KR20120073705A - Dc-dc converter and display device including the same - Google Patents

Abstract

PURPOSE: A DC-DC converter and a display device including the same are provided to reduce a switching loss by preventing an over voltage and an over current of a switch using a protection circuit. CONSTITUTION: One side terminal of an input voltage(Vin) is connected to one side of a first inductor(L1). The other side of the first inductor is connected to a drain electrode(D) and one side of a second inductor(L2). The one side of the second inductor is connected to a first electrode of an output capacitor and a first electrode of a first diode(D1). The other side of the second inductor is connected to a first electrode of a second capacitor(C2) and a first electrode of a fourth diode(D4). A second electrode of the output capacitor is connected to a second electrode of a first capacitor(C1) and a second electrode of a third capacitor(C3).

Description

DC-DC converter and display device including the same}

The present invention relates to a DC-DC converter, and more particularly, to a DC-DC converter and a display device including the same.

As the information society develops, the demand for display devices for displaying images is increasing in various forms. Recently, liquid crystal displays (LCDs), plasma display panels (PDPs), organic fields Various flat display devices such as organic light emitting diodes (OLEDs) are being utilized.

These flat panel displays include a DC-DC converter to stably supply voltages for driving the display panel and various driving units.

In this case, the conventional DC-DC converter has a switching loss caused by the overlap of the voltage and the current at the time of turn-on and turn-off of the switch, and furthermore, when operating at a higher driving frequency, the switching loss is proportionally increased.

In addition, the increase of the driving frequency as described above has a problem of causing interference between electronic equipment due to the change amount of current (di / dt) and the change amount of voltage (dv / dt).

The problem is to reduce the switching loss caused by the overlap of voltage and current in the switch during turn-on and turn-off of a DC-DC converter operating at a high driving frequency.

In addition, there is a problem in reducing the EMI effect.

In order to achieve the above object, the present invention, the switch; And a protection circuit unit for reducing a loss of the switch, wherein the protection circuit unit includes first and second capacitors and first to third diodes, and the first electrode of the first capacitor is formed of the first diode. A second electrode, connected to a first electrode of the second diode, and a second electrode of the second capacitor is connected to a second electrode of the second diode, a first electrode of a third diode, and the first electrode The first electrode of the diode is connected to the drain electrode of the switch, the second electrode of the first diode is connected to the first electrode of the second diode, and the second electrode of the second diode is of the third diode. Provided is a DC-DC converter connected with a first electrode.

The DC-DC converter further includes first and second inductors and an output capacitor, wherein the first inductor and the second inductor are connected to each other to form an autotransformer, and the first electrode of the output capacitor is One side of the first inductor and the second inductor, a drain electrode of the switch, a first electrode of the first diode, a second electrode of the output capacitor, a source electrode of the switch, The first electrode of the two capacitors is connected to the other side of the second inductor.

Further comprising a third capacitor and a fourth diode, wherein the first electrode of the fourth diode is connected to the other side of the second inductor, the second electrode of the second capacitor, the second electrode of the fourth diode The first electrode of the third capacitor is connected to the second electrode of the third diode, and the second electrode of the third diode is connected to the first electrode of the third capacitor.

A flat panel display comprising a display panel for displaying an image, the flat panel display comprising: a switch and a protection circuit to reduce the loss of the switch, wherein the protection circuit includes first and second capacitors and first to third diodes. Wherein the first electrode of the first capacitor is connected to the second electrode of the first diode and the first electrode of the second diode, and the second electrode of the second capacitor is the first electrode of the second diode. A second electrode, a first electrode of the third diode, a first electrode of the first diode is connected to a drain electrode of the switch, and a second electrode of the first diode is a first electrode of the second diode And a second electrode of the second diode is connected to the first electrode of the third diode.

The DC-DC converter further includes first and second inductors and an output capacitor, wherein the first inductor and the second inductor are connected to each other to form an autotransformer, and the first electrode of the output capacitor is One side of the first inductor and the second inductor, a drain electrode of the switch, a first electrode of the first diode, a second electrode of the output capacitor, a source electrode of the switch, The first electrode of the two capacitors is connected to the other side of the second inductor.

Further comprising a third capacitor and a fourth diode, wherein the first electrode of the fourth diode is connected to the other side of the second inductor, the second electrode of the second capacitor, the second electrode of the fourth diode The first electrode of the third capacitor is connected to the second electrode of the third diode, and the second electrode of the third diode is connected to the first electrode of the third capacitor.

When the DC-DC converter operating at a high driving frequency is turned on and off, there is an effect to reduce the switching loss caused by the overlap of the voltage and current in the switch.

In addition, there is an effect of reducing the EMI effect.

1 is a schematic cross-sectional view showing a flat panel display device according to an embodiment of the present invention.
2 is an equivalent circuit diagram of a pixel according to an embodiment of the present invention.
3 is a schematic cross-sectional view showing a DC-DC converter according to an embodiment of the present invention.
4 is a schematic cross-sectional view showing the duty ratio.
5 and 6 are cross-sectional views schematically showing types of DC-DC converters.
7 is a schematic cross-sectional view of a circuit of a DC-DC converter according to an embodiment of the present invention.
8 is a circuit diagram illustrating an operation at turn-on of a DC-DC converter according to an embodiment of the present invention.
9 is a circuit diagram illustrating an operation of turning off a DC-DC converter according to an embodiment of the present invention.
10 is a waveform diagram of a voltage and a current applied to a switch at turn-on and turn-off of the DC-DC converter.
11 shows driving simulation results of a general DC-DC converter.
12 is a driving simulation result of the DC-DC converter according to the embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is a view schematically showing a flat panel display device according to an embodiment of the present invention, Figure 2 is an equivalent circuit diagram of a pixel according to an embodiment of the present invention.

First, for convenience of description, the liquid crystal display device 100 of the flat panel display device 100 will be described as an example.

As shown, the liquid crystal display device 100 according to the exemplary embodiment of the present invention includes a display panel 200 and a driving circuit unit 300.

In the display panel 200, a plurality of gate lines GL extend in a first direction, for example, in a row direction. The plurality of data lines DL extend in the second direction, for example, the column direction, which intersects the first direction. As described above, the plurality of gate lines GL and the plurality of data lines DL that cross each other define a plurality of pixels P arranged in a matrix form.

Referring to FIG. 2, each pixel P includes a thin film transistor T, a pixel electrode, a common electrode, a liquid crystal capacitor Clc, and a storage capacitor Cst.

The thin film transistor T is formed at the intersection of the gate line GL and the data line DL. The thin film transistor T is connected to the pixel electrode. Meanwhile, a common electrode is formed corresponding to the pixel electrode. When a data voltage is applied to the pixel electrode and a common voltage is applied to the common electrode, an electric field is formed therebetween to drive the liquid crystal. The pixel electrode, the common electrode, and the liquid crystal positioned between these electrodes constitute a liquid crystal capacitor Clc. Meanwhile, a storage capacitor Cst is further configured in each pixel P, which serves to store the data voltage applied to the pixel electrode until the next frame.

Each pixel P may be configured of, for example, R, G, and B subpixels representing red, green, and blue. In other words, the neighboring R, G, and B subpixels constitute a pixel which is a unit of video display.

The backlight 800 serves to supply light to the liquid crystal panel 200. As the backlight 800, a Cold Cathode Fluorescent Lamp (CCFL), an External Electrode Fluorescent Lamp (EEFL), a Light Emitting Diode (LED), or the like may be used.

The driving circuit unit D may include a timing controller 300, a gate driver 400, a data driver 500, a power generator 600, and a gamma voltage supply unit 700.

Here, the timing controller 300 may enable the image data signal RGB, the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, the clock signal CLK, and the data enable from an external system such as a TV system or a video card. The control signal TCS, such as the signal DE, is received. Although not shown, such signals may be input through an interface configured in the timing controller 300.

The timing controller 300 uses the input control signal TCS to output a gate control signal GCS for controlling the gate driver 400 and a data control signal DCS for controlling the data driver 500. Create The gate control signal GCS includes a gate start pulse (GSP), a gate shift clock (GSC), a gate output enable signal (GOE), and the like.

The data control signal (DCS) includes a source start pulse (SSP), a source sampling clock (SSC), a source output enable signal (SOE), and a polarity signal (POL). It may include.

The gate start pulse (GSP) informs the start line of the screen, that is, the first line, among the 1 vertical, and the gate shift clock (GSC) is a thin film transistor configured in the pixel (P) of the display panel 200. It designates the time (T of FIG. 2) turns on. In addition, the gate output enable signal GOE controls the output of the gate driver 400.

The source start pulse SSP informs the start point of the data, that is, the first pixel P, in one horizontal, and the source sampling clock SSC latches the data based on the rising and falling edges. (latch) In addition, the source output enable signal SOE serves to control the output of the data driver 500, and the polarity signal POL controls the data voltage of the display panel 200 to be positive (+) polarity or negative (−). It is a signal indicating the polarity to drive the polarity.

In addition, the timing controller 300 receives the image data signal RGB from an external system, arranges the image data signal RGB, and transmits the image data signal RGB to the data driver 500.

The data driver 500 supplies the data voltages to the plurality of data wirings DL in response to the data control signal DCS and the image data RGB supplied from the timing controller 300. In other words, for example, a data voltage corresponding to the image data signal RGB is generated using the gamma voltage Vgamma, and the generated data voltage is output to the data wiring DL.

The gate driver 400 sequentially scans the plurality of gate wirings GL in response to the gate control signal GCS supplied from the timing controller 300. For example, a plurality of gate lines GL are sequentially selected during each frame, and a gate voltage is output for the selected gate lines GL. By the gate voltage, the thin film transistor T positioned in the corresponding row line is turned on. Meanwhile, a turn off voltage is supplied to the gate line GL until the next frame is scanned, so that the thin film transistor T is maintained in the turn off state.

The gamma voltage supply unit 700 divides the high potential common voltage and the low potential common voltage generated from the power generator 600, generates a gamma voltage Vgamma, and supplies the generated gamma voltage Vgamma to the data driver 500.

The power generator 600 generates various driving voltages necessary for driving the flat panel display 100. For example, the power supply voltage supplied to the timing controller 300, the data driver 500, and the gate driver 400, the gate high voltage and the gate low voltage supplied to the gate driver 400 are generated.

The flat panel display apparatus 100 may use a plurality of DC-DC converters in the display panel 200, the driving circuit unit D, and the like.

Hereinafter, a DC-DC converter according to an embodiment of the present invention will be described in more detail with reference to FIG. 3.

3 is a view schematically showing a DC-DC converter according to an embodiment of the present invention.

First, as shown in FIG. 3, the DC-DC converter 910 may be connected to the PWM controller 920.

Here, the PWM controller 920 generates a pulse width modulation (PWM) control signal PWM and outputs it to the DC-DC converter 910.

The PWM control signal PWM is a square wave signal that adjusts the duty ratio of the on time and the off time of the DC-DC converter 910. Therefore, according to the on-off duty width of the PWM control signal PWM, the on time of the DC-DC converter 910 is adjusted. That is, by adjusting the duty ratio of the PWM control signal PWM, it is possible to adjust the level of the output voltage Vout of the DC-DC converter 910 to the target voltage level.

Specifically, referring to FIG. 4, the duty ratio D may be expressed by Equation (1). 4 is a diagram illustrating an output voltage Vout according to the duty ratio D.

Equation (1): D = Ton / T (Ton: time when switching element is on, T: switching cycle of switching element)

Therefore, when the output voltage is Vout (A), since the on period is larger than when the output voltage Vout (B), the duty ratio D becomes larger when the output voltage is Vout (A).

Hereinafter, the DC-DC converter 910 according to an embodiment of the present invention will be described in more detail with reference to FIGS. 5 and 7.

5 and 6 schematically illustrate circuits of various types of DC-DC converters, and FIG. 7 is a diagram illustrating circuits of a DC-DC converter according to an embodiment of the present invention.

First, the DC-DC converter 910 receives a power supply voltage supplied from the outside as an input voltage Vin, and generates and outputs the output voltage Vout at a desired level.

As shown in FIG. 5, the DC-DC converter 910 includes, for example, a buck converter (buck-step-down) (FIG. 5A) and a boost converter (step-up) ( (B) of FIG. 5, a buck-boost converter ((c) of FIG. 5), etc. are mentioned.

The buck converter (step-down converter) is a converter in which the output voltage Vout is lower than the input voltage Vin. At this time, the output voltage Vout is as shown in Equation (2).

Equation (2): Output voltage (Vout) = D * Input voltage (Vin).

The boost converter (step-up converter) is a converter in which the output voltage Vout is output higher than the input voltage Vin. At this time, the output voltage Vout is as shown in Equation (3).

Equation (3): Output voltage (Vout) = (1 / (1-D)) * Input voltage (Vin).

The buck-boost converter is a mixture of a buck converter and a boost converter. At this time, the output voltage (Vout) is as shown in equation (4).

Equation (4): Output voltage (Vout) = (D / (1-D)) * Input voltage (Vin).

Another type of DC-DC converter 910 is a boost converter using an autotransformer.

An autotransformer refers to a transformer in which primary and secondary coil wires are not separated and some of them are commonly used.

FIG. 6 is a diagram schematically illustrating a circuit of a converter in which an autotransformer is coupled to a boost converter (see FIG. 5B).

At this time, the relationship between the input voltage Vin and the output voltage Vout is as shown in Equation (5).

Equation (5): Output voltage (Vout) = (sqrt (L4 / L3) * (1 / (1-D)) * Input voltage (Vin).

Here, L4 is a fourth inductor of FIG. 6, and L2 is a third inductor of FIG. 6. In addition, the third inductor L3 and the fourth inductor L4 constitute an autotransformer.

That is, the converter circuit combining the autotransformer can adjust the boost ratio by adjusting the turn ratio of the third inductor L3 and the fourth inductor L4, and thus various designs are possible. Here, the boost ratio may be expressed as an output voltage Vout / input voltage Vin.

Hereinafter, the DC-DC converter 910 according to the embodiment of the present invention will be described in more detail with reference to FIG. 7.

As shown in FIG. 7, the DC-DC converter 910 according to the embodiment of the present invention may further include a protection circuit unit 911 in the DC-DC converter using the aforementioned autotransformer.

Specifically, the DC-DC converter 910 according to the embodiment of the present invention includes the first and second inductors L1 and L2, the output capacitor Coss, and the first to third capacitors C1, C2, C3), first to fourth diodes D1, D2, D3, and D4, and a switch M may be included.

Here, the first to third diodes D1, D2, and D3 and the first and second capacitors C1 and C2 form a protection circuit unit 911.

First, the connection relationship of the DC-DC converter 910 according to the embodiment of the present invention will be described.

One side of the first inductor L1 is connected to one terminal (+) of the input voltage Vin. The other side of the first inductor L1 includes one side of the second inductor L2, an input terminal of the switch M, for example, a drain electrode D, a first electrode of the output capacitor Coss, and a first diode ( It is connected to the first electrode of D1), for example an anode electrode.

One side of the second inductor L2 is an input terminal of the switch M, for example, a drain electrode D, a first electrode of the output capacitor Coss, and a first electrode of the first diode D1, for example, an anode. Connected with the electrode. The other side of the second inductor L2 is connected to the first electrode of the second capacitor C2 and the first electrode of the fourth diode D4, for example, the anode electrode.

Here, the first inductor L1 and the second inductor L2 form an autotransformer AT. As described above, the autotransformer AT refers to a transformer in which primary and secondary coil wires are not separated and a part thereof is commonly used. Here, a part of the first inductor L1 is an example. For example, it can function as a primary coil wire, and part of the second inductor L2 can function as a secondary coil wire, for example.

Therefore, by adjusting the turn ratio of the first inductor L1 and the second inductor L2, the boost ratio can be adjusted, and various boost ratio ratio designs can be designed.

The input terminal of the switch M is connected to the first electrode of the output capacitor Coss and, for example, the anode electrode of the first diode D1. The output terminal of the switch M, for example, the source electrode S is connected to one terminal (-) of the input voltage Vin, the second electrode of the output capacitor Coss, and the second electrode of the first capacitor C1. The second electrode of the third capacitor C3 is connected to the output terminal of the output voltage Vout.

In addition, the gate electrode G of the switch M is connected to the PWM controller 920 to receive the PWM control signal PWM. Thus, the switch M is turned on / off in accordance with the duty ratio of the PWM control signal PWM.

Here, the switch M may be, for example, a bipolar junction transistor (BJT) or a metal oxide silicon field effect transistor (MOSFET) that is a multi-carrier semiconductor device. It will be apparent to those skilled in the art that other types of transistors can be used.

The first electrode of the output capacitor Coss is connected to the anode electrode of the first diode D1. The second electrode of the output capacitor Coss is connected to the second electrode of the first capacitor C1, the second electrode of the third capacitor C3, and the output terminal of the output voltage Vout.

The first electrode of the first capacitor C1 is connected to a second electrode of the first diode D1, for example, a cathode, and a first electrode of the second diode D2, for example, an anode. The second electrode of the first capacitor C1 is connected to the second electrode of the third capacitor C3 and the output terminal of the output voltage Vout.

The first electrode of the second capacitor C2 is connected to the first electrode of the fourth diode D4, for example, the anode electrode. The second electrode of the second capacitor C2 is connected to a second electrode of the second diode D2, for example, a cathode, and a first electrode of the third diode D3, for example, of an anode.

The first electrode of the third capacitor C3 is connected to the second electrode of the third and fourth diodes D3 and D4, for example, a cathode electrode, and an output terminal of the output voltage Vout. The second electrode of the third capacitor C3 is connected to the output terminal of the output voltage Vout.

A second electrode, for example a cathode, of the first diode D1 is connected to a first electrode, for example, an anode of the second diode D2.

The second electrode of the second diode D2 is connected to the first electrode of the third diode D3.

The second electrode of the third diode D3 is connected to the second electrode of the fourth diode D4.

Although not shown, the output terminal of the switch M, the output capacitor Coss, and the second electrodes of the first and third capacitors C1 and C3 may be grounded.

Here, the fourth diode D4 sends the input charge and the input voltage Vin to the output terminal of the output voltage Vout.

The third capacitor C3 removes and stabilizes the ripple component of the output voltage Vout at the output terminal. That is, the ripple component is included in the output voltage Vout in which the input voltage Vin is boosted by the high speed switching of the switch M, and serves to remove the ripple component.

8 and 9, the operation mode of the DC-DC converter 910 according to the embodiment of the present invention will be described.

8 is an operation circuit diagram when the switch M is turned on, and FIG. 9 is an operation circuit diagram when the switch M is turned off.

First, the first mode is a mode in which the switch M is turned on.

Referring to FIG. 8, when the switch M is turned on, current flows through the first inductor L1 and the switch M, where the first inductor L1 corresponds to the input voltage Vin. Energy is stored.

In addition, when the switch M is turned off, the energy charged in the first capacitor C1 is transferred to the second capacitor C2 through the second diode D2 and thus, the second capacitor C2. ) Is charged with energy.

The second mode is a mode in which the switch M is turned off.

9, the switch M is turned off so that current does not pass through the switch M and charges the first capacitor C1 through the output capacitor Coss and the first diode D1. do.

At this time, the second capacitor C2 discontinues supply of current from the first capacitor C1, and thus discharges energy received from the first capacitor C1 in the first mode.

In addition, energy stored in the first inductor L1 is transferred to the second inductor L2. Here, as described above, the first inductor L1 and the second inductor L2 form an autotransformer AT, and are input according to the turn ratio of the first inductor L1 and the second inductor L2. The voltage Vin is stepped up. In addition, the boosted input voltage Vin is output through the fourth diode D4 as the output voltage Vout.

At this time, the current flowing in the second inductor L2 decreases to zero. In addition, the sum of the input voltage Vin and the output voltage Vout is applied between the drain electrode D and the source electrode S of the switch M. FIG. That is, it is applied to the output capacitor Coss.

The third mode is a mode in which the switch M is turned on.

Referring back to FIG. 8, energy is stored in the first inductor L1. In addition, energy charged in the first capacitor C1 is transferred to the second capacitor C2 through the second diode D2.

Here, the effect of the DC-DC converter 910 according to the embodiment of the present invention will be described in more detail.

FIG. 10 is a diagram illustrating voltage and current waveforms of the switch M when the protection circuit unit 911 is not provided.

Referring to FIG. 10, when the switch M is turned off, the voltage of the switch M is charged with a predetermined slope, and the current also decreases with a predetermined slope. On the other hand, when the switch M is turned on, the voltage of the switch M discharges with a predetermined slope, and the current increases with a predetermined slope.

In this case, the overlap of the voltage and the current causes the conduction loss of the switch M and the overvoltage and overcurrent stress. In addition, the overlapped portion is represented as a switching loss due to hard switching. In addition, an electromagnetic interference (EMI) phenomenon is a factor that occurs.

Here, when the switch M is turned on, the switching loss reduction method by the protection circuit unit 911 is as follows.

First, as described above, switching loss due to overvoltage and overcurrent occurs when the switch M is turned on. Specifically, a loss of (1/2) * Coss * Vⁿ occurs by the output capacitor Coss. Here, Coss refers to the voltage of the output capacitor Coss, and n is a natural number, for example, may be 2.

At this time, when the current flowing through the second inductor L2 becomes 0, the voltage of the output capacitor Coss is higher than the input voltage Vin (because, as described above, the input voltage Vin and the output voltage Vout). ) Is applied to the output capacitor (Coss), and the resonance of the first inductor (L1) and the output capacitor (Coss), the amplitude of the output voltage (Vout) around the input voltage (Vin) Resonance. Here, when the voltage of the output capacitor Coss becomes minimum, when the gate signal is applied to the gate electrode G of the switch M, the switching loss is almost zero.

When the switch M is turned off, the switching loss reduction method by the protection circuit unit 911 is as follows.

First, as described above, switching losses due to overvoltage and overcurrent occur when the switch M is turned off.

At this time, when the switch M is turned off, the current delivered to the drain electrode D of the switch M is transmitted to the output capacitor Coss, and at the same time to the first capacitor C1. Through this, the overcurrent of the drain electrode D of the switch M can be prevented, and thus switching loss can be improved.

FIG. 11 is a simulation result when driving a DC-DC converter using a general autotransformer, and FIG. 12 is a simulation result when driving a DC-DC converter 910 according to an embodiment of the present invention.

As shown in FIG. 11 and FIG. 12, it can be seen that the DC-DC converter 910 according to the embodiment of the present invention reduces power loss than a general DC-DC converter.

It can also be seen that abrupt changes in voltage and current are improved.

As described above, the DC-DC converter 910 according to the embodiment of the present invention further includes a protection circuit unit 911, thereby preventing switching over voltage and over current of the switch M to improve switching loss. Accordingly, the EMI characteristic is also improved.

The embodiments of the present invention described above are examples of the present invention, and modifications can be made freely within the scope of the present invention. Accordingly, the invention includes modifications of the invention within the scope of the appended claims and their equivalents.

100: flat panel display 200: display panel
910: DC-DC converter 911: protection circuit
D: Diode C: Capacitor L: Inductor
Vin: Input Voltage Vout: Output Voltage

Claims (6)

A switch;
It includes a protection circuit for reducing the loss of the switch,
The protection circuit unit,
First and second capacitors, and first to third diodes,
The first electrode of the first capacitor is connected to the second electrode of the first diode, the first electrode of the second diode,
The second electrode of the second capacitor is connected with the second electrode of the second diode, the first electrode of the third diode,
The first electrode of the first diode is connected with the drain electrode of the switch, the second electrode of the first diode is connected with the first electrode of the second diode,
The second electrode of the second diode is connected with the first electrode of the third diode.
DC-DC converter.
The method of claim 1,
The DC-DC converter further includes first and second inductors and an output capacitor,
The first inductor and the second inductor are connected to each other to form an autotransformer,
The first electrode of the output capacitor is connected to one side of the first inductor and the second inductor, the drain electrode of the switch, and the first electrode of the first diode, and the second electrode of the output capacitor is the switch. Connected to the source electrode of
The first electrode of the second capacitor is connected to the other side of the second inductor
DC-DC converter.
The method of claim 2,
Further comprising a third capacitor and a fourth diode,
The first electrode of the fourth diode is connected to the other side of the second inductor, the second electrode of the second capacitor, the second electrode of the fourth diode is connected to the first electrode of the third capacitor, and the second electrode. Connected to the second electrode of the three diodes,
The second electrode of the third diode is connected with the first electrode of the third capacitor.
DC-DC converter.
In the flat panel display device comprising a display panel for displaying an image,
A switch, and a protection circuit portion for reducing the loss of the switch,
The protection circuit unit,
First and second capacitors, and first to third diodes,
The first electrode of the first capacitor is connected to the second electrode of the first diode, the first electrode of the second diode,
The second electrode of the second capacitor is connected with the second electrode of the second diode, the first electrode of the third diode,
The first electrode of the first diode is connected with the drain electrode of the switch, the second electrode of the first diode is connected with the first electrode of the second diode,
The second electrode of the second diode is connected with the first electrode of the third diode.
Flat panel display including a DC-DC converter.
The method of claim 4, wherein
The DC-DC converter further includes first and second inductors and an output capacitor,
The first inductor and the second inductor are connected to each other to form an autotransformer,
The first electrode of the output capacitor is connected to one side of the first inductor and the second inductor, the drain electrode of the switch, and the first electrode of the first diode, and the second electrode of the output capacitor is the switch. Connected to the source electrode of
The first electrode of the second capacitor is connected to the other side of the second inductor
Flat panel display including a DC-DC converter.
The method of claim 5, wherein
Further comprising a third capacitor and a fourth diode,
The first electrode of the fourth diode is connected to the other side of the second inductor, the second electrode of the second capacitor, the second electrode of the fourth diode is connected to the first electrode of the third capacitor, and the second electrode. Connected to the second electrode of the three diodes,
The second electrode of the third diode is connected with the first electrode of the third capacitor.
Flat panel display including a DC-DC converter.

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