Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
1999-10-05
2001-05-08
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S765010, C324S763010, C714S718000
Reexamination Certificate
active
06229326
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for testing an electronic device in a burn-in process.
BACKGROUND OF THE INVENTION
Usually, the final step of manufacturing an electronic device is a testing process. The testing process is used for detecting a defect of the product. One of these testing processes is a burn-in process. In the burn-in process, a lot of electronic devices are operated under a temperature higher than the room temperature for a period of time. It is easier to detect a poor electronic device at a high temperature. The quality of the electronic device passing the burn-in test is better.
The output power signal of the electronic device is measured in the burn-in process. The state of the electronic device is detected by checking the output power signal. The electronic device is in a normal state when the output power signal has a voltage level greater than a predetermined minimal value and the electronic device is in an abnormal state when the output power signal has a voltage level lower than a predetermined minimal value. For example, if the standard power of an electronic device is 5V and the corresponding minimal value is 3.3V, the electronic device is in an abnormal state when the actual output power of the electronic device is smaller than 3.3V.
In the conventional burn-in process, an indicating lamp is connected with the electronic device. When the electronic device is in the normal state, an indicating signal will be generated and then the indicating lamp will be turned on. On the contrary, the lamp will be turned off when the electronic device is in the abnormal state.
The major disadvantage of the conventional burn-in process is that some failed electronic devices may not be found. The output power signal of the electronic device may not be stable when the electronic device is operated. The voltage level of the power signal might be smaller than its minimal value in the first time and larger than the minimal value in the second time. That is, the electronic device might be in the abnormal state during the first burn-in testing period and in the normal state at the next testing period. So, the electronic device having a transient defect will be determined as a good one. The quality of the electronic device will be reduced. Therefore, it is tried by the applicant to solve the above-described problem.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a method and an apparatus for testing an electronic device in a burn-in process.
Another object of the present invention is to provide a method and an apparatus for testing a circuit in a burn-in process.
According to the present invention, the method for testing an electronic device having a plurality of output signals in a burn-in process includes steps of (a) providing a test circuit electrically connected to the electronic device, (b) detecting one of a normal and an abnormal state of the electronic device by checking the output signals, and (c) generating a first signal when the electronic device is in the normal state and generating a second signal when the electronic device is in the abnormal state. The method further includes steps of (d) rechecking the plurality of output signals and (e) generating a third signal when the electronic device is in the abnormal state at previously testing period and in the normal state at subsequently testing period.
Certainly, the plurality of output signals include a 12V output signal, a 5V output signal, a 3.3V output signal, and a power good signal.
Certainly, the electronic device is in the normal state when each of the output signals has a voltage level greater than a predetermined minimal value and the electronic device is in the abnormal state when one of the output signals has a voltage level lower than a predetermined minimal value.
Certainly, the predetermined minimal value is 8.5V when the voltage level of the output signal is 12V. The predetermined minimal value is 3.3V when the voltage level of the output signal is 5V. The predetermined minimal value is 2.2V when the voltage level of the output signal is 3V. The predetermined minimal value of the power good signal is 3V.
Certainly, the first signal is a green light signal, the second signal is a red light signal, and the third signal is an orange light signal by combining the green light signal and the red light signal.
Certainly, the step (c) further includes a step of maintaining the second signal when the electronic device is in the abnormal mode.
In accordance with another aspect of the present invention, a method for testing an electronic device having an output signal in a burn-in process includes steps of (a) providing a test circuit electrically connected to the electronic device, (b) detecting one of a normal and a abnormal state of the electronic device by checking the output signal, (c) generating a first signal when the electronic device is in the normal state and generating a second signal when the electronic device is in the abnormal state, (d) rechecking the output signal, and (e) generating a third signal when the electronic device is in the abnormal state at previously testing period and in the normal state at subsequently testing period.
Certainly, the electronic device is in the normal state when the output signal has a voltage level greater than a predetermined minimal value and the electronic device is in the abnormal state when the output signal has a voltage level lower than a predetermined minimal value.
In accordance with another aspect of the present invention, an apparatus for testing an electronic device having a plurality of output signals in a burn-in process includes a first test circuit and a second test circuit. The first test circuit is electrically connected to the electronic device for detecting one of a normal state and an abnormal state of the electronic device by checking the output signals and generating a first signal when the electronic device is in the normal state. The second test circuit is electrically connected to the first test circuit for checking the output signals and generating a second signal when the electronic device is in the abnormal state. A third signal is generated to indicate that the electronic device is in the abnormal state at a previously testing period and in the normal state at a subsequently testing period after the electronic device is re-tested by the first and second test circuit.
Certainly, the first test circuit includes a plurality of photo-coupled transistors, a first light-emitting diode (LED) for generating the first signal in response to the normal state of the electronic device, and a buffer gate electrically connected between the first LED and the photo-coupled transistors for allowing the first LED to generate the first signal.
Certainly, the buffer gate includes a plurality AND gates connected in parallel.
Certainly, the second test circuit includes a second LED for generating the second signal in response to the abnormal state of the electronic device, and a switch mounted between the first test circuit and the second LED for allowing the second LED to generate the second signal.
Certainly, the switch includes two AND gates and two silicon-controlled rectifiers (SCR).
The present invention may best be understood through the following description with reference to the accompanying drawings, in which:
REFERENCES:
patent: 4296375 (1981-10-01), Takezaki
patent: 4707654 (1987-11-01), Suzuki et al.
patent: 5570035 (1996-10-01), Dukes et al.
Delta Electronics , Inc.
Metjahic Safet
Nguyen Jimmy
LandOfFree
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