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:
Nov. 24, 1992
Filed:
Sep. 12, 1991
Claus Schneider, Leinfelden, DE;
Karsten-Erik Thiele, Eberdingen-Hochdorf, DE;
Robert Bosch GmbH, Stuttgart, DE;
Abstract
A current regulating circuit for an inductive load (12) is proposed, in particular for an electrohydraulic pressure regulator for an automatic transmission of a motor vehicle. A push-pull end stage (16) controls the flow of current through the load (12). Connected in series with the load (12) is a measuring resistor (11), the voltage drop of which, as an actual current value, is applied along with a command current value to a comparison stage (23, 34), by the clocked output signal of which the end stage (16) can be controlled. The measuring resistor (11) is disposed between the load (12) and a first switch transistor (10) of the end stage (16). The potential at one of the pickups (19, 20) of the measuring resistor (11) is provided as a variable reference potential for an auxiliary voltage source (31) supplying the comparison stage (23, 34), which source has switch means (40) for generating an auxiliary voltage (Uh) that is constant relative to the variable reference potential. By means of this integratable and hence economical arrangement, only a few external components and no external calibration are necessary. Nevertheless, high precision is assured, over a wide temperature range that depends essentially on the precision of the measuring resistor (11) and on the precision of the analog command value present via the resistor (30).