STEVAL-TLL013V1 STMicroelectronics

STEVAL-TLL013V1 5-channel (2 LEDs in series per channel) step-up white LED driver demonstration board based on the STLED25 Data brief Features Operating input voltage range from 2.3 V to 5.5 V 7.5% LED current accuracy Two LEDs in series per channel High-side current source Up to 125 mA of total LED current 86% efficiency at 100 mA PWM dimming with automatic shutdown time window 2.5 MHz switching frequency RoHS compliant STEVAL-TLL013V1 Description The STEVAL-TLL013V1 demonstration board was designed to demonstrate the performance of the STLED25, a fixed frequency, high-efficiency, boost DC-DC converter with five parallel high-side current sources. The STLED25 is able to provide 125 mA of total current with a maximum voltage of 7.5 V on each channel. Each current source supports single or dual LED connections. The output voltage of the step-up converter is automatically set at 100 mV above the highest voltage required on any driver to guarantee the proper operation of the linear current sources. The device implements a self- test feature to detect any failure of the LEDs and to disable the related channel. The failure status is reset as soon the IC is disabled. This mode of failure detection allows the device to continue operating driver channels that are operating normally, while avoiding excessive power consumption or associated thermal issues. September 2011 Doc ID 022250 Rev 1 1/4 For further information contact your local STMicroelectronics sales office. www.st.com 4 Schematic circuit STEVAL-TLL013V1 1 Schematic circuit Figure 1. Application schematic Table 1. Typical external components Component Manufacturer Part number Value Size C Murata GRM155R60J155M 1.5 F 0402 IN C Murata GRM219R61A116U 10 F 0805 OUT L Samsung CIG21K4R7SCE 4.7 H 0805 (1) R 25 k 0402 SET 1. For 20 mA per branch. 2/4 Doc ID 022250 Rev 1