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 signal generation circuit, comprising:
a dynamic node driver for driving a ring oscillator that generates a test signal, said dynamic node driver comprising:
a pre-charge device comprising a pre-charge device input; and
a leakage test device that is biased to an off state, said leakage test device coupled with said pre-charge device at a dynamic node;
a differential amplifier coupled to said dynamic node;
a test signal measurement unit coupled to said differential amplifier and for measuring a frequency of said test signal;
a leakage current estimation unit coupled to said test signal measurement unit and for estimating a leakage current of said leakage test device from said frequency of said test signal; and
a delay unit coupled to said differential amplifier and to said pre-charge device input.
2. The signal generation circuit of claim 1 wherein said leakage test device measures a transistor leakage current.
3. The signal generation circuit of claim 1 wherein said leakage test device comprises a first transistor and a second transistor with differing orientation.
4. The signal generation circuit of claim 1 wherein said leakage test device measures a gate leakage current.
5. A signal generation circuit, comprising:
a dynamic node driver for driving a ring oscillator that generates a test signal, said dynamic node driver comprising:
a pre-charge device comprising a pre-charge device input; and
a leakage test device that is biased to an off state, said leakage test device coupled with said pre-charge device at a dynamic node;
a test signal measurement unit coupled to said dynamic node driver and for measuring a frequency of said test signal;
a leakage current estimation unit coupled to said test signal measurement unit and for estimating a leakage current of said leakage test device from said frequency of said test signal; and
a delay unit coupled to said dynamic node driver and to said pre-charge device input.
6. The signal generation circuit of claim 5 wherein said leakage test device measures a transistor leakage current.
7. The signal generation circuit of claim 5 wherein said leakage test device measures a gate leakage current.
8. The signal generation circuit of claim 5 wherein said leakage test device further comprises a first transistor and a second transistor with differing orientation.
9. A signal generation circuit, comprising:
a test oscillator comprising: a dynamic node driver; and a test loop delay;
wherein said dynamic node driver comprises: a pre-charge device; and a leakage test device that is biased to an off state; and
a reference oscillator having a reference loop delay comparable to said test loop delay.
10. The signal generation circuit of claim 9 wherein said test oscillator produces a test signal and said reference oscillator produces a reference signal, and wherein said signal generation circuit further comprises:
a test signal measurement system measuring said test signal and producing a test measurement; and
a reference signal measurement system measuring said reference signal and producing a reference measurement.
11. The signal generation circuit of claim 10 , further comprising:
a leakage current estimator that receives said test measurement and said reference measurement.
12. A signal generation circuit, comprising:
a dynamic node driver for driving a ring oscillator that generates a test signal, said dynamic node driver comprising:
a pre-charge device comprising a pre-charge device input; and
a leakage test device that is biased to an off state, said leakage test device coupled with said pre-charge device at a dynamic node;
an isolation gate coupled to said dynamic node;
a differential amplifier coupled to said isolation gate;
a test signal measurement unit coupled to said differential amplifier and for measuring a frequency of said test signal;
a leakage current estimation unit coupled to said test signal measurement unit and for estimating a leakage current of said leakage test device from said frequency of said test signal; and
a delay unit coupled to said differential amplifier and to said pre-charge device input.
13. The signal generation circuit of claim 12 further comprising a bypass gate coupled to said differential amplifier and to said pre-charge device input.
14. The signal generation circuit of claim 12 wherein said leakage test device measures a transistor leakage current.
15. The signal generation circuit of claim 12 wherein said leakage test device further comprises a first transistor and a second transistor with an orientation differing from said first transistor.
16. A signal generation circuit, comprising:
a dynamic node driver for driving a ring oscillator that generates a test signal, said dynamic node driver comprising:
a pre-charge device comprising a pre-charge device input; and
a leakage test device that is biased to an off state, said leakage test device coupled with said pre-charge device at a dynamic node;
a test signal measurement unit coupled to said differential amplifier and for determining a frequency of said test signal; and
a leakage current estimation unit coupled to said test signal measurement unit and for estimating a leakage current of said leakage test device using said frequency of said test signal.
17. The signal generation circuit of claim 16 wherein said leakage test device measures a transistor leakage current.
18. The signal generation circuit of claim 16 wherein said leakage test device comprises a first transistor and a second transistor with differing orientation.
19. The signal generation circuit of claim 16 wherein said leakage test device measures a gate leakage current.