STEVAL-ILL008V1 STMicroelectronics, STEVAL-ILL008V1 Datasheet - Page 11

• Manufacturer Part Number: STEVAL-ILL008V1
• Description: EVAL BOARD CREE LED FLASHLIGHT
• Manufacturer: STMicroelectronics

Specifications of STEVAL-ILL008V1

• Mfg Application Notes: Low Voltage LED Driver AppNote
• Design Resources: STEVAL-ILL008V1 Gerber Files STEVAL-ILL008V1 Schematic STEVAL-ILL008V1 Bill of Materials
• Outputs And Type: 1, Non-Isolated
• Voltage - Output: 3.5V
• Features: 1V Start up Input Voltage
• Voltage - Input: 1 ~ 5.5 V
• Utilized Ic / Part: L6920
• Product: Display Modules
• Core Chip: L6920DA
• Output Voltage: 3.5V
• Kit Contents: L6920D, L4971, L6902D Reference Board
• Development Tool Type: Hardware - Eval/Demo Board
• Tool / Board Applications: LED Flashlight
• Mcu Supported Families: L6920DA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Output / Channel: -
• Lead Free Status / Rohs Status: Details
• Other names: 497-5516

4 L6902D BUCK LED DRIVER:
Another buck topology reference design that is much simpler, less expensive and requires
fewer external components is the L6902D LED driver. The features of the L6902D are:
4.1 L6902D Description
The L6902D is a complete and simple step down switching regulator with adjustable constant
voltage and constant current. By means of a current sense resistor set to give a 0.1V drop
across it, the current ca be set to any desired value up to 1 amp. Iout=0.1V/Rsense.
Figure 15. Internal Block Diagram:
The L6902D contains a voltage and a current error amplifier with an internal reference of 3.3V
and 1.235 with a tolerance of ±2%. Most of the external circuits of the previous design are in-
corporated inside this battery charger chip. This 8 pin chip minimizes pin count by fixing the
switching frequency and allowing 2 pins for current sensing, 1 for sensing the output voltage.
– Up to 1A of output current
– Input voltage from 8V to 36V
– Built in 5% output current accuracy
– 250KHz internally fixed frequency
– Adjustable current limit
– Thermal shut down
AN1941 APPLICATION NOTE
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