Bitline voltage driver
View Patent ↗A method and structure for passing a bitline voltage regardless of its voltage level via a bitline in a memory device is disclosed. In one embodiment, the method includes detecting the bitline voltage of the bitline, feeding a control signal at an activation voltage level to the bitline pass device to maintain a pass voltage differential of the bitline pass device when the bitline is selected and passing the bitline voltage via the bitline pass device in response to the control signal, where the pass voltage differential is greater than a threshold voltage of the bitline pass device regardless of a level of the bitline voltage.
1. A bitline voltage system, comprising:
a bitline pass device for passing a bitline voltage via a bitline; and
a voltage control module to control the bitline pass device,
wherein the control comprises maintaining a pass voltage differential that enables the bitline pass device to pass the bitline voltage when the bitline is selected; and
wherein the pass voltage differential is greater than a threshold voltage of the bitline pass device regardless of a level of the bitline voltage which is limited by a breakdown voltage of the bitline pass device.
2. The system of claim 1 , wherein the voltage control module is a variable voltage control module for forwarding a control signal in response to various voltage levels in the bitline voltage.
3. The system of claim 1 , wherein the pass voltage differential is less than a positive supply voltage (V cc ) of the memory device minus the threshold voltage.
4. The system of claim 1 , wherein the bitline pass device is coupled between a node at the bitline voltage and a memory cell node.
5. The system of claim 1 , wherein the bitline pass device comprises a pass transistor.
6. The system of claim 1 , wherein the bitline voltage comprises a voltage greater than a positive supply voltage (Vcc) subtracted by the pass voltage differential.
7. The system of claim 1 , wherein the voltage control module comprises a voltage level adjuster for forwarding a control signal for controlling the bitline pass device.
8. The system of claim 7 , wherein the voltage level adjuster is shared by at least one additional bitline of a memory device comprising the bitline.
9. The system of claim 7 , wherein the voltage control module further comprises a logic circuit to select a voltage level of the control signal based on at least one bitline control signal.
10. The system of claim 7 , wherein the variable voltage control module further comprises an inverter coupled between the voltage level adjuster and the bitline pass device.
11. The system of claim 9 , wherein the variable voltage control module further comprises an intrinsic device coupled between the voltage level adjuster and the inverter.
12. The system of claim 10 , wherein the intrinsic device is controlled by at least one of a zero threshold transistor and another intrinsic device.
13. A voltage bitline control module in a memory device, comprising:
a voltage level adjuster for forwarding a control signal to control a bitline pass device; and
a bitline select module to select a voltage level of the control signal,
wherein the control signal is at an activation voltage level that maintains a pass voltage differential regardless of a bitline voltage level when a bitline associated with the bitline pass device is selected and the control signal is at a deactivation voltage level that turns off the bitline pass device when the bitline is not selected; and
wherein the bitline voltage is limited by a breakdown voltage of the bitline pass device.
14. The control module of claim 13 , wherein the voltage level of the control signal is determined based on at least one of the bitline voltage, a threshold voltage of the bitline pass device, a positive supply voltage (V cc ) and at least one bitline control signal of the memory device.
15. The control module of claim 14 , wherein the bitline select module comprises a logic circuit to select between the activation voltage level and the deactivation voltage level based on the at least one bitline control signal.
16. The control module of claim 13 , wherein the voltage level of the control signal is configured in response to a voltage level configuration signal.
17. The control module of claim 13 , wherein the voltage level adjuster is a voltage level shifter, a multiplexer or a voltage divider.
18. A bitline voltage pass method, comprising:
detecting a bitline voltage of a bitline with a bitline pass device;
feeding a control signal at an activation voltage level to a bitline pass device to maintain a pass voltage differential of the bitline pass device when the bitline is selected; and
passing the bitline voltage via the bitline pass device in response to the control signal,
wherein the pass voltage differential is greater than a threshold voltage of the bitline pass device regardless of a level of the bitline voltage limited by a breakdown voltage of the bitline pass device.
19. The method of claim 18 , wherein the feeding the control signal further comprises selecting the activation voltage level based on the bitline voltage, the threshold voltage and a positive supply voltage (V cc ) of a memory device.
20. The method of claim 18 , further comprising feeding the control signal at a deactivation voltage level to the bitline pass device to turn off the bitline pass device, wherein the deactivation voltage level is based on the bitline voltage, the threshold voltage and a positive supply voltage (V cc ) of a memory device.