| 摘要 |
<p>A cascaded amplifier is comprised of a number of amplifying stages connected in cascade such as the dual emitter-coupled amplifier shown. A first pair of transistors (14,20) provides limiting amplification and a second pair of transistors (16,18) with degeneration (22,24) provide linear amplification. Each pair of transistors is driven by a current source (28,26) which supplies a current (IT, IT2) proportional to absolute temperature (PTAT). The small signal amplification is then substantially independent of temperature and the value of the limited output is proportional to absolute temperature. This latter effect is countered by including a translinear variable current gain amplifier (54,56,58,60) in the last dual-gain stage of the cascaded amplifier to modify the output voltage in a manner inversely proportional to absolute temperature. A transfer function may thus be provided which is substantially independent of temperature. <IMAGE> <IMAGE></p> |
