AS3685C

Datasheet

www.austriamicrosystems.com/AS3685

(ptr)

1.1

11 - 21

The control waveform is shown in the next figure:

Figure

14 – Timing Diagram of the AS3685 using active Low strobe function

If the strobe function is not used at all, the interface can be addressed like a normal slave (only writing access).

The strobe function does not violate the two wire interface specification.

Data1 setups the flash current from 0mA to 1000mA, Data2 can be used to set the preview current and Data3

will set the operating mode, can lock 1:2 charge pump mode and set or disable the flash mode timeout time.

Table 7 – Current and Mode Setting for the AS3685

Register

Purpose

Comments

Data1<7:0>

Current Setting Flash

Flash Mode current setting, Flash Timeout timer used if the

mode setting uses this current

0mA to 700mA

Data2<6:0>

Current Setting Torch (Preview)

Torch (=Preview or Assist) Mode current setting, no timeout

timer used for this current setting

0mA to 500mA

0mA to 350mA

Data2<7>

not used – leave at 0

not used

Data3<2:0>

Mode setting

000 … Off (Power down; Charge Pump in 1:1 mode)

001 … Indicator Mode

Data2<7> = 0: ILED = 0.5mA

Data2<7> = 1: ILED = 1.0mA

010 … Torch (=Preview) Mode (Data2 sets current)

011 … Flash Mode (Data1 sets current)

100 … Preview / Flash Mode, STROBE active high

STROBE=H: Flash mode (Data1 sets current)

STROBE=L: Preview mode (Data2 sets current)

101 … Preview / Flash Mode, STROBE active low

STROBE=L: Flash mode (Data1 sets current)

STROBE=H: Preview mode (Data2 sets current)

110 … Force Charge Pump into 1:1.5 mode; no current is

flowing through the current sink (AS3685 can be

used as voltage generator for e.g. backlight LEDs

with additional external current source(s))

111 … Force Charge Pump into 1:2 mode; no current is

flowing through the current sink (AS3685 can be

used as voltage generator for e.g. backlight LEDs

with additional external current source(s))