Rainbow-electronics MAX1698 Manual de usuario descargar pdf (Pagina 5)

MAX1698

High-Efficiency Step-Up

Current Regulator for LEDs

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NAME FUNCTION

1 V

IC Supply Voltage Input. Power for internal circuitry. Input range is 2.7V to 5.5V.

SHDN

Active-Low Shutdown Input. In shutdown, the MOSFET turns off, but a current path still exists between the

input and output. The minimum forward voltage of the LED array must exceed the maximum V

BATT

to ensure

that the LEDs are off in shutdown.

3 REF

1.25V Reference Output. Capable of sourcing 150µA for external loads. This pin is internally compensated.

Do not connect any bypass capacitors at REF.

4 ADJ Adjust Input. Allows dynamic adjustment of the output current. FB regulates to 300mV when ADJ = REF.

6 FB Feedback Input. Connect to the external LED current-sense feedback resistor.

8 PGND Power Ground

9 CS FET Current-Sense Input

5, 7 GND Ground

10 EXT Gate Driver Output

Pin Description

UNDERVOLTAGE

LOCKOUT/

SHUTDOWN

PGND

EXT

REF

GND

ADJ

SHDN

MAX t

MIN t

OFF

MAX1698

SOFT-START

1.25V REFERENCE

Figure 1. Functional Diagram

1 2 3 4 5 6 7 8

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Rainbow-electronics MAX1698 Manual de usuario Pagina 5