Jun M Honda, Age 53Laguna Beach, CA

7417504, Aug 26, 2008

Aug 3, 2007

11/833587

Johan Tjeerd Strydom - Santa Clara CA, US
Jun Honda - El Segundo CA, US

International Rectifier Corporation - El Segundo CA

H03F 3/217

330251, 330207 A, 330302

A method of minimizing an audible click noise from a speaker in a Class D audio power amplifier upon shutdown or startup of a switching stage having two switches series connected at a node, the speaker being connected to the node via an output filter comprising an inductor and a capacitor, the switches being controlled by a controller. The method including the steps of determining a timing interval at the node to transition a peak voltage of the capacitor, the capacitor voltage being a speaker voltage; and eliminating the audible transient voltage excursion across the speaker that causes a click noise during the timing interval, wherein at startup ON and OFF times of the switches are incrementally increased from zero to a normal mode and at shutdown the ON OFF times of the switches are incrementally decreased from the normal mode to zero.

7548029, Jun 16, 2009

Jun 2, 2005

11/144205

Xiao-Chang Cheng - San Jose CA, US
Jun Honda - El Segundo CA, US
Dana Wilhelm - Temple City CA, US

International Rectifier Corporation - El Segundo CA

G05F 1/00

315291, 315224, 363 98

An apparatus and method for determining the output current in a bridge-connected switched transistor output circuit including high-side and low-side transistor switches, typically MOSFETS. The voltage at a common node between the high and low side switches is sensed, and offset in a first circuit by a fixed amount so that the voltage is positive for all positive or negative output currents of interest. The output current is actually determined in a second circuit which receives the offset voltage signal only predetermined times in relation to the on-time of the low side switch. The first circuit includes a current reference source/level shifter and a current mirror circuit formed of a plurality of transistors in a particular circuit configuration. The second circuit is coupled to an output of the first circuit by a gated NMOS transistor at the desired times to provide the current measurement signal. The second circuit includes a second current reference source having substantially the same electrical characteristics as the first current reference source, and a second plurality of transistors respectively matched to the input side circuit transistors, and connected in the same circuit configuration.

7636227, Dec 22, 2009

Apr 18, 2007

11/736679

Xiao-chang Cheng - San Jose CA, US
Jun Honda - El Segundo CA, US
Gabriele Bernardinis - Marina del Rey CA, US

International Rectifier Corporation - El Segundo CA

H02H 9/08

361 931, 361 939

A circuit for providing over-current protection, the circuit including a gate driver circuit for controlling a bridge circuit including a half bridge stage having high and low switches. The circuit includes a feedback loop circuit for counting over-current indicators sensed during one or more consecutive PWM cycles; wherein when an over-current indicator is sensed, the low switch is turned OFF for duration of a first time period after which the low switch is turned back ON, to enable determination of an over-current condition where false noise signals are rejected thereby preventing circuit shutdowns due to false over-current condition.