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:
Oct. 27, 1998
Filed:
Nov. 10, 1997
Bert White, Irvine, CA (US);
Texas Instruments Incorporated, Dallas, TX (US);
Abstract
The present invention discloses a circuit to reduce current and voltage spikes when switching inductive loads. The circuit of the present invention achieves this reduction in voltage and current spikes without requiring the prior art's large sizes for the transistors driving the inductive load. The invention results in reduced cost and power consumption. Moreover, the invention's circuit maintains a fast switching time for the transistors driving the inductive load. The invention's circuit comprises a current steering mechanism which directs current to one of the two drivers driving an inductive load. According to the invention, current is directed to the driver coupled to the supply voltage, the driver coupled to ground, or both in different amounts. The current is directed to the drivers such that the effect of flyback voltage caused by switching the inductive load is reduced. When current flows from the inductive load into the driver circuitry, a temporary discharge path is provided such that the body diode between the inductive load and the supply voltage is not forward biased. Conversely, when current flows from the driver circuitry into the inductive load, a temporary discharge path is provided such that the body diode between the inductive load and ground in not forward biased. The prevention of the forward biasing of the body diodes results in a reduction of the stored charge in the body diodes. This in turn results in a reduction of current and voltage spikes in the supply voltage and ground.