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. 09, 1995
Filed:
Dec. 07, 1993
Alan E Brown, Austin, TX (US);
Benchmarq Microelectronics, Inc., Carrollton, TX (US);
Abstract
A DC-DC converter is provided which is operable to drive a reactive circuit (10) that includes both a series inductor (12) and a capacitor (14) disposed between the output node and ground. The DC-DC converter includes two switches, a transistor switch (20) connected between a positive supply and an input node (16) and a second transistor (28) connected between the node (16) and ground. In one mode of operation, the transistors (20) and (28) operate in an asynchronous regulation mode with clock signals provided to the gates thereof. In a second asynchronous mode of operation, transistor (28) is turned off and replaced by its junction isolation diode (48). The transistor (20) is driven by a clock signal in accordance with an asynchronous regulation mode of operation. In a third mode of operation, the modified asynchronous duty cycle to the gate of transistor (20) is altered. In a fourth mode of operation, a linear regulation circuit (51) and an internal regulation transistor (49) are provided which are connected to the node (16) through a resistor (44). During this mode of operation, transistors (20) and (28) are turned off. By sensing current to the input of transistor (20) during the first, second and third modes of operation, a determination can be made for switching between the first three modes of operation and from the third mode of operation to the fourth mode of operation. The voltage on the input node (16) is sensed through resistor (44) to make a decision to switch from the first to the second mode of operation. At any time, the output voltage on node (18) can be sensed by a switching regulator control circuit (26) to determine that the regulation provided thereby falls below a predetermined regulation threshold and then the asynchronous mode of operation selected.