Datasheet

VREG
0.1 µF
IN1 ISET1
R
ISET1
ISENSE1
R
SENSE1
GATE1
DISCH1 VSENSE1
R
VSENSE1_TOP
R
VSENSE1_BOTTOM
+
FAULT
V
O1
or
V
O2
FAULT
TIMER
IN2 ISET2 ISENSE2 GATE2 DISCH2 VSENSE2
ENABLE
DGND
AGND
R
ISET2
R
g1
R
VSENSE2_TOP
R
VSENSE2_BOTTOM
+
V
O1
V
O2
ENABLE
1 µF ∼ 10 µF
R
SENSE2
1 µF ∼ 10 µF
12 V IN1
3.3 V IN2
TPS2301
+
V
O3
1 µF ∼ 10 µF
5 V IN3
System Board
R
g2
PWRGD1
PWRGD2
PWRGD1
PWRGD2
TPS2300
TPS2301
SLVS265H –FEBRUARY 2000–REVISED JULY 2013 www.ti.com
SINGLE-CHANNEL OPERATION
Some applications may require only a single external MOS transistor. Such applications should use GATE1 and
the associated circuitry (IN1, ISENSE1, ISET1, DISCH1). The IN2 pin should be grounded to disable the circuitry
associated with the GATE2 pin. The VSENSE2 and PWRGD2 circuitry is unaffected by disabling GATE2, and
may still be used if so desired.
POWER-UP CONTROL
The TPS2300/01 includes a 500 µs (nominal) start-up delay that ensures that internal circuitry has sufficient time
to start before the device begins turning on the external MOSFETs. This delay is triggered only upon the rapid
application of power to the circuit. If the power supply ramps up slowly, the undervoltage lockout circuitry
provides adequate protection against undervoltage operation.
3-CHANNEL HOT-SWAP APPLICATION
Some applications require hot-swap control of up to three voltage rails, but may not explicitly require the sensing
of the status of the output power on all three of the voltage rails. One such application is device bay, where dv/dt
control of 3.3 V, 5 V, and 12 V is required. By using channel 2 to drive both the 3.3-V and 5-V power rails and
channel 1 to drive the 12-V power rail, as is shown below, TPS2300/01 can deliver three different voltages to
three loads while monitoring the status of two of the loads.
Figure 28. Three-Channel Application
Figure 29 shows ramp-up waveforms of the three output voltages.
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