发明名称 |
MULTIPLE FUNCTION OPERATIONAL AMPLIFIER CIRCUIT |
摘要 |
<p>A MULTIPLE FUNCTION OPERATIONAL AMPLIFIER CIRCUIT An operational amplifier capable of selectively performing a variety of circuit functions is provided. A single operational amplifier utilizes switched capacitors for sampling and holding an input signal, for establishing a low frequency pole, for applying the sample to an output capacitance to charge the capacitance and for comparing the input signal with a reference. The multi-function circuit provides a large savings in circuit area and permits versatility of circuit applications. One embodiment of the invention is to utilize a companding DAC having a capacitor array which may be used as the output capacitance of the operational amplifier circuit. The DAC provided utilizes an R ladder DAC coupled directly to a C DAC and has a switching structure that is simpler than comparable prior art circuits, The DAC is asynchronous and has programmable Aand Mu-255 law PCM conversion capability. Coupled directly to the C DAC is an operational amplifier receive filter circuit which utilizes the C DAC as an input capacitor thereby eliminating the need for a buffer amplifier and allowing the DAC to be used for both analog to digital and digital to analog conversion.</p> |
申请公布号 |
CA1172709(A) |
申请公布日期 |
1984.08.14 |
申请号 |
CA19820401184 |
申请日期 |
1982.04.19 |
申请人 |
MOTOROLA, INC. |
发明人 |
ALLGOOD, ROBERT N.;KELLEY, STEPHEN H.;ULMER, RICHARD W.;WURZBURG, HENRY |
分类号 |
H03F1/34;H03F1/30;H03H19/00;H03M1/12;(IPC1-7):H03F1/34 |
主分类号 |
H03F1/34 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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