| 摘要 |
The device (DAS) comprises within a pre-amplifier stage (ETPA) a control block (MCTL) which can deliver a digital word (MN) representative of the conductivity of the main MOS transistors (TPA,TPB) of an output stage (ETS). The output stage (ETS) also comprises one or more supplementary pairs of complementary MOS transistors (TSAi,TSBi) connected in parallel to the pair of the main transistors by the intermediary of pairs of interrupters (ITSAi,ITSBi) controlled by the digital word for activating or not the supplementary transistors. The supplementary transistors are dimensioned so that at the time of their activation the equivalent impedance of the output stage is substantially constant, for example equal to the minimum impedance of the main transistors. The control block (MCTL) contains a variable current source delivering a current which is a function of the environmental parameters, a constant current source, and means for comparing the two currents. An integrated circuit (claimed) comprises the device as claimed. The method (claimed) for controlling the impedance of the output amplification device is implemented by the device as claimed.
|
