The latest market research report shows that demand for consumer electronics is still strong. As these consumer electronics products become smaller and lighter and have longer battery life, portable audio/video players are gaining popularity in consumer electronics. However, consumer demand for more features and higher performance continues to expand. Processors with faster video codecs and increasingly powerful hard drive capabilities enable the integration of audio/video in one device, the portable media player. Depending on the compression ratio, a typical high-end player with a 20GB hard drive can store MPGE video with a duration of 60-80 hours or MP3 audio with a duration of 500-600 hours. Some models may also have FM or digital camera capabilities. Design challenge Evolving consumer demand poses new challenges to technology. Audio/video playback, gaming, and more require efficient battery power. Stylish, compact, and user-friendly devices require extremely small electronic and mechanical integration components. In order to maximize working hours, it is important to carefully consider the chemical characteristics and capacity of the battery and the battery fuel monitoring function. The correct choice of power conversion circuitry also determines the efficiency with which the battery powers the system. Devices have tight size requirements, so designers should use integrated components in small, thin packages to ensure good power performance. While advanced power ICs can integrate several power channels on the same device, we must understand the power grouping of the system to avoid over-integration. In complex electronic systems, if all of the power components are concentrated in the same location, the traces of the power management device to the actual load point are too long, which can cause noise and heat dissipation problems, thereby extending development time. Innovative solutions A portable media player processor, memory, and display require several different voltage rails and a large amount of power. The battery must be efficiently charged and managed, and achieve efficient conversion from battery voltage to IC supply voltage. Otherwise, the battery life for audio lasts for 16 hours and the battery life for video playback lasts for 5 hours. Figure 1 Power Subsystem of a Typical Portable Media Player The charger must have the ability to manage several input sources, such as the USB port of the computer and peripherals and the AC/DC wall adapter. The input voltage rating on the adapter pins is as high as 18V, which not only avoids system overvoltage spikes on the DC power line, but also uses a lower-cost unregulated wall supply. The charging IC can determine the actual charging current to enter the battery and the current used by the system. Therefore, in the case where the battery is charged and the system is running at the same time, the charging process does not cause an abnormal termination problem. The above solution enables dynamic power management to properly distribute the available DC input power between the system and the battery. If the system current rises, the battery charging current will automatically decrease, and vice versa. This helps to optimize costs so that the wall power supply can meet the average power requirements of the system as a whole for the battery and the application, rather than having to use a power supply that meets the most stringent power requirements. We can further improve battery management by using a battery fuel gauge to accurately determine the remaining battery power. In this way, the processor can effectively adopt a low-power mode and alert the user when charging is needed to better manage the power consumption of the media player. The power conversion of the media player is mainly achieved by converting the DC regulator. We believe that linear regulator solutions have the advantages of small size and low cost in terms of voltage regulation. However, if the current exceeds 300A, it will require a large and expensive heat sink because the power consumption is too high. This type of problem can occur if the output current is high and the input-to-output voltage differential is large. Suppose we use a 3.6V lithium-ion battery to provide a 1.2V core voltage. The linear regulator is only 33% efficient, and most of the battery power is dissipated. The DC/DC converter is actually operating at more than 90% efficiency and consumes only a fraction of the power of the low-dropout regulator (LDO). Figure 3 shows an example of efficient power conversion. To provide core voltage to the 1.5V 500mA encoder/decoder engine, we used a highly integrated synchronous DC/DC converter with FETs to achieve maximum power efficiency and minimize external component count. With this solution, it is not necessary to use a heat sink with a large footprint. The highly integrated DC/DC converter uses an on-chip conversion FET and implements an internal compensation mechanism compared to a DC/DC controller solution. This means that design engineers do not have to choose external transistors or use expensive and difficult design software to analyze compensation and stability conditions. The component selection is very convenient, we only need to use the recommended inductor according to the product manual. Figure 2 Dual DC Input Linear Charging Solution with Dynamic Power Management Figure 3. High-frequency 3MHz DC/DC converter with a small number of components and a small package The DC/DC buck solution in Figure 3 shows space-saving features. Since the switching transistor is integrated, the circuit requires only one inductor and two capacitors. The device's unique control architecture allows the power supply to react quickly to load transients and maintain high-precision regulation. The extremely high 3MHz switching frequency reduces the inductor size to only 1μH, enabling the use of chip inductors less than 1mm in height. The overall solution can be constructed to fit 5mm x 5mm applications. To further reduce power consumption, advanced DC/DC regulators also offer automatic PFM/PWM mode conversion to maximize conversion efficiency over a wide load range. The converter can enter pulse frequency modulation (PFM) mode at low load currents, and pulse width modulation (PWM) control schemes support load currents greater than 50mA. Conclusion Consumers expect small devices to offer more features and achieve longer working hours. Battery technology and the continuous development of low-power semiconductor components can help engineers gradually meet the above requirements. Accurate monitoring of battery capacity helps to fully utilize all of the battery's power, combined with efficient power conversion, to help you get the most out of your battery. We use highly integrated power management devices and minimize external component count and package size, which helps to efficiently utilize limited board space to integrate more features and reduce product size and weight. More information about the chip TPS62303YZD: integrated circuit query network http:// Langrui Energy (Shenzhen) Co.,Ltd , https://www.langruibattery.com
Figure 1 shows the power subsystem for a portable media player. The Li-Ion battery charger safely and accurately recharges the battery, while the accurate battery fuel gauge device determines the state of charge and helps the system make the most of any available power. Several power converters convert the battery voltage to the desired system voltage. The most important thing is to power the TFT LCD display with display controller and backlight function. For memory and other components, a 3.3V rail typically requires up to 1A of current. For a hard disk, the 3.3V power supply is usually provided by a separate mains voltage rail, because the voltage rail is individually controlled by the system to turn it off when not needed, thus saving energy. The processing engine needs some ultra-low core voltage, 1.2V or 1.8V. The audio must be a regulated output with a linear regulator to filter the noise of the switching converter.