公开(公告)号：GB2381977B

公开(公告)日：2005-03-30

申请号：GB0224321

申请日：2002-10-18

Applicant: COUNCIL CENT LAB RES COUNCILS

Inventor： STEPHENSON RICHARD

IPC: H03F3/70

公开(公告)号：GB2381977A

公开(公告)日：2003-05-14

申请号：GB0224321

申请日：2002-10-18

Applicant: COUNCIL CENT LAB RES COUNCILS

Inventor： STEPHENSON RICHARD

IPC: H03F3/70

Abstract: A gain block particularly useful for charge preamplifiers for use in low noise input stages is described. The charge amplifier shown comprises a gain block 3 and feedback components R1,C1. The gain block 3 comprises an input source follower based on a JFET T3 followed by a current feedback amplifier 7. A suitable commercial device for amplifier 7 is Analogue Devices type AD 8011. One of the characteristics of the current feedback amplifier is the low impedance of its inverting input. As can be seen the output from the input source follower stage is passed to this inverting input and this ensures that the signal is passed to the amplifier 7 with maximum efficiency. The gain block of the invention allows the use of a current feedback amplifier with a conventional feedback network such as would normally be associated with voltage feedback stages.