TSL2671

DIGITAL PROXIMITY DETECTOR

TAOS118 − JANUARY 2011

12

r

r

Copyright

E 2011, TAOS Inc.

The LUMENOLOGY

r Company

www.taosinc.com

Power Management

Power consumption can be controlled through the use of the wait state timing because the wait state consumes

only 65

μA of power. Figure 14 shows an example of using the power management feature to achieve an

average power consumption of 138

μA current with four 100-mA pulses of proximity detection.

4 IR LED Pulses

65

ms (29 ms LED On Time)

2.72 ms

43.52 ms

5.44 ms

Prox ADC

Prox Accum

Wait

Wait

Delay

Average Current = ((0.029

State

Duration (ms)

Current (mA)

Prox Accum

0.065 (Note 1)

LED On

0.029 (Note 2)

100.0

Prox ADC

2.72

0.175

Wait

43.52

0.065

Wait Delay

5.44

0.175

Example: ~49 ms Cycle TIme

Note 1: Prox Accum = 16.3

ms per pulse

Note 2: LED On = 7.2

ms per pulse

Figure 12. Power Consumption Calculations