L6566B datasheet(43/51 Pages) STMICROELECTRONICS

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L6566B

Application information

43/51

It is worth reminding that “Auto-restart” means that the device will work intermittently as long

as the condition that is activating the function is not removed; “Latched” means that the

device is stopped as long as the unit is connected to the input power source and the unit

must be disconnected for some time from the source in order for the device (and the unit) to

restart. Optionally, a restart can be forced by pulling the voltage of pin 16 (AC_OK) below

0.45 V.

Protection

Description

Caused by

behavior

Vcc

restart

(V)

IC Iq

(mA)

VREF

(V)

VCOMP

(V)

OSC

(V)

FMOD

VFF

Shutdown2

Shutdown

by VCOMP

low

VCOMP <

VCOMPOFF

Latched

0.33

ADAPTIVE

UVLO

Shutdown

by Vcc going

below Vccoff

(lowering of

Vccoff

threshold at

light load)

Vcc < 9.4V

(VCOMP >

VCOMPL)

Auto

restart

5 V

0.18

Vcc < 7.2V

(VCOMP >

VCOMPO)

Use One external diode from VFF (#15) to AC_OK (#16), cathode to AC_OK

Use one external diode from SS (#14) to VREF (#10), cathode to VREF

If Css and the Vcc capacitor are such that Vcc falls below UVLO before latch tripping (Figure 21 on page 34)

If Css and the Vcc capacitor are such that the latch is tripped before Vcc falls below UVLO (Figure 21 on page 34)

When TJ < 110

Discharged to zero by Vcc going below UVLO

Table 6.

L6566B protections (continued)

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