DC/DC converter and audio device incorporating the same
First Claim
Patent Images
1. A DC/DC converter comprising:
- a first load circuit including primarily an electric power output circuit constituting a heavy load for an electric power to be outputted;
a second load circuit including primarily a control IC circuit constituting a light load for the electric power to be outputted and connected in parallel with said first load circuit so as to constitute parallel loads;
a switching circuit which includes a transistor for switching a DC power source line and feeds an electric power to said loads,a switching control circuit which controls the switching period of the transistor so as to maintain an output voltage for the loads at a predetermined constant value; and
,an oscillation circuit which turns ON or OFF the transistor at a predetermined period, wherein when an electric power is fed from said switching circuit to said first load circuit, said switching control circuit is caused to operate, and when an electric power is fed to said second load circuit without feeding to said first load circuit, the operation of said switching control circuit is ceased and said oscillation circuit is caused to operate.
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Abstract
A DC/DC converter and an audio device incorporating the same performs a switching operation of a transistor through a driving control merely by an oscillation circuit under a light load condition other than a switching control circuit which shows a low conversion efficiency under a light load condition, thereby the conversion efficiency therewith under a light load condition is improved.
24 Citations
8 Claims
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1. A DC/DC converter comprising:
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a first load circuit including primarily an electric power output circuit constituting a heavy load for an electric power to be outputted; a second load circuit including primarily a control IC circuit constituting a light load for the electric power to be outputted and connected in parallel with said first load circuit so as to constitute parallel loads; a switching circuit which includes a transistor for switching a DC power source line and feeds an electric power to said loads, a switching control circuit which controls the switching period of the transistor so as to maintain an output voltage for the loads at a predetermined constant value; and
,an oscillation circuit which turns ON or OFF the transistor at a predetermined period, wherein when an electric power is fed from said switching circuit to said first load circuit, said switching control circuit is caused to operate, and when an electric power is fed to said second load circuit without feeding to said first load circuit, the operation of said switching control circuit is ceased and said oscillation circuit is caused to operate. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An audio device comprising:
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a first load circuit including a DC motor driving circuit, a DC motor adapted to be driven by said DC motor driving circuit and an audio output circuit; a second load circuit including primarily a control IC circuit which generates a variety of control signals to the audio device; a battery; and
,a DC/DC converter including a switching circuit having a transistor for switching a power source line connected to said battery and feeds an electrical power to the loads;
a switching control circuit which controls the switching period of said transistor so as to maintain an output voltage for the loads at a predetermined constant value; and
an oscillation circuit which turns ON or OFF said transistor at a predetermined period, wherein when an electric power is fed from said switching circuit to said first load circuit said switching control circuit is caused to operate, and when an electric power is fed to said second load circuit without feeding to said first load circuit, the operation of said switching control circuit is ceased and said oscillation circuit is caused to operate. - View Dependent Claims (8)
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Specification