CN210667755U - Voltage conversion circuit, liquid crystal panel driving circuit and liquid crystal display - Google Patents
Voltage conversion circuit, liquid crystal panel driving circuit and liquid crystal display Download PDFInfo
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- CN210667755U CN210667755U CN201922068912.3U CN201922068912U CN210667755U CN 210667755 U CN210667755 U CN 210667755U CN 201922068912 U CN201922068912 U CN 201922068912U CN 210667755 U CN210667755 U CN 210667755U
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Abstract
The utility model discloses a voltage conversion circuit, liquid crystal panel drive circuit and LCD, this voltage conversion circuit includes: a temperature detection module for detecting the temperature of the liquid crystal panel driving circuit; the control module is connected with the temperature detection module and outputs control signals of different levels according to whether the temperature of the liquid crystal panel driving circuit exceeds a set value or not; the first power supply module is connected with the control module and outputs first power supply voltages with different levels according to the control signal; the second power supply module is connected with the control module and outputs second power supply voltages with different levels according to the control signal; and the first power supply voltage and the second power supply voltage form two groups of voltages corresponding to two levels of the control signal, wherein each group of voltages are used as a grid opening voltage and a grid closing voltage under different conditions, and the group of voltages with smaller absolute values corresponds to the condition that the temperature of the liquid crystal panel driving circuit exceeds a set value, so that the technical problem that the liquid crystal panel driving circuit generates heat seriously is solved.
Description
Technical Field
The utility model relates to a liquid crystal display technical field, more specifically relates to voltage conversion circuit, liquid crystal panel drive circuit and liquid crystal display.
Background
A TFT-LCD (Thin Film Transistor Liquid Crystal Display) is a common flat panel Display device in the high performance Display field, and fig. 1 shows a schematic block diagram of a Liquid Crystal panel driving circuit in the TFT-LCD. Referring to fig. 1, the liquid crystal panel driving circuit mainly includes: the display device comprises a direct current voltage conversion circuit, a gamma correction circuit, a Timing control circuit (Tcon for short), a grid driving circuit and a source driving circuit.
The liquid crystal panel driving circuit inputs a Low-voltage differential Signaling (LVDS) signal to Tcon through the interface connector, then the Tcon generates a Mini LVDS signal to the source electrode driving circuit, and the Mini LVDS signal is converted into a data voltage by the source electrode driving circuit and is output to a data line of the display panel; meanwhile, Tcon outputs control signals such as STV (Start Vertical) and CPV (Clock Pulse Vertical) to the gate driving circuit, and the gate driving circuit outputs a switching voltage to the gate lines of the display panel line by line in accordance with the control signals, and controls the TFT switching of each sub-pixel on the gate lines by the switching voltage. Further, when the TFT is turned on, the pixel electrode on the display panel is charged by the data voltage output from the data line at this time; when the TFT is closed, the pixel electrode keeps the data voltage before the TFT is closed, and the voltage on the pixel electrode is used for controlling the display gray scale of the pixel.
In the prior art, a dc voltage converting circuit generates a gate-on Voltage (VGH) and a gate-off Voltage (VGL) by a charge pump (charge pump) disposed therein, wherein the gate driving circuit controls a TFT to be turned on by an output switch voltage when receiving VGH, and the gate driving circuit controls the TFT to be turned off by the output switch voltage when receiving VGL. However, as the size of the display panel increases, the required values of the gate voltage and the gate current become larger, so that the charge pump is required to provide a larger output power, but as the output power increases, the conversion efficiency of the charge pump decreases more seriously, and the heat energy loss increases, so that the liquid crystal panel driving circuit has a technical problem of more serious heat generation.
SUMMERY OF THE UTILITY MODEL
In order to solve the problems existing in the prior art, the utility model provides a voltage conversion circuit, liquid crystal panel drive circuit and LCD to solve the comparatively serious technical problem that liquid crystal panel drive circuit generates heat.
According to the utility model discloses an aspect provides a voltage conversion circuit, include:
the temperature detection module is used for detecting the temperature of the liquid crystal panel driving circuit;
the control module is connected with the temperature detection module and outputs control signals of different levels according to whether the temperature of the liquid crystal panel driving circuit exceeds a set value or not;
the first power supply module is connected with the control module to receive the control signal and output first power supply voltages with different levels according to the control signal, wherein the first power supply voltages with different levels are respectively a first voltage and a second voltage, and the first voltage corresponds to the liquid crystal panel driving circuit when the temperature of the liquid crystal panel driving circuit does not exceed the set value, otherwise, the second voltage corresponds to the liquid crystal panel driving circuit;
the second power supply module is connected with the control module to receive the control signal and output second power supply voltages with different levels according to the control signal, wherein the second power supply voltages with different levels are respectively a third voltage and a fourth voltage, and the third voltage corresponds to the liquid crystal panel driving circuit when the temperature of the liquid crystal panel driving circuit does not exceed the set value, otherwise, the fourth voltage corresponds to the liquid crystal panel driving circuit;
and a larger absolute value of the first voltage and the third voltage is larger than a larger absolute value of the second voltage and the fourth voltage, and a smaller absolute value of the first voltage and the third voltage is larger than a smaller absolute value of the second voltage and the fourth voltage.
Optionally, the control module comprises: a signal generating unit and a transistor comprising a control terminal, an input terminal and an output terminal, wherein,
the signal generating unit is used for generating a comparison signal according to whether the temperature of the liquid crystal panel driving circuit exceeds a set value or not;
the control end is connected with the signal generating unit and used for receiving the comparison signal and controlling the on-off between the input end and the output end through the comparison signal; and the number of the first and second groups,
the input end is connected with the ground;
the output terminal is connected with a first power supply.
Optionally, the signal generating unit includes:
the first switch and the second power supply are connected between the control end and the ground in series, and the voltage of the second power supply is not less than the conducting voltage of the transistor;
a second switch connected in series between the control terminal and ground, wherein,
when the temperature of the liquid crystal panel driving circuit does not exceed the set value, the first switch is switched off and the second switch is switched on; when the temperature of the liquid crystal panel driving circuit exceeds the set value, the first switch is closed and the second switch is opened.
Optionally, the transistor is an NPN-type triode, the control terminal is a base of the triode, the input terminal is an emitter of the triode, and the output terminal is a collector of the triode.
Optionally, the control module further comprises:
one end of the first resistor is connected with the output end, and the other end of the first resistor is connected with the first power supply; and/or the presence of a gas in the gas,
and one end of the second resistor is connected with the output end, and the other end of the second resistor is connected with the first power supply module and the second power supply module.
Optionally, the first power supply module comprises a first comparator and provides the first power supply voltage through the first comparator, the second power supply module comprises a second comparator and provides the second power supply voltage through the second comparator, wherein,
the non-inverting input end of the first comparator is connected with the inverting input end of the second comparator;
the inverting input end of the first comparator is connected with the non-inverting input end of the second comparator
One of a non-inverting input terminal and an inverting input terminal of the first comparator is connected to the control module to receive the control signal, and the other is connected to a third power supply having a voltage less than a voltage value of the control signal in a high level state and greater than a voltage value of the control signal in a low level state, and,
the positive power supply voltage of the first comparator is greater than the positive power supply voltage of the second comparator, and the absolute value of the reverse power supply voltage of the first comparator is less than the absolute value of the reverse power supply voltage of the second comparator.
Optionally, the first power supply module further includes a first capacitor, and the first capacitor is respectively connected to the output end of the first comparator and ground;
the second power supply module further comprises a second capacitor, and the second capacitor is respectively connected with the output end of the second comparator and the ground.
Optionally, the voltage conversion circuit further includes:
and one end of the voltage measuring instrument is connected with a target node, and the other end of the voltage measuring instrument is connected with the ground, wherein the target node is a connection node between the control module and the first power supply module as well as the second power supply module.
According to a second aspect of the present invention, there is provided a liquid crystal panel driving circuit for driving a liquid crystal panel, the liquid crystal panel driving circuit comprising the first aspect of the voltage conversion circuit, to pass through the voltage conversion circuit provides a gate-on voltage and a gate-off voltage.
According to a third aspect of the present invention, there is provided a liquid crystal display, comprising:
a liquid crystal panel; and the number of the first and second groups,
and a liquid crystal panel driving circuit for supplying a working voltage and a working signal to the liquid crystal panel, wherein the liquid crystal panel driving circuit comprises the voltage conversion circuit of the first aspect.
The utility model discloses a voltage conversion circuit, liquid crystal display panel drive circuit and LCD, among this voltage conversion circuit, first power module is according to the first power supply voltage of the different levels of control signal output, and second power module is according to the second power supply voltage of the different levels of control signal output, wherein, under the liquid crystal display panel drive circuit temperature did not exceed under the condition of setting value, first power module is the first voltage according to the first power supply voltage of control signal output, and second power module is the third voltage according to the second power supply voltage of control signal output; under the condition that the temperature of the liquid crystal panel driving circuit exceeds the set value, the first power supply voltage output by the first power supply module according to the control signal is the second low voltage, and the second power supply voltage output by the second power supply module according to the control signal is the fourth voltage; and the greater absolute value of the first voltage and the third voltage is greater than the greater absolute value of the second voltage and the fourth voltage, and the smaller absolute value of the first voltage and the third voltage is larger than the smaller absolute value of the second voltage and the fourth voltage, and thus, the first supply voltage and the second supply voltage supplied are simultaneously reduced after the temperature of the liquid crystal panel driving circuit exceeds a set value, namely, the gate-on voltage and the gate-off voltage are supplied to the gate driving circuit through the voltage converting circuit, it is possible to reduce the gate-on voltage and the gate-off voltage supplied to the gate driving circuit after the temperature of the liquid crystal panel driving circuit exceeds a set value, therefore, heat energy generated by current is reduced, the temperature of the liquid crystal panel driving circuit is reduced, and the technical problem that the liquid crystal panel driving circuit generates heat seriously is solved.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.
Fig. 1 is a block diagram showing a conventional liquid crystal panel driving circuit;
fig. 2 is a block diagram showing a voltage conversion circuit according to a first embodiment of the present invention;
FIG. 3 is a schematic diagram of a voltage converting circuit according to a first embodiment of the present invention, in which the temperature of the driving circuit of the liquid crystal panel does not exceed a predetermined value;
fig. 4 is a schematic diagram of a voltage converting circuit according to a first embodiment of the present invention, in which the temperature of the liquid crystal panel driving circuit exceeds a predetermined value;
fig. 5 is a block diagram showing a liquid crystal display device according to a third embodiment of the present invention.
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale. Moreover, certain well-known elements may not be shown in the figures.
Numerous specific details of the invention, such as structure, materials, dimensions, processing techniques and techniques of the devices are described below in order to provide a more thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.
Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.
Fig. 2 shows a voltage conversion circuit according to a first embodiment of the present invention. Referring to fig. 2, the voltage conversion circuit includes:
the temperature detection module is used for detecting the temperature of the liquid crystal panel driving circuit;
the control module is connected with the temperature detection module and outputs control signals of different levels according to whether the temperature of the liquid crystal panel driving circuit exceeds a set value or not;
the first power supply module is connected with the control module to receive the control signal and output first power supply voltages with different levels according to the control signal, wherein the first power supply voltages with different levels are respectively a first voltage and a second voltage, and the first voltage corresponds to the condition that the temperature of the liquid crystal panel driving circuit does not exceed a set value, and otherwise, the second voltage corresponds to the condition that the temperature of the liquid crystal panel driving circuit does not exceed the set value;
the second power supply module is connected with the control module to receive the control signal and output second power supply voltages with different levels according to the control signal, wherein the second power supply voltages with different levels are respectively a third voltage and a fourth voltage, the third voltage corresponds to the condition that the temperature of the liquid crystal panel driving circuit does not exceed a set value, and the fourth voltage corresponds to the condition that the temperature of the liquid crystal panel driving circuit does not exceed the set value;
and a larger absolute value of the first voltage and the third voltage is larger than a larger absolute value of the second voltage and the fourth voltage, and a smaller absolute value of the first voltage and the third voltage is larger than a smaller absolute value of the second voltage and the fourth voltage.
When the voltage switching circuit is used as a supply circuit of the gate-on voltage and the gate-off voltage in the gate driving circuit, the set value can be determined according to the upper limit of the operating temperature of the liquid crystal panel driving circuit, and the set value is smaller than the upper limit of the operating temperature of the liquid crystal panel driving circuit but can be adjusted according to the ambient temperature. It should be understood that, since the control signal includes both high and low levels, there are two sets of the first supply voltage and the second supply voltage corresponding to the high and low levels of the control signal, and the smaller of the sets of voltages is used as the gate-off voltage and the larger is used as the gate-on voltage to achieve control of the TFT switches of the pixels on the gate line.
In the embodiment of the present invention, when the temperature of the liquid crystal panel driving circuit does not exceed the set value, the first power supply module outputs the first power supply voltage according to the control signal as the first voltage, and the second power supply module outputs the second power supply voltage according to the control signal as the third voltage; under the condition that the temperature of the liquid crystal panel driving circuit exceeds the set value, the first power supply voltage output by the first power supply module according to the control signal is the second low voltage, and the second power supply voltage output by the second power supply module according to the control signal is the fourth voltage; and the greater absolute value of the first voltage and the third voltage is greater than the greater absolute value of the second voltage and the fourth voltage, and the smaller absolute value of the first voltage and the third voltage is larger than the smaller absolute value of the second voltage and the fourth voltage, and thus, the first supply voltage and the second supply voltage supplied are simultaneously reduced after the temperature of the liquid crystal panel driving circuit exceeds a set value, namely, the gate-on voltage and the gate-off voltage are supplied to the gate driving circuit through the voltage converting circuit, it is possible to reduce the gate-on voltage and the gate-off voltage supplied to the gate driving circuit after the temperature of the liquid crystal panel driving circuit exceeds a set value, therefore, heat energy generated by current is reduced, the temperature of the liquid crystal panel driving circuit is reduced, and the technical problem that the liquid crystal panel driving circuit generates heat seriously is solved.
Fig. 3 is a schematic diagram showing the voltage conversion circuit when the temperature of the liquid crystal panel driving circuit does not exceed the set value, fig. 4 is a schematic diagram showing the voltage conversion circuit when the temperature of the liquid crystal panel driving circuit exceeds the set value, and the voltage conversion circuit will be described in detail with reference to fig. 3 and 4.
In an alternative embodiment, the control module 100 includes: the liquid crystal display device comprises a signal generating unit 101, a transistor Q1 and a first resistor R1 which plays a role in protection, wherein the transistor Q1 comprises a control end, an input end and an output end, the signal generating unit 101 is used for generating a comparison signal SK according to whether the temperature of a liquid crystal panel driving circuit exceeds a set value or not; the control end of the transistor Q1 is connected with the signal generating unit 101, and is used for receiving the comparison signal SK and controlling the on-off between the input end and the output end through the comparison signal SK; and, the input terminal of the transistor Q1 is connected to ground and the output terminal is connected to the first power supply V1 through the first resistor R1. Based on the above structure of the control module 100, when the comparison signal SK controls the input end and the output end to be turned on, the control signal QR is at a low level, and when the comparison signal SK controls the input end and the output end to be turned off, the control signal QR is at a high level, that is, the control module 100 regulates and controls the level state of the control signal QR through the comparison signal SK generated by the signal generation unit 101.
The signal generation unit 101 may include: the first switch S1A and the second power supply V2 are connected in series between the control terminal and the ground, and the voltage of the second power supply V2 is not less than the turn-on voltage of the transistor Q1; a second switch S2A connected in series between the control terminal and ground, wherein when the temperature of the liquid crystal panel driving circuit does not exceed a set value, the first switch S1A is opened and the second switch S2A is closed (as shown in FIG. 3); when the temperature of the liquid crystal panel driving circuit exceeds a set value, the first switch S1A is closed and the second switch S2A is opened (as shown in fig. 4). Therefore, when the temperature of the liquid crystal panel driving circuit does not exceed a set value, the transistor is disconnected; when the temperature of the liquid crystal panel driving circuit exceeds a set value, the transistor is conducted, so that the temperature of the liquid crystal panel driving circuit indirectly controls the level state of the control signal QR. Here, the switches of the first switch S1A and the second switch S2A are determined by the control module 100 according to whether the temperature of the liquid crystal panel driving circuit received by the temperature detection module exceeds a set value, and specifically, the temperature detection module and the control module 100 can be connected through an existing thermal relay to realize the switch control of the first switch S1A and the second switch S2A, which is as follows: firstly, the temperature detection module senses the temperature of the liquid crystal panel driving circuit through a thermal resistor, the thermal resistor converts the temperature of the liquid crystal panel driving circuit into current flowing into a thermal element in a thermal relay, namely, the temperature detection device and the thermal relay are firstly electrically connected to realize interconnection, and the larger the temperature of the liquid crystal panel driving circuit is, the larger the current flowing into the thermal element in the thermal relay is; for the thermal relay, the current flowing into the thermal element generates heat, so that the bimetallic strips with different expansion coefficients deform, and when the deformation reaches a certain distance, the bimetallic strips push the connecting rod to act; and the connecting rod of the thermal relay is linked with the contact, the first switch S1A and the second switch S2A are a group of single-pole double-throw switches, the contact is a single pole in the single-pole double-throw switches, namely, the thermal relay and the control module 100 are interconnected through mechanical connection. Based on the principle, one or more parameters of the resistance value of the thermal resistor, the current flowing into the thermal element, the expansion coefficient of the bimetallic strip and the link driving force are configured according to the set values, so that the first switch S1A can be controlled to be closed or the second switch S2A can be controlled to be closed according to whether the temperature of the liquid crystal panel driving circuit exceeds the set values or not. It should be emphasized that the connection manner between the temperature detection module and the control module 100 includes, but is not limited to, the connection implemented by the conventional thermal relay, and after the temperature detection module and the control module 100 are connected, the control module 100 can output different level control signals according to whether the temperature of the liquid crystal panel driving circuit exceeds the set value.
The transistor Q1 may be an NPN transistor, for example, a NPN transistor of type 2N2219, wherein the control terminal is a base of the transistor, the input terminal is an emitter of the transistor, and the output terminal is a collector of the transistor.
In an alternative embodiment, the control module 100 further comprises: one end of a second resistor R2 and one end of a second resistor R2 are connected with the output end of the transistor Q1, the other end of the second resistor R2 are connected with the first power supply module 200 and the second power supply module 300, and the second resistor R2 has the function of current limiting and plays the role of current limiting protection on the voltage conversion circuit.
In an alternative embodiment, the first power supply module 200 includes a first comparator U1C and provides a first supply voltage VG1 through a first comparator U1C, and the second power supply module 300 includes a second comparator U2A and provides a second supply voltage VG2 through a second comparator U2A, wherein,
the non-inverting input terminal of the first comparator U1C is connected with the inverting input terminal of the second comparator U2A;
the inverting input terminal of the first comparator U1C is connected to the non-inverting input terminal of the second comparator U2A;
one of the non-inverting input terminal and the inverting input terminal of the first comparator U1C is connected to the control module 100 to receive the control signal, and the other is connected to a third power supply V3, wherein the voltage of the third power supply V3 is smaller than the voltage value of the control signal QR in the high level state and larger than the voltage value of the control signal QR in the low level state, and,
the forward supply voltage V4 of the first comparator U1C is greater than the forward supply voltage V5 of the second comparator U2A, and the absolute value of the reverse supply voltage V6 of the first comparator U1C is less than the absolute value of the reverse supply voltage V7 of the second comparator U2A.
Specifically, the first comparator U1C and the second comparator U2A may be constructed by using an operational amplifier with model LM324 AD.
When the non-inverting input terminal of the first comparator U1C is connected to the control module 100 and the inverting input terminal is connected to the third power supply V3, the temperature of the liquid crystal panel driving circuit exceeding the set value corresponds to the low level state of the control signal QR; when the non-inverting input terminal of the first comparator U1C is connected to the third power source V3 and the inverting input terminal is connected to the control module 100, the temperature of the liquid crystal panel driving circuit exceeds the set value and corresponds to the high level state of the control signal QR.
For convenience of understanding, the following description will be made by taking as an example that the non-inverting input terminal of the first comparator U1C is connected to the control module 100 and the inverting input terminal is connected to the third power supply V3:
in the high-level state of the control signal QR, since the voltage of the third power source V3 is smaller than the voltage value in the high-level state of the control signal QR, the first comparator U1C outputs a voltage value related to the forward power supply voltage V4 thereof (the first power supply voltage VG1 is V4 in the case where each non-resistive element of the first power supply module 200 has no resistance), and the second comparator U2A outputs a voltage value related to the reverse power supply voltage V7 thereof (the second power supply voltage VG2 is V7 in the case where each non-resistive element of the second power supply module 300 has no resistance); in the low-level state of the control signal QR, since the voltage of the third power source V3 is greater than the voltage value of the control signal QR in the low-level state, similarly, the first comparator U1C outputs a voltage value related to the reverse power supply voltage V6 thereof, and the second comparator U2A outputs a voltage value related to the forward power supply voltage V5 thereof. The temperature of the liquid crystal panel driving circuit exceeds the set value and corresponds to the low level state of the control signal QR, therefore, when the temperature of the liquid crystal panel driving circuit exceeds the set value, V5 is used as the gate-on voltage, | V6| is used as the gate-off voltage, and since V5< V4, | V6| < | V7|, the purpose of providing the gate-on voltage and the gate-off voltage by using a smaller set of the first power supply voltage and the second power supply voltage is achieved.
It should be noted that the gate-on voltage and the gate-off voltage are absolute values of voltages, that is, the TFTs are turned on after the absolute value of the voltage is greater than the turn-on voltage of the TFTs, whereas the TFTs are turned off, so that the absolute value of the negative voltage is emphasized when the first power supply voltage and the second power supply voltage are negative voltages, and then the smaller one of the two sets of the first power supply voltage and the second power supply voltage is the smaller absolute value.
In an alternative embodiment, the first power supply module 200 of the voltage conversion circuit further includes a first capacitor C1, and the first capacitor C1 is respectively connected to the output terminal of the first comparator U1C and the ground; the second power supply module 300 further comprises a second capacitor C2, the second capacitor C2 being connected to the output of the second comparator U2A and to ground, respectively.
In the embodiment of the present invention, the output terminals of the first comparator U1C and the second comparator U2A are respectively provided with a capacitor, which can filter the output voltage of the first comparator U1C and the second comparator U2A.
In an alternative embodiment, the voltage conversion circuit further comprises: and a voltage measuring instrument XM having one end connected to a target node P and the other end connected to ground, wherein the target node P is a connection node between the control module 100 and the first and second power supply modules 200 and 300.
In the embodiment of the invention, the voltage measuring instrument XM can check the level state of the control signal QR, thereby being convenient for a user to indirectly know whether the temperature of the liquid crystal panel driving circuit exceeds a set value; moreover, after the user can manually sense that the temperature of the liquid crystal panel driving circuit exceeds the set value, if the level state of the voltage measuring instrument XM is not correspondingly changed, it indicates that the control module 100 needs to be repaired, so that the user can quickly position the module of the voltage conversion circuit which needs to be repaired.
In the voltage conversion circuit provided by the embodiment of the invention, the following values can be selected for each element: r1 ═ 10k Ω, R2 ═ 10k Ω, C1 ═ 1 μ F, C2 ═ 1 μ F, V1 ═ 3.3V, V2 ═ 3.3V, V3 ═ 3.0V, V4 ═ 19.5V, V5 ═ 18.0V, V6 ═ 6V, V7 ═ 11V, and under these values, the test:
(1) when the temperature of the liquid crystal panel driving circuit does not exceed a set value, the grid opening voltage VGH is 18.066V, and the grid closing voltage VGL is-11.561V;
(2) when the temperature of the liquid crystal panel driving circuit does not exceed the set value, the gate-on voltage VGH is 16.567V (16.567V <18.066V), and the gate-off voltage VGL is-9.561V (9.561V < 11.561V).
It should be emphasized that the above-mentioned values of the circuit elements are only an example of the values of the various elements of the present invention, and do not represent a limitation to the voltage converting circuit provided by the present invention.
The utility model discloses the second embodiment provides a liquid crystal panel drive circuit, this liquid crystal panel drive circuit includes the first embodiment voltage conversion circuit to the charge pump among the current liquid crystal panel drive circuit of this voltage conversion circuit replacement provides grid opening voltage and grid closing voltage, thereby solves traditional liquid crystal panel drive circuit and generates heat comparatively serious technical problem.
Fig. 5 is a block diagram showing a liquid crystal display according to a third embodiment of the present invention. Referring to fig. 5, the liquid crystal display includes a liquid crystal panel 1 and a liquid crystal panel driving circuit 2 for providing a working voltage and a working signal to the liquid crystal panel, and the liquid crystal panel driving circuit 2 includes the voltage converting circuit described in the first embodiment, thereby reducing the heat generation of the liquid crystal panel driving circuit 2 in the liquid crystal display and solving the technical problem of the conventional liquid crystal display that the heat generation is serious.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
In accordance with the embodiments of the present invention as set forth above, these embodiments are not exhaustive and do not limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and its various embodiments with various modifications as are suited to the particular use contemplated. The present invention is limited only by the claims and their full scope and equivalents.
Claims (10)
1. A voltage conversion circuit, comprising:
the temperature detection module is used for detecting the temperature of the liquid crystal panel driving circuit;
the control module is connected with the temperature detection module and outputs control signals of different levels according to whether the temperature of the liquid crystal panel driving circuit exceeds a set value or not;
the first power supply module is connected with the control module to receive the control signal and output first power supply voltages with different levels according to the control signal, wherein the first power supply voltages with different levels are respectively a first voltage and a second voltage, and the first voltage corresponds to the liquid crystal panel driving circuit when the temperature of the liquid crystal panel driving circuit does not exceed the set value, otherwise, the second voltage corresponds to the liquid crystal panel driving circuit;
the second power supply module is connected with the control module to receive the control signal and output second power supply voltages with different levels according to the control signal, wherein the second power supply voltages with different levels are respectively a third voltage and a fourth voltage, and the third voltage corresponds to the liquid crystal panel driving circuit when the temperature of the liquid crystal panel driving circuit does not exceed the set value, otherwise, the fourth voltage corresponds to the liquid crystal panel driving circuit;
and a larger absolute value of the first voltage and the third voltage is larger than a larger absolute value of the second voltage and the fourth voltage, and a smaller absolute value of the first voltage and the third voltage is larger than a smaller absolute value of the second voltage and the fourth voltage.
2. The voltage conversion circuit of claim 1, wherein the control module comprises: a signal generating unit and a transistor comprising a control terminal, an input terminal and an output terminal, wherein,
the signal generating unit is used for generating a comparison signal according to whether the temperature of the liquid crystal panel driving circuit exceeds a set value or not;
the control end is connected with the signal generating unit and used for receiving the comparison signal and controlling the on-off between the input end and the output end through the comparison signal; and the number of the first and second groups,
the input end is connected with the ground;
the output terminal is connected with a first power supply.
3. The voltage conversion circuit according to claim 2, wherein the signal generation unit includes:
the first switch and the second power supply are connected between the control end and the ground in series, and the voltage of the second power supply is not less than the conducting voltage of the transistor;
a second switch connected in series between the control terminal and ground, wherein,
when the temperature of the liquid crystal panel driving circuit does not exceed the set value, the first switch is switched off and the second switch is switched on; when the temperature of the liquid crystal panel driving circuit exceeds the set value, the first switch is closed and the second switch is opened.
4. The voltage converting circuit of claim 2, wherein the transistor is an NPN-type transistor, the control terminal is a base of the transistor, the input terminal is an emitter of the transistor, and the output terminal is a collector of the transistor.
5. The voltage conversion circuit of claim 2, wherein the control module further comprises:
one end of the first resistor is connected with the output end, and the other end of the first resistor is connected with the first power supply; and/or the presence of a gas in the gas,
and one end of the second resistor is connected with the output end, and the other end of the second resistor is connected with the first power supply module and the second power supply module.
6. The voltage conversion circuit of claim 1, wherein the first power supply module comprises a first comparator and provides the first power supply voltage through the first comparator, wherein the second power supply module comprises a second comparator and provides the second power supply voltage through the second comparator, wherein,
the non-inverting input end of the first comparator is connected with the inverting input end of the second comparator;
the inverting input end of the first comparator is connected with the non-inverting input end of the second comparator;
one of a non-inverting input terminal and an inverting input terminal of the first comparator is connected to the control module to receive the control signal, and the other is connected to a third power supply having a voltage less than a voltage value of the control signal in a high level state and greater than a voltage value of the control signal in a low level state, and,
the positive power supply voltage of the first comparator is greater than the positive power supply voltage of the second comparator, and the absolute value of the reverse power supply voltage of the first comparator is less than the absolute value of the reverse power supply voltage of the second comparator.
7. The voltage conversion circuit of claim 6,
the first power supply module further comprises a first capacitor, and the first capacitor is respectively connected with the output end of the first comparator and the ground;
the second power supply module further comprises a second capacitor, and the second capacitor is respectively connected with the output end of the second comparator and the ground.
8. The voltage conversion circuit of claim 1, further comprising:
and one end of the voltage measuring instrument is connected with a target node, and the other end of the voltage measuring instrument is connected with the ground, wherein the target node is a connection node between the control module and the first power supply module as well as the second power supply module.
9. A liquid crystal panel drive circuit, comprising: the voltage conversion circuit of any of claims 1-8 to provide a gate-on voltage and a gate-off voltage through the voltage conversion circuit.
10. A liquid crystal display, comprising:
a liquid crystal panel; and the number of the first and second groups,
a liquid crystal panel driving circuit which supplies an operating voltage and an operating signal to the liquid crystal panel, the liquid crystal panel driving circuit comprising the voltage converting circuit according to any one of claims 1 to 8.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113345361A (en) * | 2021-05-20 | 2021-09-03 | 惠科股份有限公司 | Driving circuit, driving method and display device |
| WO2022111089A1 (en) * | 2020-11-27 | 2022-06-02 | 京东方科技集团股份有限公司 | Level conversion circuit, display panel drive circuit, and display apparatus |
| CN115086562A (en) * | 2022-07-25 | 2022-09-20 | 荣耀终端有限公司 | Power supply circuit, power supply control method and electronic equipment |
-
2019
- 2019-11-26 CN CN201922068912.3U patent/CN210667755U/en active Active
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2022111089A1 (en) * | 2020-11-27 | 2022-06-02 | 京东方科技集团股份有限公司 | Level conversion circuit, display panel drive circuit, and display apparatus |
| CN113345361A (en) * | 2021-05-20 | 2021-09-03 | 惠科股份有限公司 | Driving circuit, driving method and display device |
| CN115086562A (en) * | 2022-07-25 | 2022-09-20 | 荣耀终端有限公司 | Power supply circuit, power supply control method and electronic equipment |
| CN115086562B (en) * | 2022-07-25 | 2023-01-17 | 荣耀终端有限公司 | Power supply circuit, power supply control method and electronic equipment |
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