Component impedance measurement and characterization at high transient voltages
Apparatus and methods for characterizing electrical components for evaluating performance in a high voltage transient protection circuit. Impedance graphs provided by manufacturers for electrical components are typically low voltage measurements that do not necessarily accurately reflect component performance at high voltages above 150 volts. It is important to characterize and understand the behavior of these components at high voltages in order to ensure the components will protect circuitry as expected. In certain embodiments, a characterization method includes obtaining time domain voltage measurements from two terminals of a device under test (DUT) as it is exposed to high voltage transients from an electrical fast transient (EFT) generator. The time domain voltage data is transformed into frequency domain voltage data using a transform algorithm, and additional analysis is performed to derive scattering parameters, impedance, and other valuable metrics for component characterization.
1. A method of electrical characterization, the method comprising:
connecting a first terminal of an electrical component to a transient generator;
connecting a second terminal of the electrical component to a load such that the electrical component and the load are connected in series between the transient generator and a ground voltage;
generating an electrical transient comprising a pulse using the transient generator;
obtaining a first plurality of voltage versus time measurements at the first terminal of the electrical component in response to the electrical transient received from the transient generator;
obtaining a second plurality of voltage versus time measurements at the second terminal of the electrical component in response to the electrical transient;
processing the first plurality of voltage versus time measurements and the second plurality of voltage versus time measurements to generate frequency domain data; and
determining at least one scattering parameter from the frequency domain data.
2. The method of claim 1 , wherein the at least one scattering parameter includes an S 21 parameter.
3. The method of claim 1 , further comprising using a fast Fourier transform (FFT) to generate the frequency domain data.
4. The method of claim 1 , wherein no current probe is used.
5. The method of claim 1 , further comprising obtaining voltage versus time measurements at the first terminal and the second terminal for a plurality of electrical transient pulses of different peak voltage levels.
6. The method of claim 1 , wherein the first plurality of voltage versus time measurements are obtained using a probe in response to the electrical transient, and wherein the second plurality of voltage versus time measurements are also obtained using the same probe in response to the transient generator reapplying the electrical transient.
7. The method of claim 1 , further comprising generating an impedance curve for the electrical component using the at least one scattering parameter.
8. The method of claim 1 , wherein the transient generator is an electrical fast transient (EFT) generator, and the electrical transient is an EFT pulse.
9. The method of claim 1 , wherein determining the at least one scattering parameter includes determining an S 21 parameter, an S 12 parameter, an S 11 parameter, and an S 22 parameter.
10. The method of claim 1 , further comprising:
providing the electrical transient to the first terminal such that the electrical component receives the full electrical transient.
11. The method of claim 1 , wherein connecting the first terminal of the electrical component to the transient generator comprises connecting the first terminal of the electrical component directly to the transient generator.
12. The method of claim 1 , wherein connecting the second terminal of the electrical component to the load comprises connecting the second terminal to the load such that the second terminal is directly connected to the load and the load is directly connected to the ground voltage.
13. The method of claim 1 , further comprising:
providing the electrical transient solely to the first terminal of the electrical component.
14. An electronic component characterization system comprising:
a transient generator configured to provide an electrical transient to a first terminal of an electrical component undergoing characterization, wherein the electrical transient comprises a pulse;
a load configured to connect to a second terminal of the electrical component such that the electrical component and the load are connected in series between the transient generator and a ground voltage;
one or more voltage probes configured to obtain a first plurality of voltage versus time measurements at the first terminal of the electrical component in response to the electrical transient, and to obtain a second plurality of voltage versus time measurements at the second terminal of the electrical component in response to the electrical transient; and
a computer configured to process the first plurality of voltage versus time measurements and the second plurality of voltage versus time measurements to generate frequency domain data, and to determine at least one scattering parameter from the frequency domain data.
15. The electronic component characterization system of claim 14 , wherein the at least one scattering parameter includes an S 21 parameter.
16. The electronic component characterization system of claim 14 , wherein the computer is further configured to generate the frequency domain data using a fast Fourier transform (FFT).
17. The electronic component characterization system of claim 14 , wherein the one or more voltage probes includes a common voltage probe that obtains the first plurality of voltage versus time measurements in response to the electrical transient, and that obtains the second plurality of voltage versus time measurements in response to the transient generator reapplying the electrical transient.
18. The electronic component characterization system of claim 14 , wherein the one or more voltage probes includes a first voltage probe that obtains the first plurality of voltage versus time measurements, and a second voltage probe that obtains the second plurality of voltage versus time measurements.
19. The electronic component characterization system of claim 14 , wherein the computer is further configured to generate an impedance curve data for the electrical component based on the at least one scattering parameter.
20. The electronic component characterization system of claim 19 , further comprising a display configured to display an impedance graph corresponding to the impedance curve data.
21. The electronic component characterization system of claim 14 , wherein the transient generator is an electrical fast transient (EFT) generator, and the electrical transient is an EFT pulse.
22. The electronic component characterization system of claim 14 , wherein determining the at least one scattering parameter includes determining an S 21 parameter, an S 12 parameter, an S 11 parameter, and an S 22 parameter.
23. The electronic component characterization system of claim 14 , wherein the computer comprises a memory storing the first plurality of voltage versus time measurements, the second plurality of voltage versus time measurements, the frequency domain data, and the at least one scattering parameter.
24. An electronic component characterization system comprising:
a transient generator configured to provide an electrical transient to a first terminal of an electrical component undergoing characterization, wherein the electrical transient comprises a pulse;
a load configured to connect to a second terminal of the electrical component such that the electrical component and the load are connected in series between the transient generator and a ground voltage;
one or more voltage probes configured to obtain a first plurality of voltage versus time measurements at the first terminal of the electrical component in response to the electrical transient, and to obtain a second plurality of voltage versus time measurements at the second terminal of the electrical component in response to the electrical transient; and
means for processing the first plurality of voltage versus time measurements and the second plurality of voltage versus time measurements to generate frequency domain data and at least one scattering parameter.