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SLOVENIA Ljubljana. INTRODUCTION. Objective. The objective of this presentation is to show how to set the operating conditions for analogue circuits and how to improve the biasing performances. Outline. Circuit Biasing Current Sources Current Mirrors Current references
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INTRODUCTION Objective The objective of this presentation is to show how to set the operating conditions for analogue circuits and how to improve the biasing performances. Outline • Circuit Biasing • Current Sources • Current Mirrors • Current references • Voltage References • Amplifiers and some other a.b. • Circuit Examples
Using Mirrored Currents - an example: 8 BIT Thermometric DA Converter
Improved mirrored current - High impedance cascode current source Output impedance: Gate voltage on Tco: Sufficient voltage on Vco: Solution on next slide
Low voltage swing cascode mirror Source follower - formed by Ts and Tso:
Regulated mirror transistor (To) -channel voltage Vds Principle Practical realisation
Low current, Low voltage - self cascode current mirror • serial - stacked Vds devices • parallel devices - summing • serial/parallel - matching due to different current gains Minimal supply voltage: Design considerations:
Emiter-resistors neglected: With emiter-resistors ( base currents neglected):
Beta buster Logarithmic dependence of Io from supply voltage:
Cascode Current Mirror Output mirrored current Io (resistors neglected):