Allegro MicroSystems A8600 Manual page 35

A8600
Table 1: Summary of Fault Mode Operation
Fault Condition Latched
SW1/2/3/4 output shorted
to GND
S1/2 output shorted to
GND
SW1/2/3/4 boot capacitor
missing
SW1/2/3/4 boot capacitor
shorted
SW1 asynchronous diode
missing
SW1/2/3/4 asynchronous
Yes
diode missing
SW1 asynchronous diode
(or LX1) hard short
SW1 asynchronous diode
(or LX1) soft short
SW1/2/3/4 asynchronous
Yes
diode (or LXx) hard short
SW1/2/3/4 asynchronous
diode (or LXx) soft short
SW1/2/3/4 FBx pin open
(V floats high)
FBx
SW1/2/3/4 overvoltage
(V > 107.5%)
FBx
LG4 more than 8.1 V for
Yes
>400 ns
LG4 in high state but
Yes
< 1 V for >400 ns
LG4 in low state but > 1 V
Yes
for >400 ns
Thermal (TSDL) Yes
SW1 Thermal (TSDH) Yes
SW2/3/4 Thermal (TSDH) Yes
1 EN/SYNC low requires a logic low for 15 clock cycles.
Quadruple Output Regulator with Two High-Side Switches,
V
SSx
Hiccup after 30 or Discharged, then
No
118 faults respond to V
No Not affected Not affected
Hiccup, after 7 Discharged, then
No
faults respond to V
Hiccup, after 30 Discharged, then
No
faults respond to V
Hiccup, after 1 Discharged, then
No
fault respond to V
Discharged after
Discharged
1 fault
Discharged, then
No Hiccup after 1 fault
respond to V
Hiccup after 30 Discharged, then
No
faults respond to V
Pulled low after
Discharged
1 fault
Hiccup after 30 Discharged, then
No
faults respond to V
Ramps high for
No Low via loop response
soft start
Ramps high for
No Low via loop response
soft start
Pulled low after
Discharged
1 fault
Pulled low after
Discharged
1 fault
Pulled low after
Discharged
1 fault
Not affected Not affected
After 2048 PWM cycles, latches in Low IQ mode
Pulled low Pulled low
BU/ACC Voltage Detectors, and Mute Delay
V V
COMPx POK
Depends on
rise V
SSx SWx
Not affected
Depends on
rise V
SSx SWx
Depends on
rise V
SSx SWx
N/A
rise
SSx
Depends on
V
SWx
N/A
rise
SSx
N/A
rise
SSx
Depends on
V
SWx
Depends on
rise V
SSx SWx
SW2/3/4 low
via V high
FBx
(OV)
Pulled Low
Depends on
V
SW4
Depends on
V
SW4
Depends on
V
SW4
Depends on
V
SWx
Depends on
V
SWx
PWM
S1, S2
Switching
Active, responds
Not affected
to VCOMPx
Foldback
Not affected
limiting
Off during hiccup Not affected
Off via UVLO
Not affected
BOOT
Active, responds
Not affected
to VCOMPx
Forced off Not affected
Active, responds
Not affected
to VCOMPx
Active, responds
Not affected
to VCOMPx
Forced off Not affected
Active, responds
Not affected
to VCOMPx
Off via V low Not affected
COMPx
Forced off Not affected
Latched off Not affected
Latched off Not affected
Latched off Not affected
Not affected Off
Off
Latched off Off
Allegro MicroSystems, LLC
115 Northeast Cutoff
Worcester, Massachusetts 01615-0036 U.S.A.
1.508.853.5000; www.allegromicro.com
Reset
Auto, remove short
Auto, remove short
Auto, replace capacitor
Auto, unshort capacitor
Auto, install diode
EN/SYNC low*
or VREG POR
via VIN1 UVLO
Auto, remove short
Auto, remove short
EN/SYNC low*
or VREG POR
via VIN1 UVLO
Auto, remove short
Auto, connect FBx pin
Auto, V to normal
FBx
range
EN/SYNC low*
or VREG POR
via VIN1 UVLO
EN/SYNC low*
or VREG POR
via VIN1 UVLO
EN/SYNC low*
or VREG POR
via VIN1 UVLO
EN/SYNC low*
or ENS low
or VREG POR
via VIN1 UVLO
EN/SYNC low*
or VREG POR
via VIN1 UVLO
EN/SYNC low*
or VREG POR
via VIN1 UVLO
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