Semiconductor device and driving method of semiconductor device
A semiconductor device that includes a clock generator which generates a clock signal; a booster which boosts a supply voltage by using the clock signal to output the boosted voltage; a potential detector which detects an output potential of the booster to output a frequency changing signal depending on the output potential; and a frequency changer which is interposed between the clock generator and the booster to change the frequency of the clock signal from the clock generator to the booster on the basis of the frequency changing signal.
1. A semiconductor device comprising:
a clock generator which generates a clock signal;
a booster which boosts a supply voltage by using the clock signal to output an output potential of the booster;
a potential detector which detects the output potential of the booster to output a frequency changing signal depending on the output potential of the booster; and
a frequency changer which is interposed between the clock generator and the booster to change a frequency of the clock signal from the clock generator to the booster on the basis of the frequency changing signal, wherein
the potential detector includes:
a voltage-divider which voltage-divides the output potential of the booster to produce a first potential and a second potential which is not more than the first potential,
a first comparator which compares the first potential with a reference potential to output the frequency changing signal on the basis of the comparison result, and
a second comparator which compares the second potential with the reference potential to output an enabling signal on the basis of the comparison result, said enabling signal determining whether or not the clock signal is caused to pass to the booster from the frequency changer,
wherein the semiconductor device further comprises a gate circuit which is interposed between the frequency changer and the booster to cause the clock signal to pass to the booster from the frequency changer or to interrupt the clock signal on the basis of the enabling signal.
2. A semiconductor device according to claim 1 , wherein
the first comparator activates the frequency changing signal when the first potential exceeds the reference potential,
the frequency changer decreases a frequency of the clock signal in a case that the frequency changing signal is active,
the second comparator deactivates the enable signal when the second potential exceeds the reference potential, and
the gate circuit interrupts the clock signal from the frequency changer to the booster in a case that the enable signal is inactive.
3. A semiconductor device according to claim 1 , wherein
the first comparator deactivates the frequency changing signal when the first potential falls below the reference potential,
the frequency changer does not change a frequency of the clock signal in a case that the frequency changing signal is inactive,
the second comparator activates the enable signal when the second potential falls below the reference potential, and
the gate circuit passes the clock signal from the frequency changer to the booster in a case that the enable signal is active.
4. The semiconductor device according to claim 1 , wherein
a plurality of boosters including the booster are provided for the one clock generator, the boosters receiving the clock signal from the clock generator in parallel with each other,
potential detectors and frequency changers are provided for each of the boosters,
each potential detector detects an output potential of the corresponding booster, and
each frequency changer changes the frequency of the clock signal fed from the clock generator to the booster corresponding to each frequency changer on the basis of the frequency changing signal supplied from the potential detector corresponding to each frequency changer.
5. A semiconductor device comprising:
a clock generator which generates a clock signal;
a booster which boosts a supply voltage by using the clock signal to output an output potential of the booster;
a potential detector which detects the output potential of the booster to output a frequency changing signal depending on the output potential of the booster; and
a frequency changer which is interposed between the clock generator and the booster to change a frequency of the clock signal from the clock generator to the booster on the basis of the frequency changing signal, wherein
the potential detector further includes:
a voltage-divider which voltage-divides the output potential of the booster to produce a first potential, a second potential and a third potential,
a first comparator which compares the first potential with a reference potential to output a first comparison result signal on the basis of the comparison result of the first comparator,
a second comparator which compares the second potential with the reference potential to output a second comparison result signal on the basis of the comparison result of the second comparator,
a third comparator which compares the third potential with the reference potential to output an enabling signal on the basis of the comparison result of the third comparator, said enabling signal determining whether or not the clock signal is caused to pass to the booster from the frequency changer, and
a latch which latches and outputs the frequency changing signal on the basis of the first and the second comparison result signals,
wherein the semiconductor device further comprises a gate circuit which passes or interrupts the clock signal from the clock generator to the booster on the basis of the enabling signal.
6. A semiconductor device according to claim 5 , wherein
the second potential is not more than the first potential, and the third potential is not more than the second potential,
the first comparator activates the first comparison result signal when the first potential exceeds the reference potential,
the second comparator activates the second comparison result signal when the second potential exceeds the reference potential,
the latch latches the frequency changing signal in an active state when both of the first and the second comparison result signals are active,
the frequency changer decreases a frequency of the clock signal when the frequency changing signal is active,
the third comparator deactivates the enable signal when the third potential exceeds the reference potential, and
the gate circuit interrupts the clock signal from the frequency changer to the booster in a case that the enable signal is inactive.
7. A semiconductor device according to claim 5 , wherein
the gate circuit is embedded in the frequency changer.
8. A semiconductor device according to claim 5 , wherein
the second potential is not more than the first potential, and the third potential is not more than the second potential,
the first comparator deactivates the first comparison result signal when the first potential falls below the reference potential,
the second comparator deactivates the second comparison result signal when the second potential falls below the reference potential,
the latch resets the frequency changing signal to an inactive state when both of the first and the second comparison result signals are inactive,
the frequency changer does not changes a frequency of the clock signal when the frequency changing signal is inactive,
the third comparator activates the enable signal when the third potential falls below the reference potential, and
the gate circuit passes the clock signal from the frequency changer to the booster in a case that the enable signal is active.
9. The semiconductor device according to claim 5 , wherein
a plurality of boosters including the booster are provided for the one clock generator, the boosters receiving the clock signal from the clock generator in parallel with each other,
potential detectors and frequency changers are provided for each of the boosters,
each potential detector detects an output potential of the corresponding booster, and
each frequency changer changes the frequency of the clock signal fed from the clock generator to the booster corresponding to each frequency changer on the basis of the frequency changing signal supplied from the potential detector corresponding to each frequency changer.
10. A semiconductor device comprising:
a clock generator which generates a clock signal;
a booster which boosts a supply voltage by using the clock signal to output an output potential of the booster;
a potential detector which detects the output potential of the booster to output a frequency changing signal depending on the output potential of the booster; and
a frequency changer which is interposed between the clock generator and the booster to change a frequency of the clock signal from the clock generator to the booster on the basis of the frequency changing signal, wherein
the potential detector includes:
a voltage-divider which voltage-divides the output potential of the booster to produce a first potential, and
a comparator which compares the first potential with a reference potential to output a comparison result signal on the basis of the comparison result, wherein
the semiconductor device further comprises:
a latch which latches the comparison result signal to output the comparison result signal as the frequency changing signal to the frequency changer, and
a gate circuit which is interposed between the frequency changer and the booster to cause the clock signal to pass to the booster from the frequency changer or to interrupt the clock signal on the basis of the comparison result signal.
11. A semiconductor device according to claim 10 , wherein
the comparator activates the comparison result signal when the first potential exceeds the reference potential,
the latch latches the frequency changing signal in an active state on the basis of the comparison result signal,
the frequency changing signal decreases a frequency of the clock signal when the frequency changing signal is active, and
the gate circuit interrupts the clock signal from the frequency changer to the booster when the comparison result signal is active.
12. A semiconductor device according to claim 10 , wherein
the comparator deactivates the comparison result signal when the first potential falls below the reference potential,
the latch keeps the frequency changing signal in an active state even though the comparison result signal is inactive,
the frequency changing signal decreases a frequency of the clock signal when the frequency changing signal is active, and
the gate circuit passes the clock signal from the frequency changer to booster when the comparison result signal is inactive.
13. The semiconductor device according to claim 10 , wherein
a plurality of boosters including the booster are provided for the one clock generator, the boosters receiving the clock signal from the clock generator in parallel with each other,
potential detectors and frequency changers are provided for each of the boosters,
each potential detector detects an output potential of the corresponding booster, and
each frequency changer changes the frequency of the clock signal fed from the clock generator to the booster corresponding to each frequency changer on the basis of the frequency changing signal supplied from the potential detector corresponding to each frequency changer.
14. A driving method of a semiconductor device, said semiconductor device including a clock generator generating a clock signal, a booster boosting a supply voltage using the clock signal to output a boosted output potential, a potential detector detecting the boosted output potential of the booster, a frequency changer interposed between the clock generator and the booster, and a gate circuit intervening between the frequency changer and the booster, comprising:
detecting the boosted output potential of the booster at the potential detector;
generating a frequency changing signal depending on the boosted output potential of the booster at the potential detector;
changing a frequency of the clock signal from the clock generator to the booster on the basis of the frequency changing signal, wherein
when detecting the output boosted potential of the booster,
voltage-dividing the output boosted potential of the booster to generate a first potential and a second potential which is not greater than the first potential,
when changing the frequency of the clock signal,
the frequency changer passes the clock signal from the frequency changer to the booster-without changing the frequency of the clock signal when the first and second potentials fall below a reference potential,
the frequency changer decreases the frequency of the clock signal and passes the clock signal from the frequency changer to the booster when the first potential exceeds the reference potential and the second potential falls below the reference potential,
the gate circuit interrupts the clock signal from the frequency changer to the booster when the first and the second potentials exceed the reference potential,
the gate circuit passes the clock signal from the frequency changer to the booster again when the second potential falls below the reference potential again, and
the frequency changer gets back the lowered frequency of the clock signal to the original frequency, when the first potential falls below the reference potential again.
15. The driving method of a semiconductor device according to claim 14 , wherein
a plurality of boosters including the booster are provided for the one clock generator, the boosters receiving the clock signal from the clock generator in parallel with each other,
potential detectors and frequency changers are provided for each of the boosters,
each potential detector detects an output potential of the corresponding booster, and
each frequency changer changes the frequency of the clock signal fed from the clock generator to the booster corresponding to each frequency changer on the basis of the frequency changing signal supplied from the potential detector corresponding to each frequency changer.
16. A driving method of a semiconductor device, said the semiconductor device including a clock generator generating a clock signal, a booster boosting a supply voltage using the clock signal to output a boosted output potential a potential detector detecting the boosted output potential of the booster, a frequency changer interposed between the clock generator and the booster, a latch latching the frequency changing signal to output the same, and a gate circuit intervening between the frequency changer and the booster, comprising:
detecting the output boosted potential of the booster at the potential detector;
generating a frequency changing signal depending on the boosted output potential of the booster at the potential detector; and
changing a frequency of the clock signal from the clock generator to the booster on the basis of the frequency changing signal, wherein
when detecting the boosted output potential of the booster,
voltage-dividing the boosted output potential of the booster to generate a first potential, a second potential which is not higher than the first potential and a third potential which is not higher than the second potential,
when changing the frequency of the clock signal,
the frequency changer passes the clock signal to the booster-without changing the frequency of the clock signal when the first, the second and the third potentials fall below a reference potential,
the latch latches the frequency changing signal, and the frequency changer decreases the frequency of the clock signal and passes the clock signal to the booster when the first and the second potentials exceed the reference potential and the third potential falls below the reference potential,
a gate circuit interrupts the clock signal to the booster when the first the, second and the third potentials exceed the reference potential,
the gate circuit passes again the clock signal with the decreased frequency to the booster when the first and the second potentials exceed the reference potential, and the third potential falls below the reference potential, and
the latch-resets the frequency changing signal, and the frequency changer gets back the lowered frequency of the clock signal to the original frequency, when the first, the second, and the third potentials fall below the reference potential again.
17. The driving method of a semiconductor device according to claim 16 , wherein
a plurality of boosters including the booster are provided for the one clock generator, the boosters receiving the clock signal from the clock generator in parallel with each other,
potential detectors and frequency changers are provided for each of the boosters,
each potential detector detects an output potential of the corresponding booster, and
each frequency changer changes the frequency of the clock signal fed from the clock generator to the booster corresponding to each frequency changer on the basis of the frequency changing signal supplied from the potential detector corresponding to each frequency changer.
18. A driving method of a semiconductor device, said semiconductor device including a clock generator generating a clock signal, a booster boosting a supply voltage using the clock signal to output a boosted output potential, a potential detector detecting the boosted output a frequency changer interposed between the clock generator and the booster, a latch latching the frequency changing signal to output the same, and a gate circuit intervening between the frequency changer and the booster, comprising:
detecting the boosted output potential of the booster at the potential detector;
generating a frequency changing signal depending on the boosted output potential of the booster at the potential detector;
changing a frequency of the clock signal from the clock generator to the booster on the basis of the frequency changing signal, wherein
when detecting the boosted output potential of the booster, voltage-dividing the boosted output potential of the booster to generate a first potential,
when changing the frequency of the clock signal, the frequency changer does not change the frequency of the clock signal when the first potential falls below a reference potential,
the latch latches the frequency changing signal, and the frequency changer lowers the frequency of the clock signal and the gate circuit interrupts the clock signal to the booster when the first potential exceeds the reference potential, and
the latch maintains the frequency changing signal, and the frequency changer does not change a state of the decreased frequency of the clock signal, and the gate circuit passes the clock signal to the booster when the first potential falls below the reference potential again.
19. The driving method of a semiconductor device according to claim 18 , wherein
a plurality of boosters including the booster are provided for the one clock generator, the boosters receiving the clock signal from the clock generator in parallel with each other,
potential detectors and frequency changers are provided for each of the boosters,
each potential detector detects an output potential of the corresponding booster, and
each frequency changer changes the frequency of the clock signal fed from the clock generator to the booster corresponding to each frequency changer on the basis of the frequency changing signal supplied from the potential detector corresponding to each frequency changer.