Current source with weak temperature dependence, for use in electronic integrated circuits or parts of circuits, e.g. in portable transmitter-receiver sets

摘要

The current source comprises a reference current source (102), and a mirror-current (104) for copying the current of the reference current source to one or more output branches (106, 108), where the first branch (106) delivers current to the reference source and the second branch (108) is connected to a load (110). The reference current source and the mirror-current have opposite coefficients of the dependence on temperature, and the mirror-current is level-headed. The reference current source has a negative dependence on temperature, and the mirror-current has a positive dependence on temperature. The reference current source (102) is of the base-emitter reference voltage type, and comprises a control transistor (126) based as a diode and connected to a supply transistor (146) in the output branch (106) of the mirror-current. The mirror-current (104) comprises the first transistor (130) in the control branch connected to the reference current source, and one or more second transistors (146, 148) connected in each output branch; the first transistor (130 is connected in series with a leveling resistor (136). The second transistor (146, 148) of the mirror-current has the emitter surface greater than that of the first transistor (130).