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:
Dec. 14, 1993
Filed:
Aug. 26, 1992
NEC Corporation, Tokyo, JP;
Abstract
A semiconductor integrated circuit which comprises a detection circuit for detecting a voltage of a semiconductor substrate and a negative voltage generating circuit for generating a negative voltage to be supplied to the substrate in accordance with an output signal of the detection circuit. The detection circuit includes a first P-channel MOS transistor having a gate connected to a ground potential, a source connected to a power source and a drain connected to a node coupled to the detection circuit, and a second P-channel MOS transistor having a gate connected to the substrate, a source connected to the node and a drain connected to ground. Current does not flow from the external power source to the substrate, so that, even if the negative voltage generating circuit does not have its electric current supplying capacity increased, the voltage of the substrate can be detected. A buffer circuit outputting a signal in accordance with the node voltage level, and ring oscillators switched in accordance with the signal of the buffer circuit may be used in supplying an electric current to the negative voltage generating circuit.