| 摘要 |
A analog-to-digital converter (DAC) comprises a plurality of circuit stages. Each of the circuit stages includes a switching circuit having an assertive circuit portion and a complementary circuit portion. A first transistor and a first resistor constitute the assertive circuit portion, which is electrically connected between a first reference voltage supply conductor and a switch output node inside the DAC. In a similar fashion, a second transistor and a second resistor constitute the complementary circuit portion, which is also electrically connected between a second reference voltage supply conductor and the switch-output node. The first and second resistors, and the resistor in the resistor network which is electrically connected to the switch output node, are substantially equal in ohmic values. Thus, when one of the circuit portions is active and the other circuit portion is inactive, the corresponding resistor in the active circuit portion operates as a part of the resistor network to provide a voltage division between the first and second reference voltage supply conductors. However, when both of the circuit portions are active, the first and second resistors operate together as a current limiting circuit to prevent an excess current surge between the first and second reference voltage supply conductors.
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