LCD TV total power supply solution creates efficient energy-saving design

Liquid crystal display (LCD) panels have been popular since the early 1990s. Their main application products have expanded from notebook computers to desktop computer screens since the second half of the 1990s, and have been developed towards TV applications since 2002. LCD TVs have rapidly entered more and more households with their advanced technical performance, beautiful and stylish appearance, low radiation, stable operation, and high reliability. They are livelihood products closely related to life and are favored by most consumers.

LCD TV development accelerates, power management IC faces new challenges

From the perspective of the international market, LCD TV shipments have been rising sharply since 2002. The sales of LCD TVs took off in the three years from 2005 to 2007. According to statistics, the global LCD TV shipments in 2005 were about 28.5 million units, and in 2006 they were more than 48 million units, which is about double the shipments in 2005. It is expected that the global LCD TV shipments will rise to 69 million units in 2007, which is another increase of 42.3% over 2006.

LCD TV has also shown strong growth momentum in China. According to the IMS report, the sales volume of LCD TV in China's domestic market reached 1.87 million units in 2005. With the promotion of digital TV technology, it is expected that by 2010, the sales volume of LCD TV in China's domestic market will increase to 21 million units, with a compound annual growth rate of 61.3%.

At present, China has become the global production base for LCD-related products. The rapid development of the LCD TV market has led to a substantial increase in the demand for LCD TV power management chips. As LCD TVs develop, power management ICs are also facing higher technical requirements. As the international situation of environmental protection and energy conservation becomes increasingly clear, countries around the world have begun to implement increasingly stringent power-saving requirements for standby power consumption and efficiency of home appliances and consumer electronics products. New international power consumption standards and technical standards, such as the United States' "Energy Star", Germany's "Blue Angel Standard" and the relevant standards formulated by the China Certification and Accreditation Center (CECP), have begun to implement high-efficiency energy conservation and environmental protection. It has become a consensus in today's world.

AC/DC

Figure 1: (a) The AC/DC part of the block diagram of the LCD TV power solution designed by Onbao; (b) The CCFL backlight part of the block diagram of the LCD TV power solution designed by Onbao.

However, the current state of technology in my country is far behind. Taking color TVs as an example, the test survey shows that the average standby power consumption of Chinese TVs is 8.07W, which is much greater than the 1W standby power stipulated by the International Energy Agency (IEA). Therefore, it is becoming increasingly important to design high-efficiency and low-cost LCD TV power supplies. For power supply manufacturers, their power supply product design and production will face a new challenge.

"Green Engine" technology covers AC/DC,

With the development of LCD TV, the new international power consumption standard puts forward higher requirements for power management. Facing such opportunities and challenges, Onbo has developed high-performance, low-power CCFL control chips and supporting AC/DC green power management chips with independent intellectual property rights, providing a full set of green power solutions for LCD TV.

Usually, the power management system of LCD TV consists of three parts: power converter, inverter (backlight power supply), and signal processing system, while Onbao's patented technology covers the two main parts of power converter and inverter (backlight power supply). With its technical advantages in the field of high-end power management, Onbao Electronics seized the opportunity of comprehensive technical upgrade of LCD TV power IC, and carried out technical research in three aspects: AC/DC power management chip, CCFL inverter control chip, and PFC power factor correction control chip, combining advanced chip design technology with deep system technology application to achieve high-end power management of LCD TV.

In terms of AC/DC power management IC: Onbao has developed a high-end power management chip series and system solutions with independent intellectual property rights GreenEngine technology, realizing the internal power supply of large-size LCD TVs and reaching the industry-leading level in terms of high efficiency and energy saving.

In terms of CCFL inverter control chips, most of the power of large-size LCD TVs is consumed by the backlight source. Onbao's CCFL inverter control chip uses technology with completely independent intellectual property rights, which greatly improves the performance of the entire inverter system. It can improve conversion efficiency, extend the life of the lamp, improve system safety, reduce costs, and increase the dynamic range of high-brightness control of the lamp. The independently innovative adaptive ZVS technology effectively improves the efficiency of the system; the "intermittent working mode" technology with independent intellectual property rights greatly improves the system's dimming dynamic range; the independently innovative feedforward compensation technology greatly improves the output current constancy of the system within the full voltage range, fully meeting the application of high-end CCFL backlight sources.

Onbao's overall power supply solution for LCD TV perfectly demonstrates the "green engine" technology

At present, the domestic large-size LCD TV multi-tube backlight driving technology and solutions are not yet mature. In the field of LCD TV power supply, whether it is the module system or the internal drive control chip, its core technology has been in the hands of companies in Europe, America, Japan, South Korea and Taiwan for many years, and most of them have patent protection restrictions. Therefore, the production of various complete machine manufacturers in mainland China all relies on imported power management solutions. The CCFL backlight source driver power IC used by local LCD TV manufacturers mainly comes from overseas manufacturers.

However, the low-cost operation and high-efficiency logistics brought by localization highlight the advantages of Onbao Electronics. More importantly, although overseas manufacturers have strong technical strength and mature market share in the CCFL backlight driver part, most of them only provide CCFL backlight driver products, and there are no AC/DC power management chips for LCD TV power management. Customers must find another AC/DC supplier. Onbao Electronics is close to the market, and its products not only cover CCFL backlight driver chips, but also AC/DC power management chips, providing an overall power solution for LCD TVs.

The AC/DC part of Onbao's overall power solution uses PFC and PWM chipsets, which can greatly simplify the power system design circuit and reduce the cost of external parts; the CCFL backlight part covers push-pull, half-bridge, full-bridge, and power tube integrated series, and can provide customers with a complete set of power solutions.

Figure 2: 32-inch LCD TV Power/Inverter complete solution.

The latest 300W LCD TV Power solution launched by Onbao is developed to meet the growing market demand for large-size LCD TVs. It can be applied to the power management system of 32-inch LCD TVs and uses OB6563, OB2263, OB2288 and OB3338 chips. According to user requirements, multiple outputs can be performed simultaneously, such as: 24V/10A, 12V/3A, and 5V/5A. Its standby power consumption is <1W, which can meet the US 80 PLUS energy efficiency.

The energy-efficient power factor corrector OB6563 is a high-performance transition mode power factor corrector (PFC). This Onbao product optimizes the traditional transition mode control design, making it easy for the system to achieve a power factor close to 1. At the same time, it integrates a number of Onbao's patented technologies to enhance the application value of customers, achieving:

1. Patented harmonic optimization technology can achieve extremely low harmonic distortion (<10%@264VAC);

2. Patented technology eliminates abnormal noise during operation;

3. Feedback open circuit protection, triple overvoltage protection, and line voltage low voltage protection ensure the safety of the system;

4. The current detection circuit has built-in dual noise suppression function, without the need for an external RC low-pass filter;

5. Lower dynamic OVP detection current, combined with PWM, the system can achieve ultra-low standby energy consumption.

The energy-saving and efficient AC/DC chip OB2288 is a PWM control chip specially designed for medium and high power AC/DC applications. It has a built-in maximum duty cycle limit of 50%, so it is suitable for forward topology architecture. OB2288 has a 1500mA Gate drive capability, a built-in high-precision Brown out/recovery module and soft start function, and a built-in 250ms overload protection module, which can easily meet the instantaneous high peak power output requirements. The chip has been carefully optimized for the application environment of medium and high power systems, so that the system design can meet various high standards. The no-load to full-load system meets the global standby power consumption requirements implemented since 2007. The built-in EMI optimization strategy simplifies the system design in many ways to reduce the system cost as much as possible.

OB2263 fully embodies the "Green Engine" technology concept of Onbao Electronics, which enables system design to easily achieve ultra-low standby power consumption, intelligent OCP compensation, precise overload and overvoltage protection, and excellent EMI characteristics. Compared with other chips in the same field, it has extremely high cost performance.

High-performance DC/AC inverter technology OB3338 is a high-precision, high-efficiency, high-performance dual-channel full-bridge inverter control chip from Onbao. It supports multi-chip cascade operation and can drive large-size multi-lamp panels. The chip has flexible dimming mode selection and wide-range dimming control, as well as complete protection functions. It is worth mentioning that the Burst frequency can also be synchronized with the video signal Frame frequency, which can greatly improve the image response and picture quality of LCD TVs.

Currently, OB6563 provides two packaging forms: DIP8 and SOP8; OB2263 provides two packaging forms: DIP8, SOP8 and SOT23-6; OB2288 provides two packaging forms: DIP8 and SOP8; OB3338 provides SOP32 packaging. All packages meet RoHS standards.

Onbao Electronics also provides power supply solutions for LCD TVs of other sizes, using high-efficiency and energy-saving CCFL chips such as OB3328, combined with green and efficient ACDC chips with independent intellectual property rights technology, to achieve high-performance, low-power consumption, and low-cost design to truly meet the various needs of customers.