Low-voltage bandgap reference circuit
US6549065B2 · kind B2 · utility
Inventor
Key dates
| Filing date | May 7, 2002 |
| Grant date | Apr 15, 2003 |
| Priority date | — |
| Expiry date | May 7, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F3/30
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A low-voltage reference circuit is provided wherein (i) the output voltage can be set to be a fraction of the silicon bandgap voltage of 1.206 volts, or on the order of 0.9 volts, (ii) the output voltage can have a zero thermal coefficient (TC), and (iii) the operating supply voltage Vcc can be less than 1.5 volts, or on the order of 1.1 volts. In one embodiment, the reference circuit modifies a conventional Brokaw bandgap circuit to lower both the required Vcc level and the output voltage by a constant offset. Referring to FIG. 3, the modification includes adding bipolar transistor (Q6), an opamp (A3) and resistors (R5, R6 and R7). In another embodiment, the reference circuit modifies a conventional circuit with PNP transistors connected to the substrate, referring to FIG. 4, by adding current source I6, NMOS transistor M3, opamp A4 and resistors R8-R10. A further embodiment modifies FIG. 4, referring to FIG. 5, by omitting the current source I6, and moving the location of resistor R4.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.