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:
May. 10, 1994
Filed:
Sep. 06, 1991
Charles C Austin, Mission Viejo, CA (US);
Silicon Systems, Inc., Tustin, CA (US);
Abstract
The present invention provides driver circuitry for commutated inductive loads, and in particular, inductive loads employed in multi-pole DC brushless motors. The preferred embodiment of the present invention typically implements three pull-up and three pull-down drivers for motor control. The pull-down driver circuit described in the present invention can be configured to be adjusted by an external component of the integrated circuit implementation in order for controlling turn-off transients. Voltage transients due to changes in load current in the control loop of the pull-down driver circuit can be minimized or deterministically controlled by controlling the rate of change of the input voltage. For the case of when the load current is to be completely switched from one inductor to another inductor, an additional unity gain buffer coupled to the input voltage is inserted into the control loop of the pull-down driver circuit for reducing the voltage transients that can result. The output voltage rise and fall times of the pull-up driver circuit of the present invention can be controlled by means of an accurate clock rate, a capacitance ratio value, an arbitrary voltage supply or by any combination of the above means. The present invention also provides circuitry for controlling the pull-up driver circuit and the pull-down driver circuits as required to assert the floating operation and as well dynamic breaking operation. The present invention is able to assert these operations by operating from either the power supply or from an energy storage capacitor that is charged to a value closely approximating the power supply voltage should the power supply be removed.