Beta-Compensated Current Mirror Circuit
Original Publication Date: 1983-Aug-01
Included in the Prior Art Database: 2005-Feb-07
The present circuit is for compensating significant changes in transistor Beta (linear current gain) which can cause inaccuracies in current mirror circuits. Current mirroring is a circuit technique often used in the design of current sources and voltage-to-current converters in integrated circuits. The present circuit compensates for varying base currents (Ib) in current mirror legs. This base current is a main contributor of error in current mirror circuits and increases with low transistor Beta (b). The technique involves converting an input current IIN into Vbe voltage and then using this bias voltage to produce a similar current I2 on adjacent transistors of the same geometry. A typical circuit is shown in Fig. 1.