| 摘要 |
An integrated circuit 100 comprises a limiter section 105 between a radio frequency (RF) input port 134 and RF output port 136, and a detector section 102 that detects a power level or an electrostatic discharge (ESD) event of an input signal and is coupled to the limiter section. A limiter drive circuit 147 may comprise a differential amplifier 160 which, when the signals from the detector outputs 139, 141 indicate an electrical overstress, switches limiter diodes 104-118 to a forward-biased low impedance condition so that most of an incoming signal is reflected by limiter section 105. Resistors 150, 152 may cooperate with voltage divider resistors 142, 144 to set the operating points, and enabling rapid switching, of detector diodes 138, 140, so that negligible distortion is added to the incoming signal at an un-attenuated power level. The integrated circuit may comprise a gallium-arsenide (GaAs) integrated circuit and differential amplifier 160 may be a silicon device or a GaAs device on the same chip (fig 1B, 172). An integrated amplifier (fig 2, 202) may precede the detector section (fig 2, 204) and may be a hetrojunction bipolar transistor (HBT) and the limiter drive circuit may comprise a comparator (fig 2, 260). A detector output (fig 3, DETout) may provide overpower indication. The limiter may comprise a directional device (fig 4, 401) such as a directional coupler or bridge, which can prevent power from the limiter being reflected toward the detector (fig 4, 404). |
