ACT5880
Rev 2, 03-Sep-13
UVLO circuit monitors the voltage at VSYS, it stops
the normal operation when the VVSYS is less than
the VUVLO, reloads registers with default power on
states and starts normal operation when the VVSYS
the REGISTER AND BIT DESCRIPTIONS section
for more details.
Table 2:
is greater than VUVLO
.
The House-keeping Oriented Interrupts.
All circuit blocks stop but the always-on VALIVE
output and the RTC circuit keep running when the
system UVLO asserts. The always-on regulator
keeps output even when its output voltage drops,
the RTC keeps running until its input voltage is too
low, the RTCEN bit is reset.
INTERRUPT FOR
CONDITIONS
VVSYS<Voltage set by
SYSLEV[3:0]
System Voltage low
REG1, REG2, REG3 output 7%
less than normal; REG4 to
REG13 11% less than normal;
REG3 over voltage in constant
current output mode.
Regulator out of
regulation
The VVSYS comparator circuit is configurable for
stopping the system as the UVLO function does or
asserting a system voltage low alert when it sees
the VVSYS is less than a programmable threshold.
The threshold is programmed by setting the
SYSLEV[3:0] in a register, refer to the GLOBAL
REGISTER MAP and REGISTER AND BIT
DESCRIPTIONS sections for more details.
Each step-down DC/DCs and the step-up DC/DC
has its own UVLO to assure it only operates when
both its input voltage and the VVSYS are in proper
range.
Over-Current
Each regulator has its own over-current protection.
For step-down DC/DCs and the step-up DC/DC ,
the over-current condition triggers to reduce the
switch frequency to ¼ of normal frequency. In
LDOs, it triggers fold-back current limit. In both
case, the over-current protection consequently
causes the drop of output voltage and so the
house-keeping interrupt assertion if this function is
enabled. Each regulator is safe in unlimited-time
output short-circuit (but not the step-up DC/DC, in
which the rectifier diode might be burned off).
Over-temperature
When the die temperature goes to about 160°C, the
whole circuit of the ACT5880 is shutdown, including
all function blocks, with about 20°C hysteresis when
temperature falls for recovering. This threshold
temperature is higher than functional temperature
thresholds used for other temperature dependent
circuits, including the die-temperature regulation in
charger and the open-drain driver circuit.
House-keeping Oriented Interrupts
There are 14 sources/conditions in 2 types interrupt
oriented for house-keeping, each is programmable
for allowing interrupt or masked.
Table 2 lists the house-keeping oriented interrupt
types. Refer to the INTERRUPT DESCRIPTIONS
section for a summary of all possible interrupts and
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