Initialization circuit and bank active circuit using the same
An initialization circuit comprises a section signal generator generating a section signal, of which a prescribed section is enabled in response to a power-up signal, a first oscillator generating a first period signal in response to the section signal, a first period multiplier generating a first multiplied signal by multiplying a period of the first period signal, and a signal selector transferring the first multiplied signal or a second multiplied signal selectively as a self-refresh enable signal in response to the section signal.
1. A bank active circuit, comprising:
an initializing unit generating a self-refresh enable signal which is enabled at least once during a prescribed section after a power-up section is terminated;
a bank active signal generating unit receiving the self-refresh enable signal, an active signal, a precharge signal and an auto-refresh signal and generate a bank active signal; and
a delay unit delaying the bank active signal by a prescribed amount of time to generate a delay signal for disabling the bank active signal,
wherein a level of an internal voltage increases as a level of an external voltage increases during the power-up section, and the prescribed section is before self-refresh operation.
2. The bank active circuit of claim 1 , wherein the initializing unit comprises:
a section signal generator generating a section signal enabled for the prescribed section in response to a power-up signal;
a first oscillator generating a first period signal in response to the section signal;
a first period multiplier multiplying a period of the first period signal to generate a first multiplied signal; and
a signal selector transferring the first multiplied signal or a second multiplied signal selectively as the self-refresh enable signal in response to the section signal.
3. The bank active circuit of claim 2 , wherein the section signal generator comprises:
a timer generating a start signal in response to the power-up signal;
a counter unit counting the first multiplied signal to generate a first counting signal; and
a section controller generating the section signal in response to the start signal and the first counting signal.
4. The bank active circuit of claim 3 , wherein the timer generates the start signal enabled when the prescribed section is elapsed after the power-up section is terminated.
5. The bank active circuit of claim 3 , wherein the counter unit comprises:
a first counter counting the first multiplied signal to generate a second counting signal;
a second counter counting the second counting signal to generate a third counting signal; and
a third counter counting the third counting signal to generate the first counting signal.
6. The bank active circuit of claim 3 , wherein the section controller comprises:
a pull-up device pull-up driving the section signal in response to the start signal; and
pull-down device pull-down driving the section signal in response to the first counting signal.
7. The bank active circuit of claim 3 , wherein the signal selector comprises:
a first transfer device transferring the first multiplied signal as the self-refresh enable signal in response to the section signal;
a second transfer device transferring the second multiplied signal as the self-refresh enable signal in response to the section signal.
8. The bank active circuit of claim 3 , further comprising:
a second oscillator receiving a self-refresh signal and generate a second period signal; and
a second period multiplier multiplying a period of the second period signal to generate the second multiplied signal.
9. The bank active circuit of claim 1 , wherein the bank active signal generating unit generates the bank active signal enabled if the self-refresh enable signal is enabled and disabled if the delay signal is enabled.
10. The bank active circuit of claim 9 , wherein the bank active signal generating unit comprises:
a pull-up device pull-up driving an output node in response to the precharge signal and the delay signal;
a pull-down device pull-down driving the output node in response to the self-refresh enable signal, the active signal and the auto-refresh signal.
11. A bank active circuit, comprising:
an initializing unit generating a self-refresh enable signal which is enabled at least once during a prescribed section after a power-up section is terminated, in response to a reset signal;
a bank active signal generating unit receiving the self-refresh enable signal an active signal, a precharge signal and an auto-refresh signal and generate a bank active signal; and
a delay unit delaying the bank active signal by a prescribed amount of time to generate a delay signal for disabling the bank active signal,
wherein a level of an internal voltage increases as a level of an external voltage increases during the power-up section, and the prescribed section is before self-refresh operation.
12. The bank active circuit of claim 11 , wherein the reset signal is a signal which is inputted to enter into a reset mode of a mode register read mode in LPDDR2.
13. The bank active circuit of claim 11 , wherein the initializing unit comprises:
a section signal generator generating a section signal enabled for the prescribed section in response to the reset signal;
a first oscillator generating a first period signal in response to the section signal;
a first period multiplier multiplying a period of the first period signal to generate a first multiplied signal;
a signal selector transferring the first multiplied signal or a second multiplied signal selectively as the self-refresh enable signal in response to the section signal.
14. The bank active circuit of claim 13 , wherein the section signal generator comprises:
a timer generating a start signal in response to the reset signal;
a counter unit counting the first multiplied signal to generate a first counting signal; and
a section controller generating the section signal in response to the start signal and the first counting signal.
15. The bank active circuit of claim 14 , wherein the timer generates the start signal enabled when the prescribed section is elapsed after the power-up section is terminated.
16. The bank active circuit of claim 14 , wherein the counter unit comprises:
a first counter counting the first multiplied signal to generate a second counting signal;
a second counter counting the second counting signal to generate a third counting signal; and
a third counter counting the third counting signal to generate the first counting signal.
17. The hank active circuit of claim 14 , further comprising:
a second oscillator receiving a self-refresh signal and generate a second period signal; and
a second period multiplier multiplying a period of the second period signal to generate the second multiplied signal.
18. The bank active circuit of claim 11 , wherein the bank active signal generating unit generates the bank active signal enabled if the self-refresh enable signal is enabled and disabled if the delay signal is enabled.