Setup
2.2
Setup
The input voltage range for the converter is 5.6 volts to 40 volts.
2.3
Operation
For proper operation of the TPS65300EVM, the jumpers should be properly configured. Set jumpers to
this configuration:
EN
Open (device will power down if IGN is transitioning low.
3.3V_PWR
Installed (supply 3.3V rail from VREG).
1.2V_PWR
Installed (supply 1.2V rail from VREG, remove before installing BRIDGE-jumper!).
BRIDGE
Open (install to supply 1.2V rail from 3.3V-rail, remove 1.2V_PWR jumper before
installing BRIDGE!).
IGN
Installed (device powers up if VIN is applied).
In this configuration, the regulators will turn on when power is applied and will power down if Vin is falling.
To prohibit initial startup, remove IGN-jumper. While IGN is high, EN has no functionality. If IGN transitions
low after the device has powered up, a high level on EN (jumper installed) will keep the regulators active,
a low (EN open) will power down the regulators if IGN goes low.
The supply for the 1.2V rail is sourced from VREG in the above configuration. BRIDGE allows to power
the external transistor of this rail from the 3.3V output, make sure to remove the jumper on 1.2V_PWR
before installing BRIDGE-jumper. This reduces the drop-out-voltage on the external transistor and such
helps to reduce power dissipation on this transistor; however, consider the extra power drawn from the
3.3V rail, causing extra dissipation on the 3.3V-rail transistor.
The switching frequency is defined by the resistor on RT (R4), here 40.2k
Ω
, setting f
SW
to approximately
2.4MHz.
Regulator Configuration (out current s given for above configuration, i.e. 1.2V rail powered from VREG):
Regulator
Output Voltage
Maximum Output Current
Switcher
5.3 V
1.2 A
3.3V regulator
3.3 V
0.3A (at room temperature, less at high temperature)
1.2V regulator
1.2 V
0.1A (at room temperature, less at high temperature)
5V regulator
5 V
0.2A
6
TPS65300EVM
SLVU685 – February 2012
Copyright © 2012, Texas Instruments Incorporated