Krishna Alpana Shenai

6608503, Aug 19, 2003

Aug 12, 2002

10/217892

Krishna Shenai - Naperville IL
Erik A. McShane - Lockport IL
Manigandan Radhakrishnan - Chicago IL

Shakti Systems, Inc.

H03K 522

327 77, 327337

A data comparator that operates on an input voltage signal and a reference voltage signal is disclosed. Internally, the comparator includes replicated circuitry to produce differential gain. Each set of replicated circuitry includes two gain stages for high amplification, high sampling rate, and for reducing kickback noise at the input voltage signal and the reference voltage signal. The comparator may further include self-biased CMOS inverters for cancellation of input offset error and a rail-to-rail regenerative output latch. The circuit can also include a comparator bias circuit that can improve the speed of the auto-zero operation.

6714049, Mar 30, 2004

Aug 12, 2002

10/217895

Krishna Shenai - Naperville IL
Erik A. McShane - Lockport IL

Shakti Systems, Inc. - Lisle IL

H03K 190175

326 82, 326 88, 324111

A logic state transition sensor circuit. The logic state transition sensor circuit detects and records transitions in voltage corresponding to a transition of a digital logic state (high to low; low to high). The logic state transition sensor circuit may include a sensing circuit containing sensing and amplification elements and a recording circuit containing recording elements. When a logic state transition occurs at an input of the sensing circuit, a positive logic pulse may be generated. Propagation of the logic pulse to the recording circuit causes a charge to be transferred to an output stage capacitor. Repeated logic state transitions cause similar incremental increases in the charge of the output stage capacitor. Charge transfer is governed by ratios of capacitors internal to the recording circuit and hence may be insensitive to process variation. The output stage capacitor may output a voltage representative of a number of logic state transitions sensed.

6791298, Sep 14, 2004

Nov 5, 2002

10/288177

Krishna Shenai - Naperville IL
Siamak Abedinpour - Chandler AZ

Shakti Systems, Inc. - Lisle IL

H01M 1046

320128

A monolithically formed battery charger may be fabricated as an integral part of a multifunctional integrated circuit or as independent monolithically formed integrated circuit. The monolithically formed battery charger includes at least one step-down converter having a given duty ratio coupled to a battery-terminal interface that provides a stepped-down output voltage and current that may be used to charge a rechargeable battery. The step-down converter includes one or more cascaded monolithically-formed synchronous-buck regulators operating at a frequency of at least one megahertz. Each regulator may include a capacitor, inductor, controller, switch, and rectifier. When cascaded, the high-side output node of a preceding synchronous-buck regulator is connected to the switch in a successive synchronous-buck regulator.

6791341, Sep 14, 2004

Aug 12, 2002

10/217894

Krishna Shenai - Naperville IL
Erik A. McShane - Lockport IL

Shakti Systems, Inc. - Lisle IL

G01R 2728

324654, 324117 H, 324117 R, 324537

A system and method for detecting, measuring, and reporting a time derivate of a current signal (di/dt). A sensing element detects current from a load. The sensing element includes an inductor. The inductor is located in series with the load and includes associated parasitic resistance. A differential potential develops across the inductor and the parasitic resistance. The differential potential is amplified and converted to a single-ended value. The single-ended value is then fed to an analog to digital converter that provides an output representative of di/dt.

6819088, Nov 16, 2004

Nov 5, 2002

10/288044

Krishna Shenai - Naperville IL, 60564
Malay Trivedi - Tempe AZ, 85282

G05F 1656

323222, 323224, 323282

A direct current to direct current boost or buck voltage converter in accordance with the invention includes a plurality of switching devices that effect voltage conversion and control current flow direction in the converter. The converter also includes a control circuit for comparing an output voltage of the converter with a reference voltage, where the control circuit produces a comparison signal based on that comparison. A resonant gate-drive circuit, also included in the converter and coupled with the control circuit and the plurality of switching devices, opens and closes the plurality of switches in response to the comparison signal to effect voltage conversion and control current flow direction.

6844251, Jan 18, 2005

Mar 22, 2002

10/104945

Krishna Shenai - Naperville IL, US
Malay Trivedi - Phoenix AZ, US
Philip Neudeck - Olmstead Falls OH, US

H01L 2128
H01L 2144

438571, 438570, 438576, 438578

A method and apparatus are provided for improving a breakdown voltage of a semiconductor device. The method includes the steps of coupling an electrode of the silicon-carbide diode to a drift layer of the semiconductor device through a charge transfer junction, said drift layer being of a first doping type and providing a junction termination layer of a relatively constant thickness in direct contact with the drift layer of the semiconductor device and in direct contact with an outside edge of the charge transfer junction, said junction termination layer extending outwards from the outside edge of the charge transfer junction, said junction termination layer also being doped with a doping material of a second doping type in sufficient concentration to provide a charge depletion region adjacent the outside edge of the charge transfer junction when the charge transfer junction is reverse biased.

20030030326, Feb 13, 2003

Aug 12, 2002

10/217840

Krishna Shenai - Naperville IL, US
Erik McShane - Lockport IL, US

Shakti Systems, Inc.

H02J001/12

307/021000, 307/029000

A power distribution management apparatus for supplying power to two or more loads includes a power and clock distribution controller capable of determining voltage, current and clock signal frequency targets for the loads. The apparatus also includes two or more power sources responsive to the controller so as to be selectively coupled with the loads to provide the target voltage and current to the loads. The power sources have switching frequencies of at least one megahertz. The apparatus further includes two or more clock signal sources responsive to the controller and coupled with the loads so as to provide clock signals to the loads at the target frequencies.

20030090244, May 15, 2003

Nov 5, 2002

10/288069

Krishna Shenai - Naperville IL, US
Siamak Abedinpour - Chandler AZ, US

G05F001/24

323/259000

A novel monolithic step-down dc-dc buck converter that uses two or more (“n”) parallel slices to achieve a high output current with a small filter capacitor is provided. Each of the n slices may be operated with a phase difference of 360/n. Each of the converter slices may be based on a synchronous rectifier topology to avoid the excessive power losses introduced by the diode component of conventional step-down buck converters. Hysteretic control may be used (with or without pulse-width modulation and pulse-frequency modulation) to provide an internal gate-drive waveform without the need to provide a dedicated clock signal or oscillator circuit. The hysteretic control is further refined using digital control techniques to enforce a brief dead time between the activation of each slice such that undesirable circulating currents are prevented. A significant advantage of the proposed multi-slice step-down dc-dc buck converter and its associated control is that the semiconductor switches, filter inductors and capacitor, and the control circuit may be fabricated as part of a single monolithic integrated circuit.