Patent ID: 7030701

Claim:
A transimpedance amplification apparatus with a signal source for generating a current signal, which comprises: a source follower stage having a source follower structure, for receiving the current signal to reduce an impedance of the signal source; a common source stage, following the source follower stage, driven by the reduced signal source impedance, for amplifying the current signal to extend a frequency bandwidth of the current signal and buffering the amplified signal with the extended frequency bandwidth thereof maintained, wherein the reduced signal source impedance serves to extend a frequency bandwidth of the common source stage; and a shunt feedback resistor, which is installed between the source follower stage and the common source stage, for adjusting an input DC bias of the source follower stage and increasing a transimpedance gain of the common source stage, wherein the common source stage includes: a first amplifying transistor for basically amplifying the current signal, wherein a gate thereof is connected to the source follower stage, while a drain thereof is coupled to a power supply and a source thereof is grounded; a first buffering transistor for buffering the basically amplified signal with the bandwidth thereof maintained, wherein a gate thereof is connected to the drain of the first amplifying transistor, while a drain thereof is coupled to a power supply and a source is grounded; a second amplifying transistor for secondarily amplifying the buffered signal, wherein a gate thereof is connected to the source of the first buffering transistor, while a drain thereof is coupled to a power supply and a source thereof is grounded; and a second buffering transistor for adjusting the output impedance to be a predetermined value and buffering the secondarily amplified signal while maintaining frequency bandwidth thereof, wherein a gate thereof is connected to the drain of the second amplifying transistor, while a drain thereof is coupled to a power supply and a source thereof is grounded.