Electronic device and method for generating a curvature compensated bandgap reference voltage
View Patent ↗The invention relates to an electronic device with a bandgap reference generator including a first path with series connection of a first bipolar transistor, a first resistor and a second resistor, and a second path with series connection of a second bipolar transistor and a third resistor. The first and second paths are supplied current via a common node through a fourth resistor controlled by an amplifier sensing voltage drops within the first and second paths. A curvature compensation stage compensates for a variation of base emitter voltage of the bipolar transistors by drawing a compensation current from the common resistor node.
1. An electronic device having a bandgap reference generator comprising:
a first bipolar transistor having a base coupled to ground, a first collector-emitter channel terminal and a second collector-emitter channel terminal coupled to ground;
a first resistor having a first terminal connected to said first collector-emitter channel terminal of said first bipolar transistor and a second terminal connected to a first common resistor node;
a second resistor having a third terminal connected to said first common resistor terminal and a fourth terminal connected to a second common resistor node;
a second bipolar transistor having a base coupled to ground, a third collector-emitter channel terminal and a fourth collector-emitter channel terminal coupled to ground;
a third resistor having a fifth terminal connected to said third collector-emitter channel terminal of said second bipolar transistor and a sixth terminal connected to said second common resistor node;
a fourth resistor having a seventh terminal connected to said second common resistor node, said seventh terminal being an output of the bandgap reference generator, and an eighth terminal;
a MOS transistor having a ninth terminal of a source-drain channel connected to a power supply, a tenth terminal of said source-drain channel connected to said eighth terminal of said fourth resistor and a gate;
an amplifier having a inverting input connected to said first common resistor node, a noninverting input connected to said third collector-emitter channel terminal of said second bipolar transistor and to said fifth terminal of said third resistor, and an output connected to said gate of said MOS transistor; and
a curvature compensation stage having an input connected to said second common resistor node drawing a compensation current into said input and out of said second common resistor node in an amount compensating for a variation of base emitter voltage variation of said first and second bipolar transistors.
2. The electronic device according to claim 1 , wherein:
said first bipolar transistor has an emitter area which is N times an emitter area of said second bipolar transistor.
3. The electronic device according to claim 1 , wherein:
the curvature compensation stage is configured as a translinear current mode circuit.
4. The electronic device according to claim 1 , wherein:
the curvature compensation stage and the amplifier comprise only resistors of the same type.
5. The electronic device according to claim 1 , wherein:
the curvature compensation stage comprises a mismatched current mirror.