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. A method of generating a reference voltage comprising the steps of:
generating a controlled current with a feedback loop comparing voltage drops in a first path including a first bipolar transistor and a second path parallel to the first path including a second bipolar transistor;
generating a non-linear compensation current for compensating a temperature dependent variation of a voltage drop across said first and second paths;
supplying the controlled current to a common node of the first path and the second path; and
drawing the compensation current from the common node thereby generating a voltage drop across a resistor carrying the controlled current with a positive temperature coefficient.
2. The method of claim 1 , wherein:
said step of generating a controlled current includes constructing said first bipolar transistor having an emitter area which is N times an emitter area of said second bipolar transistor.
3. The method of claim 1 , wherein:
said step of generating a non-linear compensation current includes forming a translinear current mode circuit.
4. The method of claim 1 , wherein:
said step of generating a controlled current includes constructing an amplifier comprising only resistors of a first type; and
said step of generating a non-linear compensation current includes forming a translinear current mode circuit comprising only resistors of said first type.
5. The method of claim 1 , wherein:
said step of generating a non-linear compensation current includes forming a mismatched current mirror.