Semiconductor memory apparatus having decreased leakage current
View Patent ↗A semiconductor memory apparatus includes a MOS transistor configured to be supplied with a first voltage through a bulk terminal thereof. The semiconductor memory apparatus also includes a current control unit configured to be connected to a source terminal of the MOS transistor, receive a power down mode enable signal and a self refresh mode enable signal, apply a second voltage to the source terminal during a power down mode or a self refresh mode, and apply the first voltage to the source terminal during modes other than the power down mode and the self refresh mode.
1. A semiconductor memory apparatus, comprising:
a MOS transistor having a bulk terminal, the MOS transistor configured to receive a first voltage through the bulk terminal thereof; and
a current control unit configured to be connected to a source terminal of the MOS transistor and receive both a power down mode enable signal and a self refresh mode enable signal,
wherein the current control unit is configured to apply a second voltage to the source terminal during at least one of a power down mode and a self refresh mode, and the current control unit is configured to apply the first voltage to the source terminal during modes other than the power down mode and the self refresh mode.
2. The semiconductor memory apparatus of claim 1 , wherein the current control unit comprises:
a first current control unit configured to be connected between the source terminal of the MOS transistor and a first voltage supply terminal, receive the power down mode enable signal and the self refresh mode enable signal, and apply the first voltage to the source terminal of the MOS transistor during the modes other than the power down mode and the self refresh mode; and
a second current control unit configured to be connected between the source terminal of the MOS transistor and a second voltage supply terminal, receive the power down mode enable signal and the self refresh mode enable signal, and apply the second voltage to the source terminal during at least one of the power down mode and the self refresh mode.
3. The semiconductor memory apparatus of claim 2 , wherein the first current control unit comprises:
a first mode determiner configured to receive the power down mode enable signal and the self refresh mode enable signal and determine an operational mode of the semiconductor memory apparatus; and
a first switch configured to be connected between the source terminal of the MOS transistor and the first voltage supply terminal and driven according to an output signal of the first mode determiner.
4. The semiconductor memory apparatus of claim 3 ,
wherein the first mode determiner is configured to output a high-level signal when both the power down mode enable signal and the self refresh mode enable signal are disabled.
5. The semiconductor memory apparatus of claim 3 ,
wherein the first switch is configured to be an NMOS transistor that is supplied with the first voltage through a bulk terminal thereof.
6. The semiconductor memory apparatus of claim 2 , wherein the second current control unit comprises:
a second mode determiner configured to receive the power down mode enable signal and the self refresh mode enable signal and determine an operational mode of the semiconductor memory apparatus; and
a second switch configured to be connected between the source terminal of the MOS transistor and a second voltage supply terminal and driven according to an output signal of the second mode determiner.
7. The semiconductor memory apparatus of claim 6 ,
wherein the second mode determiner is configured to output a high-level signal when at least one of the power down mode enable signal and the self refresh mode enable signal is enabled.
8. The semiconductor memory apparatus of claim 6 ,
wherein the second switch is configured to be an NMOS transistor that is supplied with the second voltage through a bulk terminal thereof.
9. The semiconductor memory apparatus of claim 2 ,
wherein the first voltage is configured to have a level lower than that of the second voltage.
10. The semiconductor memory apparatus of claim 2 ,
wherein the first voltage is configured to be a board bias voltage.
11. The semiconductor memory apparatus of claim 2 ,
wherein the second voltage is configured to be a ground voltage.
12. The semiconductor memory apparatus of claim 2 ,
wherein the MOS transistor is configured to be an NMOS transistor.