| 摘要 |
PROBLEM TO BE SOLVED: To provide a capacitor microphone for SMD which improves compatibility between itself and an electret capacitor microphone (ECM), solves the problem of a direction of a round capacitor microphone in a surface mount device (SMD) process, maintains a constant electric field after high-temperature reflow work, and has no sensitivity loss. SOLUTION: The capacitor microphone is provided with: a ground terminal for coupling to an external circuit, a power source and output terminal for coupling to the external circuit; a pair of diaphragm/backplate in which one end is coupled to the ground terminal, capacity is varied and sound is converted into an electric signal; a DC-DC converter for providing a bias voltage to form a static electric field on one end of this pair; a buffer integrated circuit element for amplifying an electric signal of sound by the pair and outputting the amplified signal; and a decoupling capacitor for shielding the bias voltage outputted from the DC-DC converter from being directly supplied to the buffer integrated circuit element, and transmitting the electric signal of sound by the pair to the buffer integrated circuit element. COPYRIGHT: (C)2005,JPO&NCIPI |
