CS1937
Step-up DC/DC Converter for White LEDs
Features
Description
●Inherently
Matched LED Current
CS1937 is a step-up DC-DC converter
●High
Efficiency: 84% Typical
specially designed to drive white LEDs with
●Drives Up to 4 LEDs from a 3.2V Supply a constant current. The device can drive
●Drives Up to Six LEDs from a 5V Supply 2, 3 or 4 LEDs in series from a Li-lon cell.
●36V Rugged Bipolar Switch
Series connection of the LEDs provides
●Fast 1.2MHz Switching Frequency
identical LED currents resulting in uniform
●Requires Only 0.22uF Output Capacitor brightness and eliminating the need for
●Uses Tiny Inductors
ballast resistors. The CS1937 switches at
●SOT23-5(6) Package
1.2MHz, allowing the use of tiny external
components. The output capacitor can be
as small as 0.22uF, saving space and
cost. A low 95mV feedback voltage
minimizes power loss in the current setting
resistor for better efficiency.
Applications
● Cellular Phones
● PDA, Notebook, Digital Cameras
● MP3, MP4, GPS Receiver
Typical Application
SAMES [ SAMES ]
