Lcd Tv Power Supply Trend Of – Lcd Tv Power Supply – Electrical Industry
With large screen, low thickness and a number of advantages such as high-definition LCD TV (LCDTV) rapid penetration in the market to upgrade, there is a market study is expected in 2009, the overall market share of LCD TVs will reach 50%. With screen sizes continue to make breakthroughs, LCD TV power have gone up. high power consumption will directly increase consumer electricity costs, and environmental protection and energy conservation goes against the trend. Therefore, governments and regulatory agencies have issued or updated energy efficiency standard for television, such as the U.S. Environmental Protection Agency (EPA) released the “Energy Star” television version 3.0 specification from 1 November 2008 entered into force.
LIPS solution to replace the traditional LCD TV power supply to reduce the large-size LCD TV power consumption, to meet all energy efficiency standards and help reduce system cost and solution size, so that LCD TV is more popular with consumers on the LCD TV power supply, we can take a variety of ways.
Traditional LCD TV power supplies include AC – DC (AC-DC) conversion, DC – DC (DC-DC) conversion and High pressure Inverter these parts. AC-DC and DC-DC in the same piece of circuit board, and inverter circuit board as an independent, usually provided with the LCD panel. One, AC-DC power supply section, electricity 110Vac/220Vac voltage after rectification, power factor correction (PFC) and the filter, converted to 200V/400V to DC high voltage. The traditional inverter input voltage requirement is 24V, so the output voltage of 200V/400V voltage PFC to go through step-down converter to produce multiple output voltage, which provides the way to 24V voltage inverter, which go through DC – AC (DC-AC) is converted to more than 1,000 V and even up to 2,000 V high voltage to drive the CCFL LCD panel backlight. This Standard 24V LCD TV Inverter Switching Power Supply Functional block diagram shown.
LCD TV currently on the market power in the power of this tradition is still in the majority. It is worth mentioning that, in various sizes of LCD TV models, in particular greater than 26 inches 32 inches and larger LCD TVs dominate the market. and for the 26-inch and larger LCD TVs in recent years emerged a new inverter concept?? high-pressure liquid crystal display integrated power supply (LCDIntegratedPowerSupply, abbreviated as LIPS). and the inverter is located in the traditional independent power supply circuit board is different from that LIPS solution AC-DC, DC-DC and inverter combined with a circuit board, the rectified mains through on, PFC and filtering, and access to 200V / 400V DC voltage, it will directly use 200V/400V input voltage as the inverter, through the DC-AC boost converter for the LCD panel required more than 1,000 V and even up to 2,000 V high voltage. This eliminates the 24V conversion section, to reduce the first significant step-up step-down to 24V and then one or two backlight kV high voltage process the large amounts of power loss, thus enhancing system efficiency and reduce chassis heat and reduce the total cost.
In this regard, ON Semiconductor and Microsemi Corporation Cooperation Combined expertise of both sides to provide a variety of power levels for high-pressure LIPS complete solution. Now, we have to develop for 32-inch LCD TV LIPS solution (shown in Figure 2 chi). In the system board power supply side, this solution uses ON Semiconductor’s NCP1606PFC controller and switching power supply NCP1351PWM as auxiliary controller; in LIPS inverter part, by the use of soft-switch technology Microsemi LX6503 Phase Shift Full Bridge Driver, which can be zero at a fixed frequency voltage switching (ZVS). and a half Bridge Structure than the full-bridge inverter of this solution has significant advantages, such as reducing electromagnetic interference (EMI) and power consumption, while improving the backlight driving current waveform, the bridge without the use of additional power diode, this full-bridge structure used four MOSFET and Transformer The current standard is half the half-bridge structure, it can directly drive power through isolation transformer MOSFET, easier to achieve the primary-side overcurrent protection (OCP) and so on.
Order to better respond to market larger LIPS LCD TV demand, ON Semiconductor is developing the next generation of LIPS LCD TV reference design, and plans to launch in 2009 of 46/47 inch reference design. In the LIPS Inverter Some devices, using the same program with 32-inch full-bridge inverter and the backlight controller LX6503, but a substantial increase in output power, can drive more CCFL lamps. while
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