CN109493817B - Drive circuit and display panel - Google Patents
Drive circuit and display panel Download PDFInfo
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- CN109493817B CN109493817B CN201811465455.5A CN201811465455A CN109493817B CN 109493817 B CN109493817 B CN 109493817B CN 201811465455 A CN201811465455 A CN 201811465455A CN 109493817 B CN109493817 B CN 109493817B
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- G—PHYSICS
- G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
- G09G—ARRANGEMENTS OR CIRCUITS FOR CONTROL OF INDICATING DEVICES USING STATIC MEANS TO PRESENT VARIABLE INFORMATION
- G09G3/00—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes
- G09G3/20—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters
- G09G3/34—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source
- G09G3/36—Control arrangements or circuits, of interest only in connection with visual indicators other than cathode-ray tubes for presentation of an assembly of a number of characters, e.g. a page, by composing the assembly by combination of individual elements arranged in a matrix no fixed position being assigned to or needed to be assigned to the individual characters or partial characters by control of light from an independent source using liquid crystals
- G09G3/3611—Control of matrices with row and column drivers
- G09G3/3696—Generation of voltages supplied to electrode drivers
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Abstract
The invention relates to a driving circuit and a display panel. The driving circuit comprises a first-order voltage reduction circuit and a second-order voltage reduction circuit, when the input direct-current voltage is larger than the standard voltage, the direct-current voltage is firstly subjected to voltage reduction processing through the first-order voltage reduction circuit, if the voltage after the voltage reduction processing is still larger than the standard voltage, the direct-current voltage after the voltage reduction processing is subjected to voltage reduction processing again through the second-order voltage reduction circuit, the direct-current after the voltage reduction processing is obtained, the direct-current voltage after the voltage reduction processing is lower than the normal working voltage range, the driving circuit stops working, a driving chip for 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:
a first-stage voltage reduction circuit, a first input end of which is connected to a dc voltage input end, and a second input end of which is connected to a standard voltage input end, for receiving the dc voltage provided by the dc voltage input end through the first input end of the first-stage voltage reduction circuit, receiving the standard voltage provided by the standard voltage input end through the second input end of the first-stage voltage reduction circuit, and determining whether the dc voltage is greater than the standard voltage, and when the dc voltage is greater than the standard voltage, performing voltage reduction processing on the dc voltage; and
a second-stage voltage-reducing circuit, a first input end of the second-stage voltage-reducing circuit is connected with an output end of the first-stage voltage-reducing circuit, the second input end of the second-stage voltage reduction circuit is connected with the first input end of the first-stage voltage reduction circuit and the direct-current voltage input end, is used for judging whether the reduced DC voltage is larger than the standard voltage or not according to the reduced DC voltage received by the first input end of the second-stage voltage reduction circuit, and when the reduced direct current voltage is greater than the standard voltage, controlling the second-order voltage reduction circuit to reduce the reduced direct current voltage again by using the reduced direct current voltage received by the first input end of the second-order voltage reduction circuit, so as to obtain the reduced direct current voltage lower than the normal working voltage range, and stopping the driving circuit.
In some embodiments provided herein, the first stage voltage reduction circuit comprises:
a first input end of the judging branch is connected with the direct-current voltage input end, a second input end of the judging branch is connected with the standard voltage input end, and the judging branch 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 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 judgment branch, the third input end of the direct current voltage reduction branch is grounded, and the output end of the direct current voltage reduction branch is connected with the first input end of the second-order voltage reduction circuit 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 second-stage voltage-reducing circuit includes:
a first input end of the trigger control branch is connected with an output end of the first direct current voltage reduction branch, a second input end of the trigger control branch is grounded and is used for receiving the reduced direct current voltage output by the first direct current voltage reduction branch, and when the reduced direct current voltage is greater than the standard voltage, the reduced direct current voltage is output through the output end of the trigger control branch;
a trigger branch, a first input end of the trigger branch being connected to the dc voltage input end, a first input end of the judging branch and a second input end of the first dc voltage-reducing branch, a second input end of the trigger branch being connected to an output end of the trigger control branch, for outputting a reduced dc voltage input through the first input end of the trigger branch when the second input end of the trigger branch receives the reduced dc voltage; and
the first input end of the second direct current voltage reduction branch circuit is connected with the output end of the first direct current voltage reduction branch circuit and the first input end of the trigger control branch circuit, the second input end of the second direct current voltage reduction branch circuit is connected with the output end of the trigger branch circuit, and the third input end of the second direct current voltage reduction branch circuit is grounded.
In some embodiments of the present invention, the determining branch includes a comparator, a positive input end of the comparator is connected to the dc voltage input end, a negative input end of the comparator is connected to the standard voltage input end, and a signal output end of the comparator is connected to the first input end of the first dc voltage decreasing branch, 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 by the present invention, the first dc voltage reduction branch includes:
a grid electrode of the first switch tube is connected with a signal output end of the 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 comparator, and a source electrode of the first switch tube is connected with a first input end of the trigger control 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 trigger control branch circuit, and the other end of the first resistor is grounded.
In some embodiments provided herein, the triggering branch comprises:
one end of the capacitor is connected with the source electrode of the first switching tube, the first resistor and the first input end of the second direct current step-down branch circuit, and the other end of the capacitor is grounded; and
and the anode of the diode is connected with the second input end of the trigger branch, and the cathode of the diode is connected with the capacitor, the first resistor and the source electrode of the first switching tube.
In some embodiments of the present invention, the triggering branch includes a trigger, a set end of the trigger is connected to the dc voltage input end, a positive input end of the comparator, and a drain of the first switching tube, a control end of the trigger is connected to an anode of the diode, and a positive output end of the trigger is connected to the second input end of the second dc voltage-reducing branch.
In some embodiments provided by the present invention, the second dc voltage reduction branch includes:
a grid electrode of the second switch tube is connected with a positive output end of the trigger, and a drain electrode of the second switch tube is connected with the capacitor, the first resistor, a source electrode of the first switch tube and a cathode of the diode; and
and one end of the second resistor is connected with the source electrode of the second switch tube, and the other end of the second resistor is grounded.
In some embodiments, the first switch tube and the second switch tube are both N-type switch tubes.
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:
a first-stage voltage reduction circuit, a first input end of which is connected to a dc voltage input end, and a second input end of which is connected to a standard voltage input end, for receiving the dc voltage provided by the dc voltage input end through the first input end of the first-stage voltage reduction circuit, receiving the standard voltage provided by the standard voltage input end through the second input end of the first-stage voltage reduction circuit, and determining whether the dc voltage is greater than the standard voltage, and when the dc voltage is greater than the standard voltage, performing voltage reduction processing on the dc voltage; and
a second-stage voltage-reducing circuit, a first input end of the second-stage voltage-reducing circuit is connected with an output end of the first-stage voltage-reducing circuit, the second input end of the second-stage voltage reduction circuit is connected with the first input end of the first-stage voltage reduction circuit and the direct-current voltage input end, is used for judging whether the reduced direct current voltage is larger than the standard voltage or not according to the reduced direct current voltage received by the first input end of the second-stage voltage reduction circuit, and when the reduced direct current voltage is greater than the standard voltage, controlling the second-order voltage reduction circuit to reduce the reduced direct current voltage again by using the reduced direct current voltage received by the first input end of the second-order voltage reduction circuit, so as to obtain the reduced direct current voltage lower than the normal working voltage range, and stopping the driving circuit.
In summary, the embodiment of the present invention provides a driving circuit, where the driving circuit includes the first-stage voltage-reducing circuit and the second-stage voltage-reducing circuit. The first input end of the first-order voltage reduction circuit is connected with the direct-current voltage input end, the second input end of the first-order voltage reduction circuit is connected with the standard voltage input end and used for receiving the direct-current voltage provided by the direct-current voltage input end through the first input end of the first-order voltage reduction circuit, receiving the standard voltage provided by the standard voltage input end through the second input end of the first-order voltage reduction circuit, 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, carrying out voltage reduction on the direct-current voltage. The first input end of the second-stage voltage reduction circuit is connected with the output end of the first-stage voltage reduction circuit, the second input end of the second-stage voltage reduction circuit is connected with the first input end of the first-stage voltage reduction circuit and the direct-current voltage input end, is used for judging whether the reduced DC voltage is larger than the standard voltage or not according to the reduced DC voltage received by the first input end of the second-stage voltage reduction circuit, and when the reduced direct current voltage is greater than the standard voltage, controlling the second-order voltage reduction circuit to reduce the reduced direct current voltage again by using the reduced direct current voltage received by the first input end of the second-order voltage reduction circuit, so as to obtain the reduced direct current voltage lower than the normal working voltage range, and stopping the driving circuit. Therefore, in the driving circuit provided by the invention, when the input direct-current voltage is greater than the standard voltage, the first-stage voltage reduction circuit is used for carrying out voltage reduction on the direct-current voltage, if the voltage after voltage reduction is still greater than the standard voltage, the second-stage voltage reduction circuit is used for carrying out voltage reduction on the direct-current voltage after voltage reduction again to obtain direct current after voltage reduction again, and the direct-current voltage after voltage reduction is lower than the normal working voltage range, so that the driving circuit stops working to prevent a driving chip receiving the output voltage of the driving circuit from being damaged, and the frequency of disconnecting the driving circuit due to overhigh input direct-current voltage is 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;
fig. 3 is a schematic circuit diagram of another driving circuit according to an embodiment of the present invention;
fig. 4 is a schematic circuit structure diagram of another driving circuit according to an embodiment of the present invention.
The reference numbers illustrate:
100 first-stage voltage reduction circuit
110 judging branch
120 first direct current voltage reduction branch
200 first-order voltage reduction circuit
210 trigger control branch
220 triggering branch
230 first DC step-down branch
D1 first comparator
D2 diode
D3 trigger
D4 inverter
R1 first resistor
R2 second resistor
C capacitor
M1 first switch tube
M2 second 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 first-stage voltage-reducing circuit 100 and a second-stage voltage-reducing circuit 200.
The first input terminal P11 of the first step-down circuit 100 is connected to a dc voltage input terminal P01, the second input terminal P12 of the first step-down circuit 100 is connected to a standard voltage input terminal P02, and is configured to receive the dc voltage provided by the dc voltage input terminal P01 through the first input terminal P11 of the first step-down circuit 100, receive the standard voltage provided by the standard voltage input terminal P02 through the second input terminal P12 of the first step-down circuit 100, determine whether the dc voltage is greater than the standard voltage, and perform step-down processing on the dc voltage when the dc voltage is greater than the standard voltage.
The first input end P21 of the second-order step-down circuit 200 is connected to the output end P13 of the first-order step-down circuit, the second input end P22 of the second-order step-down circuit 200 is connected to the first input end P11 of the first-order step-down circuit 100 and the dc voltage input end P01, and is configured to determine whether the stepped-down dc voltage is greater than the standard voltage according to the stepped-down dc voltage received through the first input end P21 of the second-order step-down circuit 200, and when the stepped-down dc voltage is greater than the standard voltage, control the second-order step-down circuit 200 to perform step-down processing on the stepped-down dc voltage again by using the stepped-down dc voltage received through the first input end P21 of the second-order step-down circuit 200, so as to obtain a stepped-down dc voltage lower than a normal operating voltage range, so that the drive circuit stops operating.
It is understood that the voltage value of the standard voltage in this embodiment is equal to the withstand voltage limit value of the driving chip supplied with power by the driving circuit. In the driving circuit provided by the invention, when the input direct current voltage is greater than the standard voltage, the first-stage voltage reduction circuit 100 is used for carrying out voltage reduction on the direct current voltage, if the voltage after voltage reduction is still greater than the standard voltage, the second-stage voltage reduction circuit 200 is used for carrying out voltage reduction on the direct current voltage after voltage reduction again to obtain direct current after voltage reduction again, and the direct current voltage after voltage reduction is lower than the normal working voltage range, so that the driving circuit stops working, a driving chip receiving the output voltage of the driving circuit is prevented from being damaged, and the times of disconnecting the driving circuit due to overhigh input direct current voltage is reduced.
In some embodiments, the first step-down circuit 100 includes a determining branch 110 and a first dc step-down branch 120.
The first input terminal P31 of the determining branch 110 is connected to the dc voltage input terminal P01, and the second input terminal P32 of the determining branch 110 is connected to the standard voltage input terminal P02, for receiving the dc voltage and the standard voltage, and generating a first determining signal according to the dc voltage and the standard voltage.
The first input end P41 of the first dc step-down branch 120 is connected to the output end P33 of the determining branch 110, the second input end P42 of the first dc step-down branch is connected to the dc voltage input end P01 and the first input end P31 of the determining branch 110, the third input end P43 of the first dc step-down branch 120 is grounded, and the output end P44 of the first dc step-down branch 120 is connected to the first input end P21 of the second-stage step-down circuit 200, and is configured to receive the first determination signal and the dc voltage, and perform step-down processing on the dc voltage according to the first determination signal.
It is understood that the 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 first dc step-down branch 120. The first 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 determining branch 110 outputs a first determining signal with a high level to the dc voltage dropping branch, and the first dc voltage dropping branch 120 provides the dc voltage for the load in the first 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 provided by the present invention, the second-stage voltage-reducing circuit 200 includes a trigger control branch 210, a trigger branch 220, and a second dc voltage-reducing branch 230:
the first input terminal P51 of the trigger control branch 210 is connected to the output terminal P44 of the first dc step-down branch 120, and the second input terminal P52 of the trigger control branch 210 is grounded, so as to receive the stepped-down dc voltage output by the first dc step-down branch 120, and output the stepped-down dc voltage through the output terminal P53 of the trigger control branch 210 when the stepped-down dc voltage is greater than the standard voltage.
The first input terminal P61 of the triggering branch 220 is connected to the dc voltage input terminal P01, the first input terminal P31 of the determining branch 110 and the second input terminal P42 of the first dc step-down branch 120, and the second input terminal P62 of the triggering branch 220 is connected to the output terminal P53 of the triggering control branch 210, so that when the second input terminal P62 of the triggering branch 220 receives the stepped-down dc voltage, the stepped-down dc voltage input through the first input terminal P61 of the triggering branch 220 is output.
The first input terminal P71 of the second dc step-down branch 230 is connected to the output terminal P44 of the first dc step-down branch 120 and the first input terminal P51 of the trigger control branch 210, the second input terminal P72 of the second dc step-down branch 230 is connected to the output terminal P63 of the trigger branch 220, and the third input terminal P73 of the second dc step-down branch 230 is connected to ground.
In some embodiments of the present invention, the determining branch 110 includes a comparator D1, a positive input terminal of the comparator D1 is connected to the dc voltage input terminal, a negative input terminal of the comparator D1 is connected to the standard voltage input terminal, and a signal output terminal of the comparator D1 is connected to the first input terminal of the first dc step-down branch, 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.
It will be appreciated that the comparator D1 receives the dc voltage through its own positive input terminal and the reference voltage through its own negative input terminal. When the dc voltage is greater than the standard voltage, the 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 comparator D1 generates a first determination signal with a low level, and outputs the first determination signal to the first dc step-down branch 120 through the signal output terminal of the comparator D1.
In some embodiments, the first dc step-down branch 120 includes a first switch M1 and a first resistor R1.
The gate of the first switch tube M1 is connected to the signal output terminal of the comparator D1, the drain of the first switch tube M1 is connected to the dc voltage input terminal P01 and the positive input terminal of the comparator D1, and the source of the first switch tube M1 is connected to the first input terminal P51 of the trigger control branch 210.
One end of the first resistor R1 is connected to the source of the first switch M1 and the first input P51 of the trigger control branch 210, and the other end is grounded.
It can be understood that, when the dc voltage is greater than the standard voltage, the 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 the 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 voltage reduction processing through the self power consumption of the first resistor R1, so as to obtain the dc voltage after voltage reduction processing. When the dc voltage is less than or equal to the standard voltage, the comparator D1 generates and outputs a first determination signal of a low level, at this time, the gate of the first switch transistor M1 is at the low level, the first switch transistor M1 is turned off, and the dc step-down branch does not operate.
In some embodiments provided herein, the triggering branch 220 includes a capacitor C and a diode D2.
One end of the capacitor C is connected to the source of the first switch M1, the first resistor R1, and the first input terminal P71 of the second dc step-down branch 230, and the other end of the capacitor C is grounded.
The anode of the diode D2 is connected to the second input terminal P62 of the triggering branch 220, and the cathode of the diode D2 is connected to the capacitor C, the first resistor R1 and the source of the first switch transistor M1.
In this embodiment, the diode D2 is a reverse breakdown recoverable diode D2, and the voltage of the diode D2 is the standard voltage. After the first switch tube M1 is turned on, the first switch tube charges the capacitor C, but due to the capacitive reactance effect of the capacitor C, the pull-up node still maintains a low voltage, in the process of charging the capacitor C, along with the gradual increase of the electric quantity of the capacitor C, the voltage at the two ends of the capacitor C also gradually rises, and after the capacitor C is charged, the voltage at the two ends of the capacitor C is the reduced dc voltage. If the reduced DC voltage is greater than the standard voltage, the diode D2 is broken down in the reverse direction, and the reduced DC voltage is provided to the trigger circuit through the diode D2. If the reduced dc voltage is less than or equal to the standard voltage, the diode D2 cannot be broken down in the reverse direction, and no current passes through the diode D2.
In some embodiments, the trigger branch 220 includes a flip-flop D3, a set terminal of the flip-flop D3 is connected to the dc voltage input terminal P01, a positive input terminal of the comparator D1 and a drain of the first switching transistor M1, a control terminal of the flip-flop D3 is connected to a positive electrode of the diode D2, and a positive output terminal of the flip-flop D3 is connected to the second input terminal P72 of the second dc step-down branch 230.
In this embodiment, the flip-flop D3 is a rising edge flip-flop D3, when the diode D2 is broken down in the reverse direction, a signal received by the control terminal of the flip-flop D3 is raised from a low level signal to the reduced dc voltage, the flip-flop D3 is triggered, and a value of the set terminal is applied to the forward output terminal, that is, the reduced dc voltage is output through the forward output terminal of the flip-flop D3.
In some embodiments, the second dc voltage dropping branch 230 includes a second switch transistor M2 and a second resistor R2.
The gate of the second switch tube M2 is connected to the forward output terminal of the flip-flop D3, the drain of the second switch tube M2 is connected to the capacitor C, the first resistor R1, the source of the first switch tube M1 and the cathode of the diode D2, and the second switch tube M2 is connected to the second resistor R2.
One end of the second resistor R2 is connected to the source of the second switch M2, and the other end of the second resistor R2 is grounded.
In this embodiment, the resistance of the first resistor R1 is much larger than the resistance of the second resistor R2. When the flip-flop D3 outputs the stepped-down dc voltage to the second switching tube M2 through its own forward output terminal, the gate of the second switching tube M2 is at a high level, the second switching tube M2 is turned on, and the second dc step-down branch 230 steps down through the self consumption of the second resistor R2 to obtain the stepped-down dc voltage again. The resistance value of the first resistor R1 is much larger than that of the second resistor R2, so that the resistance value of the first resistor R1 and the second resistor R2 after being connected in parallel is approximately equal to that of the second resistor R2, and since the power consumption of the resistors is inversely proportional to the resistance, the power consumption in the first dc voltage reduction circuit and the second dc voltage reduction circuit increases sharply, at this time, the power provided by the driving circuit is mainly consumed by the first resistor R1 and the second resistor R2, so that the dc voltage after being reduced again is smaller than the normal working voltage range, the driving circuit stops working, and the problem that the driving chip is damaged due to the fact that the input dc voltage exceeds the withstand voltage value of the driving chip is avoided.
In some embodiments, the first switch tube M1 and the second switch tube M2 are both N-type switch tubes.
In some embodiments, the first switch transistor M1 and the second switch transistor M2 are both fets or triodes. In addition, a field effect transistor may be used as the first switching transistor M1, and a triode may be used as the second switching transistor M2; alternatively, a triode is used as the first switch transistor M1, and a field effect transistor is used as the second switch transistor M2.
In this embodiment, the dc input voltage Vin is an input voltage value (usually 12V) of the liquid crystal panel PCB, the standard voltage V1 is a withstand voltage limit value (usually 14V) of the driving chip on the PCB, and Vout is an actual input value of the driving circuit, and the PCB is supplied with the voltage for the driving circuit to operate. Typically, the second resistor R2 has a resistance of about 10 times the resistance of the first resistor R1-1The specific ratio of the second resistor R2 to the first resistor R1 should be set according to the circuit design. The first switch tube M1 and the second switch tube M2 are both N-type fets, and for an N-type fet, when its gate is at a high level, the N-type fet is turned on, and when its gate is at a low level, the N-type fet is turned off. For the comparator D1, when the voltage input to the positive input terminal is greater than the voltage input to the negative input terminal, the first determination signal generated and output by the comparator D1 is at a high level, and when the voltage input to the positive input terminal is less than or equal to the voltage input to or output from the negative input terminal, the first determination signal generated and output by the comparator D1 is at a low level. For the rising edge flip-flop D3, when its control terminal receives the rising edge of the signal, its set terminal is given its positive output terminal.
When the driving circuit works normally, 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 (typically 14V), and Vin < V1. At this time, the first determination signal output by the 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 diode D2 cannot be broken down, the control terminal of the flip-flop D3 has no signal input, the flip-flop D3 cannot be triggered, and the second switch tube M2 remains turned off.
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 more than V1, the first judgment signal output by the 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.
After the first switch M1 is turned on, the capacitor C is charged through the first switch M1, and due to the existence of the capacitor C, the cathode of the diode D2 is kept at a low level, and the second switch M2 is kept off. After the capacitor C is charged, the cathode voltage of the diode D2 is equal to the stepped-down dc voltage, the diode D2 is broken down in the reverse direction, at this time, a signal at the control end of the flip-flop D3 rises from a low-level voltage to the stepped-down dc voltage, the flip-flop D3 is triggered, a value at the set end of the flip-flop D3 is applied to the forward output end of the flip-flop, the stepped-down dc voltage is output through the forward output end of the flip-flop and is provided to the gate of the second switching tube M2, the second switching tube M2 is turned on, the first resistor R1 is connected in parallel with the second resistor R2, and at this time, the resistance value of the discharge resistor in the driving circuit is R1R 2/(R1+ R2). Because the resistance value of the second resistor R2 is much smaller than the resistance value of the first resistor R1, the current in the second resistor R2 is much larger than the current in the first resistor R1, at this time, the power of the driving circuit is mainly consumed by the first resistor R1 and the second resistor R2, the voltage of the driving circuit is rapidly reduced, the dc voltage after the voltage is reduced again is obtained, which is smaller than the normal operating voltage range, and the driving circuit stops operating.
Referring to fig. 3, in some embodiments provided by the present invention, the triggering branch 220 includes a flip-flop D3, a set terminal of the flip-flop D3 is connected to the dc voltage input terminal, a forward input terminal of the comparator D1 and a drain of the first switch transistor M1, a control terminal of the flip-flop D3 is connected to an anode of the diode D2, and a reverse output terminal of the flip-flop D3 is connected to the second input terminal of the second dc step-down branch 230.
The second dc step-down branch 230 includes a second switch M2 and a second resistor R2. The gate of the second switch tube M2 is connected to the forward output terminal of the flip-flop D3, and the source of the second switch tube M2 is connected to the capacitor C, the first resistor R1, the source of the first switch tube M1, and the cathode of the diode D2. One end of the second resistor R2 is connected with the drain of the second switch tube M2, and the other end is grounded.
The first switch tube M1 is an N-type switch tube, and the second switch tube M2 is a P-type switch tube.
It can be understood that when the diode D2 is broken down and the flip-flop D3 is triggered, the flip-flop D3 assigns the value of the set terminal to its inverted output terminal, and outputs a low-level trigger signal through its inverted output terminal, at this time, the P-type second switch transistor M2 is turned on, and the driving circuit discharges the driving circuit through the first resistor R1 and the second resistor R2 at the same time, so that the driving circuit stops operating.
Referring to fig. 4, in some embodiments of the present invention, the triggering branch 220 includes a trigger D3 and an inverter D4. The set end of the flip-flop D3 is connected to the dc voltage input end, the positive input end of the comparator D1, and the drain of the first switch transistor M1, the control end of the flip-flop D3 is connected to the anode of the diode D2, and the positive output end of the flip-flop D3 is connected to the second input end of the second dc step-down branch 230. The input end of the inverter D4 is connected with the positive output end of the trigger D3, and the output end of the inverter D4 is connected with the gate of the second switch tube M2.
The second dc step-down branch 230 includes the second switch transistor M2 and the second resistor R2. The gate of the second switch transistor M2 is connected to the output terminal of the inverter D4, and the drain of the second switch transistor M2 is connected to the capacitor C, the first resistor R1, the source of the first switch transistor M1, and the cathode of the diode D2. One end of the second resistor R2 is connected with the source of the second switch tube M2, and the other end is grounded.
The first switch tube M1 is an N-type switch tube, and the second switch tube M2 is a P-type switch tube.
It can be understood that when the diode D2 is broken down and the flip-flop D3 is triggered, the flip-flop D3 assigns a value of a set terminal to a forward output terminal thereof, outputs a high level trigger signal through the forward and reverse directions, and then performs a reverse processing on the high level trigger signal by using the inverter D4 to generate and output a low level trigger signal, at which time the P-type second switch tube M2 is turned on, and the driving circuit discharges the driving circuit through the first resistor R1 and the second resistor R2 at the same time, so as to stop the driving.
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. The driving circuit comprises a voltage reduction circuit and a switching circuit.
The first input end of the first-order step-down circuit 100 is connected to the dc voltage input end, and the second input end of the first-order step-down circuit 100 is connected to the standard voltage input end, and is configured to receive the dc voltage provided by the dc voltage input end through the first input end of the first-order step-down circuit 100, receive the standard voltage provided by the standard voltage input end through the second input end of the first-order step-down circuit 100, determine whether the dc voltage is greater than the standard voltage, and perform step-down processing on the dc voltage when the dc voltage is greater than the standard voltage.
A first input terminal of the second step-down circuit 200 is connected to an output terminal of the first step-down circuit, a second input terminal of the second step-down circuit 200 is connected to the first input terminal of the first step-down circuit 100 and the dc voltage input terminal, for judging whether the stepped-down dc voltage is greater than the standard voltage according to the stepped-down dc voltage received through the first input terminal of the second-stage step-down circuit 200, and when the reduced direct current voltage is greater than the standard voltage, controlling the second-order voltage reduction circuit 200 to reduce the reduced direct current voltage again by using the reduced direct current voltage received by the first input end of the second-order voltage reduction circuit 200 to obtain the reduced direct current voltage lower than the normal working voltage range, so that the driving circuit stops working.
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 (10)
1. A driver circuit, comprising:
a first-stage voltage reduction circuit, a first input end of which is connected to a dc voltage input end, and a second input end of which is connected to a standard voltage input end, for receiving the dc voltage provided by the dc voltage input end through the first input end of the first-stage voltage reduction circuit, receiving the standard voltage provided by the standard voltage input end through the second input end of the first-stage voltage reduction circuit, and determining whether the dc voltage is greater than the standard voltage, and when the dc voltage is greater than the standard voltage, performing voltage reduction processing on the dc voltage; and
the second-order voltage reduction circuit comprises a trigger control branch circuit, a trigger branch circuit and a second direct current voltage reduction branch circuit, and is used for judging whether the reduced direct current voltage is greater than the standard voltage according to the reduced direct current voltage received by the first input end of the second-order voltage reduction circuit, and when the reduced direct current voltage is greater than the standard voltage, controlling the second-order voltage reduction circuit to reduce the voltage of the reduced direct current voltage again by using the reduced direct current voltage received by the first input end of the second-order voltage reduction circuit, so as to obtain the reduced direct current voltage which is lower than the normal working voltage range, and enable the driving circuit to stop working;
wherein the content of the first and second substances,
the first input end of the trigger control branch circuit is connected with the output end of the first-order voltage reduction circuit, the second input end of the trigger control branch circuit is grounded, and the trigger control branch circuit is used for receiving the reduced direct-current voltage output by the first-order voltage reduction circuit through the first input end of the trigger branch circuit and outputting the reduced direct-current voltage through the output end of the trigger control branch circuit when the reduced direct-current voltage is greater than the standard voltage; the first input end of the trigger control branch circuit and the first input end of the second-stage voltage reduction circuit are the same input end;
the first input end of the trigger branch circuit is connected with the direct-current voltage input end and the first input end of the first-stage voltage reduction circuit, the second input end of the trigger branch circuit is connected with the output end of the trigger control branch circuit, and the trigger control branch circuit is used for outputting the reduced direct-current voltage input through the first input end of the trigger branch circuit when the second input end of the trigger branch circuit receives the reduced direct-current voltage;
the first input end of the second direct current voltage reduction branch circuit is connected with the output end of the first-order voltage reduction circuit and the first input end of the trigger control branch circuit, the second input end of the second direct current voltage reduction branch circuit is connected with the output end of the trigger branch circuit, and the third input end of the second direct current voltage reduction branch circuit is grounded.
2. The drive circuit of claim 1, wherein the first stage voltage-dropping circuit comprises:
a first input end of the judging branch is connected with the direct-current voltage input end and the first input end of the triggering branch, and a second input end of the judging branch 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 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 judgment branch, the third input end of the direct current voltage reduction branch is grounded, and the output end of the direct current voltage reduction branch is connected with the first input end of the trigger branch and the first input end of the second direct current voltage reduction branch, is 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 driving circuit according to claim 2, wherein the determining branch comprises a comparator, a positive input terminal of the comparator is connected to the dc voltage input terminal, a negative input terminal of the comparator is connected to the standard voltage input terminal, and a signal output terminal of the comparator is connected to the first input terminal of the first dc step-down branch, 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.
4. The driver circuit of claim 3, wherein the first DC down branch comprises:
a grid electrode of the first switch tube is connected with a signal output end of the 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 comparator, and a source electrode of the first switch tube is connected with a first input end of the trigger control 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 trigger control branch circuit, and the other end of the first resistor is grounded.
5. The drive circuit of claim 4, wherein the trigger branch comprises:
one end of the capacitor is connected with the source electrode of the first switching tube, the first resistor and the first input end of the second direct current step-down branch circuit, and the other end of the capacitor is grounded; and
and the anode of the diode is connected with the second input end of the trigger branch, and the cathode of the diode is connected with the capacitor, the first resistor and the source electrode of the first switching tube.
6. The driving circuit according to claim 5, wherein the trigger branch comprises a flip-flop, a set terminal of the flip-flop is connected to the dc voltage input terminal, a positive input terminal of the comparator, and a drain of the first switching tube, a control terminal of the flip-flop is connected to an anode of the diode, and a positive output terminal of the flip-flop is connected to the second input terminal of the second dc voltage-reducing branch.
7. The driving circuit of claim 6, wherein the second DC down branch comprises:
a grid electrode of the second switch tube is connected with a positive output end of the trigger, and a drain electrode of the second switch tube is connected with the capacitor, the first resistor, a source electrode of the first switch tube and a cathode of the diode; and
and one end of the second resistor is connected with the source electrode of the second switch tube, and the other end of the second resistor is grounded.
8. The driving circuit as claimed in claim 7, wherein the first switch tube and the second switch tube are N-type switch tubes.
9. The drive circuit of claim 7, wherein the trigger branch comprises:
the position end of the trigger is connected with the direct-current voltage input end, the positive input end of the comparator and the drain electrode of the first switching tube, the control end of the trigger is connected with the anode of the diode, and the positive output end of the trigger is connected with the second input end of the second direct-current voltage reduction branch; and
and the input end of the phase inverter is connected with the positive output end of the trigger, and the output end of the phase inverter is connected with the grid electrode of the second switching tube.
10. 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:
a first-stage voltage reduction circuit, a first input end of which is connected to a dc voltage input end, and a second input end of which is connected to a standard voltage input end, for receiving the dc voltage provided by the dc voltage input end through the first input end of the first-stage voltage reduction circuit, receiving the standard voltage provided by the standard voltage input end through the second input end of the first-stage voltage reduction circuit, and determining whether the dc voltage is greater than the standard voltage, and when the dc voltage is greater than the standard voltage, performing voltage reduction processing on the dc voltage; and
the second-order voltage reduction circuit comprises a trigger control branch circuit, a trigger branch circuit and a second direct current voltage reduction branch circuit, and is used for judging whether the reduced direct current voltage is greater than the standard voltage according to the reduced direct current voltage received by the first input end of the second-order voltage reduction circuit, and when the reduced direct current voltage is greater than the standard voltage, controlling the second-order voltage reduction circuit to reduce the voltage of the reduced direct current voltage again by using the reduced direct current voltage received by the first input end of the second-order voltage reduction circuit, so as to obtain the reduced direct current voltage which is lower than the normal working voltage range, and enable the driving circuit to stop working;
wherein the content of the first and second substances,
the first input end of the trigger control branch circuit is connected with the output end of the first-order voltage reduction circuit, the second input end of the trigger control branch circuit is grounded, and the trigger control branch circuit is used for receiving the reduced direct-current voltage output by the first-order voltage reduction circuit through the first input end of the trigger branch circuit and outputting the reduced direct-current voltage through the output end of the trigger control branch circuit when the reduced direct-current voltage is greater than the standard voltage; the first input end of the trigger control branch circuit and the first input end of the second-stage voltage reduction circuit are the same input end;
the first input end of the trigger branch circuit is connected with the direct-current voltage input end and the first input end of the first-stage voltage reduction circuit, the second input end of the trigger branch circuit is connected with the output end of the trigger control branch circuit, and the trigger control branch circuit is used for outputting the reduced direct-current voltage input through the first input end of the trigger branch circuit when the second input end of the trigger branch circuit receives the reduced direct-current voltage;
the first input end of the second direct current voltage reduction branch circuit is connected with the output end of the first-order voltage reduction circuit and the first input end of the trigger control branch circuit, the second input end of the second direct current voltage reduction branch circuit is connected with the output end of the trigger branch circuit, and the third input end of the second direct current voltage reduction branch circuit is grounded.
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| CN110335571A (en) * | 2019-06-27 | 2019-10-15 | 惠科股份有限公司 | A kind of driving device, driving method and display panel |
| CN114267300A (en) * | 2021-12-13 | 2022-04-01 | 江西合力泰科技有限公司 | Light source split type liquid crystal display management system |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101447738A (en) * | 2008-12-29 | 2009-06-03 | 重庆航天工业公司 | Flameproof intrinsically safe power supply device |
| 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 |
| CN105788556A (en) * | 2016-05-20 | 2016-07-20 | 深圳市华星光电技术有限公司 | Overvoltage protection circuit and method and liquid crystal drive circuit |
| CN107204613A (en) * | 2017-08-04 | 2017-09-26 | 郑州云海信息技术有限公司 | A kind of over-pressure safety device and method |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007074794A (en) * | 2005-09-06 | 2007-03-22 | Rohm Co Ltd | Overcurrent protective circuit, load driving unit, motor driving unit, electrical equipment, and power unit |
| JP6122257B2 (en) * | 2012-07-04 | 2017-04-26 | ローム株式会社 | DC / DC converter and control circuit thereof, power supply using the same, power adapter, and electronic device |
-
2018
- 2018-12-03 CN CN201811465455.5A patent/CN109493817B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101447738A (en) * | 2008-12-29 | 2009-06-03 | 重庆航天工业公司 | Flameproof intrinsically safe power supply device |
| 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 |
| CN105788556A (en) * | 2016-05-20 | 2016-07-20 | 深圳市华星光电技术有限公司 | Overvoltage protection circuit and method and liquid crystal drive circuit |
| CN107204613A (en) * | 2017-08-04 | 2017-09-26 | 郑州云海信息技术有限公司 | A kind of over-pressure safety device and method |
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