CN109586568B - Drive circuit and display panel - Google Patents
Drive circuit and display panel Download PDFInfo
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- CN109586568B CN109586568B CN201811465452.1A CN201811465452A CN109586568B CN 109586568 B CN109586568 B CN 109586568B CN 201811465452 A CN201811465452 A CN 201811465452A CN 109586568 B CN109586568 B CN 109586568B
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/02—Conversion of dc power input into dc power output without intermediate conversion into ac
- H02M3/04—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters
- H02M3/10—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
- H02M3/145—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
- H02M3/155—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only
- H02M3/156—Conversion of dc power input into dc power output without intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only with automatic control of output voltage or current, e.g. switching regulators
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage
- H02H3/202—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage for dc systems
Abstract
The invention relates to a driving circuit and a display panel. The driving circuit comprises a voltage reduction circuit and a switch circuit, whether the direct current voltage is larger than the standard voltage or not is judged through the voltage reduction circuit, when the direct current voltage is larger than the standard voltage, the direct current voltage is subjected to voltage reduction treatment, whether the reduced direct current voltage is larger than the standard voltage or not is judged through the switch circuit, and when the reduced direct current voltage is larger than the standard voltage, a loop between the output end of the driving circuit and the input end of the driving circuit is disconnected through the switch circuit, so that a driving chip receiving the output voltage of the driving circuit is prevented from being damaged, and the frequency of disconnecting the driving circuit due to overhigh input direct current voltage is reduced.
Description
Technical Field
The invention relates to the field of display, in particular to a driving circuit and a display panel.
Background
Thin Film Transistor Liquid Crystal Display (TFT-LCD) panels are one of the major products of flat panel displays, and have become an important Display platform in the modern information technology industry and video products. In the working process of the TFT-LCD display panel, a power supply and a signal are mainly provided for a display area through a driving chip on a printed circuit board, so that image display is realized.
However, during the operation of the tft-lcd, the dc voltage supplied to the driving chip may exceed the withstand voltage of the driving chip, which may cause the driving chip to be burned or damaged.
Disclosure of Invention
In view of the above, it is necessary to provide a driving circuit and a display panel, aiming at the problem that the driving chip is damaged because the input dc voltage exceeds the withstand voltage of the driving chip at present.
An embodiment of the present invention provides a driving circuit, including:
the first input end of the voltage reduction circuit is connected with a direct-current voltage input end, the second input end of the voltage reduction circuit is connected with a standard voltage input end, the output end of the voltage reduction circuit is connected with a pull-up node, the direct-current voltage provided by the direct-current voltage input end is received through the first input end of the voltage reduction circuit, the standard voltage provided by the standard voltage input end is received through the second input end of the voltage reduction circuit, whether the direct-current voltage is greater than the standard voltage or not is judged, and when the direct-current voltage is greater than the standard voltage, voltage reduction processing is carried out on the direct-current voltage; and
the switch circuit, switch circuit's first input with direct current voltage input end and step down circuit's first input is connected, switch circuit's second input with step down circuit's second input and the standard voltage input is connected, is used for through switch circuit's first input receives the direct current voltage after stepping down, through switch circuit's second input receives standard voltage judges whether the direct current voltage after stepping down is greater than standard voltage, and when direct current voltage after stepping down is greater than during the standard voltage, the disconnection drive circuit's output with return circuit between drive circuit's the input.
In some embodiments provided herein, the voltage reduction circuit includes:
a first judging branch, a first input end of which is connected with the direct-current voltage input end, and a second input end of which is connected with the standard voltage input end, and is used for receiving the direct-current voltage and the standard voltage and generating a first judging signal according to the direct-current voltage and the standard voltage; and
the first input end of the direct current voltage reduction branch is connected with the output end of the first judgment branch, the second input unit of the direct current voltage reduction branch is connected with the direct current voltage input end and the first input end of the first judgment branch, and the output end of the direct current voltage reduction branch is connected with the pull-up node and used for receiving the first judgment signal and the direct current voltage and carrying out voltage reduction processing on the direct current voltage according to the first judgment signal.
In some embodiments provided herein, the switching circuit includes:
a first input end of the first switch branch is connected with the pull-up node, and a second input end of the first switch branch is connected with the direct-current voltage input end, the first input end of the first judgment circuit and the first input end of the direct-current step-down branch;
a second judging branch, a first input end of the second judging branch being connected to the output end of the first switching branch, a second input end of the second judging branch being connected to the second input end of the first judging branch, and configured to receive the stepped-down dc voltage and the standard voltage, and generate a second judging signal according to the stepped-down dc voltage and the standard voltage; and
a second switch branch, a first input end of the second switch branch being connected to the dc voltage input end, the first input end of the first determining circuit, the first input end of the dc step-down branch, and a second input end of the second determining circuit, a second input end of the second switch branch being connected to an output end of the second determining branch, and an output end of the second switch branch being connected to an output end of the driving circuit, and configured to receive the second determining signal and disconnect the connection between the input end of the driving circuit and the output end of the driving circuit according to the determining signal.
In some embodiments of the present invention, the first determining branch includes a first comparator, a positive input end of the first comparator is connected to the dc voltage input end, and a negative input end of the first comparator is connected to the standard voltage input end, and is configured to receive the dc voltage and the standard voltage, and generate the first determining signal according to the dc voltage and the standard voltage.
In some embodiments provided in the present invention, the dc voltage reduction branch includes:
a grid electrode of the first switch tube is connected with a signal output end of the first comparator, a drain electrode of the first switch tube is connected with the direct-current voltage input end and a positive input end of the first comparator, and a source electrode of the first switch tube is connected with a first input end of the first switch branch circuit; and
and one end of the first resistor is connected with the source electrode of the first switching tube and the first input end of the first switching branch, and the other end of the first resistor is grounded.
In some embodiments provided herein, the first switching leg comprises:
a gate of the second switching tube is connected to the drain of the first switching tube and the first resistor, a drain of the second switching tube is connected to the dc voltage input terminal, the positive input terminal of the first comparator and the drain of the first switching tube, and a source of the second switching tube is connected to the first input terminal of the second judgment branch; and
and one end of the capacitor is connected with the drain electrode of the first switch tube, the first resistor and the grid electrode of the second switch tube, and the other end of the capacitor is grounded.
In some embodiments of the disclosure, the second determining branch includes a second comparator, a positive input end of the second comparator is connected to the drain of the second switch tube, a negative input end of the second comparator is connected to the negative input end of the first comparator and the standard voltage input end, and a signal output end of the second comparator is connected to the second input end of the second switch branch.
In some embodiments, the second switching branch includes a third switching tube, a gate of the third switching tube is connected to the signal output terminal of the second comparator, a source of the third switching tube is connected to the dc voltage input terminal, the positive input terminal of the first comparator, the drain of the first switching tube, and the drain of the second switching tube, and a source of the third switching tube is connected to the output terminal of the driving circuit.
In some embodiments, the first switch tube and the second switch tube are N-type switch tubes, and the third switch tube is a P-type switch tube.
Based on the same inventive concept, the embodiment of the invention further provides a display panel, wherein the display panel comprises a display area and a peripheral circuit area matched with the display area, and the peripheral circuit area is provided with a driving circuit for providing a driving signal for the display area;
wherein the driving circuit includes:
the voltage reducing circuit comprises a voltage reducing circuit, a first input end of the voltage reducing circuit is connected with a direct current voltage input end, a second input end of the voltage reducing circuit is connected with a standard voltage input end, and an output end of the voltage reducing circuit is connected with a pull-up node and is used for receiving direct current voltage provided by the direct current voltage input end through the first input end of the voltage reducing circuit, receiving standard voltage provided by the standard voltage input end through the second input end of the voltage reducing circuit, judging whether the direct current voltage is greater than the standard voltage or not, and reducing the direct current voltage when the direct current voltage is greater than the standard voltage; and
the switch circuit, switch circuit's first input with direct current voltage input end and step down circuit's first input is connected, switch circuit's second input with step down circuit's second input and the standard voltage input is connected, is used for through switch circuit's first input receives the direct current voltage after stepping down, through switch circuit's second input receives standard voltage, and judges whether the direct current voltage after stepping down is greater than standard voltage, and when direct current voltage after stepping down is greater than during the standard voltage, the disconnection drive circuit's output with return circuit between drive circuit's the input.
To sum up, the embodiment of the present invention provides a driving circuit, which includes a voltage-reducing circuit and a switching circuit. The first input end of the voltage reduction circuit is connected with the direct-current voltage input end, the second input end of the voltage reduction circuit is connected with the standard voltage input end, the output end of the voltage reduction circuit is connected with the pull-up node, the voltage reduction circuit receives the direct-current voltage provided by the direct-current voltage input end through the first input end of the voltage reduction circuit, receives the standard voltage provided by the standard voltage input end through the second input end of the voltage reduction circuit, judges whether the direct-current voltage is greater than the standard voltage, and when the direct-current voltage is greater than the standard voltage, the direct-current voltage is subjected to voltage reduction processing. The first input end of the switch circuit is connected with the direct-current voltage input end and the first input end of the voltage reduction circuit, the second input end of the switch circuit is connected with the second input end of the voltage reduction circuit and the standard voltage input end, the switch circuit receives the direct-current voltage after voltage reduction through the first input end of the switch circuit, receives the standard voltage through the second input end of the switch circuit, judges whether the direct-current voltage after voltage reduction is greater than the standard voltage, and when the direct-current voltage after voltage reduction is greater than the standard voltage, the circuit between the output end of the drive circuit and the input end of the drive circuit is disconnected. Therefore, in the driving circuit provided by the invention, when the input direct-current voltage is greater than the standard voltage, the direct-current voltage is subjected to voltage reduction processing, and if the voltage subjected to voltage reduction processing is still greater than the standard voltage, a loop between the output end of the driving circuit and the input end of the driving circuit is disconnected, so that the voltage output by the driving circuit is terminated, a driving chip receiving the voltage output by the driving circuit is prevented from being damaged, and the times of disconnecting the driving circuit due to overhigh input direct-current voltage are reduced.
Drawings
FIG. 1 is an electrical schematic diagram of an exemplary display panel;
fig. 2 is a schematic circuit structure diagram of a driving circuit according to an embodiment of the present invention.
The reference numbers illustrate:
100 step-down circuit
110 first judging branch
120 DC voltage reduction branch
200 switching circuit
210 first switching leg
220 second judging branch
230 second switching leg
D1 first comparator
D2 second comparator
R1 first resistor
C capacitor
M1 first switch tube
M2 second switch tube
M3 third switch tube
Detailed Description
In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in detail below. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed as broadly as the present invention is capable of modification in various respects, all without departing from the spirit and scope of the present invention.
The TFT-LCD display panel is one of the major products of the current flat panel display, and has become an important display platform in the modern information technology industry and video products. Referring to fig. 1, the main driving principle of the TFT-LCD display panel includes: the system mainboard connects data such as pixel signals, control signals and the like and a power supply with a connector on a Printed Circuit Board (PCB) through wires, the data are processed by a Timing Controller (TCON) integrated Circuit on the PCB, and then are connected with a display area through the PCB and a Source-Chip on Film (S-COF) and a Gate-Chip on Film (G-COF), so that the display area obtains the required power supply and data to realize image display.
However, during the operation of the tft-lcd, the dc voltage supplied to the driving chip may exceed the withstand voltage of the driving chip, which may cause the driving chip to be burned or damaged.
In view of the above problems, embodiments of the present invention provide a driving circuit. Referring to fig. 2, the driving circuit includes a voltage step-down circuit 100 and a switching circuit 200.
The first input end of the voltage reduction circuit 100 is connected with the direct-current voltage input end, the second input end of the voltage reduction circuit 100 is connected with the standard voltage input end, and the output end of the voltage reduction circuit 100 is connected with the pull-up node. The step-down circuit 100 receives the dc voltage provided by the dc voltage input terminal through the first input terminal of the step-down circuit, receives the standard voltage provided by the standard voltage input terminal through the second input terminal of the step-down circuit, determines whether the dc voltage is greater than the standard voltage, and performs step-down processing on the dc voltage when the dc voltage is greater than the standard voltage. The first input end of the switch circuit 200 is connected with the DC voltage input end and the first input end of the voltage reduction circuit 100, the second input end of the switch circuit 200 is connected with the second input end of the voltage reduction circuit 100 and the standard voltage input end, the switch circuit 200 receives the DC voltage after voltage reduction through the first input end of the switch circuit, receives the standard voltage through the second input end of the switch circuit, judges whether the DC voltage after voltage reduction is greater than the standard voltage, and breaks a loop between the output end of the drive circuit and the input end of the drive circuit when the DC voltage after voltage reduction is greater than the standard voltage
It can be understood that when the input dc voltage is greater than the standard voltage, the step-down circuit 100 performs step-down processing on the dc voltage, and if the voltage after the step-down processing is still greater than the standard voltage, the switch circuit 200 is used to open the loop between the output terminal of the driving circuit and the input terminal of the driving circuit, so that the driving circuit stops outputting the voltage. On one hand, the driving chip receiving the output voltage of the driving circuit can be prevented from being burned or damaged by the step-down of the step-down circuit 100 and the forced stopping of the power supply of the driving circuit by the switching circuit 200. On the other hand, if the dc voltage after the voltage reduction processing by the voltage reduction circuit 100 is smaller than the standard voltage, it is not necessary to disconnect the loop between the output terminal of the driving circuit and the input terminal of the driving circuit, and the driving circuit is guaranteed to operate normally, thereby reducing the number of times of disconnecting the driving circuit due to the overhigh input dc voltage.
In some embodiments, the voltage-reducing circuit 100 includes a first determining branch 110 and a dc voltage-reducing branch 120.
The first input end of the first judging branch 110 is connected to the dc voltage input end, and the second input end of the first judging branch 110 is connected to the standard voltage input end, and is configured to receive the dc voltage and the standard voltage, and generate a first judging signal according to the dc voltage and the standard voltage. The first input end of the dc voltage reduction branch 120 is connected to the output end of the first determining branch 110, the second input unit of the dc voltage reduction branch 120 is connected to the dc voltage input end and the first input end of the first determining branch 110, the output end of the dc voltage reduction branch 120 is connected to the pull-up node, and the dc voltage reduction branch 120 is configured to receive the first determining signal and the dc voltage, and perform voltage reduction processing on the dc voltage according to the first determining signal.
It is understood that the first determining branch 110 receives the dc voltage and the standard voltage, generates a first determining signal according to the dc voltage and the standard voltage, and outputs the first determining signal to the dc voltage dropping branch 120. The dc voltage dropping branch 120 performs voltage dropping processing on the dc voltage according to the received first determination signal. In this embodiment, when the dc voltage is greater than the standard voltage, the first determining branch 110 outputs a first determining signal with a high level to the dc voltage dropping branch 120, and the dc voltage dropping branch 120 provides the dc voltage for the load in the dc voltage dropping branch 120 according to the first determining signal with the high level, so as to reduce the voltage in the driving circuit through the self-consumption of the load, thereby achieving the purpose of performing voltage dropping processing on the input dc voltage.
In some embodiments, the switching circuit 200 includes a first switching branch 210, a second determining branch 220, and a second switching branch 230.
A first input terminal of the first switching branch 210 is connected to the pull-up node, and a second input terminal of the first switching branch is connected to the dc voltage input terminal, the first input terminal of the first determining circuit, and the first input terminal of the dc step-down branch 120.
A first input end of the second determining branch 220 is connected to the output end of the first switching branch 210, and a second input end of the second determining branch 220 is connected to a second input end of the first determining branch 110, and is configured to receive the reduced dc voltage and the standard voltage, and generate a second determining signal according to the reduced dc voltage and the standard voltage.
The first input end of the second switching branch 230 is connected to the dc voltage input end, the first input end of the first determining circuit, the first input end of the dc step-down branch 120, and the second input end of the second determining circuit, the second input end of the second switching branch 230 is connected to the output end of the second determining branch 220, and the output end of the second switching branch 230 is connected to the output end of the driving circuit, and is configured to receive the second determining signal and disconnect the connection between the input end of the driving circuit and the output end of the driving circuit according to the determining signal.
In some embodiments, the first determining branch 110 includes a first comparator D1, a positive input terminal of the first comparator D1 is connected to the dc voltage input terminal, a negative input terminal of the first comparator D1 is connected to the standard voltage input terminal, and the first comparator D1 is configured to receive the dc voltage and the standard voltage, and generate the first determining signal according to the dc voltage and the standard voltage.
It is understood that, in this embodiment, the first comparator D1 receives the dc voltage through its own positive input terminal, and receives the standard voltage through its own negative input terminal. When the dc voltage is greater than the standard voltage, the first comparator D1 generates and outputs a first determination signal of a high level. When the dc voltage is less than or equal to the standard voltage, the first comparator D1 generates and outputs a first determination signal of a low level.
In some embodiments, the dc step-down branch 120 includes a first switch M1 and a first resistor R1.
The gate of the first switch transistor M1 is connected to the signal output terminal of the first comparator D1, the drain of the first switch transistor M1 is connected to the dc voltage input terminal and the positive input terminal of the first comparator D1, and the source of the first switch transistor M1 is connected to the first input terminal of the first switch branch 210.
One end of the first resistor R1 is connected to the source of the first switch transistor M1 and the first input end of the first switch branch 210, and the other end of the first resistor R1 is grounded.
It can be understood that, when the dc voltage is greater than the standard voltage, the first comparator D1 generates and outputs a first determination signal with a high level, at this time, the gate of the first switch tube M1 is at a high level, the first switch tube M1 is turned on, the dc voltage is provided to the first resistor R1 through the first switch tube M1, and the dc voltage is subjected to a step-down process through the first resistor R1, so as to obtain a step-down processed dc voltage. When the dc voltage is less than or equal to the standard voltage, the first comparator D1 generates and outputs a first determination signal with a low level, at this time, the gate of the first switch transistor M1 is at a low level, the first switch transistor M1 is turned off, and the dc step-down branch 120 does not operate.
In some embodiments, the first switching branch 210 includes a second switching tube M2 and a capacitor C.
A gate of the second switching tube M2 is connected to the drain of the first switching tube M1 and the first resistor R1, a drain of the second switching tube M2 is connected to the dc voltage input terminal, the positive input terminal of the first comparator D1 and the drain of the first switching tube M1, and a source of the second switching tube M2 is connected to the first input terminal of the second determining branch 220.
One end of the capacitor C is connected to the drain of the first switch transistor M1, the first resistor R1, and the gate of the second switch transistor M2, and the other end of the capacitor C is grounded.
It can be understood that after the first switch tube M1 is turned on, the capacitor C is charged through the first switch tube, but due to the capacitive reactance of the capacitor C, the pull-up node still maintains a low voltage, and during the process of charging the capacitor C, as the electric quantity of the capacitor C increases gradually, the voltage at two ends of the capacitor C also increases gradually, that is, the voltage at the pull-up node increases gradually, and when the capacitor C is charged completely, the voltage at the pull-up node is equal to the reduced dc voltage, the second switch tube M2 is turned on, and the reduced dc voltage is provided to the second determining branch 220 through the second switch tube M2.
In some embodiments, the second determining branch 220 includes a second comparator D2, a positive input terminal of the second comparator D2 is connected to the drain of the second switching tube M2, a negative input terminal of the second comparator D2 is connected to the negative input terminal of the first comparator D1 and the reference voltage input terminal, and a signal output terminal of the second comparator D2 is connected to the second input terminal of the second switching branch 230.
It is understood that the positive input terminal of the second comparator D2 receives the stepped-down dc voltage inputted through the second switch tube M2, and the negative input terminal of the second comparator D2 receives the standard voltage. And when the reduced direct current voltage is greater than the standard voltage, generating and outputting a second judgment signal with a high level. And when the reduced direct current voltage is less than or equal to the standard voltage, generating and outputting a second judgment signal with a low level.
In some embodiments of the present invention, the second switching branch 230 includes a third switching tube M3, a gate of the third switching tube M3 is connected to the signal output terminal of the second comparator D2, a source of the third switching tube M3 is connected to the dc voltage input terminal, the positive input terminal of the first comparator D1, the drain of the first switching tube M1 and the drain of the second switching tube M2, and a source of the third switching tube M3 is connected to the output terminal of the driving circuit.
It can be understood that, if the stepped-down dc voltage is greater than the standard voltage, the gate of the third switching tube M3 receives the second determination signal with a high level output by the second comparator D2, the gate of the third switch is at a high level, and the third switching tube M3 is turned off, so as to break a loop between the input terminal of the driving circuit and the output terminal of the driving circuit, and terminate the voltage output by the driving circuit, thereby preventing a driving chip powered by the driving circuit from being burned out due to an excessive voltage. If the reduced dc voltage is less than or equal to the standard voltage, the gate of the third switch receives the second determination signal of low level output by the second comparator D2, the gate of the third switch M3 is at low level, the third switch M3 is kept on, and the driving circuit provides the reduced dc voltage for the chip connected to the driving circuit.
In some embodiments, the first switching transistor M1, the second switching transistor M2, and the third switching transistor M3 are all fets or triodes. In addition, the first switch tube M1, the second switch tube M2, and the third switch tube M3 may also partially adopt field effect transistors, and partially adopt triodes.
In some embodiments, the first switch tube M1 and the second switch tube M2 are N-type switch tubes, and the third switch tube M3 is P-type switch tube.
It is understood that the first switch tube M1 and the second switch tube M2 are both N-type fets, and the third switch tube M3 is a P-type fet. For an N-type field effect transistor, when the gate is at a high level, the N-type field effect transistor is turned on, and when the gate is at a low level, the N-type field effect transistor is turned off. For a P-type field effect transistor, when the grid electrode of the P-type field effect transistor is at a high level, the P-type field effect transistor is disconnected, and when the grid electrode of the P-type field effect transistor is at a low level, the P-type field effect transistor is connected. For the first comparator D1, when the voltage input to the positive input terminal thereof is greater than the voltage input to the negative input terminal thereof, the first determination signal generated and output by the first comparator D1 is at a high level, and when the voltage input to the positive input terminal thereof is less than or equal to the voltage input to the negative input terminal thereof, the first determination signal generated and output by the first comparator D1 is at a low level. The operation principle of the second comparator D2 is similar to that of the first comparator D1, and thus the detailed description thereof is omitted.
In this embodiment, when the driving circuit normally operates, the dc voltage input by the input end of the driving voltage is a constant dc voltage, and the voltage value of the dc voltage is Vin (usually 12V). The standard voltage has a voltage value of V1, generally the voltage value of V1 is equal to the withstand voltage value of a driving chip, and Vin < V1. At this time, the first determination signal output by the first comparator D1 is a low level signal, the first switch tube M1 is turned off, the source of the first switch tube M1 is grounded through the first resistor R1, the pull-up node connected to the first switch tube M1 is at a low level, the gate of the second switch tube M2 is also at a low level, the second switch tube M2 is turned off, the low level second determination signal output by the second comparator D2, the gate of the third switch tube M3 is at a low level, the third switch tube M3 is turned on, and the driving circuit outputs the dc voltage.
When the voltage at the input end is increased due to the abnormal input end and exceeds the voltage withstanding value on the driving chip, namely Vin is greater than V1, the first judgment signal output by the first comparator D1 is a high-level signal, the first switching tube M1 is conducted, and discharge is carried out through the first resistor R1, so that the input direct-current voltage is reduced, and if the voltage provided by the input end of the driving circuit is U, the power consumption of the first resistor R1 is U2and/R1. At this time, the stepped-down dc voltage output by the output terminal of the driving circuit is smaller than the dc voltage input by the input terminal of the driving circuit.
Due to the existence of the capacitor C, after the first switch tube M1 is turned on, the voltage of the pull-up node is still kept at a low level, the second switch tube M2 is kept off, the third switch tube M3 is kept on, and the capacitor C is charged through the first switch tube. After the capacitor C is charged, the voltage of the pull-up node is equal to the stepped-down dc voltage, the gate of the second switch transistor M2 is at a high level, the second switch transistor M2 is turned on, and the stepped-down dc voltage is provided to the positive input terminal of the second comparator D2 through the second switch transistor M2. At this time, if the stepped-down dc voltage is less than or equal to V1, the second comparator D2 outputs a low level signal, the third switching tube M3 remains on, and the driving circuit operates normally. If the reduced dc voltage is still greater than V1, the second comparator D2 outputs a high level signal, and the third switching tube M3 is turned off, so as to open the loop between the input terminal of the driving circuit and the output terminal of the driving circuit, and the driving circuit stops operating.
It can be seen that, in the driving circuit provided in the present invention, when the input dc voltage is greater than the standard voltage, the step-down circuit 100 performs step-down processing on the dc voltage, and if the voltage after step-down processing is still greater than the standard voltage, the switch circuit 200 is used to disconnect the loop between the output terminal of the driving circuit and the input terminal of the driving circuit, so that the driving circuit stops outputting the voltage. On one hand, the driving chip receiving the output voltage of the driving circuit can be prevented from being burned or damaged by the step-down of the step-down circuit 100 and the forced stopping of the power supply of the driving circuit by the switching circuit 200. On the other hand, if the dc voltage after the voltage reduction processing by the voltage reduction circuit 100 is smaller than the standard voltage, it is not necessary to disconnect the loop between the output terminal of the driving circuit and the input terminal of the driving circuit, and the driving circuit is guaranteed to operate normally, thereby reducing the number of times of disconnecting the driving circuit due to the overhigh input dc voltage.
Based on the same inventive concept, the embodiment of the invention also provides a display panel. The display panel comprises a display area and a peripheral circuit area matched with the display area. The peripheral circuit region is provided with a drive circuit for providing a drive signal for the display region. Wherein the driving circuit is the driving circuit of any of the above embodiments.
In this embodiment, the driving circuit includes a voltage step-down circuit and a switching circuit.
The first input end of the voltage reduction circuit is connected with the direct-current voltage input end, the second input end of the voltage reduction circuit is connected with the standard voltage input end, the output end of the voltage reduction circuit is connected with the pull-up node and used for receiving the direct-current voltage provided by the direct-current voltage input end through the first input end of the voltage reduction circuit and receiving the standard voltage provided by the standard voltage input end through the second input end of the voltage reduction circuit, and judging whether the direct-current voltage is greater than the standard voltage or not, and when the direct-current voltage is greater than the standard voltage, the direct-current voltage is subjected to voltage reduction processing.
The first input end of the switch circuit is connected with the direct-current voltage input end and the first input end of the voltage reduction circuit, the second input end of the switch circuit is connected with the second input end of the voltage reduction circuit and the standard voltage input end, and the second input end of the switch circuit is used for receiving the direct-current voltage after voltage reduction and judging whether the direct-current voltage after voltage reduction is greater than the standard voltage or not, and when the direct-current voltage after voltage reduction is greater than the standard voltage, the output end of the drive circuit is disconnected with a loop between the input ends of the drive circuit.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.
Claims (9)
1. A driver circuit, comprising:
the voltage reducing circuit comprises a voltage reducing circuit, a first input end of the voltage reducing circuit is connected with a direct current voltage input end, a second input end of the voltage reducing circuit is connected with a standard voltage input end, and an output end of the voltage reducing circuit is connected with a pull-up node and is used for receiving direct current voltage provided by the direct current voltage input end through the first input end of the voltage reducing circuit, receiving standard voltage provided by the standard voltage input end through the second input end of the voltage reducing circuit, judging whether the direct current voltage is greater than the standard voltage or not, and reducing the direct current voltage when the direct current voltage is greater than the standard voltage; and
a switch circuit, a first input end of which is connected to the dc voltage input end and the first input end of the step-down circuit, and a second input end of which is connected to the second input end of the step-down circuit and the standard voltage input end, for receiving the stepped-down dc voltage through the first input end of the switch circuit, receiving the standard voltage through the second input end of the switch circuit, and determining whether the stepped-down dc voltage is greater than the standard voltage, and when the stepped-down dc voltage is greater than the standard voltage, disconnecting a loop between an output end of the driving circuit and the input end of the driving circuit;
wherein the switching circuit comprises:
a second switch tube, a grid electrode of which is connected with the pull-up node, and a drain electrode of which is respectively connected with the direct current voltage input end and the first input end of the voltage reduction circuit, and is used for responding to the voltage of the pull-up node and receiving the reduced direct current voltage; and
and one end of the capacitor is connected with the pull-up node and the grid electrode of the second switch tube respectively, and the other end of the capacitor is grounded.
2. The drive circuit according to claim 1, wherein the voltage-decreasing circuit includes:
a first judging branch, a first input end of which is connected with the direct-current voltage input end, and a second input end of which is connected with the standard voltage input end, and is used for receiving the direct-current voltage and the standard voltage and generating a first judging signal according to the direct-current voltage and the standard voltage; and
the first input end of the direct current voltage reduction branch is connected with the output end of the first judgment branch, the second input end of the direct current voltage reduction branch is connected with the direct current voltage input end and the first input end of the first judgment branch, and the output end of the direct current voltage reduction branch is connected with the pull-up node and used for receiving the first judgment signal and the direct current voltage and carrying out voltage reduction processing on the direct current voltage according to the first judgment signal.
3. The drive circuit of claim 2, wherein the switching circuit further comprises:
a second judging branch, a first input end of the second judging branch is connected with a source electrode of the second switching tube, a second input end of the second judging branch is connected with a second input end of the first judging branch, and the second judging branch is used for receiving the reduced direct-current voltage and the standard voltage through the second switching tube, and generating a second judging signal according to the reduced direct-current voltage and the standard voltage; and
a second switch branch, a first input end of the second switch branch being connected to the dc voltage input end, the first input end of the first determining circuit, the first input end of the dc step-down branch, and a second input end of the second determining circuit, a second input end of the second switch branch being connected to an output end of the second determining branch, and an output end of the second switch branch being connected to an output end of the driving circuit, and configured to receive the second determining signal and disconnect the connection between the input end of the driving circuit and the output end of the driving circuit according to the determining signal.
4. The driving circuit according to claim 3, wherein the first determining branch comprises a first comparator, a positive input terminal of the first comparator is connected to the dc voltage input terminal, a negative input terminal of the first comparator is connected to the standard voltage input terminal, and is configured to receive the dc voltage and the standard voltage, and generate the first determining signal according to the dc voltage and the standard voltage.
5. The driving circuit of claim 4, wherein the DC down branch comprises:
a grid electrode of the first switch tube is connected with a signal output end of the first comparator, a drain electrode of the first switch tube is connected with the direct-current voltage input end and a positive input end of the first comparator, and a source electrode of the first switch tube is connected with the pull-up node; and
and one end of the first resistor is connected with the source electrode of the first switch tube and the grid electrode of the second switch tube respectively, and the other end of the first resistor is grounded.
6. The driving circuit as claimed in claim 5, wherein the second determining branch comprises a second comparator, a positive input terminal of the second comparator is connected to the source of the second switch tube, a negative input terminal of the second comparator is connected to the negative input terminal of the first comparator and the reference voltage input terminal, and a signal output terminal of the second comparator is connected to the second input terminal of the second switch branch.
7. The driving circuit as claimed in claim 6, wherein the second switching branch comprises a third switching tube, a gate of the third switching tube is connected to the signal output terminal of the second comparator, a source of the third switching tube is connected to the dc voltage input terminal, the positive input terminal of the first comparator, the drain of the first switching tube, and the drain of the second switching tube, and a source of the third switching tube is connected to the output terminal of the driving circuit.
8. The driving circuit as claimed in claim 7, wherein the first switch tube and the second switch tube are N-type switch tubes, and the third switch tube is P-type switch tube.
9. A display panel, comprising:
a display area; and
a peripheral circuit region arranged in match with the display region, the peripheral circuit region being provided with a drive circuit for supplying a drive signal to the display region;
wherein the driving circuit includes:
the voltage reducing circuit comprises a voltage reducing circuit, a first input end of the voltage reducing circuit is connected with a direct current voltage input end, a second input end of the voltage reducing circuit is connected with a standard voltage input end, and an output end of the voltage reducing circuit is connected with a pull-up node and is used for receiving direct current voltage provided by the direct current voltage input end through the first input end of the voltage reducing circuit, receiving standard voltage provided by the standard voltage input end through the second input end of the voltage reducing circuit, judging whether the direct current voltage is greater than the standard voltage or not, and reducing the direct current voltage when the direct current voltage is greater than the standard voltage; and
a switch circuit, a first input end of which is connected to the dc voltage input end and the first input end of the step-down circuit, and a second input end of which is connected to the second input end of the step-down circuit and the standard voltage input end, for receiving the stepped-down dc voltage through the first input end of the switch circuit, receiving the standard voltage through the second input end of the switch circuit, and determining whether the stepped-down dc voltage is greater than the standard voltage, and when the stepped-down dc voltage is greater than the standard voltage, disconnecting a loop between an output end of the driving circuit and the input end of the driving circuit;
wherein the switching circuit comprises:
a second switch tube, a grid electrode of which is connected with the pull-up node, and a drain electrode of which is respectively connected with the direct current voltage input end and the first input end of the voltage reduction circuit, and is used for responding to the voltage of the pull-up node and receiving the reduced direct current voltage; and
and one end of the capacitor is connected with the pull-up node and the grid electrode of the second switch tube respectively, and the other end of the capacitor is grounded.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811465452.1A CN109586568B (en) | 2018-12-03 | 2018-12-03 | Drive circuit and display panel |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201811465452.1A CN109586568B (en) | 2018-12-03 | 2018-12-03 | Drive circuit and display panel |
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| CN109586568A CN109586568A (en) | 2019-04-05 |
| CN109586568B true CN109586568B (en) | 2020-12-22 |
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| US8400131B2 (en) * | 2010-03-09 | 2013-03-19 | Analog Devices, Inc. | Voltage converter and LED driver circuits with progressive boost, skip, and linear mode operation |
| JP5822041B1 (en) * | 2015-03-19 | 2015-11-24 | 富士電機株式会社 | Power converter |
| CN105510655A (en) * | 2016-01-26 | 2016-04-20 | 昆山龙腾光电有限公司 | Over-voltage protection circuit and testing power source |
| CN105788556B (en) * | 2016-05-20 | 2018-12-11 | 深圳市华星光电技术有限公司 | A kind of overvoltage crowbar and method, liquid crystal display drive circuit |
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