AN993

L6574 ballast driver

Doc ID 5656 Rev 10

7/27

8

EN1

Enable 1. This pin (active high), forces the device into a latched shutdown state (like

in undervoltage conditions). There are two ways of resuming normal operation: the

first is by reducing the supply voltage below the undervoltage threshold and then

increasing it again until the valid supply is recognized; the second is by activating the

EN2 input (see Figure 9). The Enable 1 is specifically designed for strong faults (for

example, in case of lamp disconnection).

9

EN2

Enable 2. EN2 input (active high) restarts the start-up procedure (preheating and

ignition sequence). This feature is useful if the lamp does not turn on after the first

ignition sequence (see Figure 10).

10

GND

Ground.

11

LVG

Low-side driver output. This pin must be connected to the low-side power MOSFET

gate of the half bridge. A resistor connected between this pin and the power

MOSFET gate can be used to reduce the peak current.

12

VS

Supply voltage. This pin is connected to the supply filter capacitor (15.6 V typical).

13

N.C.

Not connected. This pin sets a distance between the pins related to the high-voltage

side and those related to the low-voltage side.

14

OUT

High-side driver floating reference. This pin must be connected close to the source of

the high-side power MOSFET or IGBT.

15

HVG

High-side driver output. This pin must be connected to the high-side power MOSFET

gate of the half bridge. A resistor connected between this pin and the power

MOSFET gate can be used to reduce the peak current.

16

VBOOT

Bootstrapped supply voltage. The bootstrap capacitor must be connected between

this pin and OUT. A patented integrated circuit replaces the external bootstrap diode

by means of a high-voltage DMOS, synchronously driven with the low-side power

MOSFET.

Table 1.

Description of device pins (continued)

Number

Name

Function