CN109686322B - Switching circuit and backlight driving circuit - Google Patents
Switching circuit and backlight driving circuit Download PDFInfo
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- CN109686322B CN109686322B CN201910121102.1A CN201910121102A CN109686322B CN 109686322 B CN109686322 B CN 109686322B CN 201910121102 A CN201910121102 A CN 201910121102A CN 109686322 B CN109686322 B CN 109686322B
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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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- 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
- G09G3/3406—Control of illumination source
Abstract
The invention discloses a switching circuit and a backlight driving circuit, wherein the switching circuit comprises: the on-off of the switch circuit is controlled by the switch tube, and the switch circuit is used for receiving input voltage and is conducted through the switch tube to provide first output voltage according to the input voltage; the enabling circuit is used for receiving the input voltage and generating an enabling signal when the input voltage is greater than a preset voltage value; the voltage reduction circuit is connected with the enabling circuit and used for providing a second output voltage according to the input voltage and the sampling signal when receiving the enabling signal; the sampling circuit is connected with the voltage reduction circuit and is used for sampling the second output voltage to provide a sampling signal; and the boosting circuit is respectively connected with the voltage reduction circuit and the switch circuit and used for providing boosting voltage according to the second output voltage when receiving the second output voltage, switching off the switch tube through the boosting voltage, enlarging the input voltage range of the switching circuit and realizing neutral-free switching when the input voltage changes.
Description
Technical Field
The invention relates to the technical field of liquid crystal display, in particular to a switching circuit and a backlight driving circuit.
Background
Liquid crystal display devices have the advantages of being light, thin, energy-saving, low in power consumption and the like, and have been widely used in electronic devices such as televisions, computers, mobile phones and the like. The liquid crystal display device as a passive display device needs a driving circuit to supply power to a backlight lamp, an adapter or a battery is used to supply power to the driving circuit at present, and a switching circuit needs to be added in front of the driving circuit because the voltage of the adapter and the voltage of the battery are different.
Fig. 1 shows a schematic structure of a conventional switching circuit, and as shown in fig. 1, the switching circuit 100 includes a first enabling circuit 110, a load switch circuit 120, a second enabling circuit 130, a voltage dropping circuit 140, and a sampling circuit 150.
The load switch circuit 120 includes a load switch chip 121 and peripheral circuits connected thereto, wherein the load switch chip 121 may use a single-channel load switch chip TPS 22810. The buck circuit 140 includes a buck conversion chip 141 and peripheral circuits connected thereto, where the buck conversion chip 141 may use a synchronous buck conversion chip TPS 54202.
The first enable circuit 110 includes a voltage divider circuit formed by a first resistor R1 and a second resistor R2, a third resistor R3, a fourth resistor R4, and a first switch transistor M1. The first resistor R1 and the second resistor R2 are connected in series between the input voltage Vin and ground. The fourth resistor R4 and the first switch tube M1 are connected in series between the power supply voltage Vcc and the ground, one end of the third resistor R3 is connected to the intermediate node between the first resistor R1 and the second resistor R2, the other end of the third resistor R3 is connected to the control end of the first switch tube M1, and the first pass end of the first switch tube M1 and the intermediate node between the fourth resistor R4 are connected to the enable end EN of the load switch chip 121 for providing the first enable signal.
The second enable circuit 130 includes a seventh resistor R7 and an eighth resistor R8 connected in series between the input voltage Vin and ground, and an intermediate node of the seventh resistor R7 and the eighth resistor R8 is connected to the enable terminal EN of the buck conversion chip 141, for dividing the input voltage Vin to obtain a second enable signal.
The sampling circuit 150 includes a ninth resistor R9 and a tenth resistor R10 connected in series between the output terminal of the buck conversion chip 141 and ground, and an intermediate node of the ninth resistor R9 and the tenth resistor R10 is connected to the feedback terminal FB of the buck conversion chip 141.
The switching circuit 100 of the prior art includes a first enabling circuit 110 and a second enabling circuit 130, and selects whether to pass through the load switch circuit 120 or the voltage dropping circuit 140 by performing resistance voltage division on the input voltage Vin, and the input voltage when the load switch circuit 120 operates is smaller than the input voltage when the voltage dropping circuit 140 operates. However, with the switching circuit 100 of the prior art, the starting voltages of the load switch chip 121 and the buck conversion chip 141 cause the resistance divided voltage to be in a neutral position in the middle area; and the maximum withstand voltage exists at the power voltage input terminal VIN of the load switch chip 121, and the maximum withstand voltage is smaller than the maximum value of the existing specification range of the input voltage of the switching circuit, so that the load switch chip 121 limits the input voltage range of the voltage reduction circuit 140 during operation, that is, the input voltage range of the switching circuit 100 is limited.
Therefore, there is a need for an improved switching circuit of the prior art to increase the input voltage range of the switching circuit and to achieve a neutral-less switching when the input voltage varies.
Disclosure of Invention
In view of the above, an object of the present invention is to provide a switching circuit and a backlight driving circuit including the same, which can increase an input voltage range of the switching circuit and realize a non-neutral switching when the input voltage varies.
According to an aspect of the present invention, there is provided a switching circuit including: the on-off of the switch circuit is controlled by a switch tube, and the switch circuit is used for receiving input voltage and is conducted through the switch tube to provide first output voltage according to the input voltage;
the enabling circuit is used for receiving the input voltage and generating an enabling signal when the input voltage is greater than a preset voltage value;
the voltage reduction circuit is connected with the enabling circuit and used for providing a second output voltage according to the input voltage and the sampling signal when receiving the enabling signal;
the sampling circuit is connected with the voltage reduction circuit and is used for sampling the second output voltage to provide the sampling signal; and the number of the first and second groups,
and the boosting circuit is respectively connected with the voltage reduction circuit and the switch circuit and used for providing boosting voltage according to the second output voltage and switching off the switch tube through the boosting voltage when receiving the second output voltage.
Optionally, the switching circuit comprises:
the first resistor, the first diode and the second resistor are connected in series between the input voltage and the control end of the switch tube, the anode of the first diode is connected with the first resistor, and the cathode of the first diode is connected with the second resistor;
and the third resistor, the first capacitor and the second capacitor are connected between the control end of the switching tube and the ground in parallel.
Optionally, the enabling circuit comprises:
a fourth resistor and a fifth resistor connected in series between the input voltage and ground, an intermediate node of the fourth resistor and the fifth resistor providing the enable signal.
Optionally, the voltage reduction circuit includes:
a third capacitor;
a power supply voltage input end of the buck conversion chip receives the input voltage, an enable signal end is connected with the enable circuit to receive the enable signal, a feedback signal input end receives the sampling signal, and a first output end and a second output end are connected through the third capacitor;
and the first end of the inductance coil is connected with the second output end of the voltage reduction conversion chip, and the second end of the inductance coil provides the second output voltage.
Optionally, the sampling circuit comprises:
and the sixth resistor and the seventh resistor are connected between the second end of the inductance coil and the ground in series, and a node between the sixth resistor and the seventh resistor is connected with a feedback signal input end of the buck conversion chip to provide the sampling signal.
Optionally, the boost circuit comprises:
the second diode and the third diode are connected between the second end of the inductance coil and the control end of the switch tube in series, the anode of the second diode is connected with the second end of the inductance coil, and the cathode of the third diode is connected with the control end of the switch tube;
and the fourth capacitor is connected between a node between the second diode and the third diode and the second output end of the buck conversion chip in series.
Optionally, the method further comprises: a first output circuit connected to the switching circuit for outputting the first output voltage provided by the switching circuit; and/or the presence of a gas in the gas,
and the second output circuit is connected to the voltage reduction circuit and used for outputting the second output voltage of the voltage reduction circuit.
Optionally, the first output circuit comprises:
and a fifth capacitor, wherein a first end of the fifth capacitor is connected with the ground, and a second end of the fifth capacitor is connected with a node between the input end and the output end of the first output circuit.
Optionally, the second output circuit comprises:
the anode of the fourth diode is connected with the input end of the second output circuit, and the cathode of the fourth diode is connected with the output end of the second output circuit;
and a first end of the sixth capacitor is connected with the ground, and a second end of the sixth capacitor is connected with a node between the fourth diode and the voltage reduction circuit.
According to another aspect of the present invention, there is provided a backlight driving circuit including: the switching circuit and the rear-stage driving circuit are connected with the switching circuit, and the driving circuit receives the output voltage provided by the switching circuit and drives backlight display according to the output voltage.
The switching circuit and the backlight driving circuit have the advantages that when the voltage reduction circuit is started, the boost circuit provides boost voltage, and the switching tube is turned off through the boost voltage to cut off the switching circuit, so that the switching without neutral in a middle area is realized. In addition, for the switching circuit provided by the invention, the on-off of the switching circuit is controlled by the switching tube, the switching tube is conducted to provide the first output voltage according to the input voltage, and the switching tube can normally work under the maximum voltage in the existing specification range of the input voltage, so that the input voltage range of the switching circuit is not limited by the maximum bearing voltage of the load switch chip any more, and the input voltage range of the switching circuit is enlarged.
Drawings
The above and other objects, features and advantages of the present invention will become more apparent from the following description of the embodiments of the present invention with reference to the accompanying drawings.
Fig. 1 shows a schematic diagram of a conventional switching circuit;
FIG. 2 is a schematic diagram of a switching circuit according to an embodiment of the present invention;
FIG. 3 shows a circuit schematic of a switching circuit of an embodiment of the invention;
FIG. 4 is a circuit diagram illustrating an output voltage test of a switching circuit according to an embodiment of the present invention at a low input voltage;
FIG. 5 is a graphical illustration of a display interface of the output voltage measured by the test circuit diagram of FIG. 4;
FIG. 6 shows a circuit diagram for testing the output voltage of the switching circuit at high input voltages according to an embodiment of the present invention;
FIG. 7 is a display interface diagram of the output voltage measured by the test circuit diagram shown in FIG. 6.
Detailed Description
The invention will be described in more detail below with reference to the accompanying drawings. Like elements in the various figures are denoted by like reference numerals. For purposes of clarity, the various features in the drawings are not necessarily drawn to scale. Moreover, certain well-known elements may not be shown in the figures.
In the following description, numerous specific details of the invention, such as structure, materials, dimensions, processing techniques and techniques of components, are set forth in order to provide a more thorough understanding of the invention. However, as will be understood by those skilled in the art, the present invention may be practiced without these specific details.
Fig. 2 shows a schematic structural diagram of a switching circuit 200 according to the present invention, and as shown in fig. 2, the switching circuit 200 according to the present invention includes a switching circuit 210, an enabling circuit 220, a voltage dropping circuit 230, a sampling circuit 240, and a voltage boosting circuit 250.
The on/off of the switch circuit 210 is controlled by a switch tube, and the switch circuit 210 is used for receiving an input voltage Vin and is conducted through the switch tube to provide a first output voltage according to the input voltage Vin.
The enable circuit 220 is configured to receive an input voltage Vin and generate an enable signal when the input voltage Vin is greater than a preset voltage value; the voltage reduction circuit 230 is connected to the enable circuit 220, and is configured to provide a second output voltage according to the input voltage Vin and the sampling signal when receiving the enable signal; a sampling circuit 240 connected to the voltage-reducing circuit 230 for sampling the second output voltage to provide a sampling signal; and the boost circuit 250 is respectively connected with the buck circuit 230 and the switch circuit 210, and is configured to provide a boost voltage according to the second output voltage when receiving the second output voltage, and turn off the switch tube through the boost voltage, so that the switch circuit 210 cannot provide the first output voltage.
Fig. 3 shows a circuit schematic diagram of a switching circuit according to an embodiment of the present invention, and as shown in fig. 3, the voltage-reducing circuit 230 includes a voltage-reducing conversion chip 231 and a peripheral circuit connected thereto, where the voltage-reducing conversion chip 231 may use a synchronous voltage-reducing conversion chip TPS 54202. Of course, the buck converter chip 231 of the present invention is not limited thereto, and those skilled in the art can select the type of the chip according to specific situations.
The switching circuit 210 includes: a first resistor R1, a first diode D1 and a second resistor R2 which are connected in series between the input voltage Vin and the control end of the switch tube M1, wherein the anode of the first diode D1 is connected with the first resistor R1, and the cathode of the first diode D1 is connected with the second resistor R2; and a third resistor R3, a first capacitor C1 and a second capacitor C2 which are connected in parallel between the control end of the switching tube M1 and the ground.
The enable circuit 220 includes: the fourth resistor R4 and the fifth resistor R5 are connected in series between the input voltage Vin and the ground, and an enable signal is provided at the middle node of the fourth resistor R4 and the fifth resistor R5.
The voltage-reducing circuit 230 includes: a third capacitance C3; the buck conversion chip 231, a power voltage input terminal VIN of the buck conversion chip 231 receives the input voltage VIN, an enable signal terminal EN is connected to the enable circuit 220 to receive an enable signal, a feedback signal input terminal FB receives a sampling signal, and a first output terminal BOOT and a second output terminal SW are connected via a third capacitor C3; and an inductor L1, wherein a first terminal of the inductor L1 is connected to the second output terminal SW of the buck converter 231, and a second terminal thereof provides a second output voltage.
The sampling circuit 240 includes: a sixth resistor R6 and a seventh resistor R7 connected in series between the second end of the inductor L1 and the ground, and a node between the sixth resistor R6 and the seventh resistor R7 is connected with the feedback signal input end of the buck conversion chip to provide a sampling signal.
The booster circuit 250 includes: a second diode D2 and a third diode D3 connected in series between the second end of the inductor L1 and the control end of the switch tube M1, wherein the anode of the second diode D2 is connected with the second end of the inductor L1, and the cathode of the third diode D3 is connected with the control end of the switch tube M1; and the fourth capacitor C4 is connected in series between the node between the second diode D2 and the third diode D3 and the second output end of the buck conversion chip. The boost circuit 250 boosts the second output voltage twice, and the boost voltage is higher than the input voltage Vin by combining with the synchronous buck conversion chip TPS54202, so that the switching tube is in an off state, and the switching circuit is turned off.
The switching circuit 200 further includes: and a first output circuit 260 connected to the switching circuit 210 for outputting the first output voltage provided by the switching circuit 210.
The first output circuit 260 includes: a fifth capacitor C5, a first terminal of the fifth capacitor C5 is connected to ground, and a second terminal is connected to a node between the input terminal and the output terminal of the first output circuit 260.
The switching circuit 200 further includes: and a second output circuit 270 connected to the step-down circuit 230 for outputting the second output voltage provided by the step-down circuit 230.
The second output circuit 270 includes: a fourth diode D4, wherein the anode of the fourth diode D4 is connected to the input terminal of the second output circuit 270, and the cathode is connected to the output terminal of the second output circuit 270; a sixth capacitor C6, a first terminal of the sixth capacitor C6 is connected to ground, and a second terminal is connected to a node between the fourth diode D4 and the step-down circuit 230.
For example, in the case where the switching transistor M1 is a P-type MOS transistor: if the input voltage Vin is not greater than the predetermined voltage value, the gate voltage of the P-type MOS transistor is lower than the source voltage due to the voltage division among the first resistor R1, the second resistor R2 and the third resistor R3, so that the P-type MOS transistor operates and the switching circuit 210 is turned on to provide the first output voltage; if the input voltage Vin is greater than the preset voltage value, the enabling circuit 220 generates an enabling signal, the buck conversion chip 231 is started, the buck circuit 230 provides the second output voltage, the boost circuit 250 performs double boosting on the second output voltage to obtain a boosted voltage, the boosted voltage is greater than the input voltage, so that the gate voltage of the P-type MOS transistor is higher than the source voltage, therefore, the P-type MOS transistor does not work, and the switch circuit 210 is switched off.
In the case of the preset voltage value of the present invention being 12V:
(1) fig. 4 is a circuit diagram illustrating the output voltage test of the switching circuit 210 with the input voltage Vin being 12V, fig. 5 is a display interface diagram illustrating the output voltage measured by the circuit diagram illustrated in fig. 4, and it can be seen from fig. 5 that the output voltage is 12V, that is, the switching circuit 210 is turned on to provide the first output voltage.
(2) Fig. 6 is a circuit diagram showing the test of the output voltage of the switching circuit 210 with the input voltage Vin being 21V, fig. 7 is a display interface diagram of the output voltage measured by the test circuit diagram shown in fig. 6, and it can be seen from fig. 7 that the output voltage is 1.084mV, that is, the switching circuit 210 is turned off and does not provide the output voltage, and the switching circuit is provided with the second output voltage by the voltage-dropping circuit 230.
According to another aspect of the present invention, a backlight driving circuit is provided, which includes the above switching circuit and a subsequent driving circuit connected thereto, and the driving circuit is configured to receive an output voltage provided by the switching circuit and drive a backlight display according to the output voltage.
In summary, the present invention improves the first enabling circuit 110 and the load switch circuit 120 of the conventional switching circuit in fig. 1, and provides a novel switching circuit. In the switching circuit provided by the invention, when the input voltage can not start the buck conversion chip 231, the switching circuit 210 provides a first output voltage; the second output voltage is provided by the voltage-dropping circuit 230 when the input voltage increases to enable the buck converter chip 231.
The switching circuit provided by the invention can provide the boost voltage by the boost circuit when the voltage reduction circuit is started, and the switching tube is switched off by the boost voltage to cut off the switching circuit, so that the switching without the neutral position of the middle area is realized. In addition, for the switching circuit provided by the present invention, the on/off of the switching circuit is controlled by the switching tube, and the switching tube is turned on to provide the first output voltage according to the input voltage, and because the switching tube can work normally under the maximum voltage in the existing specification range of the input voltage, the switching tube does not limit the input voltage range when the step-down circuit 230 works, that is, the switching circuit can work under any voltage in the existing specification range of the input voltage, thereby increasing the input voltage range of the switching circuit.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.
While embodiments in accordance with the invention have been described above, these embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments described. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. The invention is limited only by the claims and their full scope and equivalents.
Claims (10)
1. A switching circuit, comprising:
the on-off of the switch circuit is controlled by a switch tube, the switch circuit is used for receiving an input voltage and is conducted through the switch tube to provide a first output voltage according to the input voltage, the input end of the switch tube receives the input voltage, and the control end of the switch tube is connected with the voltage division output end of the input voltage;
the enabling circuit is used for receiving the input voltage and generating an enabling signal when the input voltage is greater than a preset voltage value;
the voltage reduction circuit is connected with the enabling circuit and used for providing a second output voltage according to the input voltage and the sampling signal when receiving the enabling signal;
the sampling circuit is connected with the voltage reduction circuit and is used for sampling the second output voltage to provide the sampling signal; and the number of the first and second groups,
and the boosting circuit is respectively connected with the voltage reduction circuit and the switch circuit and used for providing a boosting voltage higher than the input voltage according to the second output voltage when receiving the second output voltage, and inputting the boosting voltage to the control end of the switch tube so as to switch off the switch tube through the boosting voltage.
2. The switching circuit of claim 1, wherein the switching circuit comprises:
the first resistor, the first diode and the second resistor are connected in series between the input voltage and the control end of the switch tube, the anode of the first diode is connected with the first resistor, and the cathode of the first diode is connected with the second resistor;
and the third resistor, the first capacitor and the second capacitor are connected between the control end of the switching tube and the ground in parallel.
3. The switching circuit of claim 1, wherein the enabling circuit comprises:
a fourth resistor and a fifth resistor connected in series between the input voltage and ground, an intermediate node of the fourth resistor and the fifth resistor providing the enable signal.
4. The switching circuit of claim 1, wherein the voltage-reduction circuit comprises:
a third capacitor;
a power supply voltage input end of the buck conversion chip receives the input voltage, an enable signal end is connected with the enable circuit to receive the enable signal, a feedback signal input end receives the sampling signal, and a first output end and a second output end are connected through the third capacitor;
and the first end of the inductance coil is connected with the second output end of the voltage reduction conversion chip, and the second end of the inductance coil provides the second output voltage.
5. The switching circuit of claim 4, wherein the sampling circuit comprises:
and the sixth resistor and the seventh resistor are connected between the second end of the inductance coil and the ground in series, and a node between the sixth resistor and the seventh resistor is connected with a feedback signal input end of the buck conversion chip to provide the sampling signal.
6. The switching circuit of claim 4, wherein the boost circuit comprises:
the second diode and the third diode are connected between the second end of the inductance coil and the control end of the switch tube in series, the anode of the second diode is connected with the second end of the inductance coil, and the cathode of the third diode is connected with the control end of the switch tube;
and the fourth capacitor is connected between a node between the second diode and the third diode and the second output end of the buck conversion chip in series.
7. The switching circuit of claim 1, further comprising: a first output circuit connected to the switching circuit for outputting the first output voltage provided by the switching circuit; and/or the presence of a gas in the gas,
and the second output circuit is connected to the voltage reduction circuit and used for outputting the second output voltage provided by the voltage reduction circuit.
8. The switching circuit of claim 7, wherein the first output circuit comprises:
and a fifth capacitor, wherein a first end of the fifth capacitor is connected with the ground, and a second end of the fifth capacitor is connected with a node between the input end and the output end of the first output circuit.
9. The switching circuit of claim 7, wherein the second output circuit comprises:
the anode of the fourth diode is connected with the input end of the second output circuit, and the cathode of the fourth diode is connected with the output end of the second output circuit;
and a first end of the sixth capacitor is connected with the ground, and a second end of the sixth capacitor is connected with a node between the fourth diode and the voltage reduction circuit.
10. A backlight driving circuit, comprising:
the switching circuit of any one of claims 1-9, and
and the driving circuit receives the output voltage provided by the output end of the switching circuit and drives backlight display according to the output voltage.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910121102.1A CN109686322B (en) | 2019-02-19 | 2019-02-19 | Switching circuit and backlight driving circuit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910121102.1A CN109686322B (en) | 2019-02-19 | 2019-02-19 | Switching circuit and backlight driving circuit |
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| CN109686322A CN109686322A (en) | 2019-04-26 |
| CN109686322B true CN109686322B (en) | 2021-11-23 |
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| CN109686322A (en) | 2019-04-26 |
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