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:
Jun. 30, 2015
Filed:
Jan. 14, 2014
Stmicroelectronics S.r.l., Agrate Brianza, IT;
Marco Martini, Acireale, IT;
Salvatore Pantano, Pedara, IT;
STMicroelectronics S.r.l., Agrate Brianza (MB), IT;
Abstract
A current driver for a string of LEDs includes a first series connection of a first transistor and a first resistance and a second series connection of a second transistor and a second resistance. The first and second series connections are coupled in parallel between the string of LEDs and a voltage reference. An operational amplifier selectively drives the first and second transistors in response to a clock signal. A switch device driven by the clock signal alternately applies a reference voltage and a respective one of the voltages across the first and second resistances to inverting and non-inverting inputs of the operational amplifier in response to the clock signal. A storage circuit is coupled to the output of the operational amplifier to store the drive signals for the first and second transistors for application to the first and second transistors in the absence of output from the operational amplifier.