| 摘要 |
A temperature compensated current source includes three successive source current paths to produce a controlled output current. Each current path has a different value of current flowing therein so that current fluctuations in one current path will tend to be isolated from the other current paths because of the difference in current flow. In the embodiment of the invention shown, a reference zener diode provides a reference voltage at the base of a first transistor to establish a first reference current as its emitter current. A second transistor uses the first current as the reference to establish a second current value which has a positive temperature coefficient. Third, fourth and fifth transistors use the second reference current to establish a third reference current value independent of the gain values of these transistors. In the embodiment of the invention described, the third reference current is used to establish a reference voltage stable with respect to variations in the power supply, transistor gain and resistivity fluctuations of the circuit but with increasing voltage as a function of temperature. This voltage variation is used in combination with a load to cancel the effect of the load variations with temperature by providing an increased source voltage as a function of temperature. |
