This application claims the priority of Korean Patent Application No. 10-2009-0062944 filed on Jul. 10, 2009, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a driver for a plasma display panel, and more particularly, to a driver for a plasma display panel, which is capable of absorbing surplus power of a plasma display panel by performing power conversion switching according to the switching of a sustain circuit and thus forming a transmission path using resonance between the inductance of a transformer for power conversion and the capacitance of the plasma display panel, without using an energy recovery circuit.
2. Description of the Related Art
Recently, various kinds of display devices have been developed and used. Representative examples of display devices include a cathode-ray tube (CRT), a liquid crystal display (LCD) and a plasma display panel (PDP).
In particular, LCDs and PDPs are being increasingly used since they are slim and easy to adapt for wide screens.
Unlike a PDP, an LCD does not illuminate by itself and therefore employs a backlight. A commonly used backlight for the LCD is a cold cathode fluorescent lamp (CCFL), which has limitations such as a large size, large power consumption and high manufacturing costs.
Therefore, a PDP is mainly used as a display device in order to meet the requirements for light and slim characteristics and cost reductions, and as well as consumer demand. However, this PDP is also required to be slimmer, lighter and more cost-effective.
An aspect of the present invention provides a driver for a plasma display panel (PDP), which is capable of absorbing surplus power of a plasma display panel by performing power conversion switching according to the switching of a sustain circuit and thus forming a transmission path using resonance between the inductance of a transformer for power conversion and the capacitance of the plasma display panel, without using an energy recovery circuit.
According to an aspect of the present invention, there is provided a driver for a plasma display panel, the driver including: a power supply unit including preset inductance, and converting alternating current (AC) commercial power into preset driving power by using the inductance; and a driving unit switching the driving power from the power supply unit according to a logic signal and supplying the switched driving power to a plasma display panel, wherein surplus power of the driving unit is transmitted to the power supply unit by resonance between the inductance of the power supply unit and capacitance of the plasma display panel.
The power supply unit may include a power conversion part receiving and switching power to convert the power into the driving power.
The driving unit may include a sustain part switching the driving power according to the logic signal and charging/discharging the plasma display panel.
The power conversion part may perform switching according to the switching of the driving unit.
The power conversion part may include: a switching circuit performing power conversion by switching the received power according to the switching of the driving unit; and a transformer including a primary winding receiving power from the switching circuit and a secondary winding forming a turns ratio with the primary winding.
The sustain part may include: a pair of Y electrode switches including a first Y electrode switch and a second Y electrode switch connected in series to each other; and a pair of X electrode switches connected in parallel to the pair of Y electrode switches and including a first X electrode switch and a second X electrode switch connected in series to each other. The first Y electrode switch may be switched ON and OFF in association with the second X electrode switch, the second Y electrode switch may be switched ON and OFF in association with the first X electrode switch, alternately with the switching of the first Y electrode switch and the second X electrode switch, and a connection point between the first and second Y electrode switches may be connected to one end of the plasma display panel, and a connection point between the first and second X electrode switches may be connected to the other end of the plasma display panel.
The switching circuit may include first and second switches connected in series to each other between two input terminals of the received power. The first switch may be switched ON when the second Y electrode switch and the first X electrode switch are switched ON, the first Y electrode switch may be switched ON alternately with the first switch, and a connection node between the first and second switches may be electrically connected to the primary winding of the transformer.
When a voltage of the plasma display panel rises, a body diode of the second switch may be turned ON in a dead time, which is a switching-off period of the first and second Y electrode switches and the first and second X electrode switches, and form a transmission path for the surplus power being transmitted from the driving unit to the power conversion part. When the voltage of the plasma display panel falls, a body diode of the first switch may be turned ON in a dead time, which is a switching-off period of the first and second Y electrode switches and the first and second X electrode switches, and form a transmission path for the surplus power being transmitted from the driving unit to the power conversion part. Inductance of the power supply unit may resonate with capacitance of the plasma display panel when the transmission path is formed.
The first and second Y electrode switches and the first and second X electrode switches may be switched OFF, and the first switch may be switched ON and then switched OFF to turn ON the body diode of the second switch in a voltage rising period of the plasma display panel. The first and second Y electrode switches and the first and second X electrode switches may be switched OFF, and the second switch may be switched ON and then switched OFF to turn ON the body diode of the first switch in a voltage falling period of the plasma display panel.
The first Y electrode switch and the second X electrode switch may be switched ON, the second Y electrode switch and the first X electrode switch may be switched OFF and the second switch may be switched ON in a maximum-voltage sustain period of the plasma display panel between the voltage rising period and the voltage falling period of the plasma display panel. The second Y electrode switch and the first X electrode switch may be switched ON, the first Y electrode switch and the second X electrode switch may be switched OFF and the first switch may be switched ON in a minimum-voltage sustain period of the plasma display panel between the voltage falling period and the voltage rising period of the plasma display panel.
The power supply unit may include: a rectifying/smoothing part rectifying and smoothing the AC commercial power; and a power factor correction part correcting a power factor of the rectified and smoothed power and supplying DC power to the power conversion part.
The inductance may be leakage inductance of the transformer, inductance of an inductor device electrically connected in series between the primary winding and the transformer, or combined inductance of the leakage inductance of the transformer and the inductance of the inductor device.
According to another aspect of the present invention, there is provided a driver for a plasma display panel, the driver including: a power supply unit switching alternating current (AC) commercial power and converting switched power into preset driving power; and a driving unit switching the driving power from the power supply unit according to a logic signal and supplying the switched driving voltage to a plasma display panel, wherein switching of the power supply unit is performed according to switching of the driving unit to thereby form a transmission path through which surplus power of the driving unit is transmitted to the power supply unit, so that the surplus power is transmitted to the power supply unit.
A body diode of the first switch or a body diode of the second switch is turned ON in a dead time, which is a switching-off period of first and second Y electrode switches and first and second X electrode switches.
The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:
Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
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The power supply unit 110 converts alternating current (AC) commercial power into driving power having a preset voltage level, and supplies the driving power to the driving unit 120. To this end, the power supply unit 110 may include a power conversion part 113 switching and converting power. In addition, the power supply unit 110 may further include a rectifying/smoothing part 111 rectifying and smoothing the AC commercial power, and a power factor correction part 112 correcting the power factor of the rectified and smoothed power to supply DC power to the power conversion part 113.
The power conversion part 113 may include a switching circuit 113a switching DC power VPFC, and a transformer 113b converting the voltage level of the switched power from the switching circuit 113a.
The switching circuit 113a may include first and second switches QR and QF of a half bridge type, which are connected in series to each other between input terminals for the DC power from the power factor correction part 112. The first and second switches QR and QF may each include a body diode.
The transformer 113b includes a primary winding Np and a secondary winding Ns having a preset turns ratio therebetween. The primary winding Np may be connected in parallel to the second switch QF of the switching circuit 113a. Leakage inductance Lp and capacitance CR may be formed separately between the primary coil Np and the second switch QF. The leakage inductance Lp may be the leakage inductance of the transformer 113b itself, or leakage inductance caused by an inductor device that is additionally connected.
The driving unit 120 may include a sustain part 121 switching driving power from the power supply unit 110 and supplying switched power to a plasma display panel forming capacitance Cp. The driving unit 120 may further include a stabilizing capacitor Co for stabilizing power supplied from the sustain part 121.
The sustain part 121 may include a pair of Y electrode switches Ys and Yg and a pair of X electrode switches Xs and Xg switched according to a logic signal S from the outside. The pair of Y electrode switches Ys and Yg may be connected in parallel with the pair of X electrode switches Xs and Xg. The stabilizing capacitor Co may be connected in parallel to the pair of Y electrode switches Ys and Yg and the pair of X electrode switches Xs and Xg.
The pair of Y electrode switches Ys and Yg may include a first Y electrode switch Ys and a second Y electrode switch Yg that are connected in series to each other. The pair of X electrode switches Xs and Xg may include a first X electrode switch Xs and a second X electrode switch Xg that are connected in series to each other.
A connection point between the first Y electrode switch Ys and the second Y electrode switch Yg may be connected to a
Y electrode of the plasma display panel forming capacitance Cp. Also, a connection point between the first X electrode switch Xs and the second X electrode switch Xg may be connected to an X electrode of the plasma display panel.
The switching of the first and second switches QR and QF is performed according to the switching of the first and second Y electrode switches Ys and Yg and the first and second X electrode switches Xs and Xg of the sustain part 121, thereby forming an LC resonance path between the leakage inductance Lp of the transformer 113b and the capacitance Cp of the plasma display panel. Thus, the surplus power of the driver 120 is transferred to the power conversion part 113. In this away, the function of an existing energy recovery circuit (ERC) can be substituted.
Hereinafter, the operation and effects of the present invention will be described with reference to accompanying drawings.
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As described above, according to the present invention, there is no need to use a separate energy recovery circuit (ERC) absorbing surplus power supplied to a plasma display panel for use. In the present invention, an LC resonance path between the leakage inductance of the transformer and the capacitance of the plasma display panel is formed by the switching of the power conversion switch performed according to the switching of the Y electrode switch and the X electrode switch, thereby transmitting surplus power from the driving unit to the power conversion part and thus functioning as an existing energy recovery circuit (ERC). Accordingly, the circuit area and components are reduced so that slimness, a light weight and cost reductions can be achieved.
As set forth above, according to exemplary embodiments of the invention, surplus power of a plasma display panel can be absorbed by performing power conversion switching according to the switching of a sustain circuit and thus forming a transmission path using resonance between the inductance of a transformer for power conversion and the capacitance of the plasma display panel, without using an energy recovery circuit (ERC).
While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.
Number | Date | Country | Kind |
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10-2009-0062944 | Jul 2009 | KR | national |