The PW5410A is a low noise, constant frequency (1.2MHz) switched capacitor voltage doubler. Itproduces a regulated output voltage from 2.7V to 5V input with up to 250mA of output current. Lowexternal parts count (one flying capacitor and two small bypass capacitors at VIN and VOUT) makethe PW5410A ideally suited for small, battery-powered applications
The PW5200A/ PW5200C is high efficiency synchronous, PWM step-up DC/DC converters optimizedto provide a high efficient solution to medium power systems. The devices work with a 1.4MHz fixedfrequency switching. These features minimize overall solution footprint by allowing the use of tiny,low profile inductors and ceramic capacitors. Automatic PWM/PFM mode switching at light loadsaves power and improves efficiency
PW2330 develops a high efficiency synchronous step down DC-DC converter capable of delivering3A output current. PW2330 operates over a wide input voltage range from 4.5V to 30V andintegrates main switch and synchronous switch with very low RDS(ON) to minimize the conductionloss. PW2330 adopts the proprietary instant PWM architecture to achieve fast transient responsesfor high step down applications and high efficiency at light loads. In addition, it operates atpseudo-constant frequency of 500kHz under continuous conduction mode to minimize the size ofinductor and capacitor
PW2205 develops a high efficiency synchronous step-down DC-DC converter capable of delivering5A output current. PW2205 operates over a wide input voltage range from 4.5V to 30V andintegrates main switch and synchronous switch with very low RDS(ON) to minimize the conductionloss.PW2205 adopts the instant PWM architecture to achieve fast transient responses for high step downapplications and high efficiency at light loads. In addition, it operates at pseudo-constant frequencyof 500kHz under continuous conduction mode to minimize the size of inductor and capacitor
The PW2163 is a high efficiency 500 kHz synchronous step-down DC-DC converter capable ofdelivering 3A current. The PW2163 operates over a wide input voltage range from 4.5V to 18V andintegrates main switch and synchronous switch with very low RDS(ON) to minimize the conductionloss. Low output voltage ripple and small external inductor and capacitor sizes are achieved with 500kHz switching frequency. It adopts the instant PWM architecture to achieve fast transient responsesfor high step down applications
The PW2053 is a high-efficiency monolithic synchronous buck regulator using a constantfrequency, current mode architecture. The device is available in an adjustable version. Supply currentwith no load is 40uA and drops to <1uA in shutdown. The 2.5V to 5.5V input voltage range makesthe PW2053 ideally suited for single Li-Ion battery powered applications. 100% duty cycle provideslow dropout operation, extending battery life in portable systems. PWM/PFM mode operationprovides very low output ripple voltage for noise sensitive applications. Switching frequency isinternally set at 1.2MHz, allowing the use of small surface mount inductors and capacitors. Lowoutput voltages are easily supported with the 0.6V feedback reference voltage
本系統采用電動機電樞供電回路串接采樣電阻的方式來實現對小型直流有刷電動機的轉速測量。該系統主要由二階低通濾波電路,小信號放大電路、單片機測量顯示電路、開關穩壓電源電路等組成。同時自制電機測速裝置,用高頻磁環作為載體,用線圈繞制磁環,利用電磁感應原理檢測電機運行時的漏磁,將變化的磁場信號轉化為磁環上的感應電流。用信號處理單元電路將微弱電信號轉化為脈沖信號,送由單片機檢測,從而達到準確測量電機的速度的要求。In this system, the sampling resistance of armature power supply circuit is connected in series to measure the speed of small DC brush motor. The system is mainly composed of second-order low-pass filter circuit, small signal amplifier circuit, single-chip measurement and display circuit, switching regulated power supply circuit and so on. At the same time, the self-made motor speed measuring device uses high frequency magnetic ring as the carrier, coil winding magnetic ring, and electromagnetic induction principle to detect the leakage of magnetic field during the operation of the motor, which converts the changed magnetic field signal into the induced current on the magnetic ring. The weak electric signal is transformed into pulse signal by signal processing unit circuit, which is sent to single chip computer for detection, so as to meet the requirement of accurate measurement of motor speed.
數字示波器功能強大,使用方便,但是價格相對昂貴。本文以Ti的MSP430F5529為主控器,以Altera公司的EP2C5T144C8 FPGA器件為邏輯控制部件設計數字示波器。模擬信號經程控放大、整形電路后形成方波信號送至FPGA測頻,根據頻率值選擇采用片上及片外高速AD分段采樣。FPGA控制片外AD采樣并將數據輸入到FIFO模塊中緩存,由單片機進行頻譜分析。測試表明:簡易示波器可以實現自動選檔、多采樣率采樣、高精度測頻及頻譜分析等功能。Digital oscilloscope is powerful and easy to use, but also expensive. The research group designed a low-cost digital oscilloscope, the chip of MSP430F5529 of TI is chosen as the main controller and the device of EP2C5T144C8 of Altera company is used as the logic control unit. Analog signal enter the programmable amplifier circuit, shaping circuit and other pre-processing circuit. The shaped rectangular wave signal is sent to FPGA for measure the frequency. According to the frequency value to select AD on-chip or off-chip high-speed AD for sampling. FPGA controls the off-chip AD sampling and buffers AD data by FIFO module. The single chip microcomputer receives the data, and do FFT for spectrum analysis. The test shows that the simple oscilloscope can realize automatic gain selection, sampling at different sampling rates, high precision frequency measurement and spectrum analysis.
超聲波換能器作為一種實用的檢測手段，能實現聲波所攜帶的信息和電能之間轉換。它的性能優良，價格低廉，操作方便，易于調試，因此在工農業生產中發揮著重要的作用。但目前換能器驅動電路的發射頻率多為40 kHz，本文針對1 MHz的超聲波換能器電路進行了設計，主要介紹了它的發射驅動電路和接收驅動電路的設計方案，并對它們的功能進行了詳細地說明。最后搭建實驗平臺，并對電路的輸入、輸出模塊進行了測試。實驗結果表明，換能器電路運行良好，可以為超聲波高精度測量領域的應用提供參考。As a practical means of detection, ultrasonic transducer can realize the conversion between theinformation carried by sound wave and electric energy.It has the advantages of excellent performance,low cost, convenient operation and debugging, so plays an important role in industrial and agriculturalproduction.However, the transmitting frequency of the driving circuit for most transducer is 40 kHz.Thecircuit of 1 MHz ultrasonic transducer is designed In this paper. It mainly introduces the emissive drivingcircuit and the receiving circuit design and the detailed function of them. Finally, the experimentalplatform is built, and the circuit of input and output were tested. Experiments show that the transducer＇ s...
射頻識別(Radio Frequency Identification，RFID)是一種允許非接觸式數據采集的自動識別技術。其中工作在超高頻(Ultra High Frequency，UHF)頻段的無源RFID系統，由于在物流與供應鏈管理等領域的潛在應用，近年來得到了人們的廣泛關注。這種系統所使用的無源標簽具有識別距離長、體積小、成本低廉等突出特點。目前在市場上出現了各種品牌型號的UHF RFID無源標簽，由于不同品牌型號的標簽在設計與制造工藝上的差異，這些標簽在性能表現上各不相同，這就給終端用戶選擇合適自己應用的標簽帶來了困難。RFID基準測試就是在實際部署RFID系統前對RFID標簽的性能進行科學評估的有效手段。然而為了在常規實驗室條件下得到準確公正的測試結果，需要對基準測試的性能指標及測試方法學開展進一步的研究。本文正是研究符合EPC Class1 Gen2標準的RFID標簽基準測試。 本文首先分析了當前廣泛應用的超高頻無源RFID標簽基準測試性能指標與測試方法上的局限性與不足之處。例如，在真實的應用環境中，由于受到各種環境因素的影響，對同一品牌型號的標簽，很難得到一致的識讀距離測試結果。另外，在某些測試場景中，使用識讀速率作為測試指標，所得到的測試結果數值非常接近，以致分辨度不足以區分不同品牌型號標簽的性能差異。在這些分析基礎上，本文把路徑損耗引入了RFID基準測試，通過有限點的測量與數據擬合分別得到不同類型標簽的路徑損耗方程，結合讀寫器天線的輻射方向圖，進一步得到各種標簽受限于讀寫器接收靈敏度的覆蓋區域。無源標簽由于其被動式能量獲取方式，其實際工作區域仍然受限于前向鏈路。本文通過實驗測試出這些標簽的最小激活功率后，得出了各種標簽在一定讀寫器發射功率下的激活區域。完成這些步驟后，根據這兩種區域的交集可以確定標簽的工作區域，從而進行標簽間的比較并達到基準測試的目的，并能找出限制標簽工作范圍的瓶頸。 本文最后從功率損耗的角度研究了標簽之間的相互干擾，為用戶在密集部署RFID標簽的場景中設置標簽之間的最小間隔距離具有重要的參考意義。
