Apparatus which uses a simulated inductor in the measurement of an electrical parameter of a device under test
First Claim
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1. 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 includinga 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, andan 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.
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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.
21 Citations
4 Claims
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1. An apparatus for measuring the AC electrical parameters of a circuit device under test, comprising:
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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.
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2. 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:
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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. - View Dependent Claims (3, 4)
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Specification