SLUUCA9A September 2020 – April 2021 TPS546B24A
To evaluate the efficiency of the power train (device and inductor), it is important to measure the voltages at the correct location. This is necessary because otherwise the measurements will include losses that are not related to the power train itself. Losses incurred by the voltage drop in the copper traces and in the input and output connectors are not related to the efficiency of the power train, which should not be included in efficiency measurements.
Input current can be measured at any point in the input wires, and output current can be measured anywhere in the output wires of the output being measured.
Table 6-1 shows the measurement points for input voltage and output voltage. VIN and VOUT are measured to calculate the efficiency. Using these measurement points will result in efficiency measurements that excludes losses due to the wires and connectors as well as PCB voltage drops.
Test Point | Node Name | Description | Comment |
---|---|---|---|
TP23 | PVIN | Input voltage measurement point for VIN+ | This pair of test points are connected to PVIN and PGND near the pins of U1. The voltage drop between input terminal to the device pins is not included for efficiency measurement. |
TP20 | PGND | Input voltage measurement point for VIN– (GND) | |
TP24 | VOUT_EFF | Output voltage measurement point for VOUT+ | This pair of test points are connected to VOUT and GND near the output inductor. The voltage drop from the output point of the inductor to the output terminals is not included for efficiency measurement. |
TP21 | GND | Output voltage measurement point for VOUT– (GND) |