General Description
The LM621 is a bipolar IC designed for commutation of
brushless DC motors. The part is compatible with both
three- and four-phase motors. It can directly drive the power
switching devices used to drive the motor. The LM621 provides
an adjustable dead-time circuit to eliminate ``shootthrough''
current spiking in the power switching circuitry.
Operation is from a 5V supply, but output swings of up to
40V are accommodated. The part is packaged in an 18-pin,
dual-in-line package.
·【英文題名】 Research of Speed Regulate System of Three Phase BLDCM Based on DSP 【作者中文名】 劉桂芬; 【導師】 孟慶春; 【學位授予單位】 遼寧工程技術大學; 【學科專業名稱】 控制理論與控制工程 【學位年度】 2007 【論文級別】 碩士 【網絡出版投稿人】 遼寧工程技術大學 【網絡出版投稿時間】 2006-01-02 【
The MAX2870 ultra-wideband phase-locked loop (PLL) and voltagecontrol oscillator (VCO) can operate in both integer-N and fractional-Nmodes, similar to the Analog Devices ADF4350 wideband synthesizer.This application note compares the MAX2870 and ADF4350 registers andloop filter design in detail. Users who already familiar with ADF4350 canuse this application note as a quick design reference.
Abstract: Many industrial/scientific/medical (ISM) band radio frequency (RF) products use crystal oscillators to generate areference for the phase-locked loop (PLL)-based local oscillator (LO). This tutorial provides a basic description of theISM-RF Crystal Calculator, which can be used to calculate various impacts on crystal frequency accuracy and startupmargin for such an LO.
Many applications require a clock signal to be synchronous, phase-locked, or derived fromanother signal, such as a data signal or another clock. This type of clock circuit is important in
Abstract: Transimpedance amplifiers (TIAs) are widely used to translate the current output of sensors like photodiode-to-voltagesignals, since several circuits and instruments can only accept voltage input. An operational amplifier with a feedback resistor fromoutput to the inverting input is the most straightforward implementation of such a TIA. However, even this simple TIA circuit requirescareful trade-offs among noise gain, offset voltage, bandwidth, and stability. Clearly stability in a TIA is essential for good, reliableperformance. This application note explains the empirical calculations for assessing stability and then shows how to fine-tune theselection of the feedback phase-compensation capacitor.
Control systems are becoming increasingly dependent on digital processing and so require sensors able to provide direct digital inputs. Sensors based on time measurement, having outputs based on a frequency or phase, have an advantage over conventional analogue sensors in that their outputs can be measured directly in digital systems by pulse counting.
