US5444356A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Buck converter having a variable output and method for buck converting power with a variable output
Assignee: Illinois Tool Works Inc
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Filing: 1994-03-03
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Granted: 1995-08-22
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Expires: 2014-03-03
Abstract
Abstract A power supply for providing an ac/dc output to a load, includes a first source of dc power and an inverter that provides an ac output to the load. A second source of dc power is provided and selectably connects the first and second sources of dc power in series with the load when the output current reverses. In one embodiment the power sources are connected in series with every output current reversal. The first source of dc power is controllable and the magnitude of the dc current is responsive to a current reference signal. A control circuit provides the current reference signal, wherein the current reference signal is pulsed immediately prior to the ac output reversing polarity. The first source of dc power source preferably includes a buck converter that is switched at a variable frequency, depending upon the desired output current. In the event the user selects either an ac or dc electrode negative output a period of electrode positive dc energy is provided at start up to help establish the arc.
Inventors
- 👤 Jon O. Reynolds
- 👤 Michael D. Madsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 12:29
CPC Classifications
B; B23; B23K; B23K9/00; B23K9/10; B23K9/1006; B23K9/1043
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
137 words
A buck converter comprising for providing a current output of adjustable magnitude: a source of dc voltage provided between first and second buses; at least one switch having a control input, wherein the switch is connected to the first bus; a current gate connected between the switch and the second bus; and at least one inductor having a first and second end, wherein the first end is connected to a node common to the switch and the current gate, wherein the output of the converter is across the second bus and the second end of the inductor; and a variable frequency saw tooth wave generator connected to the control input, wherein the switch is turned on at the frequency of the saw tooth wave, and further wherein the frequency is inversely related to the current output magnitude.
Claim 2
Dependent Claim
137 words
A buck converter comprising for providing a current output of adjustable magnitude: a source of dc voltage provided between first and second buses; at least one switch having a control input, wherein the switch is connected to the first bus; a current gate connected between the switch and the second bus; and at least one inductor having a first and second end, wherein the first end is connected to a node common to the switch and the current gate, wherein the output of the converter is across the second bus and the second end of the inductor; and a variable frequency saw tooth wave generator connected to the control input, wherein the switch is turned on at the frequency of the saw tooth wave, and further wherein the frequency is inversely related to the current output magnitude.
Claim 3
Dependent Claim
24 words
The buck converter of claim 1 wherein the at least one switch includes two MOSFETs and the at least one inductor includes two inductors.
Claim 4
Dependent Claim
16 words
The buck converter of claim 1 wherein the frequency varies from 220 kHz to 60 kHz.
Claim 5
Dependent Claim
24 words
The buck converter of claim 1 wherein the frequency is substantially 60 kHz when the output current has a magnitude of substantially 1 amp.
Claim 6
Dependent Claim
24 words
The buck converter of claim 1 wherein the frequency is substantially 20 kHz when the output current has a magnitude of substantially 400 amps.
Claim 7
Independent Claim
67 words
A method of controlling the output of a pulse width modulated buck converter comprising the steps of; providing a source of dc voltage to the buck converter; monitoring a magnitude of the output; pulse width modulating the dc voltage with the buck converter at a controllable variable frequency in response to the magnitude of the output, wherein the frequency is inversely related to the current output magnitude.
Claim 8
Independent Claim
67 words
A method of controlling the output of a pulse width modulated buck converter comprising the steps of; providing a source of dc voltage to the buck converter; monitoring a magnitude of the output; pulse width modulating the dc voltage with the buck converter at a controllable variable frequency in response to the magnitude of the output, wherein the frequency is inversely related to the current output magnitude.
Claim 9
Dependent Claim
15 words
The method of claim 6 wherein the frequency varies from 20 kHz to 60 kHz.
Claim 10
Dependent Claim
23 words
The method of claim 7 wherein the frequency is substantially 60 kHz when the output current has a magnitude of substantially 1 amp.
Claim 11
Dependent Claim
23 words
The method of claim 7 wherein the frequency is substantially 20 kHz when the output current has a magnitude of substantially 400 amps.
Claim 12
Dependent Claim
15 words
The buck converter of claim 1 wherein the buck converter is not a resonant converter.
Claim 13
Dependent Claim
21 words
The buck converter of claim 1 wherein the converter does not include an energy storage device operating in a resonant circuit.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-08-21 | 1999-02-20 | 1999-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-08-21 | 2003-02-20 | 2003-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-08-21 | 2007-02-20 | 2007-08-22 | $7700.00 | Window Closed / Lapsed |