KR100992452B1 - Circuit for power factor correction - Google Patents

Abstract

The present invention relates to a power factor correction circuit.

According to an embodiment of the present invention, a power factor correction circuit includes a first booster for boosting an input voltage while a positive input voltage is applied, a second booster for boosting an input voltage while a negative input voltage is applied, and charging of the first booster. Detecting a current flowing through the first booster switching element that controls the over-discharge, the second booster switching element that controls the charging and discharging of the second booster, and the first booster switching element, and converting the detected current value into a positive voltage. And a detection voltage providing unit which detects a current flowing through the second booster switching element and provides a detected current value as a positive voltage.

The embodiment of the present invention is very simple in configuration, and can effectively suppress the invention due to the forward voltage drop.

Power factor correction, bridge rectifier circuit, booster

Description

Power factor correction circuit {CIRCUIT FOR POWER FACTOR CORRECTION}

The present invention relates to a power factor correction (PFC) circuit.

In general, the power factor correction circuit is a circuit that adjusts the power factor so that the waveform of the current provided by the power supply voltage is as close as possible to the voltage waveform.

The power factor correction circuit described above is a circuit that is very useful for supplying power to flat panel display devices such as plasma display panels (PDPs) and liquid crystal displays (LCDs). In addition, efforts are being made to miniaturize and reduce the power factor correction circuit.

Conventional power factor correction circuit may be composed of a bridge rectifier circuit and a booster circuit consisting of four diodes, the bridge rectifier circuit consisting of four diodes two diodes are turned on, the forward voltage drop is generated by about 2V . Since a large amount of heat is generated due to the forward voltage drop of about 2 V, a very large heat sink is required for a conventional power factor correction circuit. Therefore, the conventional power factor correction circuit has a great difficulty in miniaturization and weight reduction.

The power factor correction circuit according to an embodiment of the present invention can reduce the forward voltage drop, thereby effectively suppressing heat generation.

Technical problems to be achieved by the present invention are not limited to the above-mentioned technical problems, and other technical problems not mentioned above are provided to those skilled in the art (hereinafter, those skilled in the art) from the following description. It will be clearly understood.

The power factor correction circuit according to an embodiment of the present invention includes a first booster for boosting an input voltage while a positive input voltage is applied, a second booster for boosting an input voltage while a negative input voltage is applied, and the first booster. A first booster switching element for controlling charging and discharging of the second booster, a second booster switching element for regulating the charging and discharging of the second booster, and a current flowing through the first booster switching element and detecting the detected current value And a detection voltage providing unit which detects a current flowing through the second booster switching element and provides a detected current value as a positive voltage.

The power factor correction circuit according to another embodiment of the present invention includes a first booster for boosting an input voltage while a positive input voltage is applied, a second booster for boosting an input voltage while a negative input voltage is applied, and the first booster. A first booster switching element for controlling charging and discharging of the second booster, a second booster switching element for controlling charging and discharging of the second booster, a first current detector for detecting a current flowing through the first booster switching element, A second current detector for detecting a current flowing through the second booster switching element, a first voltage providing unit providing a current value detected by the first current detector as a positive voltage, and the second current detector And a second voltage providing unit configured to provide the current value as a positive voltage.

The power factor correction circuit of the present invention does not include a bridge rectifier circuit composed of four diodes, and thus the configuration is very simple, and the invention due to the forward voltage drop can be effectively suppressed.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific details of other embodiments are included in the detailed description and the drawings. Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. Like reference numerals refer to like elements throughout.

1 is a circuit diagram of a power factor correction circuit according to an embodiment of the present invention.

As shown in FIG. 1, a power supply device according to an embodiment of the present invention includes a first booster 100, a second booster 200, a first booster switching element Q1, and a second booster switching element ( Q2) and the detection voltage providing unit 300 may be included.

Here, the first booster 100 includes a first inductor L1 and a first diode D1, boosts the input voltage Vin while a positive input voltage Vin is applied, and first booster 100. The switching element Q1 controls the charging and discharging of the first booster 100.

Meanwhile, the second booster 200 includes a second inductor L2 and a second diode D2, boosts the input voltage Vin while the negative input voltage Vin is applied, and switches the second booster switching. The element Q2 controls the charging and discharging of the second booster 200.

Specifically, when the first booster switching element Q1 is turned on, when the first inductor L1 and the second inductor are charged, and when the first booster switching element Q1 is turned off, the current becomes the first inductor L1. The first inductor L1 and the second inductor L2 are discharged to the load through the second inductor L2 and the first diode D1. Therefore, the charging time and the discharging time of the first inductor L1 and the second inductor L2 are adjusted by the duty ratio of the signal applied to the first booster switching element Q1, and thus the load is supplied to the load. Adjust the voltage level. The duty ratio of the signal applied to the first booster switching element Q1 may be adjusted by detecting a current flowing through the first booster switching element Q1.

On the other hand, when the second booster switching element Q2 is turned on, the first inductor L1 and the second inductor L2 are charged, and when the second booster switching element Q2 is turned off, the current becomes the first inductor ( L1), the second inductor L2, and the second diode D2 flow through the load, and the first inductor L1 and the second inductor L2 are discharged. Accordingly, the charging time and the discharging time of the first inductor L1 and the second inductor L2 are adjusted by the duty ratio of the signal applied to the second booster switching element Q2, and thus the load is supplied to the load. Adjust the voltage level. The duty ratio of the signal applied to the second booster switching element Q2 may be adjusted by detecting a current flowing through the second booster switching element Q2.

Here, the first inductor L1 and the second inductor L2 do not necessarily need to form separate elements, but may also be configured as one element.

In addition, the detection voltage providing unit 300 detects a current flowing through the first booster switching element Q1, converts the detected current value into a positive voltage C / S, and the second booster switching element Q2. Detects the current flowing through and converts the detected current value into a positive voltage (C / S).

Specifically, the detection voltage providing unit 300 detects the current flowing through the first current detector 311 and the second booster switching element Q2 for detecting the current flowing through the first booster switching element Q1. The first current providing unit 331 and the second current detection unit for converting the current value detected by the second current detection unit 312, the first current detection unit 311 to provide a positive voltage (C / S) for And a second voltage providing unit 332 which converts the current value detected by 312 into a positive voltage C / S and provides the converted voltage.

Here, the first current detector 311 is composed of the first detection resistor RS1, the second current detector 312 is composed of the second detection resistor RS2, and one end of the first detection resistor RS1. And one end of the second detection resistor RS2 are connected to ground.

On the other hand, the first voltage providing unit 331 is composed of a first providing switching element (Q31), the first providing switching element (Q31) is connected to the other end of the first detection resistor, the first detection when the input voltage is positive The voltage detected by the resistor is transferred to the positive voltage (C / S).

In addition, the second voltage providing part 332 is composed of a second providing switching element Q32, and the second providing switching element Q32 is connected to the other end of the second detecting resistor to detect the second when the input voltage is positive. The voltage detected by the resistor is transferred to the positive voltage (C / S).

Specific operations of the first voltage providing unit and the second voltage providing unit will be described with reference to FIGS. 2 and 3.

The first voltage detector 411 provides a first positive voltage signal PV1 when the input voltage Vin is positive, and the second voltage detector 412 provides a first negative voltage when the input voltage Vin is negative. Provide the signal NV1.

In detail, the first voltage detector 411 includes a first photodiode PH1A and a first phototransistor PH1B, and the first photodiode PH1A is turned on when the input voltage Vin is positive. The first phototransistor PH1B provides the first positive voltage signal PV1 when the first photodiode PH1A is turned on, and the second voltage detector 412 provides the second photodiode PH2A and the second phototransistor. And a second photodiode PH2A is turned on when the input voltage Vin is negative, and the second phototransistor PH2B is turned on when the second photodiode PH2A is turned on. Provide (NV1).

Here, the resistor Rp is for preventing excessive voltage from being applied to the first photodiode PH1A or the second photodiode PH2A.

When the first negative voltage signal NV1 is not transmitted to the gate of the first providing switching device Q31, the power supply voltage VCC is applied to the gate of the first providing switching device Q31, so that the first providing switching device ( Since Q31 is turned on, the voltage detected by the first detection resistor RS1 is transferred to the positive voltage C / S.

On the other hand, when the first negative voltage signal NV1 is transferred to the gate of the first providing switching element Q31, the power supply voltage VCC and the first negative voltage signal NV1 are provided at the gate of the first providing switching element Q31. Is applied, and the first providing switching element Q31 is turned off, so that the voltage detected by the first detection resistor RS1 is not transmitted.

Here, the resistor RC1 is for preventing excessive voltage from being applied to the gate of the first providing switching element Q31.

On the other hand, if the first positive voltage signal PV1 is not transmitted to the gate of the second providing switching element Q32, the power supply voltage VCC is applied to the gate of the second providing switching element Q32 to provide the second providing switching element ( Since Q32 is turned on, the voltage detected by the second detection resistor RS2 is transferred to the positive voltage C / S.

On the other hand, when the first positive voltage signal PV1 is transferred to the gate of the second providing switching element Q32, the power supply voltage VCC and the first positive voltage signal PV1 are connected to the gate of the second providing switching element Q32. Since the difference is applied and the second providing switching element Q32 is turned off, the voltage detected by the second detection resistor RS2 is not transmitted.

Here, the resistor RC2 is for preventing excessive voltage from being applied to the gate of the second providing switching element Q32.

The third voltage detector 511 provides the second positive voltage signal PV2 when the input voltage Vin is positive and the first booster switching element Q1 is turned off. 512 provides a second negative voltage signal NV2 when the input voltage Vin is negative and the second booster switching element Q2 is turned off.

Specifically, the third voltage detector 511 includes an eleventh distribution resistor R11, a twelfth distribution resistor R12, and an eleventh distribution that are connected in series between a drain and a source of the first booster switching element Q1. First sensing switching in which a gate is connected to one end of the eleventh charging resistor C11 and an eleventh distribution resistor R11 and a source is connected to the other end of the eleventh distribution resistor R11 in parallel with the resistor R11. The element Q11 is included.

Meanwhile, the fourth voltage detector 512 includes a twenty-first distribution resistor R21, a twenty-second distribution resistor R22, and a twenty-first distribution resistor connected in series between a drain and a source of the second booster switching element Q2. A second detection switching element having a twenty-first charging capacitor C21 connected in parallel to R21, a gate connected to one end of the twenty-first distribution resistor R21, and a source connected to the other end of the twenty-first distribution resistor R21; (Q12).

When the input voltage Vin is positive and the first booster switching element Q1 is turned on, since the drain voltage of the first booster switching element Q1 is close to a level near 0 V, the first detection switching element Q11 is Is turned off.

When the input voltage Vin is positive and the first booster switching element Q1 is turned off, the drain voltage of the first booster switching element Q1 rises to a voltage applied to the capacitor Co, and R11 / The ratio of (R11 + R12) is applied as the gate voltage of the first detection switching element Q11, so that the first detection switching element Q11 is turned on.

In addition, the eleventh charging capacitor C11 is charged with a voltage applied to the eleventh distribution resistor R11, and the voltage charged in the eleventh charging capacitor C11 is turned on when the first detection switching element Q11 is turned on. 2 is transferred to the positive voltage signal PV2.

On the other hand, when the input voltage Vin is positive, the drain voltage of the second booster switching element Q2 approaches a level of almost 0 V regardless of whether the second booster switching element Q2 is turned on.

The third voltage detector 511 may further include a twelfth charging capacitor C12 connected in parallel to the twelfth distribution resistor R12. As a result, the charging time of the eleventh charging capacitor C11 can be shortened effectively.

In addition, the third voltage detector 511 may further include an eleventh diode D11 between the twelfth distribution resistor R12 and the drain of the first booster switching element Q1. As a result, the backflow of the current from the first detection switching element Q11 to the first booster switching element Q1 can be effectively suppressed.

When the input voltage Vin is negative and the second booster switching element Q2 is turned on, since the drain voltage of the second booster switching element Q2 is close to a level near 0 V, the second detection switching element Q12 is Is turned off.

When the input voltage Vin is positive and the second booster switching element Q2 is turned off, the drain voltage of the second booster switching element Q2 rises to a voltage applied to the capacitor Co, and R21 / The ratio of (R21 + R22) is applied to the gate voltage of the second detection switching element Q12, so that the second detection switching element Q12 is turned on.

In addition, the twenty-first charging capacitor C21 is charged with a voltage applied to the twenty-first distribution resistor R21, and the voltage charged in the twenty-first charging capacitor C21 is turned on when the second detection switching device Q12 is turned on. 2 is transferred to the negative voltage signal NV2.

On the other hand, if the input voltage Vin is negative, the drain voltage of the first booster switching element Q1 approaches a level of almost 0 V regardless of whether the first booster switching element Q1 is turned on.

The fourth voltage detector 512 may further include a twenty-second charging capacitor C22 connected in parallel to the twenty-second distribution resistor R22. As a result, the charging time of the twenty-first charging capacitor C21 can be shortened effectively.

In addition, the fourth voltage detector 512 may further include a twenty-first diode D21 between the twenty-second distribution resistor R22 and the drain of the second booster switching element Q2. As a result, the backflow of the current from the second detection switching element Q12 to the second booster switching element Q2 can be effectively suppressed.

On the other hand, when the second negative voltage signal NV2 is not transmitted to the gate of the first providing switching element Q31, the power supply voltage VCC is applied to the gate of the first providing switching element Q31 to provide the first providing switching element ( Since Q31 is turned on, the voltage detected by the first detection resistor RS1 is transferred to the positive voltage C / S.

On the other hand, when the second negative voltage signal NV2 is transferred to the gate of the first providing switching element Q31, the power supply voltage VCC and the second negative voltage signal NV2 are provided at the gate of the first providing switching element Q31. Is applied, and the first providing switching element Q31 is turned off, so that the voltage detected by the first detection resistor RS1 is not transmitted.

On the other hand, when the second positive voltage signal PV2 is not transmitted to the gate of the second providing switching device Q32, the power supply voltage VCC is applied to the gate of the second providing switching device Q32 to provide the second providing switching device ( Since Q32 is turned on, the voltage detected by the second detection resistor RS2 is transferred to the positive voltage C / S.

On the other hand, when the second positive voltage signal PV2 is transmitted to the gate of the second providing switching element Q32, the power supply voltage VCC and the first positive voltage signal PV1 are provided at the gate of the second providing switching element Q32. Since the difference is applied and the second providing switching element Q32 is turned off, the voltage detected by the second detection resistor RS2 is not transmitted.

Here, the capacitor Co is for smoothing the voltage provided to the load.

The power factor correction circuit according to the embodiments of the present invention does not include a bridge rectifier circuit composed of four diodes, so that the configuration is very simple and effectively suppresses the invention due to the forward voltage drop.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

Rather, it will be apparent to those skilled in the art that many changes and modifications to the present invention are possible without departing from the spirit and scope of the appended claims.

Accordingly, all such suitable changes and modifications and equivalents should be considered to be within the scope of the present invention.

1 is a circuit diagram of a power factor correction circuit according to an embodiment of the present invention.

FIG. 2 is a circuit diagram of a voltage detection circuit according to a first embodiment for providing a first negative voltage signal and a first positive voltage signal to a first voltage providing portion and a second voltage providing portion of the power factor correction circuit of FIG. 1, respectively.

3 is a circuit diagram of a voltage detection circuit according to a second embodiment of providing a second negative voltage signal and a second positive voltage signal to a first voltage providing part and a second voltage providing part of the power factor correction circuit of FIG. 1, respectively.

<Description of Signs of Major Parts of Drawings>

100: first booster 200: second booster

300: detection voltage providing unit

Claims (7)

A first booster for boosting the input voltage while a positive input voltage is applied; A second booster for boosting the input voltage while a negative input voltage is applied; A first switching element that controls charging and discharging of the first booster; A second switching element that controls charging and discharging of the second booster; And Providing a detection voltage for detecting current flowing through the first switching element and providing a detected current value as a positive voltage, and detecting a current flowing through the second switching element and providing a detected current value as a positive voltage Includes wealth, The detection voltage providing unit includes a first current detector for detecting a current flowing through the first switching element, a second current detector for detecting a current flowing through the second switching element, and the first current detector. And a second voltage providing unit providing a detected current value as a positive voltage, and a second voltage providing unit providing a current value detected by the second current detector as a positive voltage. delete The method of claim 1, The first current detector includes a first detection resistor, the second current detector includes a second detection resistor, and one end of the first detection resistor and one end of the second detection resistor are connected to ground. Power factor correction circuit. The method of claim 3, wherein The first voltage providing part is composed of a first providing switching element, the second voltage providing part is composed of a second providing switching element, and the first providing switching element is connected to the other end of the first detection resistor to provide the input voltage. In the case of a positive voltage, the voltage detected by the first detection resistor is transferred as a positive voltage, and the second providing switching element is connected to the other end of the second detection resistor to detect the second voltage when the input voltage is negative. A power factor correction circuit, wherein the voltage detected by the resistor is transferred to a positive voltage. A first booster for boosting the input voltage while a positive input voltage is applied; A second booster for boosting the input voltage while a negative input voltage is applied; A first booster switching element that controls charging and discharging of the first booster; A second booster switching element that controls charging and discharging of the second booster; A first current detector for detecting a current flowing through the first booster switching element; A second current detector for detecting a current flowing through the second booster switching element; A first voltage providing unit providing a current value detected by the first current detection unit as a positive voltage; And And a second voltage providing unit providing a current value detected by the second current detecting unit as a positive voltage. The method of claim 5, The first current detector includes a first detection resistor, the second current detector includes a second detection resistor, and one end of the first detection resistor and one end of the second detection resistor are connected to ground. Power factor correction circuit. The method of claim 6, The first voltage providing part is composed of a first providing switching element, the second voltage providing part is composed of a second providing switching element, and the first providing switching element is connected to the other end of the first detection resistor to provide the input voltage. In the case of a positive voltage, the voltage detected by the first detection resistor is transferred as a positive voltage, and the second providing switching element is connected to the other end of the second detection resistor to detect the second voltage when the input voltage is negative. A power factor correction circuit characterized in that the voltage detected by the resistor is transferred to a positive voltage.

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