US Patent 7629785 Circuit and method supporting a one-volt bandgap architecture

A system includes a transistor coupled to a voltage rail, a first resistor coupled in series with the transistor, and a second resistor coupled in series with the first resistor. The system also includes a bandgap reference circuit operable to generate a bandgap reference voltage of less than 1.2 volts (such as one volt) between the first and second resistors. The bandgap reference circuit includes a diode configured to generate a complementary-to-absolute-temperature (CTAT) voltage and a third resistor configured to generate a first proportional-to-absolute-temperature (PTAT) voltage using a first current. The bandgap reference circuit also includes a current source configured to sink a CTAT current from the first current to generate a second current and a fourth resistor configured to generate a second PTAT voltage using the second current. A sum of the CTAT voltage, the first PTAT voltage, and the second PTAT voltage is less than 1.2 volts.