Patent ID: 8494171

Claim:
An energy saving PWM sound device for a PWM output of a voice-ICs product, comprising: a hollow core body having a top rim, a bottom rim, and two side rims to define a through channel therewithin, wherein said hollow core comprises two or more planer impedance members, each having a base portion and first and second extension portions spacedly and parallely extended from said base portion to form a C-shaped configuration, wherein said impedance members are stacked together to form said core body that said first extension portions of said impedance members are overlapped to form said top rim, said second extension portions of said impedance members are overlapped to form said bottom rim, and said base portions are said side rims respectively; and an elongated conductive element winding around said top rim of said core body through said through channel to retain said impedance members in position, wherein two ends of said conductive element are adapted for connecting with said PWM output, such that when said conductive element is electrically conducted, said core body acts as an inductor at lower frequency and a frequency-dependent resistor in series with said inductor at higher frequency for blocking most of PWM carrier frequency so as to reduce a power consumption of the voice-ICs product.