Apparatus which uses a simulated inductor in the measurement of an electrical parameter of a device under test
AssigneeHewlett-Packard Company
InventorsHideshi Tanaka, Kazuyuki Yagi, Shigeru Tanimoto, Yasuaki Komatsu, Koichi Yanagawa, Yoichi Kuboyama
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Abstract
The present invention relates to apparatus for measuring the AC electrical parameters of a circuit element (Device-Under-Test, DUT), such as a resistor, a capacitor or an inductor, at the desired frequency of a signal while applying a DC bias to the DUT. The present invention provides an apparatus capable of measurement with less error even in the lower-frequency range.
Claims4
An apparatus for measuring the AC electrical parameters of a circuit device under test, comprising:
- an AC signal source means for applying an AC signal coupled to one terminal of said device under test;
- a DC bias source means for applying a DC bias coupled to the one terminal of a device to be tested, the DC bias source means including
- a transistor,
- an operational amplifier whose non-inverting input, inverting input and output are coupled to a reference voltage source, an emitter and a base of said transistor, respectively,
- first resistor coupled to said emitter,
- serial circuit including second resistor and capacitor being coupled to a collector of said transistor, and
- an inductor coupled between a load and said collector;
- an AC voltage measurement means coupled for measuring the AC voltage across the device under test;
- a simulated inductor means coupled to another terminal of the device under test;
- and
- an AC current measurement means coupled for measuring the AC current through the device under test.
An apparatus for measuring the AC electrical parameters of a circuit device under test, the circuit device under test having a first terminal and a second terminal, the apparatus comprising:
- an AC signal source means for applying an AC signal coupled to the first terminal of the circuit device under test;
- a DC bias source means for applying a DC bias coupled to the first terminal of the circuit device under test;
- an AC voltage measurement means coupled for measuring the AC voltage across the circuit device under test;
- a simulated inductor means coupled to the second terminal of the device under test, the simulated inductor including
- a non-inverting amplifier having a first input coupled to the second terminal of the circuit device under test,
- an integrator having an input coupled to an output of the non-inverting amplifier, and
- a voltage controlled current source having a control input coupled to an output of the integrator and having a current input coupled to the second terminal of the circuit device under test;
- and,
- an AC current measurement means, coupled for measuring the AC current through the circuit device under test.
Dependencies are inferred from the claim text.