L6585D

Device description

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Device description

Designed in High-voltage BCD Off-line technology, the L6585D embeds a PFC controller, a

half-bridge controller, the relevant drivers and the logic necessary to build an electronic

ballast.

The advanced and precise logic circuitry, combined with the programmability of the End-of-

Life windows comparator threshold, makes the L6585D compliant with either "lamp-to-

ground" or "block capacitor-to ground" configurations.

Another outstanding feature is the possibility of controlling and limiting the lamp voltage

during the ignition phase.

The pre-heating and ignition durations are independently settable as well as the half-bridge

switching frequencies for each operating phases (pre-heating, ignition and normal mode).

Other features (half-bridge over-current with frequency increase, PFC over-voltage) allow

building a reliable and flexible solution with a reduced part count.

The PFC section achieves current mode control operating in Transition Mode; the highly

linear multiplier includes a special circuit, able to reduce AC input current distortion, that

allows wide-range-mains operation with an extremely low THD, even over a large load

range.

The PFC output voltage is controlled by means of a voltage-mode error amplifier and a

precise internal voltage reference.

The driver of the PFC is able to provide 300mA (source) and 600mA (sink) and the drivers of

the half-bridge provide 290mA source and 480mA sink.

Figure 2.

Typical system block diagram

MULT

PFCS

PFG

ZCD

INV

COMP

GND

OSC

RF

EOI

Tch

CTR

EOLP

Vcc

BOOT

HSD

LSD

OUT

HBCS

HV BUS

LAMP

AC MAINS

Charge

pump

L

B

L

PFC

12

3

45

EOL-R

6

7

8

9

10

11

12

13

14

15

17

20

19

16

18

L6585D

MULT

PFCS

PFG

ZCD

INV

COMP

GND

OSC

RF

EOI

Tch

CTR

EOLP

Vcc

BOOT

HSD

LSD

OUT

HBCS

HV BUS

LAMP

AC MAINS

Charge

pump

L

B

L

PFC

12

3

45

EOL-R

6

7

8

9

10

11

12

13

14

15

17

20

19

16

18

L6585D