AS3645 austriamicrosystems, AS3645 Datasheet - Page 12

• Manufacturer Part Number: AS3645
• Description: 1000/720ma Ultra Small High Efficient Single/dual Led Flash Driver With Safety Features
• Manufacturer: austriamicrosystems

AS3645
Datasheet - D e t a i l e d D e s c r i p t i o n
Single/Dual LED Maximum Current Protection
If a dual flash LED is detected (see
I
Note: Disable the single/dual LED detection and protection when using boost_current=1 by setting led_det_on=0 and
Device Startup and Operating Mode selection
AS3645A Operating Mode
The AS3645A chooses the operating mode according to the digital input level on pin I2C/EN. If I2C/EN=H, I
is selected, if I2C/EN=L parallel interface mode with fixed output currents is used.
AS3645B Operating Mode
Figure 17. AS3645B operating mode selection flow
If the AS3645B detects a high level on I2C/EN, I
V
adjustable output currents’ is selected otherwise ‘parallel interface mode with fixed output currents’ is selected.
Single/Dual LED Detection
During startup of the main current source (pin LED_OUT), the current source is ramped to I
pin LED_OUT is above V
otherwise cleared:
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LED_OUT
ISET
6. To obtain higher currents, set led_det_on=0 and led_amount=0.
. If the resulting current into the pin I2C/EN is then lower than I
led_amount=0.
(400mA) in I
2
C mode
LED_DET
6
and parallel interface mode with fixed output currents.
, two flash LEDs in series are assumed and the bit
Single/Dual LED Detection on page
parallel interface mode
with adjustable output

2
$ % & 
currents
C mode is used. If a low level is detected, the pin I2C/EN is pulled to


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RISETMAX

 

parallel interface mode
12) the maximum flash current is limited to
with fixed output
, the mode ‘parallel interface mode with

 % & 
currents

led_amount (see page 24)
LED_DET
. If the voltage on
2
C mode
12 - 33
is set,