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:
May. 07, 2002
Filed:
Apr. 02, 2001
Davide Brambilla, Rho, IT;
Mauro Cleris, Bareggio, IT;
STMicroelectronics S.r.l., Agrate Brianza, IT;
Abstract
An integrated circuit for producing a small slope voltage ramp includes a circuit for generating a periodic triangular current signal, and a circuit for generating, at the beginning of each period of the triangular signal, a pulse of a certain duration which is much smaller than the period of the triangular signal. A control loop is input at a node with the triangular current signal and produces the desired slow voltage ramp on the output node. The control loop includes a first hold circuit coupled to the input node via a first switch controlled by the pulse, and a transconductance operational amplifier, whose inputs are respectively coupled to the input node and to the output node. Also, the control loop includes a second hold circuit coupled to the output of the operational transconductance amplifier via a second switch controlled in a complementary manner with respect to the first switch. A resistor of a much smaller value than the ratio between the period of the triangular signal and the capacitance of the storage capacitor of the first hold circuit is connected between the output of the second hold circuit and the input node.