| 摘要 |
In a voltage-switching digital-to-analog converter, each bit is switched by a switching circuit which uses a p-channel MOSFET as a Vref switch and an n-channel MOSFET as an Agnd switch, with a control circuit for controlling the signal applied to the gate of one of the devices (e.g., the n-channel device) to cause its "ON" resistance to match the "ON" resistance of the other device (e.g., the p-channel device). The control circuit includes reference n-channel and p-channel devices. A control signal is developed to drive the reference n-channel device to a condition wherein its drain current and drain-source voltage match those of the reference p-channel device, thereby causing their RONs to match. The drive signal is taken as the output of the control means and is used to power the driver for the n-channel Agnd switches.
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