Data I/O control signal generating circuit in a semiconductor memory apparatus
View Patent ↗A circuit for generating a data I/O control signal used in a semiconductor memory apparatus comprises a delay block for generating a delay signal having a relatively short delay value and a delay signal having a relatively long delay values, and a selection block for selecting any one of the delay signals according to an operational mode. The selection block selects an output signal of the first delay unit in a high-speed operation mode and selects an output signal of the second delay unit in a low-speed operation mode.
1. A circuit for generating a data I/O control signal used in a semiconductor memory apparatus, comprising:
a first delay block configured to receive an input pulse, to delay the input pulse by a first delay value, and to output a first delay signal;
a second delay block configured to receive the input pulse, to delay the input pulse by a second delay value being larger than the first delay value, and to output a second delay signal; and
a selection block configured to receive the first delay signal and the second delay signal and to select one of the first delay signal and the second delay signal according to a value of a CAS latency signal.
2. The circuit of claim 1 , wherein the selection block is configured to select the first delay signal when the selection block receives the CAS latency signal which is more than a predetermined value, and to select the second delay signal when the selection block receives the CAS latency signal which is less than the predetermined value.
3. The circuit of claim 1 , wherein the selection block includes:
a first pass gate for transferring the first delay signal according to the CAS latency signal which is more than a predetermined value; and
a second pass gate for transferring the second delay signal according to the CAS latency which is less than the predetermined value.
4. The circuit of claim 3 , wherein the selection block further includes a signal combination unit for generating a column selection signal by logically combining the input pulse with any one of the first and second delay signals.
5. A circuit for generating a data I/O control signal used in a semiconductor memory apparatus, comprising:
a first delay block configured to receive an input pulse, to delay the input pulse by a first delay value, and to output a first delay signal;
a second delay block configured to receive the input pulse, to delay the input pulse by a second delay value, and to output a second delay signal; and
a selection block configured to receive the first delay signal and the second delay signal and to select one of the first delay signal and the second delay signal according to a CAS latency signal and output a selected signal as a column selecting signal,
wherein the column selecting signal is a signal which is inputted to a sense amplifier.
6. The circuit of claim 5 , wherein the selection block is configured to select the first delay signal when the selection block receives the CAS latency signal which is more than a predetermined value, and to select the second delay signal when the selection block receives the CAS latency signal which is less than the predetermined value.
7. The circuit of claim 5 , wherein the selection block includes:
a first pass gate for transferring the first delay signal according to the CAS latency signal which is more than a predetermined value; and
a second pass gate for transferring the second delay signal according to the CAS latency which is less than the predetermined value.
8. The circuit of claim 5 , wherein the selection block further includes a signal combination unit for generating the column selection signal by logically combining the input pulse with any one of the first and second delay signals.