AL1783Q

Document number: DS46208 Rev. 1 - 2

2 of 14

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January 2024

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AL1783Q

Typical Application Circuit

PWM1

PWM2

FAULTB

REF1

GND

LED1

LED2

3.3V

RFAULTB

RREF1

VIN

VIN up to 55V

MCU

AL1783Q

RREF2

REF2

PWM3

RREF3

REF3

LED3

CIN

R

G

B

R

G

B

Figure 1. Typical Application

Pin Descriptions

Pin Number

Pin Name

Function

VIN

1

Power Supply for Chip

NC

2

No Connection

PWM1

3

PWM Dimming Signal and Enable Input for 1st Channel of LED1, Internally Pulled Down 200k

Ω Typical.

PWM2

4

PWM Dimming Signal and Enable Input for 2nd Channel of LED2, Internally Pulled Down 200k

Ω Typical.

PWM3

5

PWM Dimming Signal and Enable Input for 3rd Channel of LED3, Internally Pulled Down 200k

Ω Typical.

GND

6

Ground

GND

7

Ground

GND

8

Ground

LED3

9

3rd Channel for LED String Cathode

LED2

10

2nd Channel for LED String Cathode

LED1

11

1st Channel for LED String Cathode

NC

12

No Connection

FAULTB

13

Fault Report. Open Drain Asserted Low to Report Faulty Conditions. Needs an External Pullup Resistor.

REF3

14

Reference Current Setting Through External Resistor (Rref3) for 3rd Channel

REF2

15

Reference Current Setting Through External Resistor (Rref2) for 2nd Channel

REF1

16

Reference Current Setting Through External Resistor (Rref1) for 1st Channel

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Exposed PAD

Exposed pad must connect to GND. It should be externally connected to GND to reduce thermal

impedance. It should not be used as an electrical conduction path.