Page 20 ams Datasheet
Document Feedback [v2-23] 2016-Mar-30
AS3685A/AS3685B − Detailed Description
AS3685B Current Setting
The current through the LED (I
LED
) can be set in several steps
using the following waveforms:
Figure 29:
AS3685B Current Setting Method A
For method A, the current is started after a certain time after
the first rising edge of EN1. The AS3685B chooses method A, if
EN1 is high at the first rising edge of EN2.
Figure 30:
AS3685B Current Setting Method B
For method B, the current is started after the second rising edge
of EN2. The AS3685B chooses method B, if EN1 is low at the first
rising edge of EN2.
Any high or low level duration for EN1 or EN2 should not be
shorter than t
PULSEWIDTH
.
The actual number of pulses on the pin EN1 (applies for
methods A and B) define the mode and the current settings for
the AS3685B:
EN2
EN1
Set current with
number of pulses
offoff
Flash/Strobe/Indicatior function
dependent on number of pulses
I
LED
t
typ. 64μs
Current can be increased
if required
Define
Method A
min.
t
PULSEW IDTH
EN2
EN1
Set current with
number of pulses
offoff
Flash/Strobe/Indicatior function
dependent on number of pulses
I
LED
t
typ. 64μs
Current can be
increased if required
no time limit
Define
Method B
min tPULSEW IDTH
