16-Channel Low Knee Voltage PWM Constant Current
LED Driver for Low Voltage Power Supply,
1:32 Time-multiplexing Applications
MBI5155 is designed for LED video applications using internal Pulse Width Modulation (PWM) control with
selectable 16-bit / 14-bit / 13-bit color depth, and the circuit characteristics is optimized for applications with 4.2V
supply voltage. MBI5155 features a 16-bit shift register which converts serial input data into each pixel’s gray scale
of the output port. Sixteen regulated current ports are designed to provide uniform and constant current sinks for
driving LEDs with a wide range of VF variations. The output current can be preset through an external resistor. The
innovative architecture with embedded SRAM is designed to support up to 1:16 time-multiplexing applications.
Users only need to send the whole frame data once and to store in the embedded SRAM of the LED driver, instead
of sending every time when the scan line is changed. It helps to save the data bandwidth and to achieve high
grayscale with very low data clock rate. With scan-type Scrambled-PWM (S-PWM) technology, MBI5155 enhances
PWM by scrambling the “on” time of each scan line into several “on” periods and sequentially drives each scan line
for a short “on” period. The enhancement equivalently increases the visual refresh rate of scan-type LED displays. In
addition, the innovative GCLK multiplier technique doubles visual refresh rate.
MBI5155 drives the corresponding LEDs to the brightness specified by image data. With MBI5155, all output
channels can be built with 16-bit color depth (65,536 gray scales). When building a 16-bit color depth video, S-PWM
technology reduces the flickers and improves the image fidelity.
Through compulsory error detection, MBI5155 detects individual LED for open-circuit errors without extra
components. MBI5155 equipped an innovative cross elimination function, and it solves the cross phenomenon
induced by failure LEDs. Besides, integrated ghost elimination circuit eases the ghosting problems. Embedded low
grayscale processing technology effectively fixed the image display defects, and improved the quality of image
- 2 - April 2015, V1.00