| 摘要 |
PURPOSE:To reduce the current consumption and to decrease the chip area by providing a current detection circuit between an output terminal and an inverting input terminal of an operational amplifier. CONSTITUTION:An output terminal OUT of an operational amplifier OA of current detection circuit CD is used as gate voltage, an N-channel transistor(TR) Q1 and a P-channel TR Q2 are provided, sources are connected to an inverting input terminal of an operational amplifier OA. In order to detect a current flowing to the TRs Q1, Q2, TRs Q3, Q4 and TRs Q5, Q6 forming a current mirror circuit are provided, then drains of the TRs Q5, Q6 and sources of TRs Q7, Q8 whose gate voltage is a reference voltage 1/2Vcc are connected to the output terminal OUT to constitute a peak detection circuit. Thus, a required signal is obtained by supplying only a minimum current to the output stage of the operational amplifier OA, the size of the TRs of the output stage is decreased and the chip area is made small. |
