Patrice R Lethellier

US Patent:

6424129, Jul 23, 2002

Filed:

Aug 21, 2001

Appl. No.:

09/935286

Inventors:

Patrice R. Lethellier - Oxnard CA

Assignee:

Semtech Corporation - Newbury Park CA

International Classification:

G05F 140

US Classification:

323272, 323290, 323282

Abstract:

An apparatus and method for accurately sensing the output current delivered to a load by a buck-type DC-to-DC switched mode power converter corrects for thermal variation of the output inductor. A first current sense signal provides a fast indication of output current of the DC-to-DC converter that is susceptible to thermal variation of the output inductor of the converter, and a second current sense signal provides a slow but accurate indication of output current that is not affected by said thermal variation. The first current sense signal is corrected using the second current sense signal to yield accurate output current sensing information. In an embodiment of the invention, an output current sensing apparatus is provided for use in a multi-phase DC-to-DC voltage converter comprising a plurality of converter modules connected to a common load and having a common input voltage source. A first current sensor is adapted to be coupled to an output inductor of at least one of the plurality of converter modules to derive a first current sense signal corresponding to current passing through an internal DC resistance of the output inductor. A second current sensor is adapted to be coupled to a sensing resistor disposed in series between the common input voltage source and the load to derive a second current sense signal corresponding to current passing through the sensing resistor.

US Patent:

6441597, Aug 27, 2002

Filed:

Oct 31, 2001

Appl. No.:

10/001722

Inventors:

Patrice R. Lethellier - Oxnard CA

Assignee:

Semtech Corporation - Camarillo CA

International Classification:

G05F 140

US Classification:

323282, 323284, 323222

Abstract:

A current sense circuit for a DC-to-DC power converter accurately senses the output inductor current without adversely affecting efficiency of the power converter. The current sense circuit produces a current sense signal having amplitude sufficiently above the noise floor so that accurate load control of the power converter is achieved. Specifically, the DC-to-DC power converter includes at least one power switch connected to an input voltage source. At least one phase sensing switch is connected to the input voltage source in parallel with the at least one power switch. A pulse width modulation circuit provides common control pulses for the at least one power switch and the at least one phase sensing switch responsive to a current sense signal. An output inductor is connected to the at least one power switch and to a load. A current sensor is coupled to the output inductor and providing the current sense signal to the pulse width modulation circuit corresponding to current passing through an internal DC resistance of the output inductor.

US Patent:

6472852, Oct 29, 2002

Filed:

Nov 2, 2000

Appl. No.:

09/705342

Inventors:

Patrice Lethellier - Oxnard CA

Assignee:

Semtech Corporation - Newbury Park CA

International Classification:

G05F 124

US Classification:

323259, 323261, 323232, 363 5601

Abstract:

A swinging inductor is used to achieve zero-current switching in a resonant buck-type voltage converter. The swinging inductor exhibits the property of a relatively high inductance at zero current and low current, but it swings back to the original resonant inductance value at high current. In this way the high and medium regions of the current sine wave remain effectively unchanged. Upon circuit power application, the current rises slowly due to the high swinging inductance value, but this is an innocuous parasitic effect. Using the swinging inductance placed in series with a switching device to control the transfer of energy from the input source to the output load allows for a very efficient transfer of energy and it also prevents the current from becoming negative. Moreover, the efficiency level is sustainable over a wide range of input and output voltage requirements.

US Patent:

6625045, Sep 23, 2003

Filed:

Dec 28, 2001

Appl. No.:

10/034347

Inventors:

Patrice R. Lethellier - Oxnard CA

Assignee:

Semtech Corporation - Newbury Park CA

International Classification:

H02M 324

US Classification:

363 89, 363126

Abstract:

A power module for a power system adapted to employ a star link topography. The power module includes a star section having an internal clock connection and a star link connection. The power system includes a plurality of power modules that each have a substantially similar star section. The star section utilizes an oscillating signal to generate an internal clock signal. The star section utilizes a star link signal to determine the phase of the oscillating signal. Either the addition of a power module to a power system or the removal of a power module from a power system including at least three power modules will result in the adjustment of the spread of the phases of each of the power modules to an amount about equal to 360 degrees divided by the number of power modules in the power system.

US Patent:

6664774, Dec 16, 2003

Filed:

Mar 27, 2002

Appl. No.:

10/112010

Inventors:

Patrice R. Lethellier - Oxnard CA

Assignee:

Semtech Corporation - Newbury CA

International Classification:

G05F 156

US Classification:

323282, 323285

Abstract:

An offset peak current mode control circuit is provided for use with a multiple-phase DC-to-DC voltage converter including a plurality of converter modules connected to a common load and having a common input voltage source, a current sensor coupled to a sensing resistor disposed in series between the common input voltage source and the load to derive a current sense signal corresponding to current passing through the sensing resistor, and a voltage error sensor coupled to the load to derive a voltage error signal corresponding to difference between an output voltage of the voltage converter and a reference voltage. When the DC-to-DC voltage converter is operated with a relatively low input voltage or a relatively high duty cycle resulting in an overlap of the current sense signal, the offset peak current mode control circuit utilizes information from the clean (i. e. , non-overlapping) portion of the current sense signal, and then stretches the duty cycle applied to an associated voltage converter module so that it extends into the time of the overlapping portion of the current sense signal.

US Patent:

6703812, Mar 9, 2004

Filed:

Feb 18, 2003

Appl. No.:

10/370412

Inventors:

Patrice R. Lethellier - Oxnard CA

Assignee:

Semtech Corporation - Camarillo CA

International Classification:

G05F 110

US Classification:

323222, 323284

Abstract:

A power converter comprises at least one output inductor having an input and output terminal. At least one first switch circuit is connected to the input terminal of the output inductor to alternately connect the input terminal to at least one voltage source and to ground. A ripple control circuit is coupled to the output terminal and is adapted to clamp output current of the output inductor to an allowable maximum level in response to an output current overshoot condition produced by a step down in load coupled to the output terminal. The ripple control circuit further comprises an inductor conducting the output current to ground upon the output current overshoot condition.

US Patent:

7319232, Jan 15, 2008

Filed:

Jun 6, 2005

Appl. No.:

11/146667

Inventors:

Robert Bell - Chandler AZ, US
Brad Benson - Chandler AZ, US
Patrice R. Lethellier - Chandler AZ, US

Assignee:

National Semiconductor Corporation - Santa Clara CA

International Classification:

G02B 27/00

US Classification:

250551, 250214 R, 327514

Abstract:

An opto-coupler interface is provided. The opto-coupler interface includes a current mirror and a resistor. The opto-coupler interface is arranged such that a relatively fixed voltage is provided across the photodetector. At one end of the photodetector, the voltage is relatively fixed because the photodetector is coupled to the input of a current mirror. Because the voltage across the opto-coupler is relative fixed, the opto-coupler interface is a current interface rather than a voltage interface. Current from the photodetector is mirrored by the current mirror to provide an output mirror current. The output mirror current is provided to a resistor such that the resistor provides a voltage that is based on the output mirror current.

US Patent:

8242704, Aug 14, 2012

Filed:

Sep 9, 2008

Appl. No.:

12/207353

Inventors:

Patrice R. Lethellier - Sunnyvale CA, US

Assignee:

Point Somee Limited Liability Company - Dover DE

International Classification:

H05B 41/16
G05F 37/02

US Classification:

315276, 315291

Abstract:

An apparatus, method and system are disclosed for supplying power to a load such as a plurality of light emitting diodes. A representative apparatus comprises a primary module, a first secondary module couplable to a first load, and a second secondary module couplable to a second load. The primary module comprises a transformer having a transformer primary. The first secondary module comprises a first transformer secondary magnetically coupled to the transformer primary, and the second secondary module comprises a second transformer secondary magnetically coupled to the transformer primary, with the second secondary module couplable in series through the first or second load to the first secondary module.