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AS7221

Functional Description

Datasheet

• PUBLIC

DS000479

• v4-00 • 2019-Jun-28

│ 19

Figure 14:

0-10 V Dimming Pin Input

For the AS7221, dimming can be accomplished from either the input pin (DIM) or smart lighting

command via the UART. For network commanded dimming, using the AS7221 Smart Lighting

Command Set, the UART interface is used. To prevent flicker effects the low end of the dimming

range can be adjusted via the ATDMLTL command to the provided range of the external dimming

device.

Local hardware inputs can be provided by, for example, a slide control dimmer. The 0-10 V DIM

analog input signal is downscaled by the AS7221 with an internal voltage divider and converted to a

10-bit digital value, 0 V=full dimming, 10 V=no dimming. When using the internal voltage divider the

voltage at the VDDHV pin has to be higher than 10 V.

If a second supply voltage is not available, VDDHV and VDD are tied together and the downscale has

to be done by an external resistor divider. The maximum range in the downscaled input is limited to

2 V. Hence, to accept a full range 10 V signal the input resistor divider has to be 5:1 ratio. Dependent

on the level at pin VDDHV the Smart Lighting Manager automatically selects either the internal or the

external voltage divider. Refer to Figure 14 and Figure 15.

If the DIM pin is not used, an external resister pull-up connecting it to VDDHV is recommended. For a

complete description of the Smart Lighting Command Set refer to Section 10 Figure 32.

Figure 15:

AUX Pin Input

AS7221 Datasheet(PDF) 20 Page - OSRAM GmbH