SC900841JVKR2 Freescale Semiconductor, SC900841JVKR2 Datasheet - Page 83

• Manufacturer Part Number: SC900841JVKR2
• Description: IC POWER MGT 338-MAPBGA
• Manufacturer: Freescale Semiconductor

Specifications of SC900841JVKR2

• Applications: PC's, PDA's
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 338-TBGA
• Input Voltage: 2.8 V to 4.4 V
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Supply: -
• Voltage - Supply: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

VOTG Operation
FSLVOTGCNTL2 bits
in the CHRGCNTL register.
response to the signals.
and the OTGB bit will control if the OTG Boost voltage is fed
to the connector. In other words, if CHRG=0, then the
isolation FET is OFF, regardless of the status of OTGB and
Table 39. VOTG On/Off Control
Under-voltage Detection
comparator that serves as an output ready signal along with
the absence of faults. When VOTG is turned on,
VOTGFAULT is asserted, the under-voltage comparator is
turned on, and V
(measured at FBOTG) reaches a steady state, VOTGFAULT
is de-asserted to indicate the VOTG output readiness to start.
During operation, if the output voltage decreased below the
under-voltage threshold, an under-voltage condition is
detected and VOTGFAULT is asserted. If the output voltage
rises above the under-voltage threshold plus hysteresis, the
VOTGFAULT signal is cleared, assuming no other fault are
occurring.
Over-current Protection
switch MOSFET current. The over-current threshold value is
set higher than the worst peak inductor current value. If an
over-current is detected, the switch MOSFET turns off, the
VOTGFAULT flag is asserted, and the regulator goes into a
cycle by cycle current limiting until the fault is serviced. If the
output current falls below the over-current threshold, normal
operation is regained and the VOTGFAULT is cleared,
assuming no other faults are occurring.
automatic restart after this event, and VOTG has to be re-
Analog Integrated Circuit Device Data
Freescale Semiconductor
CHRG
VOTG on/off control is based on a combination of signals,
The CHRG bit will direct if the OTG Host mode is allowed,
VOTG features an output under-voltage detection
VOTG limits the peak inductor current by sensing the
0
0
0
0
1
1
1
1
OTGB
0
0
1
1
0
0
1
1
OOTG
CTLVOTG
(Table
starts ramping up. When V
OFF
OFF
OFF
OFF
ON
ON
ON
ON
Table 39
40), and CHRG and OTGB bits
VOTG
OFF
OFF
OFF
ON
ON
ON
ON
ON
summarizes VOTG
Isolation
OFF
OFF
OFF
OFF
OFF
OFF
FET
ON
ON
OOTG
Since CHRG=0, then
SC900841 the system
intends for the charger to
work in the buck mode, so no
OTG host mode is required.
The isolation FET should
stay OFF
Since CHRG=1, then the
system intends the charger
to work in the boost mode, so
the OTG host mode is
allowed. The isolation FET
can be turned off/on to
supply OTG voltage to the
connector
SC900841
CTLVOTG, and the boost is controlled directly via the
CTLVOTG.
OTGB signal. If OTGB=0, then the boost is on and the
isolation FET is on. If OTGB=1, then the boost is controlled
via CTLVOTG.
before the switch (LEDs) and after the switch (OTG Host).
This is why it is extremely important to separate the operation
of the Boost output and the isolation FET. See
truth table of the discussion.
Short-circuit Protection
currents, in case of an output short, by detecting the voltage
on the FBOTG feedback pin. If the FBOTG voltage falls
below a set threshold, VOTG detects a short-circuit, turns off
VOTG, turns off the isolation switch, and asserts the
VOTGFAULT flag. There is no automatic restart after this
event, and VOTG has to be re-enabled in order to clear the
VOTGFAULT flag.
prevent false or premature detection of a short-circuit
condition, as the block will be subjected to an inrush current,
possibly higher than the trip threshold. If a short were already
present when starting up, soft start would end after about
4.0 ms and then, SC is detected and the boost is disabled as
described.
Over-voltage Protection
comparator that senses the output voltage through an
internal resistor divider connected at the FBOTG pin. It
compares it to an internal reference, shuts down the
regulator, in the case that an excessive voltage occurs for
any reason. It then asserts the VOTGFAULT flag. The over-
voltage threshold is fixed at 5.77V, typical. There is no
enabled in order to clear the VOTGFAULT flag.
If CHRG=1, then the isolation FET is controlled via the
Remember that the VOTG can handle two different loads,
VOTG protects the internal MOSFET from excessive
Short-circuit protection is disabled during soft start to
VOTG features an output over-voltage protection
This does not mean that we cannot use VOTG (the
node before the isolation switch) to supply other
loads like RGB LEDs. This is why the VOTG output is
controlled directly by the CTLVOTG. Notice if
CHRG=0, OTGB does not play a role, and software
should plan for that
OTG mode is allowed, now supplying the voltage to
the connector, which is controlled via the OTGB bit,
directly turning the isolation FET on/off.
If OTGB=0, then the OTG voltage is supplied to the
connector (VOTG and isolation FET are on).
If OTGB=1, then the isolation FET is OFF and the
VOTG voltage is controlled directly through the
CTLVOTG bits to supply another load if desired
FUNCTIONAL DEVICE OPERATION
Comments
POWER SUPPLIES
Table 39
900841
for a
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