TPS56837 is selected for bench tests. The TPS56837 is a high-efficiency, easy-to-use, synchronous buck converter with a wide input voltage range of 4.5-V to 28-V, and supports up to 8-A continuous output current at output voltages between 0.6-V and 13-V. This switch mode power supply (SMPS) IC is optimized for applications requiring very low power consumption, such as printers, DTV, monitor and some industrial applications, by providing an Eco-mode (pulse-skipping).

Bench tests are conducted on the TPS56837EVM. For details, see the TPS56837EVM Evaluation Module User's Guide. The bench test setup and configuration is listed in Table 3-1.

Results are summarized in Table 3-2. All tests are conducted with 24Vin to 5Vout with 500kHz setting. Loading is changed from 0A to 0.8A. DC bias effect is considered and effective value of C_OUT is used in calculation. Equation 9 is used for calculation and 7 comparisons are conducted between calculated value, bench test value and Webench simulated value.

It is clear from the table that calculations do not have much error compared with bench test results, meaning it can be used for estimating output voltage ripple in DCM operation of D-CAP parts. For Webench simulation, simulated results do show not much deviation in most of loading conditions and can be used for design reference.