Electrical current measurement system

A test system for measuring electrical current consumption of a device under test (DUT), the test system comprising:

• a power capacitor comprising a power terminal and a ground terminal, the power capacitor configured to provide capacitor voltage at the power terminal;
• a voltage regulator comprising a regulator input terminal and a regulator output terminal, the voltage regulator configured to generate a DUT operating voltage at the regulator output terminal based on an input voltage at the regulator input terminal;
• a first switching element between a direct current (DC) voltage source and the regulator input terminal;
• a second switching element between the DC voltage source and the power terminal of the power capacitor;
• and
• a controller coupled to the power capacitor, the voltage regulator, the first switching element, and the second switching element, the controller configurable to:
• close the first and second switching elements to charge the power capacitor with the DC voltage source;
• after the power capacitor has reached a charged voltage, open the first and second switching elements such that the power capacitor provides the capacitor voltage to the voltage regulator;
• record a measurement start time associated with opening of the first switching element when the second switching element is open;
• after the power capacitor has reached a discharged voltage in response to loading, close the first switching element;
• record a measurement end time associated with closing of the first switching element when the second switching element is open;
• and
• calculate electrical current provided by the power capacitor between the measurement start time and the measurement end time, based on a sampled value of the charged voltage of the power capacitor, a sampled value of the discharged voltage of the power capacitor, and discharge characteristics of the power capacitor.

An automated method of measuring electrical current of a device under test (DUT) with a test system having a power capacitor, a voltage regulator to generate a DUT operating voltage for the DUT, a switching circuit to regulate electrical connections between a direct current (DC) voltage source, the power capacitor, and the voltage regulator, and a processor-based controller, the method comprising:

• automatically controlling the switching circuit with the controller to place the test system into a charging state, such that the DC voltage source charges the power capacitor;
• after the power capacitor has reached a charged voltage, automatically controlling the switching circuit with the controller to transition the test system into a measurement state, such that the power capacitor provides capacitor voltage to the voltage regulator while the test system is in the measurement state, wherein the DUT is coupled to a regulator output terminal of the voltage regulator while the test system is in the measurement state;
• recording, with the controller, a measurement start time;
• after the power capacitor has reached a discharged voltage in response to operation of the DUT, automatically controlling the switching circuit with the controller to transition the test system into a post-measurement state;
• recording, with the controller, a measurement end time;
• calculating electrical current consumed by the DUT between the measurement start time and the measurement end time, based on a sampled value of the charged voltage, a sampled value of the discharged voltage, and discharge characteristics of the power capacitor;
• and
• generating the calculated electrical current as an output of the test system.