TW201626354A - Voltage converting device and related display system - Google Patents

Abstract

A voltage converting module for a display system, includes a voltage converting unit, coupled to a voltage source for generating a supply voltage at an output end to the display system according to a power voltage of the voltage source and a control signal; and a feedback control unit, coupled to the voltage converting unit for generating the control signal according to the supply voltage.

Description

Voltage conversion device and display system thereof

The invention relates to a voltage conversion device and a display system thereof, in particular to a voltage conversion module and a display system thereof, which do not need to mount an additional voltage stabilizing capacitor.

Electronic devices typically contain different components, each of which may require different operating voltages. Therefore, in an electronic device, it is necessary to pass a DC-to-DC voltage conversion circuit to achieve voltage level adjustment (boost or step-down) and stabilize it at a set voltage value. Many different types of DC-to-DC voltage converters can be extended depending on different power requirements, but they are derived from Buck/Step Down Converter and Boost/Step Up. Converter). As the name suggests, the buck converter reduces the DC voltage at the input to a predetermined voltage level, while the boost converter boosts the DC voltage at the input. Regardless of the buck converter or boost converter, as circuit technology evolves, both have evolved to accommodate different architectures or to meet different needs.

In general, when a boost converter implemented by an inductor generates a voltage, the output of the boost converter must be coupled to an external voltage stabilizing capacitor to stabilize the voltage generated by the boost converter. However, the addition of an external regulated capacitor will increase the cost of using a boost converter. In addition, the boost converter also needs to additionally charge or discharge an external Zener capacitor when boosting or lowering the voltage, thereby increasing the power consumption of the boost converter. From the above, it is known that there is a need for improvement in the prior art.

In order to solve the above problems, the present invention provides a voltage conversion module and a display system thereof that do not need to mount an additional voltage stabilizing capacitor.

The invention discloses a voltage conversion module for a display system, comprising a voltage conversion unit coupled to a voltage source for generating a supply at an output according to a power supply voltage and a control signal of the voltage source. The voltage is applied to the display system; and a feedback control unit is coupled to the voltage conversion unit for generating the control signal according to the supply voltage.

The invention further discloses a display system comprising a display panel; a gate drive module for enabling a plurality of scan lines; a source drive module for enabling a plurality of data lines; and a power conversion mode The group includes a voltage conversion unit coupled to a voltage source for generating at least one supply voltage to the display panel and the gate driving module at an output according to a power supply voltage and a control signal of the voltage source And the at least one of the source driving modules; and a feedback control unit coupled to the voltage conversion unit for generating the control signal according to the at least one supply voltage.

10‧‧‧Display system

100‧‧‧ panel

102‧‧‧ drive

104‧‧‧Gate drive module

106‧‧‧Source Drive Module

108‧‧‧Voltage conversion module

200, 400, 500, 700, 800‧‧‧ voltage conversion unit

202, 402, 502, 702, 802‧‧ ‧ feedback control unit

204, 404, 504, 704, 804‧‧‧ voltage sensors

206, 406, 506, 706, 806‧‧ ‧ controller

CS, CL‧‧‧ capacitor

DIO‧‧‧ diode

SL1~SLm‧‧‧ data line

L‧‧‧Inductance

MN‧‧•O crystal

OP‧‧‧ buffer

OS‧‧‧ output stage

OUT‧‧‧ output

GL1~GLn‧‧‧ scan line

SW_MN, SW_MP‧‧‧ transistor

TP‧‧‧ time interval

VCOM‧‧‧ common reference voltage

VDD‧‧‧voltage source

VGAT1, VGAT2, VSOU1, VSOU2‧‧‧ supply voltage

VGATP, VSOUP‧‧‧ supply voltage

VGATN, VSOUN‧‧‧ negative supply voltage

VTH1~VTH5‧‧‧Preset voltage

FIG. 1A is a schematic diagram of a display system in an embodiment of the present invention.

Fig. 1B is a schematic diagram of the equivalent circuit of the display system shown in Fig. 1A.

FIG. 2 is a schematic diagram of an implementation of the voltage conversion module shown in FIG. 1B and some components of the source driving module.

Figure 3 is a schematic diagram of the relevant signals when the voltage conversion module shown in Figure 2 operates.

FIG. 4 is a schematic diagram showing another implementation of the voltage conversion module shown in FIG. 1B and some components of the source driving module.

Figure 5 is another implementation of the voltage conversion module shown in Figure 1B and the gate drive module portion. Schematic diagram of the component.

Figure 6 is a schematic diagram of the relevant signals when the voltage conversion module shown in Figure 5 operates.

FIG. 7 is another schematic diagram of the voltage conversion module shown in FIG. 1B and a schematic diagram of some components of the gate driving module.

Figure 8 is a schematic diagram showing another implementation of the voltage conversion module shown in Figure 1B and some components of the display panel.

Figure 9 is a schematic diagram of the relevant signals when the voltage conversion module shown in Figure 8 operates.

Please refer to FIG. 1A. FIG. 1A is a schematic diagram of a display system 10 according to an embodiment of the present invention. The display system 10 can be an electronic product having a display panel such as a Thin Film Transistor (TFT) liquid crystal display or a smart phone. The display system 10 includes a display panel 100 and a drive unit 102. As shown in FIG. 1A, the display panel 100 includes a plurality of pixels PIX, and the display panel 100 and the driving device 102 are disposed on the same substrate. For a brief description, please refer to FIG. 1B. FIG. 1B is a schematic diagram of the equivalent circuit of the display system 10 shown in FIG. 1A. In FIG. 1B, the panel 100 includes scan lines GL1 to GLn and data lines SL1 to SLm. For the sake of brevity, FIG. 1B only shows the scanning lines GL1 GL GL3 and the data lines SL1 s SL4 as representatives. Each of the intersections of the scan lines GL1 GL GLn and the data lines SL1 - SLm is coupled to the transistor MN , which is coupled to the capacitors CS , CL . The capacitor CL can be regarded as the equivalent capacitance of the pixel PIX in the display panel 100, and the capacitors CS and CL are all coupled to a common reference voltage VCOM in the display system 10. The driving device 102 includes a gate driving module 104, a source driving module 106 and a voltage conversion module 108. The gate driving module 104 enables the scanning lines GL1 GL GLn of the panel 100 to control the conduction state of the transistor MN by using the supply voltage VGAT generated by the voltage conversion module 108. The source driving module 106 adjusts the voltage on the data lines SL1 to SLm of the panel 100 by using the supply voltage VSOU generated by the voltage conversion module 108 to control the potential difference across the equivalent capacitance CL of each liquid crystal molecule. Thereby, the thin film transistor liquid crystal display 10 can sequentially control each liquid The potential difference between the equivalent capacitance CL of the crystal molecule.

It should be noted that when the voltage conversion module 108 generates the supply voltage VGAT, VSOU and the common reference voltage VCOM, the operating state of the voltage is adjusted according to the supply voltage VGAT, VSOU and the common reference voltage VCOM. Accordingly, the voltage conversion module 108 does not need to be coupled to an additional voltage stabilizing capacitor to generate a stable supply voltage VGAT, VSOU, and a common reference voltage VCOM, and the display system 10 operates normally.

For details, please refer to FIG. 2 , which is a schematic diagram of an implementation of the voltage conversion module 108 and a partial component of the source driving module 106 shown in FIG. 1B . As shown in FIG. 2, the voltage conversion module 108 includes a voltage conversion unit 200 and a feedback control unit 202. The voltage conversion unit 200 is a boost converter implemented by using an inductor, and the composition and architecture thereof can be applied according to different applications. And the design concept is changed. In this embodiment, the voltage conversion unit 200 includes an inductor L, a transistor SW_MN, and a diode DIO for generating a supply voltage VSOU1 at an output terminal OUT according to a power supply voltage of the voltage source VDD and a control signal CON. The buffer OP for driving the data lines SL1 to SLm (the second figure shows only the data lines SL1 to SL3 as representatives) to the source driving module 106. It should be noted that the supply voltage VSOU1 generated by the voltage conversion module 108 in FIG. 2 is the positive supply voltage of the buffer OP, and the negative supply voltage VSOUN of the buffer OP may be from the other voltage conversion module 108 in the display system 10. provide. The feedback control unit 202 includes a voltage sensor 204 and a controller 206 for adjusting the control signal CON according to the voltage value of the supply voltage VSOU1 to control the operating state of the voltage conversion unit 200. When the voltage value of the supply voltage VSOU1 exceeds a predetermined voltage VTH1, the feedback control unit 202 adjusts the control signal CON to cause the voltage conversion unit 200 to stop operating. In this way, the voltage conversion module 108 does not need to mount the voltage stabilizing capacitor at the output terminal OUT, thereby generating a stable supply voltage VSOU1.

Regarding the detailed operation process of the voltage conversion module 108 shown in FIG. 2, for example, under. Please refer to FIG. 3 together. FIG. 3 is a schematic diagram of related signals when the voltage conversion module 108 shown in FIG. 2 operates. The controller 206 periodically adjusts the control signal CON before a time point T1. When the control signal CON generated by the controller 206 is at a high logic level, the transistor SW_MN is turned on, and the inductor L stores energy in a time interval TP. When the control signal CON is at a low logic level, the inductor L begins to supply energy to the output terminal OUT. Since each of the buffers OP stops operating when the voltages of the corresponding data lines SL1 to SLm reach the target voltage value, the supply voltage VSOU1 gradually rises when the control signal CON is at a low logic level. At time T1, the voltage value of the supply voltage VSOU1 reaches the preset voltage VTH1, and the controller 206 maintains the control signal CON at a low logic level according to the voltage sensed by the voltage sensor 204 to continuously turn off the transistor SW_MN. When the energy stored in the inductor L is used up, the supply voltage VSOU1 will gradually decrease. Until a time point T2, the voltage value of the supply voltage VSOU1 is less than the preset voltage VTH1, and the controller 206 re-adjusts the control signal CON to a high logic level to charge the inductor L in the time interval TP after the time point T2. In this way, the voltage conversion module 108 can generate a stable supply voltage VSOU1 to the source driving module 106 without mounting the voltage stabilizing capacitor at the output terminal OUT. In addition, the power consumption of the voltage conversion module 108 also decreases.

Please refer to FIG. 4 . FIG. 4 is a schematic diagram of another implementation of the voltage conversion module 108 and the components of the source driving module 106 shown in FIG. 1B . The voltage conversion module 108 shown in FIG. 4 is similar to the voltage conversion module 108 shown in FIG. 2, and thus components and symbols having similar functions are denoted by the same reference numerals. As shown in FIG. 4, the voltage conversion module 108 includes a voltage conversion unit 400 and a feedback control unit 402. The voltage conversion unit 400 includes an inductor L, a transistor SW_MP, and a diode DIO, and the feedback control unit 402 includes a voltage sensor 404 and a controller 406. Unlike the voltage conversion module 108 shown in FIG. 2, the supply voltage VSOU2 generated by the voltage conversion module 108 shown in FIG. 4 is the negative supply voltage of the buffer OP (such as the supply voltage VSOUN shown in FIG. 2). And the positive supply voltage VSOUP of the buffer OP may be the supply voltage VSOU1 shown in FIG. In addition, the controller 406 shown in FIG. 4 is connected to the supply voltage VSOU2 down to a pre- When the voltage VTH2 is set, the control signal CON is adjusted to turn off the transistor SW_MP to stop the voltage conversion unit 400 from operating. Accordingly, the voltage conversion module 108 shown in FIG. 4 does not need to mount the voltage stabilizing capacitor at the output terminal OUT, thereby generating a stable supply voltage VSOU2 to the source driving module 106 and reducing power consumption. For the detailed operation of the voltage conversion module 108 shown in FIG. 4, reference may be made to the voltage conversion module 108 shown in FIG. 2 for the sake of brevity, and details are not described herein.

Please refer to FIG. 5 . FIG. 5 is a schematic diagram of another implementation of the voltage conversion module 108 and the components of the gate driving module 104 shown in FIG. 1B . The voltage conversion module 108 shown in FIG. 5 is similar to the voltage conversion module 108 shown in FIG. 2, and thus components and symbols having similar functions follow the same symbols. As shown in FIG. 5, the voltage conversion module 108 includes a voltage conversion unit 500 and a feedback control unit 502. The voltage conversion unit 500 includes an inductor L, a transistor SW_MN, and a diode DIO, and the feedback control unit 502 includes a voltage sensor 504 and a controller 506. It should be noted that FIG. 5 only shows a part of the output stage OS and the scan lines GL1 GL33 of the gate driving module 104 as representatives. In this embodiment, the supply voltage VGAT1 output by the voltage conversion module 108 is the positive supply voltage of the output stage OS in the gate drive module 104, and the negative supply voltage VGATN of the output stage OS in the gate drive module 104 can be Provided by another voltage conversion module 108 in display system 10. In this case, the output stage OS of the gate driving module 104 charges the scanning lines GL1 GL GLn with the supply voltage VGAT1 to increase the gate voltage of the transistor MN of the display panel 100. Therefore, when the supply voltage VGAT1 rises above a predetermined voltage VTH3, the output stage OS can use the supply voltage VGAT1 to conduct the transistor MN. That is, the controller 506 can adjust the control signal CON to stop the voltage conversion unit 500 when the voltage value of the supply voltage VGAT1 sensed by the voltage sensor 504 reaches the preset voltage VTH3 (eg, 15 volts).

Next, since the gate of the transistor MN has a leakage current and the voltage conversion module 108 does not mount the voltage stabilizing capacitor at the output terminal OUT, the supply voltage VGAT1 gradually decreases. When the supply voltage VGAT1 falls below the preset voltage VTH3, the controller 506 adjusts the control signal CON to The voltage conversion unit 500 is caused to operate to raise the supply voltage VGAT1. Accordingly, the voltage conversion module 108 does not need to mount the voltage stabilizing capacitor at the output terminal OUT, thereby generating a stable supply voltage VGAT1.

Please refer to FIG. 6. FIG. 6 is a schematic diagram of related signals when the voltage conversion module 108 shown in FIG. 5 operates. As shown in FIG. 6, the control signal CON is initially at a high logic level to conduct the crystal SW_MN and charge the inductor L. At time point T1, the control signal CON is adjusted to a low logic level, the inductor L begins to supply energy to the output terminal OUT, the supply voltage VGAT1 rises rapidly and reaches the preset voltage VTH3 at the time point T2. At this time, the control signal CON will be maintained at a low logic level. When the energy of the inductor L is used up, the supply voltage VGAT1 will gradually drop due to the gate leakage gate switch. At a time point T3, the supply voltage VGAT1 falls below the preset voltage VTH3, and the controller 506 adjusts the control signal CON to a high logic level to start charging the inductor L in the time interval TP after the time point T3. analogy. Accordingly, the voltage conversion module 108 can generate a stable supply voltage VGAT1 to the gate driving module 104 without mounting the voltage stabilizing capacitor at the output terminal OUT.

Please refer to FIG. 7. FIG. 7 is another schematic diagram of the voltage conversion module 108 shown in FIG. 1B and a schematic diagram of some components of the gate driving module 104. The voltage conversion module 108 shown in FIG. 7 is similar to the voltage conversion module 108 shown in FIG. 5, and thus components and symbols having similar functions follow the same symbols. As shown in FIG. 7, the voltage conversion module 108 includes a voltage conversion unit 700 and a feedback control unit 702. The voltage conversion unit 700 includes an inductor L, a transistor SW_MP, and a diode DIO, and the feedback control unit 702 includes a voltage sensor 704 and a controller 706. Different from the voltage conversion module 108 shown in FIG. 5, the supply voltage VGAT2 outputted by the voltage conversion module 108 shown in FIG. 7 is the negative supply voltage of the output stage OS (such as the VGATN shown in FIG. 5). And the positive supply voltage VGATP of the output stage OS can be the supply voltage VGAT1 output by the voltage conversion module 108 shown in FIG. The controller 706 shown in FIG. 7 adjusts the control signal CON to turn off the transistor when the supply voltage VGAT2 falls below a predetermined voltage VTH4. SW_MP, so that the voltage conversion unit 700 stops operating; and when the supply voltage VGAT2 rises above the preset voltage VTH4, the control signal CON is adjusted to conduct the power-on crystal SW_MP, so that the voltage conversion unit 700 starts to operate. Accordingly, the voltage conversion module 108 shown in FIG. 7 does not need to mount the voltage stabilizing capacitor at the output terminal OUT, thereby generating a stable supply voltage VGAT2 to the gate driving module 104 and reducing power consumption. For a detailed operation of the voltage conversion module 108 shown in FIG. 7, reference may be made to the voltage conversion module 108 shown in FIG. 5. For the sake of brevity, details are not described herein.

Please refer to FIG. 8. FIG. 8 is a schematic diagram showing another implementation of the voltage conversion module 108 shown in FIG. 1B and some components of the display panel 100. The voltage conversion module 108 shown in FIG. 8 is similar to the voltage conversion module 108 shown in FIG. 7, and thus components and symbols having similar functions follow the same symbols. As shown in FIG. 8, the voltage conversion module 108 includes a voltage conversion unit 800 and a feedback control unit 802. The voltage conversion unit 800 includes an inductor L, a transistor SW_MP, and a diode DIO, and the feedback control unit 802 includes a voltage sensor 804 and a controller 806. In this embodiment, the common voltage VCOM generated by the voltage conversion unit 800 is coupled to the capacitors CS, CL in the display panel. The controller 806 maintains the common reference voltage VCOM substantially at a reference voltage VREF (eg, 2 volts or 0.5 volts) by adjusting the control signal CON.

For example, the controller 806 can use the reference voltage VREF as the preset voltage VTH5 for controlling the voltage conversion module 108 shown in FIG. When the common reference voltage VCOM falls below the preset voltage VTH5 (ie, the reference voltage VREF), the controller 806 stops the operation of the voltage conversion unit 800 by adjusting the control signal CON; and when the common reference voltage VCOM rises beyond the preset voltage At VTH5, the controller 806 causes the voltage conversion unit 800 to start operation by adjusting the control signal CON. Accordingly, the voltage conversion module 108 can generate a stable common reference voltage VCOM to the display panel 100 without mounting the voltage stabilizing capacitor at the output terminal OUT.

Please refer to FIG. 9. FIG. 9 is a diagram showing the operation of the voltage conversion module 108 shown in FIG. Schematic diagram of the relevant signal. As shown in FIG. 9, first, the controller 806 adjusts the control signal CON to a low logic level, and the transistor SW_MP is turned on to start the charging of the inductor L. At time point T1, the control signal CON is adjusted to a high logic level, the inductor L starts to send energy to the output terminal OUT, the common reference voltage VCOM continues to drop and reaches the preset voltage VTH5 at the time point T2. At this time, the control signal CON is maintained at a high logic level, thereby causing the voltage conversion unit 800 to stop operating. Next, when the energy stored in the inductor L is used up, the common reference voltage VCOM gradually rises due to the switching of the gate, the charge and discharge of the source, or the leakage current, and rises above the preset voltage VTH5 at the time point T3, and controls The 806 adjusts the control signal CON to a high logic level to conduct the transistor SW_MP to charge the inductor L, and so on. Accordingly, the voltage conversion module 108 can generate a stable common reference voltage VCOM to the display panel 100 without mounting the voltage stabilizing capacitor at the output terminal OUT.

In summary, the voltage conversion module for the display system in the above embodiment can adjust the operating state of the power conversion unit that generates the supply voltage and the common reference voltage according to the supply voltage and the common reference voltage generated by the respective embodiments. Under this condition, the voltage conversion module does not need to mount an additional voltage regulator capacitor at the output to generate a stable supply voltage and a common reference voltage. Accordingly, the manufacturing cost and power consumption of the display system can be effectively reduced.

The above are only the preferred embodiments of the present invention, and all changes and modifications made to the scope of the present invention should be within the scope of the present invention.

200‧‧‧Voltage conversion unit

202‧‧‧Return control unit

204‧‧‧Voltage sensor

206‧‧‧ Controller

DIO‧‧‧ diode

SL1~SL3‧‧‧ data line

L‧‧‧Inductance

OP‧‧‧ buffer

OUT‧‧‧ output

SW_MN‧‧‧O crystal

VDD‧‧‧voltage source

VSOU1‧‧‧ supply voltage

VSOUN‧‧‧negative supply voltage

Claims (8)

A voltage conversion module for a display system includes: a voltage conversion unit coupled to a voltage source for generating a supply voltage at an output terminal according to a power supply voltage and a control signal of the voltage source And the feedback control unit is coupled to the voltage conversion unit for generating the control signal according to the supply voltage. The voltage conversion module of claim 1, wherein the output terminal is not mounted with a voltage stabilizing capacitor. The voltage conversion module of claim 1, wherein the supply voltage is provided to a source driving module of the display system, and is used to charge or discharge a plurality of data lines in the display system. The voltage conversion module of claim 1, wherein the supply voltage is provided to a gate driving module of the display system, and is used to charge or discharge a plurality of scanning lines in the display system. The voltage conversion module of claim 1, wherein the feedback control unit adjusts the control signal when the absolute value of the supply voltage is greater than a predetermined voltage, so that the voltage conversion unit stops operating. The voltage conversion module of claim 1, wherein the feedback control unit adjusts the control signal when the absolute value of the supply voltage is less than a predetermined voltage, so that the voltage conversion unit starts to operate. The voltage conversion module of claim 1, wherein the supply voltage is a total of the display system Same as the reference voltage. A display system includes: a display panel; a gate drive module for enabling a plurality of scan lines; a source drive module for enabling a plurality of data lines; and a power conversion module, The method includes a voltage conversion unit coupled to a voltage source for generating at least one supply voltage to the display panel and the gate driving module according to a power supply voltage and a control signal of the voltage source. And the at least one of the source driving modules; and a feedback control unit coupled to the voltage conversion unit for generating the control signal according to the at least one supply voltage.