Power supply circuit of liquid crystal display equipment, power supply device and liquid crystal display system

Abstract

The utility model discloses a power supply circuit of liquid crystal display equipment, a power supply device and a liquid crystal display system, and relates to the field of circuits. The power supply is converted into the first preset voltage corresponding to the size of the required positive voltage and the second preset voltage corresponding to the size of the required negative voltage, and the first preset voltage can be directly amplified by the power amplification module and then is output as the positive voltage. The second preset voltage needs to be converted into reverse-phase negative voltage through the reverse-phase amplification module and then is output, and therefore positive voltage and negative voltage needed for driving the liquid crystal display device are generated at the same time. According to the power supply circuit of the liquid crystal display device, the negative voltage for driving can be generated without the negative preset voltage by arranging the inverting amplification module, so that circuits required for generating the negative preset voltage are reduced, and the design difficulty of the power supply circuit of the liquid crystal display device is reduced.

Description

Technical Field

[0001] The utility model relates to the field of circuits, in particular to a power supply circuit, a power supply device and a liquid crystal display system of a liquid crystal display device. Background Art

[0002] With the continuous development of liquid crystal display (LCD) devices, the question of how to power these devices has become a key development direction. LCDs primarily use electric current to stimulate liquid crystal molecules to create dots, lines, and surfaces, which, in conjunction with backlighting, form the display. Liquid crystal molecules inherently carry an electric charge, and under the influence of an applied electric field, their orientation undergoes subtle changes, thereby altering the direction of light propagation. However, applying a voltage of the same polarity to the liquid crystal molecules for extended periods of time can cause the mobile ions in the liquid crystal layer to migrate, forming an internal electric field. This internal electric field can cause the liquid crystal to align differently from its original state, even without an applied voltage, resulting in color shifts in the display. Due to this characteristic of liquid crystal molecules, the polarity of the electric field applied to an LCD device must be altered to prevent poor polarization of the liquid crystal. Therefore, driving LCDs with positive and negative voltages is a common method that effectively avoids this phenomenon. However, developing a power supply circuit capable of simultaneously outputting both positive and negative voltages to drive LCDs is a pressing technical challenge. Utility Model Content

[0003] The purpose of the present utility model is to provide a power supply circuit, a power supply device and a liquid crystal display system for a liquid crystal display device. By providing an inverting amplifier module, a negative voltage for driving can be generated without a negative preset voltage, thereby reducing the circuit required to generate the negative preset voltage and alleviating the design difficulty of the power supply circuit of the liquid crystal display device.

[0004] In order to solve the above technical problems, the present invention provides a power supply circuit for a liquid crystal display device, comprising:

[0005] a voltage conversion module, the input end of which is connected to the power supply, and is used to convert the power supply into a first preset voltage and a second preset voltage respectively; the first preset voltage and the second preset voltage are both positive voltages;

[0006] a power amplification module, whose input end is connected to the first output end of the voltage conversion module, and whose output end serves as a positive voltage output end of the power supply circuit, for outputting a positive voltage after power amplification of the first preset voltage;

[0007] The inverting amplifier module has an input end connected to the second output end of the voltage conversion module, and an output end serving as a negative voltage output end of the power supply circuit, for outputting a negative voltage with a phase opposite to that of the second preset voltage.

[0008] Optionally, the power amplification module includes:

[0009] a first operational amplifier, a non-inverting input terminal connected to the first output terminal of the voltage conversion module;

[0010] a first resistor, a first end of which is connected to the output end of the first operational amplifier and serves as a positive voltage output end of the power supply circuit;

[0011] The second resistor has a first end connected to the second end of the first resistor and the inverting input end of the first operational amplifier, and a second end grounded.

[0012] Optionally, also include:

[0013] A bandgap reference voltage source, whose input end is connected to the power supply and whose output end is connected to the input end of the voltage conversion module, is used to generate a positive reference voltage based on the power supply so that the voltage conversion module can use the positive reference voltage to convert the first preset voltage and the second preset voltage.

[0014] Optionally, the voltage conversion module includes:

[0015] a plurality of first voltage-dividing resistors connected in series, wherein a first end of a circuit formed by connecting the first voltage-dividing resistors in series is connected to a power supply, and a second end thereof is grounded;

[0016] a first selection circuit, having an input end connected to the first ends of the plurality of first voltage-dividing resistors respectively, and an output end connected to the input end of the power amplification module, for selecting a first voltage-dividing resistor from the plurality of first voltage-dividing resistors and outputting a voltage at the first end of the first voltage-dividing resistor as a first preset voltage;

[0017] The second selection circuit has an input end connected to the first ends of several first voltage-divider resistors respectively, and an output end connected to the input end of the inverting amplifier module, and is used to select a first voltage-divider resistor from the several first voltage-divider resistors and output the voltage of its first end as the second preset voltage.

[0018] Optionally, the inverting amplification module includes:

[0019] A second operational amplifier, wherein the non-inverting input terminal is grounded;

[0020] a third resistor, a first end of which is connected to the output end of the second operational amplifier and serves as a negative voltage output end of the power supply circuit;

[0021] A fourth resistor has a first end connected to the second end of the third resistor and the inverting input end of the second operational amplifier, and a second end connected to the output end of the second selection circuit.

[0022] Optionally, also include:

[0023] A unit gain buffer, a first input end of which is connected with an output end of the second selection circuit, and a second input end of which is connected with the output end and a second end of the fourth resistor respectively.

[0024] Optionally, the voltage conversion module comprises:

[0025] A plurality of second voltage dividing resistors connected in series, a first end of a circuit after the second voltage dividing resistors being connected in series being connected with the power supply, and a second end being grounded.

[0026] A third selection circuit, input ends of which are connected with the first ends of the second voltage dividing resistors respectively, and an output end of which is connected with the input end of the power amplification module, for selecting one second voltage dividing resistor from the second voltage dividing resistors and outputting a voltage at the first end of the second voltage dividing resistor as the first preset voltage.

[0027] An adjustable resistor, a first end of which is connected with the power supply, and a second end of which is connected with the input end of the inverting amplification module.

[0028] Optionally, the inverting amplification module comprises:

[0029] A third operational amplifier, a non-inverting input end of which is grounded.

[0030] A fifth resistor, a first end of which is connected with the output end of the third operational amplifier and serves as a negative voltage output end of the power circuit, and a second end of which is connected with the non-inverting input end of the third operational amplifier and the second end of the adjustable resistor respectively.

[0031] To solve the above technical problems, the utility model further provides a power supply device, including power supply and the power circuit of liquid crystal display equipment as described above, the power circuit of liquid crystal display equipment is connected with power supply.

[0032] To solve the above technical problems, the utility model further provides a liquid crystal display system, including liquid crystal display equipment and the power supply device as described above, the output end of power supply device is connected with the power supply end of liquid crystal display equipment.

[0033] The utility model provides a power supply circuit for a liquid crystal display device, comprising a voltage conversion module, a power amplifier module, and an inverting amplifier module. The voltage conversion module can convert a power supply into a first preset voltage corresponding to the magnitude of the required positive voltage and a second preset voltage corresponding to the magnitude of the required negative voltage, according to the power supply requirements of the liquid crystal display device. The first preset voltage can be directly amplified by the power amplifier module and output as a positive voltage, while the second preset voltage needs to be converted into an inverted negative voltage by the inverting amplifier module and then output, thereby simultaneously generating the positive and negative voltages required to drive the liquid crystal display device. By providing the inverting amplifier module, the negative voltage used for driving can be generated without the need for a negative preset voltage, reducing the circuitry required to generate the negative preset voltage and alleviating the design difficulty of the power supply circuit for the liquid crystal display device.

[0034] The utility model also provides a power supply device and a liquid crystal display system, which have the same beneficial effects as the power supply circuit of the liquid crystal display device. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the prior art and the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0036] Figure 1 A schematic structural diagram of a power supply circuit of a liquid crystal display device provided by the present invention;

[0037] Figure 2 A schematic structural diagram of a power supply circuit of a liquid crystal display device provided in the first embodiment of the present utility model;

[0038] Figure 3 This is a structural diagram of a power supply circuit of a liquid crystal display device provided in the second embodiment of the present utility model. DETAILED DESCRIPTION

[0039] The core of the present utility model is to provide a power supply circuit, a power supply device and a liquid crystal display system for a liquid crystal display device. By setting an inverting amplifier module, a negative voltage for driving can be generated without a negative preset voltage, thereby reducing the circuit required to generate the negative preset voltage and alleviating the design difficulty of the power supply circuit of the liquid crystal display device.

[0040] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0041] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the structure of a power supply circuit of a liquid crystal display device provided by the present invention. To solve the above technical problems, the present invention provides a power supply circuit of a liquid crystal display device, comprising:

[0042] The voltage conversion module 1 has an input end connected to the power supply, and is used to convert the power supply into a first preset voltage and a second preset voltage respectively; the first preset voltage and the second preset voltage are both positive voltages;

[0043] The power amplifier module 2 has an input end connected to the first output end of the voltage conversion module 1, and an output end serving as a positive voltage output end of the power supply circuit, for outputting a positive voltage VP after power amplification of the first preset voltage;

[0044] The inverting amplifier module 3 has its input end connected to the second output end of the voltage conversion module 1 and its output end serves as a negative voltage output end of the power supply circuit, for outputting a negative voltage VN with a phase opposite to the second preset voltage.

[0045] It is understood that the power supply circuit needs to be able to simultaneously output a positive voltage and a negative voltage of opposite polarity required to drive the liquid crystal display device. Considering that the voltage levels required for the positive and negative voltages may be inconsistent, the voltage conversion module 1 generates a first preset voltage and a second preset voltage based on the power supply. The first preset voltage is used to generate the positive voltage VP when driving the liquid crystal display device, and the second preset voltage is used to generate the negative voltage VN when driving the liquid crystal display device. The first preset voltage and the second preset voltage are both positive voltages. Therefore, the first preset voltage can be directly used as the positive voltage VP when driving the liquid crystal display device. However, to ensure its own driving capability, the power supply circuit is also provided with a power amplifier module 2 to amplify the first preset voltage so that it can drive a larger load. Since the second preset voltage is itself a positive voltage, the power supply circuit is provided with an inverting amplifier module 3 to invert the second preset voltage, converting the originally positive second preset voltage into a negative voltage, thereby generating the negative voltage VN when driving the liquid crystal display device. At the same time, the inverting amplifier module 3 generally also performs a power amplification function.

[0046] It should be noted that the inverting amplifier module 3 generally has the function of amplifying the input signal and inverting the output. In the present application, inversion means that the positive and negative signs of the voltage are reversed, that is, the positive voltage input signal is converted into a negative voltage output signal. For example, when the second preset voltage is +5V, taking the amplification gain as 1 as an example, the output signal of the inverting amplifier module 3 is -5V. The voltage values ​​of the first preset voltage and the second preset voltage output by the voltage conversion module 1 may be equal or unequal, and can be set and adjusted according to the specific application requirements and actual application conditions of the liquid crystal display device. This application does not make any special restrictions here. The specific values ​​of the first preset voltage and the second preset voltage can be set and adjusted according to the power supply requirements of the liquid crystal display device and the actual situation of the power supply.

[0047] It is not difficult to understand that the specific types and implementation methods of the voltage conversion module 1, the power amplifier module 2, and the inverting amplifier module 3 are not specifically limited in this application. The voltage conversion module 1 can be implemented by a DC converter, a voltage divider circuit, etc. The power amplifier module 2 and the inverting amplifier module 3 can be implemented by an operational amplifier and corresponding peripheral circuits. The amplification gain of the power amplifier module 2 and the inverting amplifier module 3 can be selected and adjusted according to the power supply requirements and actual voltage level of the liquid crystal display device. This application does not specifically limit it. In the power supply circuit, the power amplifier module 2 acts as a driver to generate a positive voltage that can effectively drive the liquid crystal display device using the first preset voltage. Therefore, the power amplifier module 2 can be implemented using other types of drive circuits or drivers. The inverting amplifier module 3 acts as a driver to generate a negative voltage that can effectively drive the liquid crystal display device using the second preset voltage. It can also be implemented using other drive circuits or drivers with an inverting input signal function. Specifically, it can be implemented using a driver chip or other methods.

[0048] Specifically, the present invention implements a negative voltage output driver using an inverting amplification circuit architecture. This allows the negative voltage output driver to output a set negative voltage when using a positive preset voltage input, reducing the circuitry required to generate the negative preset voltage. The power supply circuit proposed in the present invention eliminates the need for a negative preset voltage, eliminating the need for circuitry to generate the negative preset voltage and the associated negative voltage control signals. This reduces design complexity, chip layout area, and testing costs.

[0049] The utility model provides a kind of power supply circuit of liquid crystal display equipment, including voltage conversion module 1, power amplifier module 2 and inverting amplifier module 3, voltage conversion module 1 can according to the power supply demand of liquid crystal display equipment, power supply is converted into the first preset voltage corresponding with the size of demand positive pressure and the second preset voltage corresponding with the size of demand negative pressure, first preset voltage can directly pass through power amplifier module 2 amplification after as positive pressure output, second preset voltage needs to be converted into the negative pressure of reverse phase after output by inverting amplifier module 3, thus simultaneously generated the positive pressure and negative pressure required to drive liquid crystal display equipment. By setting inverting amplifier module 3, so that without negative preset voltage also can generate negative pressure for driving, reduce the circuit required to generate negative preset voltage, reduce the design difficulty of power supply circuit of liquid crystal display equipment.

[0050] On the basis of the above embodiment: please refer to Figure 2 , Figure 2 It is the structural diagram of power supply circuit of liquid crystal display equipment provided by the first embodiment of the utility model;Please refer to Figure 3 , Figure 3 It is the structural diagram of power supply circuit of liquid crystal display equipment provided by the second embodiment of the utility model.

[0051] As an optional embodiment, power amplifier module 2 includes:

[0052] First operational amplifier U1, the same phase input end is connected with the first output end of voltage conversion module 1;

[0053] First resistance R1, first end is connected with the output end of first operational amplifier U1, and as the positive pressure output end of power supply circuit;

[0054] Second resistance R2, first end is respectively connected with the second end of first resistance R1 and the opposite phase input end of first operational amplifier U1, second end ground connection.

[0055] It is understandable that the power amplification module 2 specifically comprises a first operational amplifier U1, a first resistor R1 and a second resistor R2, which constitute the circuit structure of the in-phase operational amplifier, the output signal of which keeps the same phase with the input signal, wherein the first operational amplifier U1 can effectively realize the amplification process of the input signal, while the first resistor R1 and the second resistor R2 can determine the feedback voltage and control the circuit gain of the power amplification module 2; the first resistor R1 and the first operational amplifier U1 constitute a feedback control loop, which can ensure the stability of the entire circuit. The specific types and implementation methods of the first operational amplifier U1, the first resistor R1 and the second resistor R2 are not particularly limited in the present application, and the first resistor R1 and the second resistor R2 can specifically be realized by fixed resistors and the like, or can be realized by variable resistors to realize the adjustment of the circuit amplification gain.

[0056] Specifically, the power amplification module 2 can be realized by the in-phase operational amplifier constituted by the first operational amplifier U1, the first resistor R1 and the second resistor R2, which has a simple structure and is easy to realize, can effectively improve the stability and reliability of the power amplification module 2 and the entire power supply circuit, and ensure the effective realization of the positive voltage output by the power supply circuit.

[0057] As an optional embodiment, it further comprises:

[0058] The band gap reference voltage source BGR is connected with the power supply at the input end and connected with the input end of the voltage conversion module 1 at the output end, and is used to generate a positive reference voltage VREF based on the power supply, so that the voltage conversion module 1 converts the first preset voltage and the second preset voltage by using the positive reference voltage.

[0059] It can be understood that, in order to improve the stability of the first preset voltage and the second preset voltage generated by the voltage conversion module 1, a bandgap reference voltage source BGR can also be arranged between the power supply and the input end of the voltage conversion module 1. The power supply is first converted into a stable positive reference voltage by the bandgap reference voltage source BGR, and then the positive reference voltage is input to the voltage conversion module 1 to obtain the first preset voltage and the second preset voltage. The bandgap reference voltage source BGR not only improves the stability of the input signal input to the voltage conversion module 1, but also pre-processes the output voltage of the power supply. For example, when the voltage difference between the output voltage of the power supply and the first preset voltage and / or the second preset voltage is too large, the bandgap reference voltage source BGR is used to adjust the output voltage of the power supply to a positive reference voltage with a smaller voltage difference between the first preset voltage and / or the second preset voltage, which is more convenient for the voltage conversion module 1 to work. The specific type and implementation of the bandgap reference voltage source BGR are not particularly limited in this application. The parameters of the bandgap reference voltage source BGR and the values of the positive reference voltage output by the bandgap reference voltage source BGR are not particularly limited in this application. They can be set and adjusted according to the voltage situation in actual application.

[0060] Specifically, the bandgap reference voltage source BGR can be further arranged in the power supply circuit to pre-process the power supply, so as to improve the efficiency and accuracy of the working process of the voltage conversion module 1, and further ensure the stability and reliability of the entire power supply circuit.

[0061] As an optional embodiment, the voltage conversion module 1 comprises:

[0062] A plurality of first voltage dividing resistors Rf1 connected in series, the first end of the circuit after the first voltage dividing resistors Rf1 connected in series is connected with the power supply, and the second end is grounded;

[0063] A first selection circuit MUX1, the input end of which is connected with the first end of each of the plurality of first voltage dividing resistors Rf1, and the output end of which is connected with the input end of the power amplification module 2, for selecting one first voltage dividing resistor Rf1 from the plurality of first voltage dividing resistors Rf1 and outputting the voltage at the first end of the selected first voltage dividing resistor Rf1 as the first preset voltage;

[0064] A second selection circuit MUX2, the input end of which is connected with the first end of each of the plurality of first voltage dividing resistors Rf1, and the output end of which is connected with the input end of the inverting amplification module 3, for selecting one first voltage dividing resistor Rf1 from the plurality of first voltage dividing resistors Rf1 and outputting the voltage at the first end of the selected first voltage dividing resistor Rf1 as the second preset voltage.

[0065] It is understandable that the voltage conversion module 1 can be implemented by a voltage dividing circuit composed of a plurality of voltage dividing resistors. A plurality of voltage points after voltage division are built by a plurality of first voltage dividing resistors Rf1, and then a first selection circuit MUX1 and a second selection circuit MUX2 are set to select one of the voltage points after voltage division. The first selection circuit MUX1 selects a voltage as a first preset voltage, and the second selection circuit MUX2 selects a voltage as a second preset voltage. The two selection circuits exist independently and can respectively realize the generation process of the first preset voltage and the second preset voltage. The number, specific type and implementation of the first voltage dividing resistors Rf1 are not particularly limited in the present application. The specific type and implementation of the first selection circuit MUX1 and the second selection circuit MUX2 are not particularly limited in the present application, which can be implemented by a MUX (multiplexer). The specific selection method of the two selection circuits can be set and adjusted according to actual application requirements.

[0066] It should be noted that when the bandgap reference voltage source BGR is used to generate a positive reference voltage in the power supply circuit, the first end of the circuit connected in series with the first voltage dividing resistor Rf1 will be connected to the positive reference voltage for voltage division, thereby generating a plurality of positive voltages after voltage division.

[0067] As a specific embodiment, as shown in Figure 2 A positive reference voltage VREF is generated by a power supply and a BGR (Bandgap Reference) circuit, a plurality of voltage dividing resistors are connected in series between VREF and Ground, and various reference voltages corresponding to positive voltage outputs are generated by resistance series voltage division. These reference voltages are connected to the input end of the first selection circuit MUX1. The first selection circuit MUX1 selects one of the input reference voltages and transmits it to the output end of the first selection circuit MUX1 through a set of logic signals. The output end of the first selection circuit MUX1 is connected to the input end of the positive voltage output stage driver, and the output end of the positive voltage output stage driver outputs a set positive voltage VP.

[0068] The resistance series voltage division is also connected to the input end of another selection circuit MUX2. In order to facilitate control, the control signal voltage domain of the second selection circuit MUX2 is the same as that of the first selection circuit MUX1 in the positive voltage path. The output end of the second selection circuit MUX2 is connected to a unity gain buffer U0, and then output to a negative voltage output stage driver. The negative voltage output stage driver is implemented using an inverting amplifier (Inverting Amplifier) architecture. The reference voltage at the input end is a positive voltage, but the output end generates a set negative voltage output VNOUT.

[0069] Specifically, the conversion generation process of the first preset voltage and the second preset voltage can be effectively realized by the combination of the voltage division circuit and the selection device, the voltage division circuit is used to realize a plurality of reference voltages, thereby meeting the requirements of the first preset voltage and the second preset voltage in different application scenarios, and the application range is wide. The voltage division circuit is realized by using a voltage division resistor, and has simple structure and is easy to realize.

[0070] As an optional embodiment, the inverting amplification module 3 comprises:

[0071] The second operational amplifier U2 is connected with the ground at the non-inverting input end;

[0072] The third resistor R3 is connected with the output end of the second operational amplifier U2 at the first end and serves as the negative voltage output end of the power supply circuit;

[0073] The fourth resistor R4 is connected with the second end of the third resistor R3 and the non-inverting input end of the second operational amplifier U2 at the first end, and connected with the output end of the second selection circuit MUX2 at the second end.

[0074] It can be understood that the inverting amplification module 3 specifically comprises the second operational amplifier U2, the third resistor R3 and the fourth resistor R4, and the second operational amplifier U2, the third resistor R3 and the fourth resistor R4 constitute the circuit structure of the inverting operational amplifier, the output signal of which is opposite to the input signal. The second operational amplifier U2 can effectively realize the amplification process of the input signal, while the third resistor R3 and the fourth resistor R4 can control the circuit gain of the inverting amplification module 3, and the circuit gain of the inverting amplification module 3 is negative, which can convert the input signal into an inverted output signal. The third resistor R3 and the second operational amplifier U2 constitute a negative feedback control loop, which can ensure the stability of the entire circuit. The specific types and implementation modes of the second operational amplifier U2, the third resistor R3 and the fourth resistor R4 are not particularly limited in the present application. The third resistor R3 and the fourth resistor R4 can specifically be realized by using a fixed resistor or a variable resistor to adjust the circuit amplification gain.

[0075] Specifically, the inverting amplification module 3 can be realized by using the inverting operational amplifier composed of the second operational amplifier U2, the third resistor R3 and the fourth resistor R4, which has simple structure and is easy to realize, and can effectively improve the stability and reliability of the inverting amplification module 3 and the entire power supply circuit, thereby ensuring the effective realization of the negative voltage output by the power supply circuit.

[0076] As an optional embodiment, the inverting amplification module 3 further comprises:

[0077] The unit gain buffer U0 is connected with the output end of the second selection circuit MUX2 at the first input end, and connected with the output end of itself and the second end of the fourth resistor R4 at the second input end.

[0078] It is not difficult to understand that the source of the voltage output by the second selection circuit MUX2 is the voltage division of a plurality of series-connected voltage division resistors, and the input end of the inverting amplification module 3 is also a resistor structure, that is, the fourth resistor R4, so that the original resistor network is changed, which affects the voltage output by the second selection circuit MUX2. Therefore, a unit gain buffer U0 needs to be additionally arranged between the inverting amplification module 3 and the second selection circuit MUX2. The unit gain buffer U0 can output the same voltage as the output end of the second selection circuit MUX2, and the output signal can not be affected by the load, so as to provide the voltage to the inverting amplification module 3 while avoiding affecting the voltage generated by the series connection of the voltage division resistors. The specific type and implementation manner of the unit gain buffer U0 are not particularly limited in the present application, and the unit gain buffer can be implemented by an operational amplifier connected between the inverting input end and the output end of the operational amplifier, as shown in the following figure. Figure 2 The unit gain buffer U0 can be implemented by an operational amplifier connected between the inverting input end and the output end of the operational amplifier.

[0079] Specifically, by additionally arranging the unit gain buffer U0, the mutual influence between the voltage conversion module 1 and the inverting amplification module 3 can be effectively avoided. The unit gain buffer U0 is an additional circuit, but it occupies a small area and is easy to implement. The area increase is very small, far less than the area occupied by the circuit required to generate the negative preset voltage, which is conducive to the accurate implementation of the entire power supply circuit.

[0080] As an optional embodiment, the voltage conversion module 1 comprises:

[0081] a plurality of second voltage division resistors Rf2 connected in series, the first end of the circuit after the series connection of the second voltage division resistors Rf2 being connected to the power supply, and the second end being grounded;

[0082] a third selection circuit MUX3, the input end of the third selection circuit MUX3 being connected to the first end of each of the plurality of second voltage division resistors Rf2, and the output end of the third selection circuit MUX3 being connected to the input end of the power amplification module 2, the third selection circuit MUX3 being configured to select one of the plurality of second voltage division resistors Rf2 and output the voltage at the first end of the selected second voltage division resistor Rf2 as the first preset voltage;

[0083] an adjustable resistor Rp, the first end of the adjustable resistor Rp being connected to the power supply, and the second end of the adjustable resistor Rp being connected to the input end of the inverting amplification module 3.

[0084] It can be understood that the voltage conversion module 1 can also be implemented by a voltage dividing circuit composed of a plurality of voltage dividing resistors, a third selection circuit MUX3 and an adjustable resistor Rp. The third selection circuit MUX3 has the same working process as the first selection circuit MUX1. One of the voltages after voltage division is selected as the first preset voltage to generate the final positive voltage output VPOUT. Since the inverting amplifier module 3 itself can adjust the voltage value of the finally generated negative voltage by adjusting the circuit gain, the adjustable resistor is directly set to cooperate with the inverting amplifier module 3 to generate negative voltages of different sizes, and there is no need to change the size of the second preset voltage by voltage division to adjust the size of the finally generated negative voltage. The number, specific type and implementation of the second voltage dividing resistor Rf2 are not particularly limited in the present application. The specific type and implementation of the third selection circuit MUX3 are not particularly limited in the present application. The MUX (multiplexer) can be used to achieve the specific selection method, which can be set and adjusted according to actual application requirements.

[0085] It should be noted that the power amplification module 2 can generally adjust the voltage value of the finally generated positive voltage by adjusting the circuit gain, so the second voltage dividing resistor Rf2 and the third selection circuit MUX3 can be replaced by an adjustable resistor Rp. The voltage conversion module 1 specifically includes a first voltage conversion submodule for adjusting the size of the output positive voltage and a second voltage conversion submodule for adjusting the size of the output negative voltage. The input end of the first voltage conversion submodule is connected with the output end of the power supply or the band gap reference voltage source BGR, and the output end is connected with the input end of the power amplification module 2. The input end of the second voltage conversion submodule is connected with the output end of the power supply or the band gap reference voltage source BGR, and the output end is connected with the input end of the inverting amplifier module 3. The first voltage conversion submodule and the second voltage conversion submodule can be implemented by voltage dividing resistors combined with selection circuits or directly using adjustable resistors Rp.

[0086] As an optional embodiment, the inverting amplifier module 3 includes:

[0087] The third operational amplifier U3 has a common input end connected with the ground.

[0088] The fifth resistor R5 has a first end connected with the output end of the third operational amplifier U3 and serving as a negative voltage output end of the power supply circuit, and a second end connected with the inverting input end of the third operational amplifier U3 and the second end of the adjustable resistor Rp, respectively.

[0089] It is easy to understand that, on the basis of setting the adjustable resistor Rp, the fourth resistor R4 in the inverting amplification module 3 can be omitted, and only the third operational amplifier U3 and the fifth resistor R5 can realize the inverting amplification module 3, and the fifth resistor R5 and the adjustable resistor Rp are combined to realize the control and adjustment of the circuit gain of the inverting amplification module 3.

[0090] As a specific embodiment, as shown in the figure, the positive reference voltage VREF output by the bandgap reference voltage source BGR is connected to the resistance input end of the inverting amplification module 3, and the input end resistance of the inverting amplification module 3 is directly replaced by the adjustable resistor Rp. Figure 3 The adjustable resistor Rp can produce corresponding resistance values of different sizes in an adjustable manner, which can be controlled by a control signal. When a negative voltage is to be output, the control signal selects the required corresponding resistance value, so that the product of the resistance value ratio of the inverting amplifier, that is, the ratio between the fifth resistor R5 and the adjustable resistor Rp, and the positive reference voltage VREF is the negative voltage value VN to be output. In order to facilitate control, the voltage domain of the control signal of the adjustable resistor Rp is the same as that of the third selection circuit MUX3 on the positive voltage path, and the unit gain buffer U0 can be omitted under this architecture, and if the area of the adjustable resistor Rp is equivalent to that of the second selection circuit MUX2, the area can be further simplified.

[0091] Specifically, on the basis of the voltage conversion module 1 adopting the adjustable resistor Rp, the inverting amplification module 3 can be realized by the third operational amplifier U3 and the fifth resistor R5, and the adjustable resistor Rp, the third operational amplifier U3 and the fifth resistor R5 jointly constitute the circuit architecture of the inverting operational amplifier, which is simple in structure, easy to realize, and can effectively improve the stability and reliability of the inverting amplification module 3 and the entire power supply circuit, and ensure the effective realization of the negative voltage output by the power supply circuit.

[0092] To solve the above technical problems, the utility model also provides a kind of power supply device, including power supply and the power supply circuit of liquid crystal display device as described above, and the power supply circuit of liquid crystal display device is connected with power supply.

[0093] It can be understood that the specific type and implementation of the power supply circuit and the power supply are not particularly limited herein, and the power supply circuit can be realized by being integrated on a chip, and can be realized by using integrated circuits or discrete circuits, and the power supply can be realized by using various types of power supplies. The input end of the power supply circuit of the liquid crystal display device is connected with the power supply, and the input end is also the input end of the voltage conversion module 1.

[0094] For the power supply device provided by the utility model for the power circuit of the liquid crystal display device, please refer to the above embodiment, the utility model does not repeat here.

[0095] To solve the above technical problems, the utility model also provides a liquid crystal display system, including liquid crystal display device and the power supply device as aforementioned, the output of power supply device is connected with the power supply end of liquid crystal display device.

[0096] It is not difficult to understand that the specific type and implementation mode of the liquid crystal display device are not particularly limited in the application, and can be selected and adjusted according to the application requirements of the user, and the output end of the power supply device is the output end of the power circuit of the liquid crystal display device.

[0097] For the liquid crystal display system provided by the utility model, please refer to the above embodiment of the power circuit of the liquid crystal display device, the utility model does not repeat here.

[0098] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts of each embodiment can be referred to each other. It should be further pointed out that in the specification, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the term "include", "contain" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0099] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the utility model. Various modifications of these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the utility model. Therefore, the utility model will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A power supply circuit for a liquid crystal display device, characterized in that: include: a voltage conversion module, the input end of which is connected to the power supply, and is used to convert the power supply into a first preset voltage and a second preset voltage respectively; the first preset voltage and the second preset voltage are both positive voltages; a power amplification module, whose input end is connected to the first output end of the voltage conversion module, and whose output end serves as a positive voltage output end of the power supply circuit, for outputting a positive voltage after power amplification of the first preset voltage; The inverting amplifier module has an input end connected to the second output end of the voltage conversion module, and an output end serving as a negative voltage output end of the power supply circuit, for outputting a negative voltage with a phase opposite to that of the second preset voltage.

2. The power supply circuit of the liquid crystal display device according to claim 1, wherein The power amplification module includes: a first operational amplifier, a non-inverting input terminal connected to the first output terminal of the voltage conversion module; a first resistor, a first end of which is connected to the output end of the first operational amplifier and serves as a positive voltage output end of the power supply circuit; The second resistor has a first end connected to the second end of the first resistor and the inverting input end of the first operational amplifier, and a second end grounded.

3. The power supply circuit of the liquid crystal display device according to claim 1, wherein Also includes: A bandgap reference voltage source, whose input end is connected to the power supply and whose output end is connected to the input end of the voltage conversion module, is used to generate a positive reference voltage based on the power supply, so that the voltage conversion module uses the positive reference voltage to convert the first preset voltage and the second preset voltage.

4. The power supply circuit of a liquid crystal display device according to any one of claims 1 to 3, wherein: The voltage conversion module includes: a plurality of first voltage-dividing resistors connected in series, wherein a first end of a circuit formed by connecting the first voltage-dividing resistors in series is connected to a power supply, and a second end thereof is grounded; a first selection circuit, having an input end connected to the first ends of the plurality of first voltage-dividing resistors respectively, and an output end connected to the input end of the power amplification module, for selecting a first voltage-dividing resistor from the plurality of first voltage-dividing resistors and outputting a voltage at the first end of the first voltage-dividing resistor as a first preset voltage; The second selection circuit has an input end connected to the first ends of several first voltage-divider resistors respectively, and an output end connected to the input end of the inverting amplifier module, and is used to select a first voltage-divider resistor from the several first voltage-divider resistors and output the voltage of its first end as the second preset voltage.

5. The power supply circuit of the liquid crystal display device according to claim 4, wherein: The inverting amplifier module includes: A second operational amplifier, wherein the non-inverting input terminal is grounded; a third resistor, a first end of which is connected to the output end of the second operational amplifier and serves as a negative voltage output end of the power supply circuit; A fourth resistor has a first end connected to the second end of the third resistor and the inverting input end of the second operational amplifier respectively, and a second end connected to the output end of the second selection circuit.

6. The power supply circuit of the liquid crystal display device according to claim 5, wherein: Also includes: A unity gain buffer has a first input terminal connected to the output terminal of the second selection circuit, and a second input terminal connected to its own output terminal and the second terminal of the fourth resistor respectively.

7. The power supply circuit of a liquid crystal display device according to any one of claims 1 to 3, wherein: The voltage conversion module includes: a plurality of second voltage-dividing resistors connected in series, wherein a first end of a circuit formed by connecting the second voltage-dividing resistors in series is connected to a power supply, and a second end thereof is grounded; a third selection circuit, having an input end connected to the first ends of the plurality of second voltage-dividing resistors respectively, and an output end connected to the input end of the power amplification module, for selecting one second voltage-dividing resistor from the plurality of second voltage-dividing resistors and outputting the voltage at the first end thereof as the first preset voltage; An adjustable resistor has a first end connected to the power supply and a second end connected to the input end of the inverting amplifier module.

8. The power supply circuit of the liquid crystal display device according to claim 7, wherein: The inverting amplifier module includes: A third operational amplifier, having a non-inverting input terminal grounded; A fifth resistor has a first end connected to the output end of the third operational amplifier and serves as a negative voltage output end of the power supply circuit, and a second end connected to the inverting input end of the third operational amplifier and the second end of the adjustable resistor respectively.

9. A power supply device, characterized in that: The device comprises a power supply and a power supply circuit of the liquid crystal display device according to any one of claims 1 to 8, wherein the power supply circuit of the liquid crystal display device is connected to the power supply.

10. A liquid crystal display system, characterized in that: The device comprises a liquid crystal display device and the power supply apparatus as claimed in claim 9, wherein the output end of the power supply apparatus is connected to the power supply end of the liquid crystal display device.

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