| 摘要 |
Disclosed herein is a variable-gain amplification circuit, wherein the sources of first and second MOSFETs (Metal Oxide Semiconductor Field Effect Transistors) are tied to a common connection point connected to a current source. An input signal is supplied to the gates of the first and second MOSFETs. The drains of the first and second MOSFETs are connected to the sources of third and fourth MOSFETs respectively whereas the drains of the third and fourth MOSFETs are connected to two output terminals respectively, a gain control voltage is supplied to the gates of both the third and fourth MOSFETs. When control is executed in order to lower the gain control voltage supplied to the gates of both the third and fourth MOSFETs, other control is also executed in order to raise a bias voltage applied to the gates of both the first and second MOSFETs.
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