Resumes
Resumes
Ernest Wittenbreder Phones & Addresses
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Sahuarita, AZ
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St Petersburg, FL
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Melbourne Beach, FL
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Sedona, AZ
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Naperville, IL
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Flagstaff, AZ
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Glendale, AZ
Business Records
Name / Title
Company / Classification
Phones & Addresses
President/ceo
TECHNICAL WITTS, INC
Publications
Us Patents
Power Electronic Circuits With Ripple Current Cancellation
View pageUS Patent:
6437999, Aug 20, 2002
Filed:
May 12, 2001
Appl. No.:
09/853561
Inventors:
Ernest H. Wittenbreder - Flagstaff AZ
Assignee:
Technical Witts, Inc. - Flagstaff AZ
International Classification:
H02M 112
US Classification:
363 39, 363 41
Abstract:
PWM DC to DC converter circuits which accomplish ripple cancellation at one or more terminals are revealed. Four or more inductors are required in each case, however, in all cases multiple inductors can be combined into a single simple coupled inductor to accomplish the ripple cancellation. Some of the circuits revealed accomplish ripple cancellation at all terminals and some also provide zero voltage switching and galvanic load isolation. The non-isolated DC to DC converter networks revealed accomplish buck, boost, buck boost (flyback), buck complement, boost complement, or flyback complement conversion using a simple circuit requiring only two switches, one of which may be a simple diode rectifier, two or more capacitors, and four or more inductors, which may be co-located on a single common magnetic core. The isolated converters revealed provide continuous and discontinuous forward converter and continuous flyback converter transfer functions. Also revealed are techniques to accomplish isolation, high order (quadrature) transfer functions, zero ripple tapped inductor topologies, and methodology for generalizing the process of changing three terminal networks with pulsating terminal currents into three terminal networks with zero ripple terminal currents.
Zero Voltage Switching Cells For Power Converters
View pageUS Patent:
6452814, Sep 17, 2002
Filed:
Sep 19, 2001
Appl. No.:
09/956711
Inventors:
Ernest H. Wittenbreder - Flagstaff AZ
Assignee:
Technical Witts, Inc. - Flagstaff AZ
International Classification:
H02M 3335
US Classification:
363 16, 363127
Abstract:
Zero voltage switching cells using a small magnetic circuit element, a pair of switches, and a capacitor are revealed. The application of the zero voltage switching cells to any of a wide variety of hard switching power converter topologies yields equivalent power converters with zero voltage switching properties, without the requirement that the magnetizing current in the main magnetic energy storage element be reversed during each switching cycle. The new switching cells either provide integral line filtering or a means to accomplish zero voltage switching with no high side switch drive mechanism. In the subject invention the energy required to drive the critical zero voltage switching transition is provided by the small magnetic circuit element, either a single winding choke or a two winding coupled choke, that forms part of the zero voltage switching cell. The application of the zero voltage switching cells to buck, buck boost, Cuk, flyback, and forward converters is shown. A variation of the zero voltage switching cell which adds a single diode to clamp ringing associated with the magnetic circuit elements and parasitic capacitance of off switches is also revealed.
Zero Voltage Switching Power Conversion Circuits
View pageUS Patent:
6462963, Oct 8, 2002
Filed:
Feb 12, 2002
Appl. No.:
10/076008
Inventors:
Ernest H. Wittenbreder - Flagstaff AZ
Assignee:
Technical Witts, Inc. - Flagstaff AZ
International Classification:
H02M 3335
US Classification:
363 16, 363127
Abstract:
A tapped inductor buck converter which achieves zero voltage switching and continuous input and output terminal currents is revealed. To achieve these results an additional switch, a small inductor, and a capacitor are required. The small inductor serves as a source of energy for driving the critical turn on transition of the main switch and the same small inductor also serves as a filter component for smoothing the input and output terminal currents. Simple adaptive gate drive circuits are revealed that improve the timing for turn on of zero voltage switches and reduce gate drive losses. A synchronous rectifier self drive mechanism is revealed which is universally applicable to zero voltage switching power converters with a single main switch which rely on an auxiliary inductor to drive the critical turn on transition of the single main switch. The wave form generated by the auxiliary inductor is ideally suited to synchronous rectifier self drive. Finally, peak current sensing techniques are revealed which are universally applicable to zero voltage switching power converters with a single main switch and an auxiliary switch which rely on an auxiliary inductor to drive the critical turn on transition of the single main switch.
Circuits And Circuit Elements For High Efficiency Power Conversion
View pageUS Patent:
6822427, Nov 23, 2004
Filed:
May 1, 2002
Appl. No.:
10/137908
Inventors:
Ernest H. Wittenbreder - Flagstaff AZ
Assignee:
Technical Witts, Inc. - Flagstaff AZ
International Classification:
G05F 156
US Classification:
323282, 323222, 323351
Abstract:
Several novel zero voltage switching (ZVS) cells and a ZVS dc to dc transformer circuit are revealed. A U core transformer structure for use with the dc to dc transformer circuit is also revealed. An optimal gate drive circuit that achieves optimal switch timing for ZVS switches is revealed. The optimal gate drive circuit achieves optimal timing for the case in which there is sufficient energy available to drive a zero voltage transition and also for the case in which there is insufficient energy to drive a zero voltage transition providing turn on current to the switch at the minimum drain voltage of the switch. A magnetically coupled multi-phase converter cell structure is revealed which achieves reduced switch ripple current and fast transient response for multi-phase systems with three or more cells. A ZVS active reset switch drive scheme is revealed for providing zero voltage switching in bi-directional power flow converters for both directions of power flow using a single active reset circuit. A primary switching network that applies only one quarter of the input dc source voltage to a winding network connected to the switching network is revealed.
Efficient Power Conversion Circuit Having Zero Voltage Switching
View pageUS Patent:
20010036088, Nov 1, 2001
Filed:
May 4, 2001
Appl. No.:
09/849178
Inventors:
Ernest Wittenbreder - Flagstaff AZ, US
International Classification:
H02M003/335
US Classification:
363/017000
Abstract:
A highly efficient and simple power conversion circuit () having zero voltage switching (ZVS) includes a novel switch timing technique, such that the need for an leakage inductor connected in series with the primary circuit of the converter and rectifier diodes is eliminated. A switch timing circuit () located in an output side circuit () enables the use of the natural stored magnetic energy in the output side circuit () to drive the critical switching transitions to accomplish soft switching for all of the switches (-) in a full bridge forward converter () for all transitions. This power conversion circuit () includes a full bridge circuit () having plurality of switching devices (-) that intermittently couple the primary winding () to the input of the power converter (). A transformer () couples to receive power from the full bridge circuit () into its primary winding (). The output side circuit () includes the switching circuit () coupled to provide stored magnetic energy to drive the switching transitions of the switching devices (-) in the full bridge circuit (). The switching circuit () closes at a predetermined time delay after the switching transitions in the full bridge circuit () to accomplish zero voltage switching for the plurality of switches in the full bridge circuit (). A converter controller provides control signals to the full bridge and the switching circuits ().
Universal Pulse Width Modulated Zero Voltage Transition Switching Cell
View pageUS Patent:
20020000795, Jan 3, 2002
Filed:
Jan 29, 2001
Appl. No.:
09/772511
Inventors:
Ernest Wittenbreder - Flagstaff AZ, US
International Classification:
G05F001/40
US Classification:
323/271000
Abstract:
A universal zero voltage transition switching cell using a small choke, a pair of switches, and a capacitor is revealed. The application of the universal zero voltage transition switching cell to any of a wide variety of hard switching pulse width modulated power converter topologies yields identical power converters with zero voltage switching properties, without the requirement that the magnetizing current in the main power choke be reversed during each switching cycle. In the subject invention the energy required to drive the critical zero voltage switching transition is provided by the small choke that forms part of the universal zero voltage transition switching cell. The application of the universal zero voltage transition switching cell to buck, boost, buck boost, Cuk, Wittenbreder, flyback, forward, and SEPIC converters is shown. A variation of the universal zero voltage transition switching cell which adds a single diode to clamp ringing associated with the parasitic capacitance of off switches is also revealed.
Synthesis Methods For Enhancing Electromagnetic Compatibility And Ac Performance Of Power Conversion Circuits
View pageUS Patent:
20020121881, Sep 5, 2002
Filed:
Sep 4, 2001
Appl. No.:
09/946691
Inventors:
Ernest Wittenbreder - Flagstaff AZ, US
International Classification:
G05F001/24
US Classification:
323/259000
Abstract:
Five circuit synthesis methods, for forming new power conversion circuits with enhanced electromagnetic compatibility and improved AC performance from old circuits with AC performance and/or electromagnetic compatibility deficiencies, are revealed. The new synthesis methods achieve performance improvements without requiring the addition of magnetic cores. In all cases a simple toroidal magnetic core structure is not precluded. In all cases splitting or adding magnetic windings is required, and, in many cases, additional capacitors are required. Many new circuits formed by applying the synthesis methods are revealed. The results achieved by application of the synthesis methods include zero ripple current at all terminals without adding magnetic cores or requiring a complex magnetic circuit element, cancellation of common mode currents, improved control loop bandwidth, and faster transient response.
Synchronous Rectifier Self Gate Drive For Zero Voltage Switching Power Conversion Circuits
View pageUS Patent:
20030151927, Aug 14, 2003
Filed:
May 28, 2002
Appl. No.:
10/157101
Inventors:
Ernest Wittenbreder - Flagstaff AZ, US
International Classification:
H02M003/335
US Classification:
363/016000
Abstract:
Synchronous rectifier self drive mechanisms are revealed which are universally applicable to zero voltage switching power converters which rely on an auxiliary inductor to drive the critical turn on transition of the main switch of the power converter. The voltage wave form generated by the auxiliary inductor is well suited to synchronous rectifier self drive. Voltage limiting circuits that reduce the voltage swing of synchronous rectifier gates are also revealed. These voltage limiting circuits reduce the energy circulated into and out of the synchronous rectifier gates and protect the synchronous rectifier gate circuits from negative over voltage.