| 摘要 |
PROBLEM TO BE SOLVED: To provide a full-wave rectifier using ICs capable of preventing degradation of accuracy when the amplitude of an input signal is small. SOLUTION: This full-wave rectifier (500) comprises a cross-coupled differential pair circuit (501) coupled with a bias circuit (510). One or more constant current sources (512, 514) are coupled with each base of transistors (506, 508) in the cross-coupled differential pair circuit (501). Differential pair transistors (502, 504) dive the cross-coupled differential pair circuit (501). The gain of a small amplitude signal is increased, using the cross-coupled devices (506, 508) as positive feedback. The bias circuit (510) comprises a current source, which suppliesαtimes of a current as large as the current supplied by the current sources (512, 514) connected with the bases of the transistors (506, 508) in the cross-coupled differential pair circuit (501). An inclination of a single value can be obtained in the vicinity of an origin point, by selecting the appropriate value for the currentα.
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