MP1523 – PRECISION 6-LAMP WHITE LED DRIVER

INITIAL RELEASE

07/04, Rev. 1.6

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3

TYPICAL PERFORMANCE CHARACTERISTICS

85

80

75

70

2.5

3.0

3.5

4.0

4.5

MP1523_TPC01

of Figure 2

23

21

19

17

15

2.5

3.0

3.5

4.0

4.5

MP1523_TPC02

Line Regulation

of Figure 2 and Figure 3

PIN FUNCTIONS

Pin #

Name

Description

1

SW

Power Switch Output. SW is the drain of the internal MOSFET switch. Connect the

power inductor and output rectifier to SW. SW can swing between GND and 25V.

2

GND Ground

3

FB

Feedback Input. The MP1523 regulates the voltage across the current sense

resistor between FB and GND. Connect a current sense resistor from the bottom of

the LED string to GND. Connect the bottom of the LED string to FB. The regulation

threshold is 0.4V.

4

EN

Regulator On/Off Control Input. A high input at EN turns on the converter, and a low

input turns it off. When not used, connect EN to the input source for automatic

startup. If EN is driven over 6V, place a resistor in series with EN to limit current to

10µA or less. Do not leave EN floating!

5

BIAS Internal Power Input. BIAS powers the internal circuitry and measures the output

voltage for open circuit protection. Connect BIAS to the output at the top of the LED

string to enable open load shutdown feature (see Figure 3). Connect BIAS to the

input to eliminate open load shutdown feature (see Figure 2).