| 摘要 |
<p>Differential amplifiers include biasing circuits therein that can automatically account for process and/or temperature induced variations in β and thereby more uniformly maintain the voltage gain of the differential amplifier at a desired level. A differential amplifier is provided that comprises first and second bipolar transistors electrically coupled together as an emitter-coupled pair (ECP) and a biasing circuit that is electrically connected to first and second emitters of the first and second≤ bipolar transistors, respectively. This biasing circuit includes a current mirror that sets a magnitude of an emitter bias current in the first emitter at a value proportional to (β+Z+1)/(β+1), where β is the gain of the first bipolar transistor and 1≤Z ≤2. In this manner, the gain of the differential amplifier can be set at a level proportional to (β2+2β)/(β2+2β1) which is a relatively weak function of β, even for small β.</p> |
