Patent ID: 6452645
Filing Date: 2002-09-17
Classification: H03F,H04N

Abstract:
A multiple preliminary stage circuit for a television tuner, comprising:a first band with a first band amplifier stage having a transistor and a second band with a second band amplifier stage having a transistor; a common chip common to said first band and said second band and having integrated therein said first band amplifier stage and said second band amplifier stage; said common chip having a terminal for receiving a band switching signal and a terminal for receiving an amplification control signal; a tuner-IC connected to said common chip for switching, with a single band switching signal, said first and second amplifier stages; a reference transistor connected to a respective transistor of a respective said amplifier stage to form a current mirror circuit; and a further transistor having a controlled section connected between said reference transistor and a reference potential for selectively blocking said controlled section of said reference transistor or connecting said controlled section through to the reference potential in dependence on the band switching signal, and wherein the respectively other amplifier stage is selectively activated and deactivated in complementary fashion via the band switching signal.