Vehicle power supply circuit to a greater extent for portable more level end receiver

摘要

A mobile radio transceiver comprises a portable transceiver and a vehicular power booster. The portable transceiver generates a RF transmit signal and sets the power of the RF signal at one of multiple power levels. The power booster is coupled by a connecting cable to the transceiver to receive the RF signal, and includes a first power detector for detecting the power of the received signal. One of multiple reference voltages is identified as corresponding to the power detected by the first power detector. A gain-controlled power amplifier stage amplifies the RF signal from the transceiver for coupling to an antenna. The output power of the power amplifier is detected and a gain control driver responds to a difference between it and the identified voltage by controlling the power amplifier so that the difference reduces to a minimum. In a modification, the power amplifier stage is a class C amplifier and the booster additionally includes a preamplifier stage. A second gain control driver is responsive to a difference between an average output voltage of the preamplifier stage and a fixed value for controlling the preamplifier so that its output is maintained constant. The output of the second gain control driver is used to identify one of the reference voltages supplied to the first gain control driver as corresponding to the power setting of the transceiver.