Patent ID: 6100756
Filing Date: 2000-08-08
Classification: H03F

Abstract:
An apparatus, comprising:a pulsewidth modulator coupled to an input of said apparatus, said pulsewidth modulator having an output;a soft switch driver having an input responsive to said output of said pulsewidth modulator, and having first and second outputs which are complementary when in steady-state, said soft switch driver further having:a first short steady-state signal path from the input of the soft switch driver to the first output, wherein the first short steady-state signal path includes a first in-line switch capable of opening the first short steady-state signal path responsive to a first control input;a first long steady-state signal path from the input of the soft switch driver to the first output;a second short steady-state signal path from the input of the soft switch driver to the second output, wherein the second short steady-state signal path includes a second in-line switch capable of opening the second short steady-state signal path responsive to a second control input;a long steady-state signal path from the input of the soft switch driver to the second output; anda control circuit responsive to the input of the soft switch driver, wherein said control circuit drives the first control input of the first in-line switch and the second control input of the second in-line switch;a low pass filter having an input, and having an output coupled to an output of the apparatus;a high side switch driven by the first output of the soft switch driver, and coupled between a voltage potential and the input of the low pass filter such that when the high side switch is closed, the input of the low pass filter is electrically coupled to the voltage potential; anda low side switch driven by the second output of the soft switch driver and coupled between a reference potential and the input of the low pass filter such that when the low side switch is closed, the input of the low pass filter is electrically coupled to the reference potential, wherein said soft switch driver drives said first and second outputs to complementary states responsive to said output of said pulsewidth modulator such that there is a low transitioning output and a high transitioning output, and the electrical signal length through said soft switch driver is shorter for the low transitioning output than for the high transitioning output.