REFERENCE CIRCUITS What is a Reference Circuit A
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REFERENCE CIRCUITS What is a Reference Circuit? A reference circuit is an independent voltage or current source which has a high degree of precision and stability Requirements for a Reference Circuit: 1. )Output voltage/current should be independent of power supply. 2. )Output voltage/current should be independent of temperature. 3. )Output voltage/current should be independent of processing variations
V-I Characteristics of an Ideal Reference i Voltage Reference Iref Current Reference Vref v
Concept of Sensitivity Definition Sensitivity (S) is a measure of dependence of Vref (Iref) upon a parameter or variable x which influences Vref (Iref). For example, if the sensitivity is 1, then a 10% change in x will cause a 10% change in Vref. Ideally, SVREFX(VDD, Temp) 0
Types of references 1. Voltage dividers - passive and active. 2. MOS diode reference. 3. PN junction diode reference. 4. Gate-source threshold referenced circuit. 5. Base-emitter referenced circuit.
Targil Kita. ØEstimate accuracy and sensitivity to power for the following Passive & Active Voltage References
PN_Junction Voltage reference and MOS Equivalent (Gate source)
Targil Kita II. ØWhat is the Voltage Reference of the PN junction and MOS equivalent circuits? ØHow can we modify these Voltages?
Bootstrapped Current Source Vgs? , Iout?
