4.5 Evaluating Single Phase Operation
The default configuration of the EVM is for 2-phase operation. For a single-phase operation, modify the EVM as
follows:
1. Short MSEL2 of U1_P1 to GND to program single-phase operation by populating R18_P1 with a 0-Ω
resistor.
2. If U1_P2 is left populated, disconnect VSHARE of the loop follower device from the loop controller by
depopulating R15_P1 (this is a 0-Ω resistor and can be used for MSEL2 pin of U1_P1 in the previous step).
3. If U1_P2 is left populated, disable U1_P2 by moving the JP2_P2 jumper to position 5-6 (GND).
Note
This will leave the AVIN (pin 26) of U1_P2 powered. If no-load leakage current or light-light efficiency
measurement is important, the U1_P2 AVIN pin should also be disconnected from the input supply.
Disconnect the loop follower U1_P2 AVIN from V
IN
by removing the jumper from JP7_P2.
4.6 Evaluating Split Rail Input
The default configuration of the EVM is for single rail input. Split rail input enables operation with 3.3-V PVIN. For
split rail operation, configure the jumpers on the EVM as follows:
1. Open JP4 to disconnect AVIN from PVIN.
2. Move the jumper JP7_P1 and JP7_P2 to position 1-2 to disconnect the AVIN pin from the PVIN pins.
3. Apply the AVIN input to T4. 4-V or greater AVIN is required to bring the VDD5 voltage high enough to enable
conversion.
4. If operation with 3.3-V PVIN is needed and the CNTL jumpers (JP2_P1 and JP2_P2) are in position 3-4, the
resistor divider at the EN/UVLO will need to be changed. Alternately, move the CNTL jumpers to position 1-2
and use the control signal to enable conversion or use the ON_OFF_CONFIG and OPERATION commands
to enable conversion.
4.7 Configuring EVM to Overdrive VDD5
The EVM has an external LDO (U2) that can be used to overdrive VDD5. The output of this LDO is set for 5.1 V
by default. This LDO is useful to minimize the power dissipation in the TPS546B24A IC when using a single rail
input. Overdriving VDD5 moves the loss from the internal LDO of the TPS546B24A to the external LDO (U2). To
use this LDO, configure the jumpers on the EVM as follows:
1. Short JP4 and JP5 to connect the input of the LDO to the input supply.
2. Open JP3 to enable the LDO.
3. Short JP1_P1 and JP1_P2 to connect the LDO output to the VDD5 pin.
4. Ensure the VDD5 output of the TPS546B24A is set below the external output voltage of the LDO.
Test Setup
SLUUC48A – FEBRUARY 2020 – REVISED FEBRUARY 2022
TPS546B24A 2-Phase SWIFT™ Step-Down Converter Evaluation Module
User's Guide
13
Copyright © 2022 Texas Instruments Incorporated