Method and apparatus for dissipative clamping of an electrical circuit
Granted: September 20, 2005
Patent Number:
6947299
Dissipative clamping apparatuses and methods for electrical circuits. In one aspect of the invention, In one aspect of the invention, a method includes switching a power supply input on an energy transfer element, regulating a power supply output by switching the power supply input on the energy transfer element, clamping a voltage on the energy transfer element to a clamp voltage and varying the clamp voltage in response to the power supply input. In another aspect, an electrical…
Method and apparatus providing a multi-function terminal for a power supply controller
Granted: July 5, 2005
Patent Number:
6914793
A power supply controller having a multi-function terminal. In one embodiment, a power supply controller for switched mode power supply includes a drain terminal, a source terminal, a control terminal and a multi-function terminal. The multi-function terminal may be configured in a plurality of ways providing any one or some of a plurality of functions including on/off control, external current limit adjustments, under-voltage detection, over-voltage detection and maximum duty cycle…
Method and apparatus for reducing audio noise in a switching regulator
Granted: May 31, 2005
Patent Number:
6900622
A switching regulator utilizing on/off control that reduces audio noise at light loads by adjusting the current limit of the switching regulator. In one embodiment, a switching regulator includes a state machine that adjusts the current limit of the switching regulator based on a pattern of feedback signal values from the output of the power supply for a preceding N cycles of the drive signal. The state machine adjusts the current limit lower at light loads such that cycles are not…
Autostereoscopic display for multiple viewers
Granted: May 17, 2005
Patent Number:
6893129
An apparatus for displaying a stereoscopic virtual image to a first viewer (12a) and to a second viewer (12b), where the stereoscopic virtual image is imaged to each viewer at a left viewing pupil (14l) and a right viewing pupil (14r). Configurations using multiple beamsplitters (16) and one or two curved mirrors (24) direct the optical path to first and second viewers (12a and 12b).
Method and apparatus for substantially reducing electrical earth displacement current flow generated by wound components
Granted: May 17, 2005
Patent Number:
6894909
An energy transfer element having an energy transfer element input winding and an energy transfer element output winding. In one aspect, the energy transfer element input winding is capacitively coupled to the energy transfer element output winding. The energy transfer element is capacitively coupled to electrical earth. One or more additional windings are introduced as part of the energy transfer element. The one or more additional windings substantially reduce capacitive displacement…
High-voltage vertical transistor with a multi-layered extended drain structure
Granted: April 19, 2005
Patent Number:
6882005
A high-voltage transistor with a low specific on-state resistance and that supports high voltage in the off-state includes one or more source regions disposed adjacent to a multi-layered extended drain structure which comprises extended drift regions separated from field plate members by one or more dielectric layers. With the field plate members at the lowest circuit potential, the transistor supports high voltages applied to the drain in the off-state. The layered structure may be…
Method and apparatus for trimming current limit and frequency to maintain a constant maximum power
Granted: April 19, 2005
Patent Number:
6882134
Methods and apparatuses to trim current limit (Ip) and frequency (f) to maintain a constant maximum power. In one aspect of the invention, a power supply regulator having a peak current limit detection threshold and an operating frequency is disclosed. The peak current limit threshold or the operating frequency are adjusted specifically to maintain the Ipm·fn product substantially constant from one power supply controller to another where m is substantially equal to 2 and n is…
Method and apparatus for extending the size of a transistor beyond one integrated circuit
Granted: April 19, 2005
Patent Number:
6882212
A technique for extending the size of a power transistor beyond one integrated circuit. In one embodiment, a method of extending the size of a power transistor beyond one integrated circuit includes a master integrated circuit comprising a master control circuit, master driver circuit and master semiconductor switch and one or more slave integrated circuits comprising a slave semiconductor switch and a slave driver circuit. In one embodiment the master semiconductor switch terminals are…
Switched mode power supply responsive to current derived from voltage across energy transfer element input
Granted: April 12, 2005
Patent Number:
6879498
A switched mode power supply having a regulated reflected voltage. In one embodiment, a switched mode power supply includes a power supply regulator coupled between a positive input supply rail of the power supply and a primary winding of an energy transfer element. The reflected voltage across the primary winding of the transfer element is related to the output voltage across a secondary winding of the energy transfer element according to the turns ratio of the energy transfer element.…
Off-line converter with digital control
Granted: April 5, 2005
Patent Number:
6876181
A DC to DC converter comprising an energy storage element comprising an energy storage element input and energy storage element output, the energy storage element input coupled to receive a first power level and the energy storage element output providing a second power level. The converter also comprises a feedback circuit comprising a feedback input and a feedback output, the feedback input coupled to the energy storage element output. The converter further comprises a regulator…
Electronic circuit control element with tap element
Granted: March 8, 2005
Patent Number:
6865093
A technique for controlling a power supply with power supply control element with a tap element. In one embodiment, a power supply regulator includes a power transistor having first, second, third and fourth terminals. A control circuit is included, which is coupled to the third and fourth terminals of the power transistor. The power transistor is configured to switch a current between the first and second terminals in response a control signal received from the control circuit at the…
Method of fabricating a high-voltage transistor with a multi-layered extended drain structure
Granted: January 4, 2005
Patent Number:
6838346
A method for fabricating a high-voltage transistor with an extended drain region includes forming an epitaxial layer on a substrate, the epitaxal layer and the substrate being of a first conductivity type; then etching the epitaxial layer to form a pair of spaced-apart trenches that define first and second sidewall portions of the epitaxial layer. A dielectric layer is formed that partially fills each of the trenches, covering the first and second sidewall portions. The remaining…
Method for reducing the cost of voltage regulation circuitry in switch mode power supplies
Granted: December 21, 2004
Patent Number:
6833689
A reduced cost voltage regulation circuit for switched mode power supplies. In one embodiment, a voltage regulation circuit includes a current sense circuit having a current sense terminal to conduct a current to be sensed by the current sense circuit. A voltage difference between the current sense terminal and a voltage reference terminal is substantially fixed when the current to be sensed by the current sense circuit is substantially equal to a first current sense threshold. The…
Method and apparatus for maintaining an approximate constant current output characteristic in a switched mode power supply
Granted: December 21, 2004
Patent Number:
6833692
A regulator circuit maintaining an approximate constant current output characteristic. In one aspect, a disclosed regulator controls a switch that has a current limit threshold. A supply terminal and feedback terminal of the regulator are connected together as a control terminal such that a shunt regulator current is the control terminal current in excess of the internal supply current consumed by the regulator. The current limit threshold of the switch is changed as a function of the…
High-voltage transistor with multi-layer conduction region
Granted: December 7, 2004
Patent Number:
6828631
A high voltage insulated gate field-effect transistor includes an insulated gate field-effect device structure having a source and a drain, the drain being formed with an extended well region having one or more buried layers of opposite conduction type sandwiched therein. The one or more buried layers create an associated plurality of parallel JFET conduction channels in the extended portion of the well region. The parallel JFET conduction channels provide the HVFET with a low on-state…
Lateral power MOSFET for high switching speeds
Granted: November 30, 2004
Patent Number:
6825536
A lateral power metal-oxide-semiconductor field effect transistor (MOSFET) having a gate structure in which the insulated gate is coupled to the gate electrode through contacts at a plurality of locations. The source electrode includes first and second segments. The first segment is interposed between the drain electrode and the gate electrode and acts as a field plate.
Method of fabricating complementary high-voltage field-effect transistors
Granted: November 16, 2004
Patent Number:
6818490
A method of fabricating complementary high-voltage field-effect transistors in a substrate of a first conductivity type includes forming first and second well regions of a second conductivity type in the substrate. A first drain region of the second conductivity type is formed in the first well region, and a first source region is formed in the substrate adjacent the first well region. Second and third drain regions of the first conductivity type are formed in the second well region…
Method and apparatus for providing input EMI filtering in power supplies
Granted: November 2, 2004
Patent Number:
6813168
A power supply electromagnetic interference (EMI) filter circuit and technique. In one embodiment, a method of filtering EMI in a power supply includes rectifying an AC signal from an AC source, smoothing the rectified AC signal with a bulk storage capacitor to provide a DC output as an input to a power conversion circuit and filtering the EMI generated by the power conversion circuit from reaching the AC source by using the bulk capacitor and one or more inductors in combination with…
Dissipative clamping of an electrical circuit with a clamp voltage varied in response to an input voltage
Granted: November 2, 2004
Patent Number:
6813171
Dissipative clamping apparatuses and methods for electrical circuits. In one aspect of the invention, In one aspect of the invention, a method includes switching a power supply input on an energy transfer element, regulating a power supply output by switching the power supply input on the energy transfer element, clamping a voltage on the energy transfer element to a clamp voltage and varying the clamp voltage in response to the power supply input. In another aspect, an electrical…
High-voltage transistor with multi-layer conduction region
Granted: October 5, 2004
Patent Number:
6800903
A high voltage insulated gate field-effect transistor includes an insulated gate field-effect device structure having a source and a drain, the drain being formed with an extended well region having one or more buried layers of opposite conduction type sandwiched therein. The one or more buried layers create an associated plurality of parallel JFET conduction channels in the extended portion of the well region. The parallel JFET conduction channels provide the HVFET with a low on-state…
