L6382D

8/14

4

APPLICATION INFORMATION

4.1 POWER MANAGEMENT

The L6382D has two stable states (

age the Start-up and fault conditions (fig. 5): the Over Current Protection is a parallel asynchronous pro-

cess enabled when in

Following paragraphs will describe each mode and the condition necessary to shift between them.

Figure 5.

4.1.1 START-UP mode

With reference to the timing diagram of figure 6, when power is first applied to the converter, the voltage

on the bulk capacitor builds up and the HV generator is enabled to operate drawing about 10mA. This cur-

rent, diminished by the IC consumption (less than 150

µA), charges the bypass capacitor connected be-

tween pin Vcc and ground and makes its voltage rise almost linear.

During this phase, all IC's functions are disabled except for:

microcontroller connected to this pin;

As the Vcc voltage reaches the start-up threshold (14V typ.) the chip starts operating and the HV generator

is switched off.

Summarizing:

■

the high-voltage start-up generator is active;

■

■

TPR is disabled;

■

OCP is disabled;

■

the drivers are disabled.

4.1.2 SAVE Mode

rent source mode to supply the

µC connected to it, whose wake-up required current must be less than

10mA: if no switching activity is detected at LGI input, the high voltage start-up generator cycles ON-OFF

keeping the Vcc voltage between VccON and VccSM.

SAVE MODE

OPERATING

MODE

SHUT DOWN

V

V

V

&

T

LGI low

for more

than 100ms

START-UP

V

or

V

V

V

SAVE MODE

OPERATING

MODE

SHUT DOWN

V

V

V

&

T

LGI low

for more

than 100ms

START-UP

V

or

V

V

V