Abstract: A resistive feedback network is often used to set the output voltage of a power supply. A mechanical potentiometer (pot)conveniently solves the problem of adjusting a power supply. For easier automatic calibration, a mechanical pot can be replaced witha digital pot. This application note presents a calibration solution that uses a digital pot, because digipots are smaller, do not movewith age or vibration, and can be recalibrated remotely. This proposed solution reduces the susceptibility of the system to thetolerance of the digital pot's end-to-end resistance, making the solution optimal fordesigners. This application note also explainssome of the equations required to calculate the resistor chain values and to use a digital pot in this way. A spreadsheet withstandard reisistor values is available for easy calculations.
上傳時間： 2013-10-31
上傳用戶：caiguoqing
Abstract: Field-programmable gate arrays (FPGAs) are used in a wide variety of applications and end markets, including digital signalprocessing, medical imaging, and high-performance computing. This application note outlines the issues related to powering FPGAs.It also discusses Maxim's solutions for powering Altera® FPGAs.
上傳時間： 2013-11-02
上傳用戶：zhaoman32
The MAX14885E, a 2:2 VGA switch, connects a VGA source to a VGA monitor. To ease direct connection to graphics controllers orthe ASIC, the MAX14885E has two supplies: VCC, a 5V ±5% supply, drives the VGA side interface; and the VL supply sets the logicswitching thresholds on the digital input pins (EN, S00, S01, S10, S11, SHA, SHB, SVA, and SVB). This application note documentsthe proper sequencing of the VCC and VL power supplies on power-up.
上傳時間： 2013-10-23
上傳用戶：wuchunzhong
Piezoelectric motors are used in digital cameras for autofocus,zooming and optical image stabilization. Theyare relatively small, lightweight and effi cient, but theyalso require a complicated driving scheme. Traditionally,this challenge has been met with the use ofseparatecircuits, including a step-up converter and an oversizedgeneric full-bridge drive IC. The resulting high componentcount and large board space are especially problematicin the design of cameras for ever shrinking cell phones.The LT®3572 solves these problems by combining astep-up regulator and a dual full-bridge driver in a 4mm× 4mm QFN package. Figure 1 shows a typical LT3572Piezo motor drive circuit. A step-up converter is usedto generate 30V from a low voltage power source suchas a Li-Ion battery or any input power source within thepart’s wide input voltage range of 2.7V to 10V. The highoutput voltage of the step-up converter, adjustable upto 40V, is available for the drivers at the VOUT pin. Thedrivers operate in a full-bridge fashion, where the OUTAand OUTB pins are the same polarity as the PWMA andPWMB pins, respectively, and the OUTA and OUTB pinsare inverted from PWMA and PWMB, respectively. Thestep-up converter and both Piezo drivers have their ownshutdown control. Figure 2 shows a typical layout
上傳時間： 2013-11-18
上傳用戶：hulee
In predominantly digital systems it is often necessaryto include linear circuit functions. Traditionally, separatepower supplies have been used to run the linear components(see Box, “Linear Power Supplies—Past, Present,and Future”).
標簽： Designing Operation Circuits Linear
上傳時間： 2013-11-04
上傳用戶：sdq_123
Permission to make digital or hard copies of all or part of this work forpersonal or classroom use is granted without fee provided that copies arenot made or distributed for profit or commercial advantage and that copiesbear this notice and the full citation on the first page. To copy otherwise, torepublish, to post on servers or to redistribute to lists, requires prior specificpermission.
標簽： 數字電源
上傳時間： 2013-10-16
上傳用戶：dddddd
保證Fluke產品從購買日起一年內，沒有材料和工藝上的瑕疵。本項擔保不包括保險絲、可棄置的電池或者因意外、疏忽、誤用或非正常情況下的使用或處理而損壞的產品。Fluke也未曾授權予經銷商將本保證期延長。保證期間如果需要維修，請將測試儀表附上故障說明送到購買儀表的分銷商處。 本項保證是閣下唯一的補償。除此以外，Fluke不做任何明示或默示的保證（例如保證某一特殊目的的適應性）。同時，凡因任何原因或推測而導致的任何特別、間接、附帶或繼起的損壞或損失，Fluke也一概不予負責。由于某些州或國家不允許對默示保證及附帶或繼起的損壞有所限制，故上述的責任范圍與規定或許與您無關。
標簽： Multimeter digital 18B 用戶手冊
上傳時間： 2013-11-07
上傳用戶：璇珠官人
SD 卡（Secure digital Memory Card）是一種為滿足安全性、容量、性能和使用環境等各方面的需求而設計的一種新型存儲器件，SD 卡允許在兩種模式下工作，即SD 模式和SPI 模式，本系統采用SPI 模式。本小節僅簡要介紹在SPI 模式下，STM32 處理器如何讀寫SD 卡，如果讀者如希望詳細了解SD 卡，可以參考相關資料。
標簽： SD卡
上傳時間： 2013-11-12
上傳用戶：huannan88
數字控制的交流調速系統所選用的微處理器、功率器件及產生PWM波的方法是影響交流調速系統性能好壞的直接因素。在介紹了正弦脈寬調制(SPWM)技術的基礎上，設計了一種以8098單片機作為控制器，以智能功率模塊IPM為開關器件的變頻調速系統。通過軟件編程，產生正弦脈沖寬度調制波形來控制絕緣柵雙極晶體管的導通和關斷，從而達到控制異步電動機轉速的目的。實驗結果表明，該系統可調頻率調電壓，穩定度高，調速范圍寬，具有較強的實用價值 Abstract: AC variable speed with digital control systems used microprocessors， power devices and generate PWM wave is the direct factors of affecting the performance AC speed regulation system. On the basis of introducing the sinusoidal pulse width modulation (SPWM) technology，this paper designed variable speed system which used 8098 as a controller， intelligent power module IPM as switching device. Through software programming， resulting in sinusoidal pulse width modulation waveform to control the insulated gate bipolar transistor turn on and off， so as to achieve the purpose of speed control of induction motors. Experimental results show that the system can adjust frequency modulation voltage， high stability， wide speed range， has a strong practical value.
上傳時間： 2013-11-14
上傳用戶：ynwbosss
HIGH SPEED 8051 μC CORE - Pipe-lined Instruction Architecture; Executes 70% of Instructions in 1 or 2 System Clocks - Up to 25MIPS Throughput with 25MHz System Clock - 22 Vectored Interrupt Sources MEMORY - 4352 Bytes Internal Data RAM (256 + 4k) - 64k Bytes In-System Programmable FLASH Program Memory - External Parallel Data Memory Interface – up to 5Mbytes/sec digital PERIPHERALS - 64 Port I/O; All are 5V tolerant - Hardware SMBusTM (I2CTM Compatible), SPITM, and Two UART Serial Ports Available Concurrently - Programmable 16-bit Counter/Timer Array with 5 Capture/Compare Modules - 5 General Purpose 16-bit Counter/Timers - Dedicated Watch-Dog Timer; Bi-directional Reset CLOCK SOURCES - Internal Programmable Oscillator: 2-to-16MHz - External Oscillator: Crystal, RC, C, or Clock - Real-Time Clock Mode using Timer 3 or PCA SUPPLY VOLTAGE ........................ 2.7V to 3.6V - Typical Operating Current: 10mA @ 25MHz - Multiple Power Saving Sleep and Shutdown Modes 100-Pin TQFP (64-Pin Version Available) Temperature Range: –40°C to +85°C
標簽： C8051F020
上傳時間： 2013-10-12
上傳用戶：lalalal
