一种DMOS电流型升压芯片的部分设计

DMOS电流型的升压芯片在多种领域都有着广泛的应用,通过对其shutdown电路,偏置电路,Gm放大器电路,振荡电路,PWM电路,过温保护电路,SR trigger电路,输出驱动电路,电流感应电路,过流保护电路的分析、研究和仿真,为此类芯片的设计开发提供借鉴。本文详细介绍了电流偏置电路模块、放大器电路模块、振荡电路模块和脉宽调制电路四个模块,给出了详细电路图和仿真改进建议。

基于BQ25570的无线传感器微弱能量收集与管理

为解决无线传感器系统的微弱能量供给问题,设计了基于BQ25570的微弱能量收集与管理方法。包括微能量升压、信息采集模块和传输模块。该系统由升压芯片BQ25570将输入端的电压升高至3.3 V存储在超级电容当中,储满后供传感器、微处理器工作,最后通过无线传输模块将数据传输至终端并在上位机显示。测试显示输入源电压为100 mV时,系统可进行以11 s为周期的信号采集传输。当输入电压超过400 mV时,可将采样频率提高到每秒一次甚至更高。

基于太阳能的微能源收获技术

通常情况下,新型微能源的功率有限且不稳定,其电压及电流都较小,这使能量的变换和收获存在一定困难.针对这个问题,介绍了一种利用直流升压芯片的充电电路,将这种低电压、弱电流的微能源高效储存起来再集中释放,从而实现微能源的收获及有效利用.

A COMPRESSION ALGORITHM FOR ECG BASED ON INTEGER LIFTING SCHEME WAVELET TRANSFORM

In view of the shortcomes of conventional ElectroCardioGram (ECG) compression algo- rithms,such as high complexity of operation and distortion of reconstructed signal,a new ECG compression encoding algorithm based on Set Partitioning In Hierarchical Trees (SPIHT) is brought out after studying the integer lifting scheme wavelet transform in detail.The proposed algorithm modifies zero-tree structure of SPIHT,establishes single dimensional wavelet coefficient tree of ECG signals and enhances the efficiency of SPIHT-encoding by distributing bits rationally,improving zero-tree set and ameliorating classifying method.For this improved algorithm,floating-point com- putation and storage are left out of consideration and it is easy to be implemented by hardware and software.Experimental results prove that the new algorithm has admirable features of low complexity, high speed and good performance in signal reconstruction.High compression ratio is obtained with high signal fidelity as well.