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Patent Searching and Data


Title:
BATTERY-DRIVEN ACOUSTIC DEVICE
Document Type and Number:
Japanese Patent JPH07184370
Kind Code:
A
Abstract:

PURPOSE: To modify an audio output amplifier into an amplifier to be driven by two kinds of power supplies, that is, the positive and negative supplies by providing a DC/DC converter which generates the powers of a battery where the voltages and polarities are inverted but the voltages are almost equal.

CONSTITUTION: A DC/DC converter 5 is provided, an output voltage of a battery 13 is detected by a voltage detecting circuit 9 and a PWM control circuit 8 generates a PWM pulse to maintain a voltage of output line 7 to the voltage which is equal to the voltage of battery 13 but is inverted therefrom in the polarity in view of driving a switching transistor Q. The output amplifiers 2, 3 are used as the amplifiers which are driven by two power supplies, that is, the positive and negative power supplies. The output side thereof is connected direct to a speaker. Amplifying distortion may be reduced to lower an output distortion even when an output level of the signal becomes large and the amplifier is driven only with single battery. The operation frequency of the DC/DC converter 5 is set to 20kHz or higher to eliminate influence on the audio signal.


Inventors:
HORIUCHI YUKITO
ISHIKAWA HIROYUKI
Application Number:
JP1993000347681
Publication Date:
July 21, 1995
Filing Date:
December 24, 1993
Export Citation:
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Assignee:
ROHM CO LTD
International Classes:
H02M3/155; H03F3/181; (IPC1-7): H02M3/155; H03F3/181
Attorney, Agent or Firm:
梶山 佶是 (外1名)