AN INTEGRATED CIRCUIT ADAPTED TO BE SELECTIVELY AC OR DC COUPLED

摘要

An integrated circuit is adapted to be selectively AC or DC coupled to an external device at a coupling point. The integrated circuit includes a first connector connected to the coupling point by way of a coupling capacitor for AC coupling, a second connector connected to the coupling point for DC coupling, and a switch to selectively short the first and second connectors and thereby the coupling capacitor, when the integrated circuit is DC coupled to the device. The switch may be a MOSFET bridge comprising a switch control MOSFET interconnected between the first and second connectors, with the switch control MOSFET receiving at its gate a mode status signal for turning on the switch control MOSFET and thereby shorting the MOSFET bridge when the integrated circuit is DC coupled to the external device. The MOSFET bridge also includes a number of dynamically biased nMOSFETs connected in series with the switch control MOSFET in order to protect switch control MOSFET from high external supply voltages, and a number of dynamically biased pMOSFETs connected in parallel with the switch control MOSFET.