Temperature compensation apparatus

Apparatus for compensating a temperature dependent characteristic of a semiconductor device having a first temperature coefficient, comprising:

• an electrical circuit including a transistor, a first resistor and a second resistor, wherein
• said transistor has a first electrode, a second electrode coupled to an operating potential, and a third electrode coupled to an operating potential and with said second electrode defining a main current conduction path of said transistor, said first and second electrodes being associated with a forward biased junction of said transistor and said first and third electrodes being associated with a reverse biased junction of said transistor;
• said first resistor couples said second electrode to said first electrode;
• said second resistor couples said third electrode to said first electrode, the ratio of the value of said second resistor to the value of said first resistor being selected such that said electrical circuit exhibits a second temperature coefficient approximating said first temperature coefficient of said semiconductor device whereby an output voltage associated with said main conduction path exhibits a magnitude which varies with temperature in accordance with said second temperature coefficient;
• means for deriving from said output voltage a control signal having a magnitude which varies in accordance with said second temperature coefficient;
• and
• means for coupling said control signal to said semiconductor device to alter said characteristic of said semiconductor device in a direction opposite to a direction produced by temperature variations wherein
• said semiconductor device is an integrated circuit;
• and
• said temperature compensating apparatus is located external to said integrated circuit.