Texas Instruments Corporation

Rahul Bhandarkar

Ajay Kumar

Abhijit Kumar Das

Krishnasawamy Nagaraj

A simple bandgap current generator combines a PTAT (proportional to absolute temperature) base-emitter voltage (VBE) measured across two binary junction devices (&#x394;VBE=VBE&#x2212;VBE) with a current that is varied by an nWell resistor with a positive temperature coefficient to produce a CTAT (complementary to absolute temperature) current instead of PTAT reference current. One of the base-emitter voltages is constrained to be VBE=VBE(&#x3b2;T). This reduces the temperature dependency of a reference current generated by the bandgap generator. This reference current may be used to generate a bandgap reference voltage by adding an IR drop to a diode voltage or to a base-emitter voltage. The simple bandgap circuit is significantly smaller in size than a precision bandgap circuit, but still provides a voltage and/or a current reference signal having a good accuracy.

Bandgap circuit for current and voltage

A system for tuning an oscillator frequency. The system includes a trimmed calibration circuit comprising a comparator and trimmed delay element and calibration logic. The calibration logic is configured to receive an output of the comparator and control an on time and an off time of an oscillator based on the output of the comparator.

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Austin, TX, United States of America

Rahul Bhandarkar