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ams Datasheet

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[v1-00] 2017-Feb-16

AS7220 − Detailed Description

Alternately, for the flexibility of being able to set these

maintenance functions with dip switches designed into the

luminaire, the AS7220 I²C master interface can be used to

interface to I²C port expanders that are native to the AS7220.

These ports are then automatically used to read dip-switch

settings for maintenance. Refer to the separate AS7220 User

Guide for detailed design information for Lumen and CCT

maintenance.

The AS7220 can also use an input, the LDIM pin, to set a

maximum LUX target for the dimmer input (0_10V_DIM pin).

The LDIM pin voltage is converted to one of five max LUX target

settings: 0 (LDIM off ), 100, 250, 500 or 1000. An LDIM setting,

other than 0 (off ), is only used if daylighting is enabled (DAY_

EN pin) and the AS7220 detects an external ams TSL4531

needed for daylighting as described above. The daylighting LUX

target is set one of two ways. If LDIM is off, the LUX target is set

after every movement of the dimmer input by briefly opening

the daylighting control loop and measuring LUX. If LDIM is on,

the dimmer input sets the LUX target by percentage (0-100%)

of the LDIM LUX maximum setting. Refer to the separate AS7220

User Guide for detailed design information for LDIM operation.

Synchronization and Reset

Figure 19:

Synchronization and Reset Circuit

Synchronization and Reset Circuit: This figure shows the basic diagram when using reset and synchronization

function together.

AS7220 provides optional synchronization of the PWMs. This

sync signal can be derived from the AC mains to enable all

luminaires in a room to be synchronized to prevent beat

frequency flicker. If the SYNC pin is left open, synchronization

is automatically disabled by the internal pull-up connected to

the SYNC/RESN pin.

Refer to the Figure above. When pulled down for more than

100ms the SYNC/RESN pin will reset the AS7220 Smart Lighting

Manager. In this case the push-button “overrides” the output of

the opto-coupler. Therefore a resistor should be placed in series

with the opto-coupler.

SYNC and Reset

CLE

SYNC/

RESN

Opto Coupler

AC Main

Push > 100ms

10k

optional