adjustable from 0 % to
99.6 % to allow the LED to be set to a specific brightness value. An additional 8-bit
resolution (256 steps) group PWM controller has both a fixed frequency of about 122 Hz
and an adjustable frequency roughly between 15 Hz to once every 16.8 seconds with a
duty cycle that is adjustable from 0 % to 99.6 % that is used to either dim or blink all LEDs
with the same value.
Each LED output can be off, on (no PWM control), set at its individual PWM controller
value or at both individual and group PWM controller values. The PCU9655 operates with
a supply voltage range of 3 V to 5.5 V and the 100 mA open-drain outputs allow voltages
up to 40 V.
The PCU9655 is one of the first LED controller devices in a new Ultra Fast mode (UFm)
family. UFm devices offer higher frequency (up to 5 MHz).
Software programmable LED Group and three Sub Call I²C-bus addresses allow all or
defined groups of PCU9655 devices to respond to a common I²C-bus address, allowing
for example, all red LEDs to be turned on or off at the same time, thus minimizing I²C-bus
commands. On power-up, PCU9655 will have a unique Sub Call address to identify it as a
16-channel LED driver. This allows mixing of devices with different channel widths. Five
hardware address pins on PCU9655 allow up to 32 devices on the same bus.
The Software Reset (SWRST) function allows the controller to perform a reset of the
PCU9655 through the I²C-bus, identical to the Power-On Reset (POR) that initializes the
registers to their default state causing the output voltage switches to be OFF (LED off).
This allows an easy and quick way to reconfigure all device registers to the same
Additionally, a thermal shutdown feature protects the device when the internal junction
temperature exceeds the overtemperature threshold.