Title:
SPEAKER DRIVING CIRCUIT
Document Type and Number:
Japanese Patent JP3168120
Kind Code:
B2
Abstract:
PURPOSE: To prevent the deterioration in an electroacoustic conversion efficiency in a low range of voices of the speaker and to obtain sufficient power supply by providing a constant current source that changes its output current according to inputted sound signals.
CONSTITUTION: An output current of a constant current source 1(1a) is changed by a received voice signal f1. A condenser speaker 2(2a) is driven by the constant current source 1(1a). An input resistor R1 receiving the voice signal f1 is connected to one input of an operational amplifier 4 of the constant current source 1a and the other input connects to a reference potential point via a reference potential point resistor R2. the output of the operational amplifier is fed back via a negative feedback resistor R3 and an output resistor R5 and a positive feedback resistor R4 respectively to the input. A connecting point between the positive feedback resistor R4 and the output resistor R5 is connected to the speaker 2a. Then the relation of (R5+R4)/R2=R3/R1 is established.
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Inventors:
Teruo Ohashi
Masahiko Takeda
Masahiko Takeda
Application Number:
JP17731494A
Publication Date:
May 21, 2001
Filing Date:
July 28, 1994
Export Citation:
Assignee:
Aiphone Co., Ltd.
International Classes:
H04R3/00; H04M1/60; H04R17/00; H04R19/02; (IPC1-7): H04R3/00; H04M1/60; H04R17/00; H04R19/02
Domestic Patent References:
| JP5327360A | ||||
| JP4132497A | ||||
| JP567360B2 |
Attorney, Agent or Firm:
Moriya Kazuo (1 person outside)