System and method for measuring transistor leakage current with a ring oscillator
View Patent ↗A method of measuring the transistor leakage current. In one embodiment, the method involves driving a ring oscillator with a dynamic node driver having a leakage test device biased to an off state to produce a test signal. The test signal is extracted and the frequency is measured. The leakage current is estimated from the measured frequency.
1. A method of estimating leakage current, said method comprising:
driving a ring oscillator with a dynamic node driver, said dynamic node driver comprising: a pre-charge device; and a leakage test device, said leakage test device biased to an off state with said pre-charge device coupled to said leakage test device at a dynamic node;
extracting a test signal from said ring oscillator;
measuring a test frequency from said test signal; and
estimating a leakage current of said leakage test device from said test frequency.
2. The method of claim 1 wherein said ring oscillator further comprises a delay unit.
3. The method of claim 1 wherein said ring oscillator further comprises a differential amplifier.
4. The method of claim 1 wherein said measuring includes conditioning said test signal.
5. The method of claim 1 wherein said ring oscillator comprises a loop delay, and further comprising:
generating a reference signal with a reference oscillator having a comparable loop delay; and
measuring a reference frequency from said reference signal.
6. The method of claim 1 wherein said leakage test device measures a transistor leakage current.
7. The method of claim 1 wherein said leakage test device measures a gate leakage current.