SYSTEM AND METHOD FOR THERMAL LIMIT CONTROL

• US 20100156492A1
• Filed: 12/22/2008
• Published: 06/24/2010
• Est. Priority Date: 12/22/2008
• Status: Active Grant

• Current Assignee: Xcerra Corporation (COHU Incorporated)
• Original Assignee: LTX Corp. (COHU Incorporated)
• Inventors: Limoges, Stephen Frederick JR., Therrien, Roger Henry, Perkins, Philip Earle, McGinley, James William, Yan, Xiaomin
• Granted Patent: US 7,969,177 B2
• Time in Patent Office: Days
• US Class Current: 327/175
• CPC Class Codes: G01R 31/2839 using signal generators, power supplies or circuit analysers G01R31/2879 takes precedence; multimeters G01R15/12, network analysers G01R27/28

Abstract

This disclosure relates to a system and method for pulse generation. A system in accordance with the present disclosure may include a power dissipating element configured to receive power from a power source. At least one of the power source and the power dissipating element may be configured to generate a first signal. The system may further include a measuring instrument in communication with the power source. The measuring instrument may be configured to measure the first signal and to provide an input corresponding to a measured signal to a duty cycle limiter. The system may also include a pulse controller operatively connected to the power source. The pulse controller may be configured to control a duty cycle of the first signal and to receive a second signal from the duty cycle limiter. The pulse controller may be configured to disable at least one of the power source and the power dissipating element if the duty cycle limiter has determined that a maximum condition has been exceeded. Other embodiments are also within the scope of the present disclosure.

Claims

1. A testing system comprising:

a voltage/current (VI) instrument including a power amplifier configured to generate a first signal of at least one of a voltage and a current, said VI instrument further configured to transmit said first signal to a device-under-test (DUT) and to perform a real-time measurement of said first signal to determine an ON-time and an OFF-time of said first signal, said VI instrument further configured to disable said power amplifier if a maximum allowable ON-time of said power amplifier is exceeded.

2. The testing system of claim 1 wherein said ON-time and OFF-time is measured by a counter, said counter configured to increment during said ON-time and decrement during said OFF-time.

3. The testing system of claim 1 wherein said VI instrument is further configured to disable said power amplifier if a maximum allowable ON-time to OFF-time duty cycle of said power amplifier is exceeded.

4. The testing system of claim 1 wherein at least one of said maximum allowable ON-time and a maximum allowable ON-time to OFF-time duty cycle of said power amplifier is adjusted in real-time.

5. The testing system of claim 1 wherein said VI instrument is further configured to provide an indication of an available ON-time before said maximum allowable ON-time is reached.

6. The testing system of claim 1 wherein said VI instrument is further configured to change said maximum allowable ON-time and a maximum allowable ON-time to OFF time duty cycle in response to at least one of a measured voltage and a measured current.

7. The testing system of claim 1 wherein said VI instrument is further configured to allow said power amplifier to be re-enabled from a disabled state and to apply at least one of said maximum allowable ON-time and a maximum allowable ON-time to OFF-time duty cycle.

8. A method for analyzing a voltage/current (VI) instrument comprising:

generating a first signal of at least one of a voltage and a current;

transmitting said first signal to a device-under-test (DUT);

performing a real-time measurement of said first signal to determine an ON-time and an OFF-time of said first signal; and

disabling said power amplifier if a maximum allowable ON-time of said power amplifier is exceeded.

9. The method of claim 8 further comprising measuring said ON-time and OFF-time by a counter, said counter configured to increment during said ON-time and decrement during said OFF-time.

10. The method of claim 8 further comprising disabling said power amplifier if a maximum allowable ON-time to OFF-time duty cycle of said power amplifier is exceeded.

11. The method of claim 8 further comprising adjusting, in real-time, at least one of said maximum allowable ON-time and a maximum allowable ON-time to OFF-time duty cycle of said power amplifier.

12. The method of claim 8 further comprising providing an indication of an available ON-time before said maximum allowable ON-time is reached.

13. The method of claim 8 further comprising changing said maximum allowable ON-time and a maximum allowable ON-time to OFF time duty cycle in response to at least one of a measured voltage and a measured current.

14. The method of claim 8 further comprising allowing said power amplifier to be re-enabled from a disabled state and to apply at least one of said maximum allowable ON-time and a maximum allowable ON-time to OFF-time duty cycle.

15. A pulsing system comprising:

a power dissipating element configured to receive power from a power source, at least one of said power source and said power dissipating element configured to generate a first signal;

at least one measuring instrument in communication with said at least one power source, said at least one measuring instrument configured to measure said first signal and to provide an input corresponding to a measured signal to a duty cycle limiter; and

a pulse controller operatively connected to said at least one power source, said pulse controller configured to control a duty cycle of said first signal, said pulse controller further configured to receive a second signal from said duty cycle limiter and to disable at least one of said power source and said power dissipating element if said duty cycle limiter has determined that a maximum condition has been exceeded.

16. The pulsing system of claim 15 wherein said pulse controller generates a variable pulsing operation.

17. The pulsing system of claim 16 wherein said pulsing system is associated with a device selected from the group consisting of a power tool and a power semiconductor device tester.

18. The pulsing system of claim 15 wherein said pulse controller generates a fixed pulsing operation.

19. The pulsing system of claim 18 wherein said pulsing system is associated with a fault protection function.

20. The pulsing system of claim 15 wherein said maximum condition is at least one of a maximum allowable ON-time and a maximum allowable duty cycle.