AN3111 datasheet(18/23 Pages) STMICROELECTRONICS

Part #	AN3111

Description	18 W single-stage offline LED driver

PDF	23 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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18 / 23 page

STEVAL-ILL027V2 demonstration board

AN3111

18/23

Doc ID 16815 Rev 2

Figure 13.

Output LED current and voltage for input voltage 260 V / 50 Hz

In case the output LEDs are disconnected, STEVAL-ILL027V2 has designed an open load

protection. Figure 14 shows open load protection after connecting mains voltage 230 V AC.

As can be seen, output voltage is regulated to 78 V.

Figure 14.

Open load measurement

Figure 15

shows short-circuit protection. As soon as the voltage on the VCC pin of the

L6562A reaches the turn-on threshold (capacitor C5 is charged via resistors R12 and R16),

the device starts switching (there is output current present) and the voltage VCC decreases,

because output voltage is almost 0 V and so the capacitor C5 cannot be supplied via the

transformer from the output voltage. As soon as the voltage on the VCC pin of the L6562A

AN3111 Datasheet(PDF) 18 Page - STMicroelectronics