Pre-delay on-die termination shifting
View Patent ↗Memory systems can include shifting an ODT information signal prior to passing it through a cloned DLL delay line. The shifted ODT information passes through a cloned DLL delay line to move it into a DLL domain. Meanwhile, a clock gate can use a command indication to select whether to provide a clock signal to a DLL delay line. The clock gate can block the clock signal in the absence of a read or write operation and can pass the clock signal during read or write operations. When the DLL delay line receives the clock signal, it delays the clock signal to be in the DLL domain. By locating the ODT shifter before the cloned DLL delay line, as opposed to after it, the ODT shifter doesn't need a signal passed through the DLL delay line. Preventing the clock signal from passing through the DLL delay line reduces power consumption.
1. An apparatus, comprising:
a signal shift circuit configured to receive a clock signal in a first domain and an information signal in the first domain and provide a shifted information signal that is shifted a specified amount;
a delay locked loop (DLL) circuit configured to receive the clock signal in the first domain and provide a delayed clock signal in a DLL domain different from the first domain;
a cloned DLL circuit configured to receive the shifted information signal from the signal shift circuit and produce a shifted and delayed information signal in the DLL domain; and
a clock gate configured to receive the clock signal in the first domain and a control signal and, in response to one or more specified control signals, allowing the clock signal to pass to the DLL circuit,
wherein the one or more specified control signals that cause the clock gate to pass the clock signal to the DLL circuit consist of control signals that indicate a read or a write command.
2. The apparatus of claim 1 , wherein the clock gate is configured to prevent the clock signal from reaching the DLL circuit when the clock gate is not receiving the control signal.
3. The apparatus of claim 1 , wherein the clock gate is configured to prevent the clock signal from reaching the DLL circuit during precharge standby ODT (IDD2NT).
4. The apparatus of claim 2 , wherein, when the clock gate prevents the clock signal from reaching the DLL circuit, a current reduction of at least 3 mA is achieved as compared to when the clock gate provides the clock signal to the DLL circuit.
5. The apparatus of claim 1 , wherein the apparatus is part of a DRAM device.
6. The apparatus of claim 1 ,
wherein the DLL circuit comprises a first set of gates; and
wherein the cloned DLL circuit comprises a second set of gates that has the same configuration as the first set of gates.
7. A method for selecting active circuits in a memory apparatus, the method comprising:
providing, to a signal shift circuit, a clock signal and an information signal;
receiving, from the signal shift circuit, a shifted information signal that is shifted a specified amount;
in response to a control signal indicating a specified condition:
controlling a gating circuit to provide, to a delay locked loop (DLL) circuit, the clock signal; and
receiving, from the DLL circuit, a delayed clock signal;
providing the shifted information signal to a cloned DLL circuit;
receiving from the cloned DLL circuit a shifted and delayed information signal,
providing, to the signal shift circuit, a second clock signal and a second information signal;
receiving, from the signal shift circuit, a second shifted information signal;
in response to no control signal or the control signal not indicating a read or a write command, controlling the gating circuit to block the second clock signal from reaching the DLL circuit;
providing the second shifted information signal to the cloned DLL circuit; and
receiving from the cloned DLL circuit a second shifted and delayed information signal;
wherein blocking the clock signal from reaching the DLL circuit results in a current reduction as compared to when the clock signal is provided to the DLL circuit.
8. The method of claim 7 ,
wherein each of the clock signal, the information signal, the control signal, and the shifted information signal are in a first domain; and
wherein each of the delayed clock signal and the shifted and delayed information signal are in a second domain different from the first domain.
9. The method of claim 7 , wherein the specified condition is an indication that an output portion of the memory apparatus does not require an indication of the clock signal.
10. The method of claim 7 , wherein the specified condition is the control signal indicating a read or a write command.
11. The method of claim 7 ,
wherein the DLL circuit comprises a first set of gates; and
wherein the cloned DLL circuit comprises a second set of gates that has the same configuration as the first set of gates.
12. The method of claim 7 , wherein the control signal is controlled by an ODT pin.