 2012 Microchip Technology Inc.

DS01465A-page 3

AN1465

FIGURE 4:

ISOLATED COMMUNICATIONS CIRCUIT

FIGURE 5:

ISOLATED COMMUNICATIONS CIRCUIT DIAGRAM

DALI Power Supply Circuits

DALI power supply needs fast response time and

efficient current limiting. This simple circuit works well.

FIGURE 6:

CIRCUIT

DALI Transmission

DALI uses Manchester (bi-phase) encoding to send the

Start bit and the information bits. The information rate

is 1200 bps with an acceptable range of ± 10%. One bit

time is 833.33 µs. The Most Significant bit (MSb) is sent

out first (Figure 7).

DALI TX

330R

R5

1

2

U1

TCLT1000

4

3

R8

1K

R4

120R

Q2

MMBT2222A-TP

+5V

DALI RX

R7

10K

4

3

1

2

U2

TCLT1000

R6

2.2K

D4

MM5Z5V1

BGX 50A E6327

3

D5

1

DALI BUS

(Interrupt Pin)

(Any GPIO)

+12-22V DC

Out DALI+ (D)