Bandgap type reference voltage source with low supply voltage

A method for generating a reference voltage in a bandgap type reference voltage source comprising a bandgap stage formed by a first and a second branch each comprising a respective diode element and a respective control element forming respectively a first and a second output node, said method comprising:

• generating a first and a second bandgap current in said respective diode elements of said first and second branches;
• drawing a first and a second input current from said first and, respectively, from said second output node;
• controlling said control elements of said first and second branch as a function of said first and second input current;
• generating an output voltage that is temperature-stable and related to a bandgap current flowing in said diode element of said first branch.

A device, comprising:

• a bandgap current source having a control terminal and first and second branches, configured to generate first and second upper branch currents, respectively, the first branch including upper and lower branches connected at a first output node to a first output line such that the first upper branch current is divided into a first lower branch current in the first lower branch and a first output current in the first output line, and the second branch including upper and lower branches connected at a second output node to a second output line such that the second upper branch current is divided into a second lower branch current in the second lower branch and a second output current in the second output line;
• means for converting the first and second output currents to first and second voltages, respectively;
• a differential amplifier having first and second inputs coupled to the first and second voltages, respectively, and an output coupled to the control terminal of the bandgap current source;
• means for generating a third current, equal to the first lower branch current;
• and
• means for converting the third current to a bandgap voltage.

A method, comprising:

• generating a branch current in a bandgap current source circuit;
• dividing the branch current into an output current and a lower branch current;
• controlling the branch current against fluctuations caused by temperature changes;
• generating a first duplicate current, equal to the lower branch current, in an output circuit;
• and
• generating a bandgap voltage from the duplicate current.