Powering DC-DC Converters with N6705A DC Power Analyzer
Application Notes
Applications where a single unregulated power source needs to be transformed to a particular regulated voltage commonly use DC-to-DC converters. For example, a mobile handset has a central battery that powers various sub-circuits in the handset. Each sub-circuit has different power requirements.
The DC-to-DC converters inside the handset transform the battery voltage into a controlled voltage. In some cases, sub-circuits drawing varying or pulsating current from the handset battery cause a ripple on the battery voltage. DC-to-DC converters regulate the ripple before the voltage reaches the handset components.
An example power test of a DC-to-DC converter is powering the converter with a DC voltage containing a small ripple and measuring the ripple rejection on the output of the converter with a measurement instrument. As shown in Figure 1, the DC-to-DC converter requires a small AC voltage riding on the DC voltage to conduct this test.