In recent years, energy collection theme has caused great interest in the electronic design world. By this program can capture, collected a small amount of energy, and then be used by the electronic device component, it is possible to complete the simple task without embedding a regular power supply in the system design. However, in order to effectively implement, the system needs to operate with the largest possible efficiency level in the predetermined components and system layout. A number of technical problems will be discussed below, and the innovative figures, simulation and power management semiconductor technology will play a key role in overcoming these technical problems.
Currently, applications using energy acquisition (or excavation) include building automation systems, remote monitor / data acquisition devices, and wireless sensor networks. Since the collection technology does not rely on conventional power forms, there are two key ecological benefits. First, it does not cause the fossil fuel reserves to be exhausted; second, it will not exacerbate the degree of pollution (the reason is not carbon emissions, nor does it need a disposable battery). In addition to the provision of wiring or cable wiring and the resulting convenience, the actual advantages of the original equipment manufacturing (OEM) and system integrators are in that once the installation is installed, since there is no fee or the trip to replace the battery The fee, etc., there is no daily operation fee.
Collecting the required energy
There are many ways to collect energy from the environment (depending on the method that is best suited for specific application settings), the generated power level is typically in the range of 10 μW to 400 μW. In the mechanism for use, there is a temperature difference, power (usually by vibration motion), solar, piezoelectric effect, thermoelectric effect, and electromagnetic effect. However, solar energy is likely to be an exception, and energy acquisition is "free" energy point of view is incorrect. Energy based on vibration or thermal gradient utilizes the large amount of energy garbage of the system, therefore needs to be included in maintenance and maintenance costs.
Real world application energy range indication
There are many uses, such as:
1. Switch (Building Automation) - The mechanical forces for opening or closing the switch are sufficient to produce a few millocused (MJ) to run the wireless transmitter, send a radio frequency signal to drive the door latch or lamp. This method is easy to operate and practical because there is no need to wiring.
2. Temperature sensor (building automation) - The temperature difference between environmental air and heater can provide the required power supply, and the temperature data will be sent back to the adjustment system using wireless mode.
3. Air conditioning (building automation) - The electromagnetic signal generated by the vibration of the air conditioning system can be controlled by electromagnetic induction. Air conditioning can also be controlled by this signal.
4. Remote monitoring (industrial / environment) - can be an unmanned meteorological station, chemical plant gas sensing system or tsunami alarm system. A solar battery or a small wind turbine provides the energy required.
5. Medical implant (health care) - such as a blood glucose monitor, through heat or body movement. The low-power wireless transceiver placed on the patient's skin will feed back the data to the hub without any battery (to improve the patient's comfort, and reduce inconvenience).
6. Watch (consumers) - can use solar or kinetic runners that run without batteries.
7. Tire pressure monitoring (TPMS, Automatic) - Use surface acoustic wave (SAW) sensing technology to avoid problems arising from battery and complex electronic devices required to support temperature / pressure sensors on each wheel for each wheel, Reduce the cost of material list and the required engineering resources.
System design elements
Only the μW of the power supply functions as much as possible to make full use of it. Engineers need to work hard to avoid loss. This involves hardware and software consolidation, which can be achieved by implementing efficient components and ensuring full design optimization. The electronic system must be composed of low voltage circuits and provide power intelligence management. Due to the occasion of these system operations, in many cases, the time of collecting energy is not directly related to the time of the subsequent application energy, and it is also necessary to consider energy storage. The storage method used must be low voltage, with high charging current and medium discharge performance, or there may be no self-discharge ability. Digital integrated circuits located in the system must be able to provide far greater than the performance of the processor to complete the system task, and can support low-voltage operations to ensure that the power budget is not exceeded. In addition, cost-effective integrated circuits must be sufficient to ensure that its implementation will not have much impact on the overall cost of the system, otherwise the system will be due overpriced, but has been unable to prove to explore a lot of energy harvesting applications deployment is reasonable.
Typically, if you need to increase performance level, give more optimized or improved integration, OEM will consider taking custom methods and approaches the specific application integrated circuit (ASIC) provider from the beginning of the project. However, since this method requires a large amount of pre-financial investment to pay NRE costs, it is usually not feasible. After that there must be high enough to recover the investment unit volume. Many energy acquisition applications do not have a large unit volume constitution to adopt the method, but in contrast, the engineer is unlikely to maximize the efficiency of the system if the method is combined with only the ready-made components. What is even worse is that the development program may require a lot of time and engineering resources.
Currently, the design selection can use the third selection, providing ASIC favorable technical properties, and has no investment and launch time shortcomings. This method combines an ultra-low-consuming high-efficiency microcontroller that can be customized to integrate preset ICs, and must have a function block, such as acquisition interfaces, and power management functions, sensors, and drive interfaces. The ETA platform of Canova Technologies provides an example of this. Based on the LC87F7932 Ultra-low-consuming microcontroller device (MCU) of the Anshare Semiconductor, this new development kit provides engineers with customizable development kits (hardware and) Software) to suit specific application requirements and thus strengthen the power / performance characteristics of the system. The ETA platform is fully configured, and the interface is capable of matching the most common energy collector on the market, processing greater than 0.9 V or (by using an external transformer) greater than dozens of millivolvic DC and AC input. The acquired energy can be transmitted / stored in different storage elements, such as chemical batteries, capacitors, and supercapacitors. Although the delivery mode is unstable, the system can effectively manage the energy storage, ensuring that it can implement energy-saving strategies, such as using embedded ultra-low-consuming simulated front ends, can complete the collection and adjustment of the system sensor signal, not External MCU supervision.
The LC87F7932B MCU is an 8-bit device based on CMOS technology, with a CPU, running at 250ns (minimum) bus cycle time. The IC sets 32 kilobytes on programmable flash memory, 2048 bytes RAM,, chip debugger, LCD controller / drive, 16-bit timer / counter, and real-time clock. When the current end is adjusted, the 12-bit, 7 channel low power analog number (ADC) converter transform the obtained signal. The digital signal can then be transmitted by the application, or stored in a wireless manner to facilitate extraction at a later stage.
In short, energy acquisition system has a lot of obstacles and puzzles. Engineers need to increase processing performance as much as possible while maintaining the overall power budget at a low level and does not cause huge expenditures, which can prove that it is a very cost-sensitive application. Every effort must be made to use the best optimized components and ensure that the development procedures are generally reasonable. By applying the development platform described in this article, engineers can overcome these obstacles based on ultra-low consumption MCU architecture and configurable customizers, which can achieve more efficient implementation.
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