EV0021
Monolithic Power Systems
General Description
The EV0021 evaluation board uses the
MP1521 to drive up to three strings of 5 White
LEDs. This MP1521 uses a peak current,
constant minimum off-time architecture and
has
three
individual
current-sensing
feedbacks. The OLS pin is designed for
detecting loose or open LED connections.
The feedback pins measure voltage across
sense resistors in series with the LED strings.
When supplying a bias current of 20mA, the
voltage drop across the sense resistor is only
0.4V to minimize power loss. Either a DC
voltage or a PWM signal at the BRT/PWM
input can control the LED brightness. The
MP1521 has an on board power MOSFET
switch that is protected by current limit, open
load shutdown, thermal shutdown, and under
voltage lockout.
MP1521 High Efficiency
White LED Driver
EVALUATION BOARD
Absolute Maximum Ratings
Supply Voltage (V
IN
)
28V
Switch Voltage to GND
-0.5V to 28V
V
EN
,V
REF
, V
BRT
, V
FB1
, V
FB2
, V
FB3
–0.3V to 6V
Storage Temperature
-55°C to +150°C
Recommended Operating Conditions
Supply Voltage (V
IN
)
2.7 V to 25V
Ordering Information
Board Number
EV0021
MPS IC Number
Figure 1: EV0021 Evaluation Board
EV0021 Rev 1.1_01/21/03
www.monolithicpower.com
1
MPS [ MONOLITHIC POWER SYSTEMS ]
