The PCU9656 is a UFm I²C-bus controlled 24-bit LED driver optimized for voltage switchdimming and blinking 100 mA Red/Green/Blue/Amber (RGBA) LEDs. Each LEDn outputhas its own 8-bit resolution (256 steps) fixed frequency individual PWM controller thatoperates at 97 kHz (typical) with a duty cycle that is adjustable from 0 % to 99.6 % toallow the LED to be set to a specific brightness value. An additional 8-bit resolution (256steps) group PWM controller has both a frequency of 190 Hz and an adjustable frequencybetween 24 Hz to once every 10.73 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 LEDn output can be off, on (no PWM control), set at its individual PWM controllervalue or at both individual and group PWM controller values. The PCU9656 operates witha supply voltage range of 2.3 V to 5.5 V and the 100 mA open-drain outputs allowvoltages up to 40 V for the LED supply.
The PCU9656 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).
The active LOW Output Enable input pin (OE) blinks all the LEDs outputs and can beused to externally PWM the outputs, which is useful when multiple devices need to bedimmed or blinked together without using software control.
Software programmable LED Group and three Sub Call I²C-bus addresses allow all ordefined groups of PCU9656 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 or marquee chasingeffect, thus minimizing I²C-bus commands. Six hardware address pins allow up to64 devices on the same bus.
The Software Reset (SWRST) Call allows the master to perform a reset of the PCU9656through the I²C-bus, identical to the Power-On Reset (POR) that initializes the registers totheir default state causing the output NAND FETs to be OFF (LED off). This allows aneasy and quick way to reconfigure all device registers to the same condition.
A new feature to control LEDn output pattern is incorporated in the PCU9656. A newcontrol byte called ‘Chase Byte’ allows enabling or disabling of selective LEDn outputsdepending on the value of the Chase Byte. This feature greatly reduces the number ofbytes to be sent to the PCU9656 when repetitive patterns need to be displayed as increating a marquee chasing effect.
Feature
- 24 LED drivers. Each output programmable at:
- Off
- On
- Programmable LED brightness
- Programmable group dimming/blinking mixed with individual LED brightness
- 5 MHz Ultra Fast-mode unidirectional I²C-bus interface
- 256-step (8-bit) linear programmable brightness per LEDn output varying from fully off(default) to maximum brightness using a 97 kHz PWM signal
- 256-step group brightness control allows general dimming (using a 190 Hz PWMsignal) from fully off to maximum brightness (default)
- 256-step group blinking with frequency programmable from 24 Hz to 10.73s andduty cycle from 0 % to 99.6 %
- 24 open-drain outputs can sink between 0 mA to 100 mA and are tolerant to amaximum off-state voltage of 40 V. No input function
- Output state change programmable on the Acknowledge (bit 9, this bit is always setto 1 by master) or the STOP Command to update outputs byte-by-byte or all at thesame time (default to ‘Change on STOP’)
- Active LOW Output Enable (OE) input pin allows for hardware blinking and dimming ofthe LEDs
- Six hardware address pins allow 64 PCU9656 devices to be connected to the sameUFm I²C-bus and to be individually programmed
- Four software programmable UFm I²C-bus addresses (one LED Group Call addressand three LED Sub Call addresses) allow groups of devices to be addressed at thesame time in any combination (for example, one register used for ‘All Call’ so that allthe PCU9656s on the I²C-bus can be addressed at the same time and the secondregister used for three different addresses so that 1⁄3 of all devices on the bus can beaddressed at the same time in a group). Software enables and disables for I²C-busaddress
- A Chase Byte allows execution of predefined ON/OFF pattern for the 24 LEDn outputs
- Software Reset feature (SWRST Call) allows the device to be reset through theUFm I²C-bus
- 25 MHz internal oscillator requires no external components
- Internal power-on reset
- Noise filter on USDA/USCL inputs
- Glitch-free LEDn outputs on power-up
- Supports hot insertion
- Low standby current
- Operating power supply voltage (VDD) range of 2.3 V to 5.5 V
- 5.5 V tolerant inputs on non-LED pins
- -40 °C to +85 °C operation
- ESD protection exceeds 2000 V HBM per JESD22-A114 and 1000 V CDM perJESD22-C101
- Latch-up testing is done to JEDEC Standard JESD78 which exceeds 100 mA
- Package offered: LQFP48
