Strobe

(50 mV/DIV)

(500 mV/DIV)

TIME

(10 ms/DIV)

Sense

High

Sense

Low

1V

VIO/VBAT

Trip Point

Decode

Current Control

Register

AVAGO APDS-9005

2.2 k:

Default TRIP POINTS

1000 LUX for Bright Ambient (900 mV) (Bright Outdoor Lighting)

No Flash

100 to 1000 LUX for Indoor Ambient (90 mV) (Office Lighting)

70% Full-Scale Flash

0 to 100 LUX for Low Ambient (Night or Movie Theater)

Full-Scale Flash

1V

1 PF

LM3550

SNVS569B – MAY 2009 – REVISED MAY 2013

www.ti.com

Most ambient light sensors suggest placing a capacitor in parallel with the voltage-setting resistor in order to help

filter the 50/60 Hz. noise generated by fluorescent overhead lighting. This capacitor can range from no capacitor

up to 10 µF. The key is to filter the noise so that the peak-to-peak voltage is less than 16 mV (LSB size of the

ALD/TEMP Sense High and Sense Low settings). Please refer to the ambient light sensor's datasheet for the

recommended capacitor value.

The Flash current drops to 70% of the peak once the voltage on the ALD/TEMP pin exceeds the Sense Low trip

point.

Figure 58. Effect of ALD/TEMP Voltage Rising during a Flash

30

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