Patent ID: 7453252

Claim:
A bandgap core, comprising: a first transistor capable of receiving an input voltage; a first resistor coupled to the first transistor; a second resistor and a third resistor coupled in series to the first transistor; a second transistor coupled to the first resistor; a third transistor coupled to the third resistor; a fourth resistor coupled between a base and a second terminal of the second transistor; and a fifth resistor coupled to a base of the third transistor and not coupled to the base of the second transistor, wherein a resistance of the fourth resistor is given by a formula of: R 1 ≈ C ⁡ ( T ) kT 2 2 ⁢ ⁢ q ⁢ ln ⁡ ( K ) · R 0 R Δ 2 · T N β N ⁢ ( γ 2 - γ 1 ) where R1 represents the resistance of the fourth resistor, C(T) represents a curvature of an output voltage of the bandgap core, k represents Boltzmann's constant, T represents a temperature in Kelvin, q represents a charge of an electron, R0 represents a resistance of the first and second resistors, RΔ represents a resistance of the third resistor, β represents a normalized current gain of the second and third transistors, TN represents a normalized temperature in Kelvin, γ1 represents a second-order temperature coefficient associated with the fourth resistor, and γ2 represents a second-order temperature coefficient associated with the fifth resistor.