AS3685B datasheet(11/25 Pages) TAOS

11 / 25 page

AS3685A/AS3685B

Datasheet

www.austriamicrosystems.com/

AS3685

(ptr)

Revision 2.2

10 - 24

Application Hint

: To obtain higher torch currents use the following circuit:

Figure 13 – AS3685A Increasing Torch Current

ISET

VBAT

EN1

EN2

VBAT

EN1

EN2

RTORCH

AS3685A

RISET

7.2.1.1 AS3685A Pulsed Indicator Mode

The torch mode is controlled by EN1=0 and EN2=1 as following figure shows:

Figure 14 – AS3685A Torch Mode

EN2

EN1

off

Torch

Current

ILED

typ. 64µs

To allow an indication function using short pulses (with torch current settings), the pulsed indicator mode can be

used. The control device sends a setup sequence (total time required: less than 128μs) to ‘program’ the

AS3685A, and the AS3685A enables its current sink for the duration tTORCH (the current used is exactly the torch

current setting). Therefore the control does not need to setup an timer to accurately define the duration of the

indicator pulse.

The duration tTORCH can be setup from 1ms to 15ms depending on the number of pulses on EN2 as shown in the

following figure and table:

AS3685B Datasheet(PDF) 11 Page - TEXAS ADVANCED OPTOELECTRONIC SOLUTIONS