Patent ID: 6545460
Filing Date: 2003-04-08
Classification: G01R

Abstract:
A power source current measurement unit provided in a semiconductor test system for measuring a power source current flowing through a device under test, comprising:a DA (digital-to-analog) converter for generating a source voltage which is supplied to the device under test based on a digital signal received; an operational amplifier for forming a negative feedback loop and supplying the source voltage from the DA converter to a power pin of the device under test thereby flowing a power source current to the power pin through a current measurement resistor whose resistance value is known; a voltage amplifier for amplifying a voltage across the current measurement resistor representing the amount of power source current supplied to the device under test; an integration circuit formed of an operational amplifier provided with an integration capacitor connected between an input and an output of the operational amplifier, a resistor series connected to the input of the operational amplifier, and a switch for open/close the integration capacitor for integrating an output signal of the voltage amplifier for a predetermined integration time in such a way that the output signal is continuously accumulated during the integration time; and an AD (analog-to-digital) converter for converting an output signal of the integration circuit to a digital signal after the integration time.