Preliminary
EUP2520
Dual Output Step-Up Converter for White
LED Backlighting and OLED Display
Power Supply
DESCRIPTION
The EUP2520 is a dual step-up DC/DC converter,
uses a single inductor and a schottky diode to provide
two outputs. One is designed to drive up to 5 white
LEDs with a constant current and the other is to
power an organic LED display with a constant
voltage. Each output is enabled by individual logic
inputs.
A single external resistor is used to set the
maximum LED current. The LED current can be
adjusted by applying a PWM signal to the EN pin.
For higher efficiency the EUP2520 operates with
pulse frequency modulation (PFM) control scheme
when the sub-display is enabled. When Main display
is enabled, the device is operating in PWM mode.
Overvoltage protection circuitry and a 1MHz
switching frequency allow for the use of small, low
cost external components.
Additional features include a low-side NFET switch
that can turn off the LED string with no DC current
path to ground. The EUP2520 is available in a small
12-pin thermally- enchanced TDFN package.
FEATURES
2.7V to 5.5V Input Voltage Range
Up to 5 LEDs at 20mA and 4 LEDs at 30mA
for Main-display Backlighting
Up to 20V @ 50mA for OLED Sub-display
Output True shutdown
80% Efficiency
0.7A DMOS Switch
1MHz Switching Frequency
23V Over Voltage Protection
Cycle-By-Cycle Current Limit
PWM Dimming Control
3mm
×
3mm TDFN-12 Package
RoHS Compliant and 100% Lead (Pb)-Free
APPLICATIONS
Clam-shell Cellular Phones with OLED/LCD
Displays
Typical Application Circuit
Figure 1.
DS2520 Ver0.1 May. 2007
1
EUTECH [ EUTECH MICROELECTRONICS INC ]
