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:
Feb. 03, 2004
Filed:
Jan. 24, 2002
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A power supply voltage detection circuit includes a voltage division circuit for linearly dividing a power supply voltage, a reference voltage circuit for providing a reference voltage, and a comparison circuit for comparing the output voltage from the voltage division circuit and the reference voltage from the reference voltage circuit. The power supply voltage detection circuit outputs a signal upon detecting that the power supply voltage is equal to or higher than the reference voltage. A PMOS transistor is provided between the voltage division circuit and the comparison circuit. The PMOS transistor includes a source terminal connected to an output terminal of the voltage division circuit, a drain terminal connected to an input terminal of the comparison circuit, and a gate terminal connected to the ground. Until the output voltage from the comparison circuit is higher than the threshold voltage of the PMOS transistor, the PMOS transistor remains OFF, thereby canceling the input of the output voltage signal from the voltage division circuit to the comparison circuit. Thus, without using external components, the signal is prevented from being erroneously output due to the output voltage from the voltage division circuit rising over, without crossing, the reference voltage from the reference voltage circuit during a sharp rise of the power supply voltage.