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. 04, 2001
Filed:
Oct. 13, 2000
Hidehiko Suzuki, Tokyo, JP;
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An on-time signal generation circuit for use in a switching DC-to-DC converter, a switching DC-to-DC converter including such a circuit, and a method for generating an on-time signal which is a binary pulse train comprising pulses T,, where the width of each pulse T,is equal to T,(V,/V,), where T,, V,, and V,are, respectively, the switching period and the input potential of a DC-to-DC converter, and a control potential. The control potential V,is one of the output potential of the DC-to-DC converter and a DC potential proportional to a desired level of such output potential. The on-time signal generation circuit includes a comparator, a ramp generator with an output coupled to one input of the comparator, and an amplifier with an output coupled to the other input of the comparator. The ramp generator generates a periodic ramped potential having peak level kV,and period T,. The amplifier receives the control potential V,, and is configured to assert an amplified potential kV,in response thereto. In response to potential kV,from the amplifier and ramped voltage kV,from the ramp generator, the comparator asserts a pulse train comprising pulses T,. The width of each pulse T,is equal to T,(V,/V,), and thus is indicative of the nominal or critical power switch on-time needed for the DC-to-DC converter to produce an output equal to V,in response to input V,. Preferably, the on-time signal generation circuit is implemented so that the width of each pulse T,is equal to T,(V,/V,) independently of process variations and variations in operating temperature.