LED7708 datasheet(40/53 Pages) STMICROELECTRONICS

Part #	LED7708

Description	16 channels x 85 mA LED driver with boost controller and 4-wire serial interface

PDF	53 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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40 / 53 page

Recommended operating conditions

LED7708

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Doc ID 022698 Rev 1

Equation 15

Figure 12.

Dimming signals and synchronization

Table 21.

Function of pins involved in dimming control

Function

GSCK

Input or output, depending on FOSC pin status;

FOSC high: grayscale clock input, internal oscillator disabled.

FOSC to resistor: grayscale clock output. The clock, internally generated by the dimming

oscillator, is provided at this pin.

FOSC

Internal oscillator frequency setting. See above.

GSSY

Input or output pin, depending on DSYS bit value. Used for dimming synchronization.

See Table 21.

Table 22.

Dimming synchronization control

DSYS

Dimming sync selector (locked if DEN is asserted)

The GSSY pin is set as output and provides a pulse at the end of each dimming cycle.

The device continuously performs a latency+dimming sequence.

The GSSY pin is set as input. The ongoing dimming sequence is reset as soon as a

rising edge on the GSSY input is detected; a new latency+dimming cycle is triggered by

the falling edge on this pin.

OSC

DIM

LED7708 Datasheet(PDF) 40 Page - STMicroelectronics