Datasheet

LDO
EXTSUP
LDO
VIN
VIN EXTSUP
VREG
typ 5.8 V
typ 7.5 V
typ 4.6 V
TPS43330-Q1
TPS43332-Q1
www.ti.com SLVSA82E –MARCH 2011–REVISED APRIL 2013
Table 2. Mode of Operation
ENABLE AND INHIBIT PINS DRIVER STATUS
DEVICE STATUS QUIESCENT CURRENT
ENA ENB ENC SYNC BUCK CONTROLLERS BOOST CONTROLLER
Low Low Low X Shut down Disabled Shutdown Approximately 4 µA
Low BuckB: LPM enabled Approximately 30 µA (light loads)
Low High Low BuckB running Disabled
High BuckB: LPM inhibited mA range
Low BuckA: LPM enabled Approximately 30 µA (light loads)
High Low Low BuckA running Disabled
High BuckA: LPM inhibited mA range
BuckA and BuckB: LPM
Low Approximately 35 µA (light loads)
enabled
BuckA and BuckB
High High Low Disabled
running
BuckA and BuckB: LPM
High mA range
inhibited
Low Low Low X Shut down Disabled Shutdown Approximately 4 µA
Approximately 50 µA (no boost,
Low BuckB: LPM enabled
Boost running for V
IN
< set
light loads)
Low High High BuckB running
boost output
High BuckB: LPM inhibited mA range
Approximately 50 µA (no boost,
Low BuckA: LPM enabled
Boost running for V
IN
< set
light loads)
High Low High BuckA running
boost output
High BuckA: LPM inhibited mA range
BuckA and BuckB: LPM Approximately 60 µA (no boost,
Low
enabled light loads)
BuckA and BuckB Boost running for V
IN
< set
High High High
running boost output
BuckA and BuckB: LPM
High mA range
inhibited
Gate-Driver Supply (VREG, EXTSUP)
The gate-driver supplies of the buck and boost controllers are from an internal linear regulator whose output (5.8
V typical) is on the VREG pin and requires decoupling with a ceramic capacitor in the range of 3.3 µF to 10 µF.
This pin has internal current-limit protection; do not use it to power any other circuits.
VIN powers the VREG linear regulator by default when the EXTSUP voltage is lower than 4.6 V (typical). If there
is an expectation of V
IN
going to high levels, there can be excessive power dissipation in this regulator, especially
at high switching frequencies and when using large external MOSFETs. In this case, it is advantageous to power
this regulator from the EXTSUP pin, which can have a connection to a supply lower than V
IN
but high enough to
provide the gate drive. When the voltage on EXTSUP is greater than 4.6 V, the linear regulator automatically
switches to EXTSUP as its input, to provide this advantage. Efficiency improvements are possible when using
one of the switching regulator rails from the TPS43330-Q1 or TPS43332-Q1 or any other voltage available in the
system to power EXTSUP. The maximum voltage for application to EXTSUP is 9 V.
Figure 23. Internal Gate-Driver Supply
Using a voltage above 5.8 V (sourced by VIN) for EXTSUP is advantageous, as it provides a large gate drive
and hence better on-resistance of the external MOSFETs.
When using EXTSUP, always keep the buck rail supplying EXTSUP enabled. Alternatively, if it is necessary to
switch off the buck rail supplying EXTSUP, place a diode between the buck rail and EXTSUP.
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Product Folder Links: TPS43330-Q1 TPS43332-Q1