LED7707 datasheet(6/48 Pages) STMICROELECTRONICS

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Pin settings

LED7707

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2.2

Pin description

Table 2.

Pin functions

N°

Function

1COMP

Error amplifier output. A simple RC series between this pin and ground is

needed to compensate the loop of the boost regulator.

2RILIM

Output generators current limit setting. The output current of the rows can be

programmed connecting a resistor to SGND.

BILIM

Boost converter current limit setting. The internal MOSFET current limit can

be programmed connecting a resistor to SGND.

4FSW

Switching frequency selection and external sync input. A resistor to SGND is

used to set the desired switching frequency. The pin can also be used as

external synchronization input. See

Section 5.1.5 on page 16 for details.

5MODE

Current generators fault management selector. It allows to detect and manage

LEDs failures. See

Section 5.3.2 on page 23 for details.

AVCC

+ 5 V analog supply. Connect to LDO5 through a simple RC filter.

7LDO5

+ 5V LDO output and power section supply. Bypass to SGND with a

1 µF ceramic capacitor.

VIN

Input voltage. Connect to the main supply rail.

9SLOPE

Slope compensation setting. A resistor between the output of the boost

converter and this pin is needed to avoid sub-harmonic instability.

Refer to

Section 6.1 on page 26 for details.

SGND

Signal ground. Supply return for the analog circuitry and the current

generators.

ROW1

Row driver output #1.

ROW2

Row driver output #2.

ROW3

Row driver output #3.

ROW4

Row driver output #4.

ROW5

Row driver output #5.

ROW6

Row driver output #6.

PGND

Power ground. Source of the internal Power MOSFET.

OVSEL

Over-voltage selection. Used to set the desired 0 V threshold by an external

divider. See

Section 5.1.4 on page 15 for details.

Switching node. Drain of the internal Power MOSFET.

DIM

Dimming input. Used to externally set the brightness by using a PWM signal.

Enable input. When low, the device is turned off. If tied high or left open, the

device is turned on and a soft-start sequence takes place.

FAULT

Fault signal output. Open drain output. The pin goes low when a fault condition

is detected (see

Section 5.3.1 on page 23 for details).

SYNC

Synchronization output. Used as external synchronization output.

Soft-start. Connect a capacitor to SGND to set the desired soft-start duration.

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