A kind of device controlling wordline leakage currentTechnical field
The present invention relates to chip field, especially a kind of device controlling wordline leakage current.
Background technology
See Fig. 1 a, Fig. 1 b, comprise overdrive voltage (VOD) power supply, wordline high voltage (VBLH) power supply, switch V1, switch V2, wordline array, common word line and current source, common dram chip is when (ACT) process of activation starts, in order to the magnitude of voltage in wordline can be increased to wordline high-voltage value (VBLH) fast, need first by the switch opens of V1 control, on the VOD power supply that wordline is connected to higher than VBLH, when word line voltage is close to VBLH voltage, again the switch that V1 controls cuts out, open the switch that V2 controls, wordline is made to be connected on VBLH power supply, and keep voltage stabilization.
Under normal circumstances, the wordline time be connected on VOD power supply can be regulated by the later stage and reach optimum, ensures that word line voltage arrives the shortest time to VBLH, ensures to make word line voltage overshoot simultaneously by the leakage current Ib of wordline.
See Fig. 2, the wordline distance VOD of different address is different with the physical distance of VBLH power supply, in figure, wordline 1 represents distance unit farthest, wordline 3 represents nearest unit, if adopt identical switch conduction times and identical leakage current Ib to the charging of different addresses wordline, the dead resistance resistance that electric current flows through on path is different with stray capacitance capacitance, the wordline of different address will be made to use during same leakage current and produce overshoot or arrival VBLH overlong time.
Summary of the invention
In order to solve existing control wordline leakage current device in there is different address wordline use the technical matters producing overshoot during same leakage current or arrive VBLH overlong time, the invention provides a kind of device controlling wordline leakage current.
Technical solution of the present invention is:
A kind of device controlling wordline leakage current, comprise VOD power supply, VBLH power supply, switch V1, switch V2, wordline array, common word line and current source, each wordline in described wordline array is connected with common word line, described common word line is connected with VOD power supply by switch V1, described common word line is connected with VBLH power supply by switch V2, described current source produces leakage current Ib by common word line to the charging wordline charging in wordline array, and its special character is: also comprise controller
Described controller is used for according to the wordline address that charges in wordline array, identifies the leakage current size needed, and controls current source and produces the leakage current Ib needed.
Above-mentioned controller is code translator, described current source comprises switch arrays and electric resistance array (R1, R2, Rn), described electric resistance array (R1, R2, the equal ground connection in one end of resistance each Rn), the other end accesses common word line by switch, and charge in the input termination wordline array of described code translator wordline address, the control end of each switch in the output termination switch arrays of described code translator.
Above-mentioned controller is DAC, and described current source is metal-oxide-semiconductor, the grid end of charge in the input termination wordline array of described DAC wordline address, the output termination metal-oxide-semiconductor of described DAC, the source ground connection of described metal-oxide-semiconductor, the drain terminal access common word line of described metal-oxide-semiconductor.
The advantage that the present invention has:
The present invention is a kind of device controlling wordline leakage current, and this device uses controller to utilize wordline address controlled discharge size of current, can produce corresponding leakage current as required, word line voltage overshoot is reduced, and reaches the effect of saving electric current.Such as: see Fig. 2, when wordline 1 far away is charged, dead resistance and electric capacity larger, the effect of leakage current is weakened, more easily produces overshoot, so utilizes controller according to the address of this wordline, configure larger leakage current, word line voltage overshoot is reduced.In like manner when nearer wordline 3 is charged, reduce leakage current, the effect of saving electric current can be reached.
Accompanying drawing explanation
Fig. 1 a is the structural representation of existing wordline charging modes;
Fig. 1 b is switch conduction sequential relationship schematic diagram;
Fig. 2 is existing structure schematic diagram;
Fig. 3 is structure principle chart of the present invention;
Fig. 4 is the structure principle chart of the embodiment of the present invention one;
Fig. 5 is the structure principle chart of the embodiment of the present invention two;
Specific embodiment
See Fig. 3, the present invention utilizes charging wordline address, identifies through controller inside the leakage current size needed, control current source generation leakage current Ib again and reach requirement, simultaneously when the wordline charging not needing larger leakage current, reduce leakage current, save wordline charging power consumption.
See Fig. 4, embodiments of the invention one adopt code translator, and switch and electric resistance array realize, leakage current Ib flows through the electric current sum of resistance under equaling the switch opened, such as: R1, R2 and R3 upper switch is opened, all the other n-3 switches cut out, and Ib equals Ib1, Ib2, Ib3 sum.Wherein code translator is existing unit, can be built obtain easily by basic logic unit.
See Fig. 5, embodiments of the invention two adopt digital analog converter DAC, and MOS realizes.Absolute value of voltage between the grid source class of leakage current Ib and metal-oxide-semiconductor is proportional, and grid source voltage absolute value is larger, and leakage current Ib is larger.Wherein digital analog converter DAC is existing unit, and what in this embodiment, metal-oxide-semiconductor adopted is NMOS tube.