LT3581 LINER [Linear Technology], LT3581 Datasheet - Page 9

• Manufacturer Part Number: LT3581
• Description: 3.3A Boost/Inverting DC/DC Converter with Fault Protection
• Manufacturer: LINER [Linear Technology]

sTaTe DiagraM
FAULT1 = OVER VOLTAGE PROTECTION ON V
OVER TEMPERATURE (T
OVER CURRENT ON SW1 (I
OVER VOLTAGE PROTECTION ON SW1 (V
OVER VOLTAGE PROTECTION ON SW2 (V
IF |V
FB > 45mV (INVERTING)
FB < 1.17V (BOOST)
OUT
| DROPS CAUSING:
OR
JUNCTION
SW1
SS < 50mV
> 1.9A MIN)
> 165°C)
• ALL SWITCHES DISABLED
• I
• FAULTS CLEARED
• SS PULLED LOW
• I
• SS CHARGES UP
• SWITCHER ENABLED
• Q1 & Q2 SWITCHES
• I
• NORMAL OPERATION
• CLKOUT ENABLED WHEN
IN
FORCED ON EVERY CYCLE
FOR AT LEAST MINIMUM
ON TIME
WHEN SS > 500mV
SS > 1.8V
SHDN < 1.33V (TYPICAL)
GATE
GATE
GATE
(V
V
IN
IN
NORMAL MODE
SAMPLE MODE
SW1
SW2
< 2.3V (TYPICAL)
OFF
ENABLED
FULLY ACTIVATED
SOFT START
> 22V MIN)
INITIALIZE
CHIP OFF
> 42V MIN)
> 42V MIN)
or
SHDN > 1.33V (TYPICAL)
V
IN
> 2.3V (TYPICAL)
Figure 2. State Diagram
AND
FAULT2 = FAULT PULLED LOW EXTERNALLY (FAULT < 0.75V)
FAULT1
FAULT1
FAULT1
FAULT1
• SS CHARGES UP
• IGATE OFF
• FAULT PIN PULLED LOW
• SWITCHER DISABLED
• CLKOUT DISABLED
• SS SLOWLY DISCHARGES
• INTERNAL FAULT PIN PULLDOWN
• SS CONTINUES DISCHARGING
INTERNALLY BY LT3581
RELEASED BY LT3581
TO GND
LOCAL FAULT OVER
POST FAULT DELAY
FAULT DETECTED
SS > 1.8V AND
NO FAULT1 CONDITIONS
STILL DETECTED
SS < 50mV
FAULT PIN > 1.0V
3581 SD
FAULT2
FAULT1
FAULT1
LT3581

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