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. 14, 1993
Filed:
Feb. 07, 1992
Balu Balakrishnan, Saratoga, CA (US);
Leif O Lund, San Jose, CA (US);
Richard A Keller, Palo Alto, CA (US);
Power Integrations, Inc., Mountain View, CA (US);
Abstract
An embodiment of the present invention is a switching power supply with high voltage positive and negative power inputs, a system ground, a sensing resistor placed between the negative power input and system ground, first and second load outputs with the first load output connected to the positive power input, and a comparator having first and second comparison inputs and a comparison output with the second comparison input connected to the system ground. A constant-current source is connected to the first comparison input of the comparator. A power MOSFET switch transistor has its drain connected to the second load output, its source connected to the system ground, and its gate controlled by the comparison output of the comparator. And a control resistor is connected between the second power input and said first comparison input of the comparator. The constant-current source, control resistor, and sensing resistor are such that when a predetermined current flowing through the first and second load outputs reaches a predetermined level (the current limit), the voltage developed across the sensing resistor will be equal to the voltage dropped across the control resistor, and the comparator will turn off the transistor to prevent further current increases.