Smooth vi mode crossover method at compliance limit threshold

Patent metadata

Field	Value
Publication number	US-9207282-B2
Application number	US-201313804579-A
Country	US
Kind code	B2
Filing date	Mar 14, 2013
Priority date	Mar 14, 2013
Publication date	Dec 8, 2015
Grant date	Dec 8, 2015

Abstract

Source measure units may operate as a voltage/current (V/I) source for a load, such as a device under test (DUT). Source measure units having a voltage controlled mode and a current controlled mode are described. The source measure units may have a suitable configuration to transition between the voltage controlled mode and current controlled mode in a smooth manner, and may be operated accordingly.

First claim

What is claimed is:

1. A method of operating a source measure unit (SMU) configured to couple to a load, the SMU operating in a plurality of modes including a voltage-controlled mode and a current-controlled mode, the method comprising:
generating a control signal to apply to a control circuit of the SMU when switching between the plurality of modes, wherein generating the control signal comprises combining a first signal, a second signal and a third signal,
wherein the first signal is indicative of a voltage error of a voltage across the load relative to a target voltage,
wherein the second signal is indicative of a first current error of a current through the load relative to an upper current threshold, and
wherein the third signal is indicative of a second current error of the current through the load relative to a lower current threshold.

2. The method of claim 1 , wherein the first signal is indicative of a voltage error of the voltage detected across the load relative to a target voltage of a drive signal of the SMU.

3. The method of claim 1 , wherein combining the first signal, the second signal and the third signal comprises generating a weighted combination of the first signal and the second signal.

4. The method of claim 1 , wherein combining the first signal, the second signal and the third signal comprises generating a weighted combination of the first signal, the second signal, and the third signal.

5. The method of claim 4 , wherein a first weighting factor is associated with the first signal, a second weighting factor is associated with the second signal, and a third weighting factor is associated with the third signal, and wherein a sum of the first weighting factor, the second weighting factor, and the third weighting factor is one.

6. The method of claim 5 , wherein the first weighting factor and/or the second weighting factor and/or the third weighting factor is variable.

7. The method of claim 6 , wherein the first weighting factor and/or second weighting factor and/or third weighting factor is generated by a function.

8. The method of claim 7 , wherein the function is dependent on voltage.

9. The method of claim 8 , wherein the function is dependent on voltage error.

10. The method of claim 7 , wherein the function is dependent on current.

11. The method of claim 10 , wherein the function is dependent on current error.

12. The method of claim 1 , wherein the load is a device under test (DUT).

13. A method of operating a source measure unit (SMU) configured to couple to a load, the SMU operating in a plurality of modes including a voltage-controlled mode and a current-controlled mode, the method comprising:
generating a control signal to apply to a control circuit of the SMU when switching between the plurality of modes, wherein generating the control signal comprises combining a first signal, a second signal and a third signal,
wherein the first signal is indicative of a first voltage error of a voltage across the load relative to an upper voltage threshold,
wherein the second signal is indicative of a current error of a current through the load relative to a target current, and
wherein the third signal is indicative of a second voltage error of the voltage across the load relative to a lower voltage threshold.

14. The method of claim 13 , wherein combining the first signal, the second signal and the third signal comprises generating a weighted combination of the first signal, the second signal, and the third signal.

15. The method of claim 14 , wherein a first weighting factor is associated with the first signal, a second weighting factor is associated with the second signal, and a third weighting factor is associated with the third signal, and wherein a sum of the first weighting factor, the second weighting factor, and the third weighting factor is one.

16. The method of claim 15 , wherein the first weighting factor and/or the second weighting factor and/or the third weighting factor is variable.

17. The method of claim 16 , wherein the first weighting factor and/or second weighting factor and/or third weighting factor is generated by a function.

18. The method of claim 17 , wherein the function is dependent on voltage.

19. The method of claim 18 , wherein the function is dependent on voltage error.

20. The method of claim 17 , wherein the function is dependent on current.

21. The method of claim 20 , wherein the function is dependent on current error.

22. A source measure unit (SMU) configured to operate in a plurality of modes including a voltage-controlled mode and a current-controlled mode, the SMU comprising:
combination circuitry configured to generate, when the SMU transitions between the voltage-controlled mode and the current controlled mode, a control signal to provide to a control circuit of the SMU, the control signal being generated by combining a first signal, a second signal and a third signal,
wherein the first signal is indicative of a voltage error of a voltage relative to a target voltage,
wherein the second signal is indicative of a first current error of a current relative to an upper current threshold, and
wherein the third signal is indicative of a second current error of the current relative to a lower current threshold.

23. The SMU of claim 22 , wherein the combination circuitry comprises weighting circuitry configured to form a weighted combination of the first signal, the second signal, and the third signal.

24. A source measure unit (SMU) configured to operate in a plurality of modes including a voltage-controlled mode and a current-controlled mode, the SMU comprising:
combination circuitry configured to generate, when the SMU transitions between the voltage-controlled mode and the current controlled mode, a control signal to provide to a control circuit of the SMU, the control signal being generated by combining a first signal, a second signal and a third signal,
wherein the first signal is indicative of a first voltage error of a voltage relative to an upper voltage threshold,
wherein the second signal is indicative of a current error of a current relative to a target current, and
wherein the third signal is indicative of a second voltage error of the voltage relative to a lower voltage threshold.

25. The SMU of claim 24 , wherein the combination circuitry comprises weighting circuitry configured to formed a weighted combination of the first signal, the second signal, and the third signal.

Assignees

• Faehnrich Richard John
• Teradyne Inc

Inventors

• Faehnrich Richard John

Classifications

• G01R31/3004

  Current or voltage test · CPC title

• G01R31/31924 Primary

  Voltage or current aspects, e.g. driver, receiver · CPC title