US 4,908,870 AGranted

Motional load driver

AssigneeYamaha Corporation

InventorKatsuo Nagi

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Abstract

A motional load driver for driving a motional load having a motional impedance includes an amplifying section for amplifying an input signal and supplying the input signal to a motional load such as a loudspeaker, a current detecting section for generating an output signal corresponding to a current flowing through the motional load, and a load impedance cancellation current generating section for generating a current corresponding to a magnitude of the output signal generated by the current detecting section and positively feeding back the current to the amplifying section. The current detecting section includes, for example, an impedance element such as a resistor series-connected to the motional load. A voltage between both the terminals of the resistor is converted into a current by a voltage/current converter arranged in the impedance cancelation current generating section, and the current is fed back to the amplifying section. With this arrangement, the motional load can be driven without being influenced by a potential difference between the input and output ground points of the amplifying section.

Claims8

Dependent claims

A motional load driver for driving a motional load having a motional impedance, comprising:

an amplifying section for amplifying an input signal and supplying the thus amplified input signal to said motional load;
a current detecting section for generating an output voltage signal corresponding to a current flowing through said motional load;
and
a load impedance cancelation generating section for generating a current corresponding to a magnitude of the output voltage signal generated by said current detecting section and feeding back the current to said amplifying section, said load impedance cancelation current generation section comprising a voltage/current converter for converting the voltage signal into a corresponding current, said voltage/current converter comprising an amplifier having inverting and non-inverting input terminals, a first input resistor one terminal of which is connected to said inverting input terminal, a second input resistor one terminal of which is connected to said non-inverting input terminal, a feedback resistor connected between said inverting input terminal and an output of said amplifier, and an output resistor one terminal of which is connected to said output of said amplifier and the other terminal of which is connected to an output of said voltage/current converter and said non-inverting input terminal of said amplifier, the voltage signal corresponding to the current flowing through said motional load being applied between the other terminal of said first input resistor and the other terminal of said second input resistor.

1 more element

Dependencies are inferred from the claim text.