The accompanying drawings illustrate one or more embodiments of the present invention and, together with the written description, serve to explain the principles of the present invention. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like elements of an embodiment, and wherein:
The present invention is more particularly described in the following examples that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art. Various embodiments of the present invention are now described in detail.
The drain 201a of the first TFT 201 is electrically coupled to the first input terminal Vin and the gate 201c thereof. The source 203b of the second TFT 203 is electrically coupled to the first power supply terminal VDD. The gate 203c of the second TFT 203 is electrically coupled to the source 201b of the first TFT 201. The source 205b of the third TFT 205 is electrically coupled to the drain 203a of the second TFT 203. The drain 205a of the third TFT 205 is electrically coupled to the second power supply terminal VSS. The source 207b of the fourth TFT 207 is electrically coupled to the gate 203c of the second TFT 203. The drain 207a of the fourth TFT 207 is electrically coupled to the second power supply terminal VSS. The gate 207c of the fourth TFT 207 is electrically coupled to the gate 205c of the third TFT 205. The gate 209c and the drain 209a of the fifth TFT 209 are electrically coupled to the second input terminal Vxin. The source 209b of the fifth TFT 209 is electrically coupled to the gate 207c of the fourth TFT 207. The gate 211c of the sixth TFT 211 is electrically coupled to the first input terminal Vin. The drain 211a of the sixth TFT 211 is electrically coupled to the second power supply terminal VSS. The source 211b of the sixth TFT 211 is electrically coupled to the source 209b of the fifth TFT 209. The output terminal Vout is electrically coupled to the source 205b of the third TFT 205.
As shown in
The first input unit 31 receives the first input signal via the first input terminal Vin, and outputs a first switching control signal 300. The second input unit 33, electrically coupled to the second power supply terminal VSS, receives the second input signal via the second input terminal Vxin, and outputs a second switching control signal 302. The gate 301c of the first TFT 301, electrically coupled to the first input unit 31, receives the first switching control signal 300. The drain 301a of the first TFT 301 is electrically coupled to the output terminal Vout. The source 301b of the first TFT 301 is electrically coupled to the first power supply terminal VDD. The disable unit 35, electrically coupled to the first input unit 31, the second input unit 33, the first TFT 301, and the second power supply terminal VSS, receives the second switching control signal 302 and disables the first TFT 301. In other words, the disable unit 35 can control the first TFT 301 to disable (namely turned off). The feedback unit 37 respectively transmits feedback signals 304 and 306 to the first input unit 31 and the disable unit 35 in response to the output signal of the output terminal Vout. The gate 303c of the second TFT 303, electrically coupled to the second input unit 33, receives the second switching control signal 302. The source 303b of the second TFT 303 is electrically coupled to the output terminal Vout. The drain 303a of the second TFT 303 is electrically coupled to the second power supply terminal VSS. In other words, the second TFT 303 receives the second switching control signal 302.
The first input unit 31 comprises a third TFT 305 and a fourth TFT 307. The second input unit 33 comprises a fifth TFT 309 and a sixth TFT 311. The disable unit 35 comprises a seventh TFT 313 and an eighth TFT 315. The feedback unit 37 comprises a ninth TFT 317 and a tenth TFT 319. All the TFTs included in the second embodiment are P-type. Those skilled in the art can easily realize that N-type TFTs are also available. The materials of the TFTs, such as amorphous silicon, poly-crystal silicon, micro-crystal silicon, single-crystal silicon, or combinations thereof, and the formations of the TFTs, such as top gate TFTs, bottom gate TFTs, or the like are not a limitation to the present invention. The connections among these elements are described below.
The gate 305c of the third TFT 305 is electrically coupled to the first input terminal Vin and the drain 305a thereof. The gate 307c of the fourth TFT 307 is electrically coupled to the gate 305c of the third TFT 305. The source 307b of the fourth TFT 307 is electrically coupled to the gate 301c of the first TFT 301. The drain 307a of the fourth TFT 307, electrically coupled to the source 305b of the third TFT 305, receives the feedback signal 304.
The gate 309e of the fifth TFT 309 is electrically coupled to the second input terminal Vxin and the drain 309a of the fifth TFT 309. The source 309b of the fifth TFT 309, electrically coupled to the gate 303c of the second TFT 303, transmits the second switching control signal 302. The gate 311c of the sixth TFT 311 is electrically coupled to the first input terminal Vin. The source 311b of the sixth TFT 311 is electrically coupled to the gate 303c of the second TFT 303 and the source 309b of the fifth TFT 309. The drain 311a of the sixth TFT 311 is electrically coupled to the second power supply terminal VSS.
The source 313b of the seventh TFT 313 is electrically coupled to the gate 301c of the first TFT 301. The source 315b of the eighth TFT 315, electrically coupled to the drain 313a of the seventh TFT 313, receives the feedback signal 306. The gate 315c of the eighth TFT 315 and the gate 313c of the seventh TFT 313, electrically coupled to the gate 303c of the second TFT 303, receive the second switching control signal 302. The drain 315a of the eighth TFT 315 is electrically coupled to the second power supply terminal VSS. In other words, the eighth TFT 315 receives the second switching control signal 302.
The gate 317c of the ninth TFT 317 is electrically coupled to the output terminal Vout and the drain 317a of the ninth TFT 317. The source 317b of the ninth TFT 317, electrically coupled to the source 305b of the third TFT 305, provides the feedback signal 304. The source 319b of the tenth TFT 319, electrically coupled to drain 313a of the seventh TFT 313 and the source 315b of the eighth TFT 315, provides the feedback signal 306. The gate 319c of the tenth TFT 319 is electrically coupled to the output terminal Vout and the drain 319a of the tenth TFT 319.
As shown in
The drain 305a of the third TFT 305 is electrically coupled to the first input terminal Vin, the source 307b of the fourth TFT 307 is electrically coupled to the gate 301c of the first TFT 301 and the disable unit 35. The gate 307c of the fourth TFT 307 is electrically coupled to the gate 305c of the third TFT 305. The gate 307a of the fourth TFT 307 is electrically coupled to the source 305b of the third TFT 305. The gate 401c of the eleventh TFT 401 is electrically coupled to the first input terminal Vin and the second input unit 33. The drain 401a of the eleventh TFT 401 is electrically coupled to the first input terminal Vin. The gate 401b of the eleventh TFT 401 is electrically coupled to the gate 307c of the fourth TFT 307. The gate 403c of the twelfth TFT 403 is electrically coupled to the gate 305c of the third TFT 305. The source 403b of the twelfth TFT 403 is electrically coupled to the first input terminal Vin. The drain 403a of the twelfth TFT 403 is electrically coupled to the gate 305c of the third TFT 305.
The source 309b of the fifth TFT 309 is electrically coupled to the gate 303c of the second TFT 303. The drain 309a of the fifth TFT 309 is electrically coupled to the second input terminal Vxin. The gate 311c of the sixth TFT 311 is electrically coupled to the first input terminal Vin. The drain 311a of the sixth TFT 311 is electrically coupled to the second power supply terminal VSS. The source 311b of the sixth TFT 311 is electrically coupled to the gate 303c of the second TFT 303. The gate 405c of the thirteenth TFT 405 is electrically coupled to the second input terminal Vxin. The source 405b of the thirteenth TFT 405 is electrically coupled to the gate 309c of the fifth TFT 309. The drain 405a of the thirteenth TFT 405 is electrically coupled to the second input terminal Vxin.
The rest connections of the elements in the third embodiment are similar to those in the second embodiment so they are not repeated herein.
The eleventh TFT 401 and the twelfth TFT 403 cause a Bootstrap effect. They, as well as the thirteenth TFT 405 of the second input unit 33, are capable of improving the performance of the whole circuit.
The drain 309a of the fifth TFT 309 is electrically coupled to the first input terminal Vin. The gate 311c of the sixth TFT 311 is electrically coupled to the second input terminal Vxin. The source 311b of the sixth TFT 311 is electrically coupled to the source 309b of the fifth TFT 309. The drain 311a of the sixth TFT 311 is electrically coupled to the second power supply terminal VSS. The gate 405c of the thirteenth TFT 405 is electrically coupled to the first input terminal Vin. The source 405b of the thirteenth TFT 405 is electrically coupled to the gate 309c of the fifth TFT 309. The drain 405a of the thirteenth TFT 405 is electrically coupled to the first input terminal Vin.
The drain 501a of the fourteenth TFT 501 is electrically coupled to the second input terminal Vxin. The source 501b of the fourteenth TFT 501 is coupled to the gate 303c of the second TFT 303. The source of 503b the fifteenth TFT 503 is electrically coupled to the gate 303c of the second TFT 303. The drain 503a of the fifteenth TFT 503 is electrically coupled to the second power supply terminal VSS. The gate 503c of the fifteenth TFT 503 is electrically coupled to the source 309b of the fifth TFT 309. The source 505b of the sixteenth TFT 505 is electrically coupled to the gate 501c of the fourteenth TFT 501. The gate 505c of the sixteenth TFT 505 is electrically coupled to the source 309b of the fifth TFT 309. The gate 507c of the seventeenth TFT 507 is electrically coupled to the gate 505c of the sixteenth TFT 505. The drain 507a of the seventeenth TFT 507 is electrically coupled to the second power supply terminal VSS. The source 507b of the seventeenth TFT 507 is electrically coupled to the drain 505a of the sixteenth TFT 505. The gate 509e of the eighteenth TFT 509 is electrically coupled to the source 501b of the fourteenth TFT 501 and the drain 509a of the eighteenth TFT 509. The source 509b of the eighteenth TFT 509 is electrically coupled to the drain 505a of the sixteenth TFT 505. The source 511b of the nineteenth TFT 511 is electrically coupled to the source 505b of the sixteenth TFT 505. The gate 513c of the twentieth TFT 513 is electrically coupled to the gate 511c of the nineteenth TFT 511 and the drain 513a of the twentieth TFT 513. The source 513b of the twentieth TFT 513 is electrically coupled to the drain 511a of the nineteenth TFT 511 and the second input terminal Vxin. The gate 515c and the drain 515a of the twenty-first TFT 515 are electrically coupled to the second input terminal Vxin. The source 515b of the twenty-first TFT 515 is electrically coupled to the drain 513a of the twentieth TFT 513.
The rest connections of the elements in the fourth embodiment are identical to those of the third embodiment so they are not repeated herein.
Table 1 shows the currents flowing through the first power supply terminal VDD of third embodiment and fourth embodiment under the different threshold voltages. One can observe that the current flowing through VDD of the fourth embodiment is apparently smaller than that of the third embodiment. Therefore, the fourth embodiment saves more power.
The present invention discloses voltage level shifters formed by single-typed TFTs. When integrating the voltage level shifters into a substrate of a TFT display, the manufacturing processes are simplified. Besides, power is saved.
The embodiments were chosen and described in order to explain the principles of the invention and their practical application so as to enable others skilled in the art to utilize the invention and various embodiments and with various modifications as are suited to the particular use contemplated. Alternative embodiments will become apparent to those skilled in the art to which the present invention pertains without departing from its spirit and scope. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description and the exemplary embodiments described therein.
Number | Date | Country | Kind |
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95114010 | Apr 2006 | TW | national |