The purpose of this application note is to show an example of how a digital potentiometer can be used in thefeedback loop of a step-up DC-DC converter to provide calibration and/or adjustment of the output voltage.The example circuit uses a MAX5025 step-up DC-DC converter (capable of generating up to 36V,120mWmax) in conjunction with a DS1845, 256 position, NV digital potentiometer. For this example, the desiredoutput voltage is 32V, which is generated from an input supply of 5V. The output voltage can be adjusted in35mV increments (near 32V) and span a range wide enough to account for resistance, potentiometer and DCDCconverter tolerances (27.6V to 36.7V).
上傳時間： 2014-12-23
上傳用戶：781354052
The LTC®1966 is a true RMS-to-DC converter that uses aDS computational technique to make it dramatically simplerto use, significantly more accurate, lower in powerconsumption and more flexible than conventional logantilogRMS-to-DC converters. The LTC1966 RMS-to-DCconverter has an input signal range from 5mVRMS to1.5VRMS (a 50dB dynamic range with a single 5V supplyrail) and a 3dB bandwidth of 800kHz with signal crestfactors up to four.
上傳時間： 2013-10-12
上傳用戶：qilin
Abstract: The DS1875 features a pulse-width modulation (PWM) controller that can be used to control aDC-DC converter. The DC-DC converter can then be used to generate the high bias voltages necessaryfor avalanche photodiodes (APDs). This application note describes the operation of a boost converterthat uses the DS1875. Discussion covers the selection of the inductor and switching frequency, and theselection of components that improve the efficiency of the converter. Test data are presented.
上傳時間： 2013-10-26
上傳用戶：lyson
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: uses the MAX641 switching controller and an external discrete charge pump to step up the input voltage. This circuitcan service low loads and is efficient when the output is two, three, four times the input voltage. Adding the MAX627 MOSdriver can further increase the output current capability.
上傳時間： 2013-11-15
上傳用戶：zwei41
高的工作電壓高達100V N雙N溝道MOSFET同步驅動 The D810DCDC is a synchronous step-down switching regulator controller that can directly step-down voltages from up to 100V, making it ideal for telecom and automotive applications. The D810DCDC uses a constant on-time valley current control architecture to deliver very low duty cycles with accurate cycle-by-cycle current limit, without requiring a sense resistor. A precise internal reference provides 0.5% DC accuracy. A high bandwidth (25MHz) error amplifi er provides very fast line and load transient response. Large 1Ω gate drivers allow the D810DCDC to drive multiple MOSFETs for higher current applications. The operating frequency is selected by an external resistor and is compensated for variations in VIN and can also be synchronized to an external clock for switching-noise sensitive applications. Integrated bias control generates gate drive power from the input supply during start-up and when an output shortcircuit occurs, with the addition of a small external SOT23 MOSFET. When in regulation, power is derived from the output for higher effi ciency.
上傳時間： 2013-10-24
上傳用戶：wd450412225
Advances in low power electronics now allow placementof battery-powered sensors and other devices in locationsfar from the power grid. Ideally, for true grid independence,the batteries should not need replacement, but instead berecharged using locally available renewable energy, suchas solar power. This Design Note shows how to producea compact battery charger that operates from a small2-cell solar panel. A unique feature of this design is thatthe DC/DC converter uses power point control to extractmaximum power from the solar panel.
上傳時間： 2014-01-20
上傳用戶：wettetw
The LTC®3610 is a high power monolithic synchronousstep-down DC/DC regulator that can deliver up to 12Aof continuous output current from a 4V to 24V (28Vmaximum) input supply. It is a member of a high currentmonolithic regulator family (see Table 1) that featuresintegrated low RDS(ON) N-channel top and bottomMOSFETs. This results in a high effi ciency and highpower density solution with few external components.This regulator family uses a constant on-time valleycurrent mode architecture that is capable of operatingat very low duty cycles at high frequency and with veryfast transient response. All are available in low profi le(0.9mm max) QFN packages.
上傳時間： 2013-11-07
上傳用戶：moerwang
為提高溫度測量效率，降低系統的成本，擴展傳輸距離，設計出一種新型溫度采集系統。單片機通過控制具有單總線方式的溫度傳感器DS18B20實現對溫度的測量，同時單片機通過控制具有單總線方式300～450MHz頻率范圍內的MAX7044與MAX7033無線發射與接收芯片實現溫度數據的無線傳輸。與傳統溫度采集系統相比，該系統利用單總線方式連接，采用無線傳輸方式實現遠距離通信，易于系統的集成與擴展。實驗結果表明，該系統結構簡單、方便移植，能夠同時實現多達上百點溫度的測量與500m范圍的傳輸。 Abstract: To improve the temperature measurement efficiency and reduce system cost,expansion of transmission distance,a new type of temperature acquisition system is designed.Microcontroller controlled temperature sensor DS18B20which has a single-bus achieves temperature measurement,while microcontroller by controlled the MAX7044and MAX7033chip with a single-bus and having300~450MHz radiofrequency to achieve the wireless transmission of temperature data.Compared with conventional temperature acquisition system,the system uses single-bus connected,and uses wireless transmission means to achieve long-distance communications,easy-to-system integration and expansion.The experimental results show that the system is simple,convenient transplantation,and can be implemented in as many as a hundred-point temperature measure-ment and the transmission range of500meters.
上傳時間： 2013-10-29
上傳用戶：515414293
設計一種基于P89V51RD2的功率因數測量儀，采用光電隔離器和專用數碼管驅動器。該測量儀是以增強型單片機P89V51RD2為核心，大大簡化系統硬件設計。而軟件部分采用模塊化設計思想，采用中值濾波和小數補償算法，實現功率因數的高精度測量。實驗測試表明，該功率因數測量儀測量精度高，運行穩定可靠。 Abstract: A power－factor measurement instrument based on P89V51RD2is designed，which uses optical coupler and specific LED drive chip.The power factor measurement instrument uses P89V51RD2as a core of which greatly simplifies the system design.Furthermore，modularization software is developed in detail.The high precision power－factor measuring system is realized by the center value filter and fractional compensation algorithm.Experiments manifests that the power－ factor measurement instrument is high precision，steady and reliable.
上傳時間： 2014-12-27
上傳用戶：CHINA526
