AS3693B

austriami crosyst ems

www.austriamicrosystems.com

Revision 1.21 / 2011-09-30

10 - 32

7

Block Description

7.1 Feedback Circuit

The AS3693B supports a flexible feedback selection for external DCDC – supplies. Beside the default setup for

RGGB lighting, each channel can be assigned to an external DCDC feedback loop. This feedback circuit is

important to reduce power dissipation of the device.

Table 6 – Feedback Control

Addr: 04h

Feedback control

Enables and Disables the Different Feedback modes

Bit

Bit Name

Default

Access

Description

0

Feedback on

1

R/W

1 = Feedback Circuit is active

0 = The entire Feedback Loop is disabled

1

Feedback on PWM

0

R/W

0 = The Feedback Regulator is always active

1 = The Feedback Regulator is only active, if PWM = 1

2

Open_Led_Det_on

0

R/W

Enables open Led Detection Comparators

0 = Open Led Detection Disabled

1 = Open Led Detection Enabled, Level: Ucurrx = 50mV

3

Short_det_on

0

R/W

Enables Short detection

0 = Short detection off

1 = Sort detection on.

5:4

Short Led Detect

Voltage(VSL)

R/W

Short led Detection Trip Voltage ( debounced 3mS )

00 = 2V

01 = 3V

7:6

DCDC_Regulation_tri

p Point (VC)

00

R/W

Trip Point voltage of the DCDC-Feedback Regulation

Circuit. (NOTE: This value has to be adjusted if Analog

Ref select Bit is changed.)

00 = 0.5V (Note use for Currents up to 70 mA)

01 = 0.6V (Note use for Currents up to 80 mA)

10 = 0.8V (Note use for Currents up to 110 mA)

11 = 1.0V (Note use for Currents up to 150 mA)