AS7220 datasheet(18/33 Pages) AMSOSRAM

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[v1-00] 2017-Feb-16

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AS7220 − Detailed Description

AS7220 Outputs

The AS7220 outputs, used to control dimming and LED

warm/cool strings, can be configured as either three PWM

outputs, two PWMs and one analog output, or two PWMs. The

PWMs are 12 bit and are factory set to 888 Hz. Refer to the Figure

below.

The three PWM outputs, PWM_1, PWM_2 and PWM_3 all switch

with the same frequency, but not simultaneously for better EMI

performance.

The PWM_1 output can be set to either analog (0-VDDHV) or

digital (0-VDDHV ) dimming. Analog dimming range is 0-100%.

Digital Dimming range is 0-100%. PWM2 and PWM3 are used

for cool white and warm white LED color controlling. Either

string can be warm or cool as the AS7220 automatically

configures string color type. Range is 0-100% for both PWM2

and PWM3.

To set the desired device operation MODE use the appropriate

RMODE resistor, also shown in the Figure below.

Figure 20:

Outputs

Note(s):

1. For VDDHV>10.5, output max is 10V, else output max tracks VDDHV.

Indicator LED

An LED, connected to pin LED_IND, is used to indicate

programming progress of the device. During programming of

the AS7220 via an external SD card, the indicator LED starts

blinking operation. When programming is finished the

indicator LED stays on. The LED_IND pin is set for 1mA operation

by the AS7220 factory firmware, and is not under user control.

Refer to the separate ams document for a complete description

of AS7220 Firmware Update Methodology.

MODE

RMODE

Setting

Outputs

PWM_1/0_10V_O

PWM_2 and PWM_3

100 Ω

0-10V analog

Analog 0-VDDHV (1)

Digital PWMs (0-VDD)

470 Ω

0-10V digital

Digital PWM (0-VDDHV) (1)

Digital PWMs (0-VDD)

1000 Ω

Digital 2-CH color tuning

n.a.

Digital PWMs (0-VDD), w/Dimming

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