The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 23, 2003
Filed:
May. 08, 2001
Ion E. Opris, San Jose, CA (US);
Jay Friedman, Felton, CA (US);
Other;
Abstract
A thermostat circuit (FIG. ) is provided which (i) works properly with very low supply voltages, (ii) does not need a separate constant value as a reference, and (iii) has improved temperature sensitivity over prior art thermostat circuits. The thermostat circuit compares two reference currents—I and I . When I >I , the output of the thermostat circuit is one logic state (either high or low). When I >I , the output of the thermostat circuit is a different logic state (either low or high). Current I comes from a PTAT current generator (FIGS. ), and current I comes from a V current generator (FIGS. ). The PTAT current generator and the V current generator may be implemented with cascode amplifiers. In an embodiment, the currents I and I can be compared at a current comparator circuit (FIG. ) with a summing node and an output node. The total current at the current comparator's output node is independent of temperature, and the output node exhibits a hysteresis behavior. The thermostat circuit can include a testing/tuning circuit (FIG. ) which is capable of injecting a test current into or subtracting a test current out of the summing node.