Patent ID: 8072329

Claim:
A Radio Frequency Identification tag circuit, comprising: a first antenna input node configured to receive wirelessly an alternating signal; a power management unit coupled to the first antenna input node, the power management unit including a voltage regulator including: a first native transistor having a first threshold voltage, the first native transistor having a first gate terminal, and a second and third terminal; a reference voltage source coupled to the second terminal of the first native transistor; a resistive element coupled between the first gate terminal of the first native transistor and the third terminal of the first native transistor; a first current source coupled to the third terminal of the first native device; a second current source coupled to the first gate terminal of the first native transistor; the current sources coupled to the first resistive element such that the resistive element establishes a voltage difference between the first gate terminal and the third terminal of the first native transistor such that the first native transistor is in a saturation region of operation; and a second native transistor having a second threshold voltage, the second native transistor having a first gate terminal, and a second and third terminal, the first gate terminal of the second transistor coupled to the first gate terminal of the first transistor, the second native transistor is configured to generate a regulated voltage at the second terminal of the second native transistor, the regulated voltage based in part on the reference voltage.