| 摘要 |
PROBLEM TO BE SOLVED: To provide an RSSI circuit wherein an offset of an output current is nullified even when the amplitude of an input signal is zero by eliminating the effect of dispersion in mutual conductance of transistors. SOLUTION: The RSSI circuit is configured by the connection of multi-stages each comprising a differential amplifier circuit comprising transistors Q1, Q2 for receiving outputs V1p, V1n of a limiter amplifier; a current mirror circuit comprising a MOS transistor Q3 for supplying a bias voltage to the differential amplifier circuit and MOS transistors Q4, Q5 and controlling an output current in response to the input voltages V1p, V1n; a bias cancel circuit comprising a current mirror circuit consisting of MOS transistors Q6, Q7 and a MOS transistor Q8 and for canceling an offset voltage produced in the differential amplifier circuit; and a detection circuit including at least resistors R1, R2, R3, R8 connected to the source of each transistor and a resistor Rrssi connected to an output terminal 6 of the RSSI circuit. COPYRIGHT: (C)2005,JPO&NCIPI
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