New 12-channel constant current LED driver

     Diodes Incorporated has introduced a new 12-channel constant-current LED driver, the AL58221. It has 12 open drain outputs rated at 24V, absorbs high-precision currents up to 60mA, and has fast transient response. The channel-to-channel LED current accuracy is usually ±1%, and the regulated output current tolerance is ±0.1%.

     With input voltages from 3V to 5.5V, the driver uses adaptive pulse density modulation (APDM) to help mitigate non-ideal IOUT distortion and improve visual refresh rate, thereby enhancing performance. It can be used in indoor and outdoor LED video signage and displays, variable information signage (VMS), architectural and decorative LED lighting systems, and LCD backlighting.

     The LED current of the device is set by three external resistors (for RGB main Settings), and the average output current of each channel is independently programmed through its digital interface. It has a 10MHz dual-edge trigger data clock input that reduces EMI. The device's two-wire serial interface sends grayscale data to a function control register that stores configuration information. It controls grayscale resolution and clock frequency, current output waveform selection and internal latch function.

     The driver uses APDM to increase the visual refresh rate of 16-bit > 1000hz and 8-bit grayscale >256kHz. This technology reduces flicker and provides two-sided processing of the output current to reduce electromagnetic interference. The device uses clock duty cycle recovery technology with pulse retiming to support longer distance connections. Its dual-wire serial interface also allows cascading applications up to 1030 devices.

     In the same LED driver family, the recently introduced AL58263 is a 16-channel device with 16-bit PWM grayscale dimming control for higher resolution and larger display panel applications.