CMOS frequency reference circuit with temperature coefficient cancellation

Abstract

Systems and methods for frequency reference generation are described. In an embodiment, a frequency reference circuit, includes: a bandgap proportional to temperature (PTAT) generator circuit that generates a bandgap PTAT current; a resistor complementary to temperature (CTAT) generator circuit that generates a resistor CTAT current; an adder that adds the PTAT current and the CTAT current to generate a constant current Icons; a switched-resistor (switched-R) circuit that receives the constant current Icons and a previously generated output clock and generates an output; a bandgap voltage reference generator circuit that generates a bandgap voltage VBG; an integrator circuit that receives the output of the switched-R circuit and the bandgap voltage VBG and generates an output; and a voltage-controlled oscillator (VCO) circuit that receives the output of the integrator circuit and generates a frequency reference.

Dependencies are inferred from the claim text.