EV0021 Datasheet, PDF (3/4 Pages) Monolithic Power Systems – MP1521 High Efficiency White LED Driver

Monolithic Power Systems
Table 1: EV0021 Bill of Materials
Parts
ICs
MP1521EQ
Capacitors
4.7µF
1µF, 25V
Resistors
10KΩ
20Ω
Inductors
15µH
Diodes
B130, 1A, 30V, Schottky
LEDS (Not Provided)
Package
QFN16
1206
1210
0603
0603
CDRH3D16
SMA
EV0021
MP1521 High Efficiency
White LED Driver
EVALUATION BOARD
Vendor
MPS
Any
Any
Any
Any
Sumida
Any
QTY Components
1 U1
1 C1
1 C2
3 R1, R2, R3
3 R4, R5, R6
1 L1
1 D1
Operating Instructions
1. Connect VCC to the power source’s positive output.
2. Connect GND to supply ground.
3. Applying a logic signal to EN pin will enable the MP1521. Logic high (V_EN>1V) turns on IC,
logic low puts it into low current shutdown mode. Place a 100KΩ resistor in series with EN if
the input is greater than 10V. For automatic start up connect EN to VCC.
4. Applying a PWM signal to the BRT will adjust the LED brightness. When used in analog
mode, apply a DC voltage of 0.3 to 1.2V. This input voltage is attenuated by 1/3 to set the
voltage across sense resistors at FB1, FB2, and FB3. Maximum brightness (20mA) occurs
with 1.2V applied. To control brightness in PWM mode, apply a PWM square wave with a
minimum voltage less the 0.18V and a maximum greater than 1.2V. When a voltage less than
0.18V is applied to this pin, the output switch is turned off. The regulator operates at
maximum brightness when more than 1.2V is applied. The frequency of the PWM signal must
be between 100 to 400 Hz.
5. The FB1, FB2 and FB3 pins can be used to measure the voltage across the current-sense
resistor that is in series with the LED strings. Unused feedback pins must be connected to
any used feedback pin.
6. OLS senses the regulator output voltage to protect IC during open load operation. When this
pin’s voltage exceeds 28V, the output switch is shut off. The output switch remains off until
the IC is reset by cycling the enable pin (EN) or input supply (VIN)
EV0021 Rev 1.1_01/21/03
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