A Widlar current source is a modification of the basic two-transistor current mirror that incorporates an emitter degeneration resistor for only the output transistor, enabling the current source to generate low currents using only moderate resistor values.[1][2][3]
The Widlar circuit may be used with bipolar transistors, MOS transistors, and even vacuum tubes. An example application is the 741 operational amplifier,[4] and Widlar used the circuit as a part in many designs.[5]
This circuit is named after its inventor, Bob Widlar, and was patented in 1967.[6][7]
- ^ PR Gray, PJ Hurst, SH Lewis & RG Meyer (2001). Analysis and design of analog integrated circuits (4th ed.). John Wiley and Sons. pp. §4.4.1.1 pp. 299–303. ISBN 0-471-32168-0.
{{cite book}}: CS1 maint: multiple names: authors list (link) - ^ AS Sedra & KC Smith (2004). Microelectronic circuits (5th ed.). Oxford University Press. Example 6.14, pp. 654–655. ISBN 0-19-514251-9.
- ^ MH Rashid (1999). Microelectronic circuits: analysis and design. PWS Publishing Co. pp. 661–665. ISBN 0-534-95174-0.
- ^ AS Sedra & KC Smith (2004). §9.4.2, p. 899 (5th ed.). ISBN 0-19-514251-9.
- ^ See, for example, Figure 2 in IC voltage regulators.
- ^ RJ Widlar: US Patent Number 03320439; Filed May 26, 1965; Granted May 16, 1967: Low-value current source for integrated circuits
- ^ See Widlar: Some circuit design techniques for linear integrated circuits and Design techniques for monolithic operational amplifiers