Output current regulation is defined as the change in output current that is caused by a change in input supply voltage, load resistance, or both. Line current regulation is specified as the percentage change in current that occurs when the supply input is varied over its specified range. Load current regulation is specified as the change in current that occurs when the load is varied from short-circuit to rated voltage. This parameter is important for high voltage supplies that are capable of operation in a "current regulated" or "constant current" mode.

Test Setup.

To measure current regulation, refer to Figure 4. RL represents the load resistor. Its value will vary from 0, at the short-circuit condition, to some finite value at the rated-voltage condition. Because a power supply cannot maintain current regulation into an open circuit, load changes are introduced by shorting portions of the load resistor. A current-sensing resistor, RS, in series with the low voltage return path, is used to develop a voltage that is proportional to the current, and which can be measured by a suitable DC voltmeter.

Figure 4

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