STLED524 STMicroelectronics

STLED524 Intelligent matrix LED display driver Datasheet - preliminary data Description The STLED524 is a 5x24 dot matrix LED display driver. It can drive each dot with a current up to 20 mA. Rows of the matrix are multiplexed. Each LED in a row is driven by a separate low-side current mirror. Current regulators are supplied by an integrated boost DC-DC converter. Its output voltage can be adjusted by the internal register to optimize efficiency according to the type of LEDs CSP 56 bumps 0.4 mm pitch 3.4x3.0 mm (their forward voltage). This reduces current mirror power dissipation and improves overall efficiency. The STLED524 also includes an Features internal LDO regulator, which can provide a supply voltage for an additional circuitry. Operating input voltage range from 2.7 V to Maximum current, provided by each current 5.5 V mirror, is adjusted by R resistor. Current of SET 5x24 LED matrix driver each LED (dot) can be dimmed in 255 steps due Adjustable luminance separately for each LED to settings of internal registers. thanks to internal registers in 255 steps The STLED524 features PWM dimming in 255 Internal registers store 2 patterns steps. Automatic slope function is also supported. Cycle time and slope time can be adjusted for 4-way scroll function with the possibility to lock each LED (dot) separately. column data PWM dimming in 255 steps Two patterns can be stored in internal registers. The automatic scrolling of the display content is Adjustable blanking time possible in 4 ways. Automatic slope function Cycle time and slope time adjustable for each Table 1. Device summary dot separately Order code Package Packaging SPI interface STLED524 CSP Tape and reel Integrated step-up converter with adjustable output voltage Integrated LDO with 3.1 V output 80 mA Boost efficiency 92% at 350 mA 2.4 MHz switching frequency CSP 56 bumps 0.4 mm pitch 3.4x3.0 mm Applications Appliance user interfaces Display driver for handheld units April 2014 DocID026217 Rev 1 1/72 This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to www.st.com 72 change without notice. Contents STLED524 Contents 1 Application schematic . 8 2 Absolute maximum ratings 11 3 Electrical characteristics 12 4 Detailed description 15 4.1 Boost converter 15 4.2 LED matrix 16 4.2.1 Blanking time . 16 4.3 LED current setting 18 4.4 Patterns 19 4.4.1 Pattern register organization . 19 4.4.2 Display size 20 4.5 Description of registers . 21 4.5.1 Software control register 21 4.5.2 Display control register . 21 4.5.3 Clock register . 22 4.5.4 Column control register . 23 4.5.5 Row control register 24 4.5.6 Blanking time register 24 4.5.7 Boost control register . 25 4.5.8 Display visual control register 25 4.5.9 PWM control register . 26 4.5.10 Scroll control 1, scroll control 2 and scroll control 3 registers 27 4.5.11 Interrupt enable register . 27 4.5.12 Latch register . 28 4.5.13 Status register 28 4.5.14 Scroll step register . 29 4.5.15 Version register . 29 4.6 Slope mode operation . 29 4.7 Scrolling 32 4.7.1 Scroll control registers 32 4.7.2 Locking columns and rows 34 2/72 DocID026217 Rev 1