System and method for a low voltage supply bandgap

A bandgap reference circuit comprising:

• an amplifier to provide a bias voltage;
• a first current branch coupled to the amplifier to receive the bias voltage and provide a first current, the first current branch comprising:
• a first p-type metal-oxide-semiconductor (PMOS) device coupled to the amplifier;
• and
• a first resistor coupled to the first PMOS device to receive the bias voltage and provide a proportional to absolute temperature (PTAT) voltage;
• a second current branch coupled to the amplifier to receive the bias voltage and provide a second current, the second current branch comprising:
• a second PMOS device coupled to the amplifier;
• and
• a bipolar junction transistor (BJT) device coupled to the second PMOS device to provide a complementary to the absolute temperature (CTAT) voltage;
• and
• a pair of variable resistors coupled in between the first current branch and the second current branch, the pair of variable resistors comprising:
• a first variable resistor coupled to the first current branch;
• a second variable resistor coupled to the second current branch;
• and
• an output node coupled in between the first variable resistor and the second variable resistor to provide a bandgap voltage that is a weighted sum of the PTAT voltage and the CTAT voltage.

A method to provide a bandgap reference, the method comprising:

• generating a first voltage that is proportional to temperature;
• generating a second voltage that is complementary to the temperature;
• and
• providing a bandgap voltage by:
• resistor-dividing, using a first variable resistor, the first voltage that is proportional to the temperature;
• resistor-dividing, using a second variable resistor, the second voltage that is complementary to the temperature;
• and
• summing the resistor-divided first voltage that is proportional to the temperature and the resistor-divided second voltage that is complementary to the temperature.