Voltage level generating device

The present invention discloses a voltage level generating device. The voltage level generating device includes: a reference voltage generating module, a first circuit module, a second circuit module, and a switch module. The voltage level generating device disclosed in the present invention only requires a buffer, a voltage regulator, and a arithmetic logic unit (ALU) to attain the same function of the conventional common voltage level generating device, and thus the circuit layout area can be reduced so as to decrease the cost of the integrated circuit (IC). In addition, the voltage level generating device disclosed in the present invention also can select different output of voltage level in order to reduce the power consumption of a display device.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a voltage level generating device, and more particularly, to a common voltage level generating device which can reduce the circuit layout area in a driver integrated circuit (IC) of a display device, and can select different output of voltage level in order to reduce the power consumption of the display device.

2. Description of the Prior Art

Please refer toFIG. 1.FIG. 1shows a simplified circuit diagram of a conventional common voltage level generating device100utilized in a driver integrated circuit (IC) of a display device (not shown) in accordance with a prior art. As shown inFIG. 1, when the conventional common voltage level generating device100is required to output a common voltage level VCOM, the conventional common voltage level generating device100uses a digital-to-analog converter (DAC)110to generate a first reference voltage level VREFH, and then generate a first voltage level VCOMH via a first buffer120, wherein the first voltage level VCOMH will be between a first specific voltage level DDVDH and a ground voltage level AGND. In addition, the conventional common voltage level generating device100uses the DAC110to generate a second reference voltage level VREFL, and then generate a second voltage level VCOML via the first reference voltage level VREFH, resistor units R1, R2R3, and R4, an operational amplifier130, and a second buffer140, wherein the second voltage level VCOML will be between a second specific voltage level VCI and a third specific voltage level VCL.

In the conventional common voltage level generating device100, the resistor units R1, R2R3, and R4having high resistance value are required in order to reduce static current consumption. In addition, the conventional common voltage level generating device100has to use at least two buffers and an operational amplifier, and thus the conventional common voltage level generating device100has a disadvantage of requiring large circuit layout area.

SUMMARY OF THE INVENTION

It is therefore one of the objectives of the present invention to provide a common voltage level generating device which can reduce the circuit layout area in a driver integrated circuit (IC) of a display device, and can select different output of voltage level in order to reduce the power consumption of the display device, so as to solve the above problem.

In accordance with an embodiment of the present invention, a voltage level generating device is disclosed. The voltage level generating device includes: a reference voltage generating module, a first circuit module, a second circuit module, and a switch module. The reference voltage generating module is utilized for providing a first reference voltage level and a second reference voltage level. The first circuit module has a first input terminal coupled to the reference voltage generating module for receiving the first reference voltage level, a second input terminal, and an output terminal coupled to the second input terminal, and the first circuit module is utilized for generating a first voltage level at the output terminal according to the first reference voltage level. The second circuit module has a first input terminal coupled to the reference voltage generating module for receiving the second reference voltage level, a second input terminal coupled to the second input terminal of the first circuit module, and an output terminal coupled to the second input terminal of the second circuit module, and the second circuit module is utilized for generating a second voltage level at the output terminal of the second circuit module according to the second reference voltage level. The switch module includes a first switch element coupled to the output terminal of the first circuit module and a second switch element coupled to the output terminal of the second circuit module, and the switch module is utilized for selectively outputting the first voltage level or the second voltage level.

DETAILED DESCRIPTION

The present invention relates to a voltage level generating device that can be implemented in an integrated circuit (IC). This document will illustrate several exemplary embodiments that apply the voltage level generating device in the present invention. A person of average skill in the pertinent art should, however, be able to understand that the voltage level generating device of the present invention also can be applied to other similar types of ICs and is not limited to the particular embodiments described in the following paragraphs or to the particular manner in which any features of such embodiments are implemented.

In general, the voltage level generating device of the present invention can be applied to all kinds of ICs. By way of example but not limitation, a common voltage level generating device applied to a driver IC of a display device is disclosed in accordance with the present invention. In addition, under a condition of not affecting the technical disclosure of the present invention, the driver IC of the display device will be used as an example to illustrate the details of the circuit configuration and the operational scheme of the voltage level generating device in the present invention.

Please refer toFIG. 2.FIG. 2shows a simplified block diagram of a voltage level generating device200in accordance with a first embodiment of the present invention. As shown inFIG. 2, the voltage level generating device200includes: a reference voltage generating module210, a first circuit module220, a second circuit module230, a switch module240, a first capacitor unit C1, and a second capacitor unit C2. The reference voltage generating module210is utilized for providing a first reference voltage level VREFH and a second reference voltage level VREFL. The first circuit module220has a first input terminal I1coupled to the reference voltage generating module210for receiving the first reference voltage level VREFH, a second input terminal, and an output terminal O1coupled to the second input terminal I2, and the first circuit module220is utilized for generating a first voltage level VCOMH at the output terminal O1according to the first reference voltage level VREFH. The second circuit module230has a first input terminal I3coupled to the reference voltage generating module210for receiving the second reference voltage level VREFL, a second input terminal I4coupled to the second input terminal I2of the first circuit module220, and an output terminal O2coupled to the second input terminal I2of the second circuit module230, and the second circuit module230is utilized for generating a second voltage level VCOML at the output terminal O1of the second circuit module230according to the second reference voltage level VREFL. The switch module240includes a first switch element S1coupled to the output terminal O1of the first circuit module220and a second switch element S2coupled to the output terminal O1of the second circuit module230, and the switch module240is utilized for selectively outputting the first voltage level VCOMH or the second voltage level VCOML as an output of a common voltage level VCOM. In addition, the first capacitor unit C1is coupled between the first voltage level VCOMH and a ground voltage level AGND, and the first capacitor unit C1is utilized for steadying a voltage level of the output terminal O1of the first circuit module220. The second capacitor unit C2is coupled between the second voltage level and the ground voltage level AGND, and the second capacitor unit C2is utilized for steadying a voltage level of the output terminal O2of the second circuit module230. In addition, please note that the above embodiment is only for an illustrative purpose and is not meant to be a limitation of the present invention. For example, the first capacitor unit C1and the second capacitor unit C2are not essential elements in the voltage level generating device200of the present invention, and thus the first capacitor unit C1and the second capacitor unit C2can be ignored in specific conditions. Next, this document will illustrate details of the circuit configuration and the operational scheme of the voltage level generating device200in the present invention.

Please refer toFIG. 3.FIG. 3shows a simplified circuit configuration diagram of the voltage level generating device200shown inFIG. 2. As shown inFIG. 3, the reference voltage generating module210includes a arithmetic logic unit (ALU)212and a digital-to-analog converter (DAC)214. The ALU212is utilized for receiving a first digital signal VCM[M] and a second digital signal VDV[N], and processing the first digital signal VCM[M] and the second digital signal VDV[N] to generate a first digital output signal (not shown) and a second digital output signal (not shown). The DAC214is coupled to the ALU212, and the DAC214is utilized for generating the first reference voltage level VREFH and the second reference voltage level VREFL according to the first digital output signal and the second digital output signal, respectively. In addition, the first circuit module220can be a buffer module, and the first circuit module220includes an operational amplifier OP1. The second circuit module230is a voltage regulating module, and the second circuit module230includes an operational amplifier OP2, a first resistor unit R1coupled between the operational amplifier OP2and the second input terminal I4of the second circuit module230, and a second resistor unit R2coupled between the first resistor unit R1and the output terminal O2. In addition, the switch module240includes a first switch element S1coupled to the output terminal O1of the first circuit module220and a second switch element S2coupled to the output terminal O1of the second circuit module230, and the switch module240can selectively output the first voltage level VCOMH or the second voltage level VCOML as an output of a common voltage level VCOM via switching a turn-on state and a turn-off state of the first switch element S1and the second switch element S2. In addition, the first capacitor unit C1is coupled between the first voltage level VCOMH and a ground voltage level AGND, and the first capacitor unit C1is utilized for steadying a voltage level of the output terminal O1of the first circuit module220. The second capacitor unit C2is coupled between the second voltage level and the ground voltage level AGND, and the second capacitor unit C2is utilized for steadying a voltage level of the output terminal O2of the second circuit module230.

Please refer toFIG. 4.FIG. 4shows a simplified block diagram of a voltage level generating device400in accordance with a second embodiment of the present invention. The voltage level generating device400is substantially the same as the voltage level generating device200in the first embodiment of the present invention, and includes: a reference voltage generating module210, a first circuit module220, a second circuit module230, a switch module240, a first capacitor unit C1, and a second capacitor unit C2. The voltage level generating device400in the second embodiment of the present invention and the voltage level generating device200in the first embodiment of the present invention have similar circuit configurations, and thus the element symbols of the voltage level generating device400inFIG. 4are the same as the element symbols of the voltage level generating device200inFIG. 2. Therefore, further explanation of the details of the circuit configuration and the operational scheme of the voltage level generating device400is omitted herein for the sake of brevity. The difference between the voltage level generating device400and the voltage level generating device200inFIG. 2is shown inFIG. 4. The switch module240further includes a third switch element S3. The third switch element S3is coupled to the ground voltage level AGND, and the switch module240can selectively output the ground voltage level AGND to replace the second voltage level VCOML as an output of a common voltage level VCOM via switching a turn-on state and a turn-off state of the third switch element S3. In addition, please note that the above embodiment is only for an illustrative purpose and is not meant to be a limitation of the present invention. For example, the ground voltage level AGND also can be replaced by a fixed voltage level which is between the first voltage level VCOMH and the second voltage level VCOML in accordance with different circuit design requirements.

Please refer toFIG. 5.FIG. 5shows a simplified block diagram of a voltage level generating device500in accordance with a third embodiment of the present invention. Like the voltage level generating device200in the first embodiment of the present invention, the voltage level generating device500also includes: a reference voltage generating module210, a first circuit module220, a second circuit module230, a switch module240, a first capacitor unit C1, and a second capacitor unit C2. The voltage level generating device500in the third embodiment of the present invention and the voltage level generating device200in the first embodiment of the present invention have similar circuit configurations, and thus the element symbols of the voltage level generating device500inFIG. 5are the same as the element symbols of the voltage level generating device200inFIG. 2. Therefore, further explanation of the details of the circuit configuration and the operational scheme of the voltage level generating device500is omitted herein for the sake of brevity. The difference between the voltage level generating device500and the voltage level generating device200inFIG. 2is shown inFIG. 5. The voltage level generating device500further includes a third switch element S3, a fourth switch element S4, and a fifth switch element S5. The third switch element S3is coupled to a ground voltage level AGND and the first input terminal I3of the second circuit module230, and the fourth switch element S4is coupled between the reference voltage generating module210and the first input terminal I3of the second circuit module230. The fifth switch element S5is coupled between the second input terminal I4of the second circuit module230and the second input terminal I2of the first circuit module220. When the voltage level generating device500is required to output the ground voltage level AGND to replace the second voltage level VCOML as an output of a common voltage level VCOM, the third switch element S3and the second switch element S2are in a turn-on state, and the fourth switch element S4, the fifth switch element S5, and the first switch element S1are in a turn-off state. In addition, the first capacitor unit C1is coupled between the first voltage level VCOMH and a ground voltage level AGND, and the first capacitor unit C1is utilized for steadying a voltage level of the output terminal O1of the first circuit module220. The second capacitor unit C2is coupled between the second voltage level VCOML and a third voltage level VCI, and the second capacitor unit C2is utilized for steadying a voltage level of the output terminal O2of the second circuit module230, wherein the third voltage level VCI is higher than the ground voltage level AGND. Similarly, please note that the above embodiment is only for an illustrative purpose and is not meant to be a limitation of the present invention. For example, the ground voltage level AGND also can be replaced by a fixed voltage level which is between the first voltage level VCOMH and the second voltage level VCOML, in accordance with different circuit design requirements.

Please refer toFIG. 6.FIG. 6shows a simplified block diagram of a voltage level generating device600in accordance with a fourth embodiment of the present invention. Like the voltage level generating device200in the first embodiment of the present invention, the voltage level generating device600also includes: a reference voltage generating module210, a first circuit module220, a second circuit module230, a switch module240, a first capacitor unit C1, and a second capacitor unit C2. The voltage level generating device600in the fourth embodiment of the present invention and the voltage level generating device200in the first embodiment of the present invention have similar circuit configurations, and thus the element symbols of the voltage level generating device600inFIG. 6are the same as the element symbols of the voltage level generating device200inFIG. 2. Therefore, further explanation of the details of the circuit configuration and the operational scheme of the voltage level generating device600is omitted herein for the sake of brevity. The difference between the voltage level generating device600and the voltage level generating device200inFIG. 2is shown inFIG. 6. The voltage level generating device600further includes a third switch element S3and a fourth switch element S4. The third switch element S3is coupled between the first input terminal I3and the second input terminal I4of the second circuit module230, and the fourth switch element S4is coupled between the reference voltage generating module210and the first input terminal I3of the second circuit module230, wherein when the voltage level generating device600is required to output the ground voltage level AGND to replace the second voltage level VCOML as an output of a common voltage level VCOM, the third switch element S3and the second switch element S2are in a turn-on state, and the fourth switch element S4and the first switch element S1are in a turn-off state. Similarly, please note that the above embodiment is only for an illustrative purpose and is not meant to be a limitation of the present invention.

Please refer toFIG. 7.FIG. 7shows a simplified block diagram of a voltage level generating device700in accordance with a fifth embodiment of the present invention. Like the voltage level generating device200in the first embodiment of the present invention, the voltage level generating device700also includes: a reference voltage generating module210, a first circuit module220, a second circuit module230, a switch module240, a first capacitor unit C1, and a second capacitor unit C2. The voltage level generating device700in the fifth embodiment of the present invention and the voltage level generating device200in the first embodiment of the present invention have similar circuit configurations, and thus the element symbols of the voltage level generating device700inFIG. 7are the same as the element symbols of the voltage level generating device200inFIG. 2. Therefore, further explanation of the details of the circuit configuration and the operational scheme of the voltage level generating device700are omitted herein for the sake of brevity. The difference between the voltage level generating device700and the voltage level generating device200inFIG. 2is shown inFIG. 7. The voltage level generating device700further includes a control unit750. The control unit750is coupled to the ALU212, and utilized for controlling the ALU212to selectively process the second digital signal VDV[N] to generate a third digital output signal (not shown), so as to let the DAC214generate the second reference voltage level VREFL according to the third digital output signal and let the second circuit module230generate a ground voltage level AGND at the output terminal O2of the second circuit module230according to the second reference voltage level VREFL to replace the second voltage level VCOML as an output of a common voltage level VCOM. Similarly, please note that the above embodiment is only for an illustrative purpose and is not meant to be a limitation of the present invention.

Briefly summarized, the voltage level generating device disclosed in the present invention only requires a buffer, a voltage regulator, and an ALU to attain the same function of the conventional common voltage level generating device, and thus the circuit layout area can be reduced so as to decrease the cost of the IC. In addition, the voltage level generating device disclosed in the present invention also can select different output of voltage level in order to reduce the power consumption of a display device.