SLUUCU3 November 2023
To evaluate the efficiency of the power train (device and inductor), to measure the voltages at the correct location is important. Otherwise, the measurements 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 must not be included in efficiency measurements.
Input current can be measured at any point in the input wires. Output current can be measured anywhere in the output wires of the output being measured.
Table 5-1 shows the measurement points for input voltage and output voltage. VIN and VOUT are measured to calculate the efficiency. Using these measurement points results in efficiency measurements that excluded losses due to the wires and connectors.
Test Point | Node Name | Description | Comment |
---|---|---|---|
VOUT | |||
TP23 | PVIN_EFF | Input voltage measurement point for VIN+ | The pair of test points are connected to the PVIN/PGND pins of U1. The voltage drop between input terminal to the device pins is not included for efficiency measurement. |
TP20 | PGND_EFF | Input voltage measurement point for VIN– (GND) | |
TP24 | VOUT_EFF | Output voltage measurement point for VOUT+ | The pair of test points are connected near the output terminals. The voltage drop from the output point of the inductor to the output terminals is not included for efficiency measurement. |
TP21 | PGND_EFF | Output voltage measurement point for VOUT– (GND) |