Temperature and process compensated current reference circuits

A circuit, comprising:

• an output transistor configured to carry a reference current;
• a first transistor coupled in series with the output transistor to carry a first portion of the reference current;
• a second transistor coupled in series with the output transistor to carry a second portion of the reference current;
• wherein the first and second transistors are coupled in parallel to each other;
• a bandgap reference voltage generator circuit configured to generate a bandgap reference voltage;
• a first biasing circuit configured to generate a first biasing voltage for application to a control terminal of the first transistor, said first biasing voltage derived from said bandgap reference voltage;
• and
• a second biasing circuit configured to generate a second biasing voltage for application to a control terminal of the second transistor, said second biasing voltage generated from a proportional to absolute temperature (PTAT) current mirrored from a current flowing in the bandgap reference voltage generator circuit;
• wherein a temperature coefficient of the current flowing in the first transistor and a temperature coefficient of the current flowing in the second transistor are opposite.

A circuit, comprising:

• a reference current path configured to carry a reference current;
• a first transistor coupled in series with the reference current path to carry the reference current;
• a second transistor coupled in series with the first transistor to the reference current;
• a bandgap reference voltage generator circuit configured to generate a bandgap reference voltage;
• a first biasing circuit configured to generate a first biasing voltage for application to a control terminal of the first transistor, said first biasing voltage derived from said bandgap reference voltage;
• and
• a second biasing circuit configured to generate a second biasing voltage for application to a control terminal of the second transistor, said second biasing voltage generated from a proportional to absolute temperature (PTAT) current mirrored from a current flowing in the bandgap reference voltage generator circuit.