Datasheet

DS
GC1
TPS43330-Q1
or
TPS43332-Q1
V
IN
V
BAT
TPS43330-Q1
TPS43332-Q1
www.ti.com SLVSA82E –MARCH 2011–REVISED APRIL 2013
The TPS43330-Q1 and TPS43332-Q1 can support the full-current load during low-power mode until the
transition to normal mode takes place. The design ensures that exit of the low-power mode occurs at 10%
(typical) of full-load current if the selection of inductor and sense resistor is as recommended. Moreover, there is
always a hysteresis between the entry and exit thresholds to avoid oscillating between the two modes.
In the event that both buck controllers are active, low-power mode is only possible when both buck controllers
have light loads that are low enough for low-power mode entry. With the boost controller enabled, low-power
mode is possible only if V
BAT
is high enough to prevent the boost from switching and if DIV is open or set to
GND. A high (V
REG
) level on DIV inhibits low-power mode, unless ENC is set to low.
Boost Controller
The boost controller has a fixed-frequency voltage-mode architecture and includes cycle-by-cycle current-limit
protection for the external N-channel MOSFET. The boost-controller switching-frequency setting is one-half of the
buck-controller switching frequency. An internal resistor-divider network programmable to 7 V, 10 V, or 11 V sets
the output voltage of the boost controller at the VIN pin, based on the low, open, or high status, respectively, of
the DIV pin. The device does not recognize a change of the DIV setting while the in the low-power mode.
The active-high ENC pin enables the boost controller, which is active when the input voltage at the VBAT pin has
crossed the unlock threshold of 8.5 V at least once. A single threshold crossing arms the boost controller, which
starts switching as soon as V
IN
falls below the value set by the DIV pin, regulating the VIN voltage. Thus, the
boost regulator maintains a stable input voltage for the buck regulators during transient events such as a
cranking pulse at VBAT.
A voltage at the DS pin exceeding 200 mV pulls the CG1 pin low, turning off the boost external MOSFET.
Connecting the DS pin to the drain of the MOSFET or to a sense resistor between the MOSFET source and
ground achieves cycle-by-cycle overcurrent protection for the MOSFET. Choose the on-resistance of the
MOSFET or the value of the sense resistor in such a way that the on-state voltage at DS does not exceed 200
mV at the maximum-load and minimum-input-voltage conditions. When using a sense resistor, TI recommends
connecting a filter network between the DS pin and the sense resistor for better noise immunity.
One can use the boost output (VIN) to supply other circuits in the system. However, they should be high-voltage
tolerant. The device regulates the boost output to the programmed value only when VIN is low, and so VIN can
reach battery levels.
Figure 21. External Drain-Source Voltage Sensing
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Product Folder Links: TPS43330-Q1 TPS43332-Q1