For battery-powered portable devices, in addition to the need to break through the processing power limitations, the performance of portable system power supplies needs to be continuously improved. This article explores the considerations for power supply design for portable embedded systems and the guidelines to be followed in design.
1 power management unit
It is not trivial to specify specific functional and architectural modules for the power supply circuit. These tasks directly affect the operating time of the battery-powered system. The power system architecture will vary depending on the embedded product and application area. The function of the power path controller is to switch to the appropriate power source when there are multiple power supplies. In some designs it may be necessary to consider powering methods such as emerging USB and Power over Ethernet (PoE).
The battery protection circuit protects the battery from overvoltage, undervoltage, overheating, overcurrent and other abnormal conditions; the dedicated battery charging circuit should charge the battery once there are other sources of power; the fuel gauge circuit continuously monitors the battery Battery status and battery status information for users and power management software.
The system may require multiple DS-DC power converters. For example, switching power supply (SMPS), LDO regulator, charge pump, etc. These different converters are used for all possible input power supplies and the different voltages required in the product design.
The digital interface or hardware button controller is responsible for turning the system on and off - sometimes called soft start. In some recently introduced power converters, the digital interface can also be used to fine tune the output voltage produced by various converters. This fine tuning is required in power-conscious power supply designs.
2 High efficiency power supply standard
In embedded applications, power efficiency is not limited to the traditional ratio of system output power to system input power. In embedded systems, efficient power solutions should meet the following criteria:
1. When using battery power, the device can work for a long time;
2. Extend battery life (number of charge and discharge);
3. Limit the temperature rise of the components and the battery itself;
4. Provide integrated software intelligence to maximize efficiency.
In fact, there is no single guideline to maximize the efficiency of your power solution. However, designers will consider the following points when developing a power system: battery life (number of charge and discharge) depends on the battery's charging characteristics; for lithium-ion batteries, manufacturers generally recommend following the optimal charging current (constant current mode). And termination/precharge current values. These specifications must be strictly adhered to when designing the charger circuit.
3 Battery Management
For consumer electronics, battery protection must be considered a basic feature because it is closely related to the user's personal safety. Adequate measures must be taken to detect overvoltage, undervoltage, and temperature of the battery; suitable devices such as temperature-dependent resistors must be used to ensure that the current is automatically limited regardless of any abnormal conditions; a fuel gauge must be used. In addition to normal battery detection, it also ensures battery safety. Most fuel gauges are mounted on the battery and can be used to detect battery temperature, discharge current, and more.
A problem that is often overlooked for power path controllers is that when switching from one power supply to another, no matter how short the time is, there is no way to form a loop between the two. This may require additional reverse connection diodes or switches. Similarly, when one of the power supplies is used, the voltage of the power supply should not pass to the input of the other power supply.
Since there are many power converter topologies available, it is not easy to properly select a power converter. In general, linear regulators must be avoided where high efficiency and high output current are required.
Where a switching power supply is used, the designer should ensure that the appropriate topology (buck, boost, buck-boost, charge pump, SEPIC, etc.) is used to ensure that even when the battery voltage drops to the minimum operating value, The power supply also maintains the desired output voltage, which helps to extend the operating time of the device.
For buck converters, synchronous converters typically have higher efficiency than non-synchronous converters. However, this architectural choice depends to a large extent on the output current and duty cycle required for the converter to operate. Therefore, the slight increase in efficiency brought about by the use of a synchronous converter is not sufficient to compensate for the increased cost.
The difference in the type of inductance used to filter the switching ripple of the switching power supply usually has a different effect on converter efficiency. Among the various inductor options, low DC impedance and inductors with low magnetic losses at the operating frequency are preferred.
Thermal design should be inseparable from electrical design. The package of each IC or passive device must be able to handle the heating problem under normal operating conditions. Many chip manufacturers recommend using thermal pads with vias and using large pads on the PCB for better heat dissipation. Compact embedded products usually do not have room for fans, but must take into account the ventilation channels on the PCB and adequate heat dissipation.
4 Summary
Power design is often treated as a pure hardware design. However, in order to get an efficient power solution, designers need to add software intelligence to the power circuit. Some of the basic functions of software control include detecting which power source is selected by the power path switch; reducing the supply current to unwanted circuits when the battery is powered.
More sophisticated power management software will include other parameters such as the type of application the system is running, the minimum peripheral requirements, the slowest clock frequency, and the minimum voltage required to run the application, and accordingly control the power output and clock generation accordingly. The status of the device and interface IC.
Following the above rule of thumb can significantly improve the power performance of portable devices. For example, a typical 30W multi-output power solution can achieve an overall efficiency of 85 to 90%. A number of highly integrated ICs are available from a number of integrated circuit manufacturers to provide these features. Depending on the power requirements, some applications may require a single-chip solution, while others may use discrete modules. After all, in the highly competitive embedded market, battery life and equipment hours are key factors influencing buyer choice.
share to:
What`s the main features appear into your mind when you look yoga laptop? Lightweight, super thinner, touch screen, 360 rotating, smaller size, like as notebook? You are right, that`s the main reasons why some people also called it as laptop yoga slim or yoga notebook. To OS, just same as Education Laptop-windows operating system, so you can see many windows yoga laptop at the market around the world. In fact, this intel yoga laptop usually is designed for normal jobs, like basic WPS, Photoshop, video or music editing, online learning, shopping, presentation when on a business trip, etc. At our store, you can see 11.6 inch n5100 360 Laptop in metal, 13.3 inch 360 flip laptop, and 14 inch 360 degree rotating laptop, etc. The people who take business trips often or prefer fashion design should like this type device.
There are education laptop also, like 14.1 inch Student Laptop for Hope or government Projects, 15.6 inch competitive celeron business laptop for normal business works, 15 inch 10th or 11th Gaming Laptop for heavier tasks, like teachers, high or university students, etc, 16.1 inch i7 16gb ram 4gb graphics laptop for engineering student, etc
Any other question or other requirements, just contact us freely.
Yoga Laptop,Laptop Yoga Slim,Yoga Notebook,Intel Yoga Laptop,Windows Yoga Laptop
Henan Shuyi Electronics Co., Ltd. , https://www.sycustomelectronics.com