一种基于有源偏置的控制电路设计-豆柴文库

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一种基于有源偏置的控制电路设计
Introduction
Inelectroniccircuits,biasingmeanstoestablishafixedDCvoltageorcurrentataparticularpointinthecircuit.Biasingplaysasignificantroleinensuringproperandefficientoperationofelectroniccircuits.ThebiasingcircuitryisusedtoestablishastableDCoperatingpointforanamplifieroranyotheractivedevice.Therearetwotypesofbiasingtechniques-thepassivebiasingandtheactivebiasingtechniques.Thepassivebiasingtechniqueissimpleandcanbeeasilyimplemented,butitisnotveryefficientinlargercircuitsduetothehighinputimpedanceoftheamplifiers.Incontrast,theactivebiasingtechniqueismoreefficientandcanbeusedinlargercircuits.Thispaperdescribesthedesignofacontrolcircuitbasedonactivebiasing.
ActiveBiasing
Activebiasinginvolvestheuseofanactiveelementinthebiasingcircuit.Theactiveelementcanbeatransistor,anoperationalamplifier,oranyotheractivecomponentthatcanprovideastableandconstantbiasvoltageorcurrent.Theactiveelementhelpsovercomethelimitationsofthepassivebiasingtechniqueassociatedwithhighinputimpedanceandsensitivitytotemperatureandsupplyvoltagevariations.
Intheactivebiasingtechnique,theactiveelementactsasavoltagedividerthatsetstheDCoperatingpointoftheamplifier.Theactiveelementsuppliesthebiasingvoltagetotheamplifierbasedonthefeedbackfromtheamplifieroutput.ThefeedbackmechanismensuresthatthebiasingvoltageisautomaticallyadjustedtomaintainastableDCoperatingpointirrespectiveofvariationsduetotemperatureandsupplyvoltagefluctuations.Therefore,theactivebiasingtechniqueismorereliableandefficientcomparedtopassivebiasing.
ControlCircuitBasedonActiveBiasing
Thedesignofthecontrolcircuitbasedonactivebiasinginvolvestheselectionofanactiveelement,selectionofappropriateresistors,andtheconfigurationofthecircuit.Thecircuitconsistsofanamplifier,afeedbacknetwork,andanactivebiasingelement.Thefeedbacknetworkconnectstheamplifieroutputtothebaseoftheactivebiasingelement.
TheactivebiasingelementusedinthecircuitisaPNPtransistorduetoitshighvoltagegainandlowinputimpedance.Thetransistorservesasavoltagedividerandsuppliesa