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专利名称：Transconductance amplifier
发明人：Moore, Paul Anthony,Cusdin, Anthony
Richard
申请号：EP93203507.4申请日：19931214公开号：EP0603942B1公开日：19980902
摘要：A transconductance amplifier comprises first and second input transistors(TO1,TO2) to the base electrodes of which an input voltage (Vi) is applied. A constantcurrent source (10) is connected to the emitters of the input transistors. Outputs arederived from their collector electrodes. A tapped impedance having two or moresegments (RO to RN,RN to RO) is connected between the base electrodes of the inputtransistors (TO1,TO2). The base of a further transistor (T1 to TN,TN to T1) is connectedto a respective tap (a1 to aN,aN to a1) of the tapped impedance. The emitter areas (e1 toeN,eN to e1) of these further transistors increase from each end of the tapped
impedance towards the centre (28) of the tapped impedance. The emitters of the furthertransistors (T1 to TN,TN to T1) are connected to the current source (10) and thecollectors are connected to a junction (26) which is connected to means (30) forcomputing the combined base currents of the further transistors (T1 to TN, TN to T1)from the combined collector currents at said junction (26). The computed current issupplied by a current mirror circuit (32) to the centre (28) of the tapped impedance topull up the voltage at the centre (28). The tapped impedance can have an increasedresistance without unduly loading a preceding stage.
申请人：PHILIPS ELECTRONICS UK LTD,KONINKL PHILIPS ELECTRONICS NV
地址：GB,NL
国籍：GB,NL
代理机构：Moody, Colin James
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