Power-supply device and hard disk drive using same
First Claim
1. A power-supply device of a step-down type DC-DC converter provided with a power semiconductor switching device, driving means of the power semiconductor switching device, a pulse-width modulation oscillator that supplies a driving signal to the driving means and an error amplifier that supplies an error signal with reference voltage to the oscillator, comprising:
- a power output filter that passes output power; and
first and second filters provided separately from the power output filter, wherein;
the first filter and one input terminal of the error amplifier are connected;
differential voltage between the output of the second filter and the output of the power output filter is added to the reference voltage; and
voltage acquired by the addition is input to the error amplifier.
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Accused Products
Abstract
The object of the invention is to compensate an effect of a voltage drop emerging in output voltage by the equivalent series resistance of a power output filter in a power-supply device. To achieve the object, a power-supply device wherein the power output filter that passes output power and first and second filters provided separately from the power output filter are provided, the first filter provided separately and one input terminal of an error amplifier are connected, new reference voltage acquired by adding differential voltage between the output of the second filter provided separately and the output of the power output filter to reference voltage is input to the other input terminal of the error amplifier and an output signal is fed back to the error amplifier is provided. According to the power-supply device, a voltage drop by equivalent series resistance emerging the output voltage of the power-supply device can be compensated.
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Citations
17 Claims
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1. A power-supply device of a step-down type DC-DC converter provided with a power semiconductor switching device, driving means of the power semiconductor switching device, a pulse-width modulation oscillator that supplies a driving signal to the driving means and an error amplifier that supplies an error signal with reference voltage to the oscillator, comprising:
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a power output filter that passes output power; and
first and second filters provided separately from the power output filter, wherein;
the first filter and one input terminal of the error amplifier are connected;
differential voltage between the output of the second filter and the output of the power output filter is added to the reference voltage; and
voltage acquired by the addition is input to the error amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 14, 16, 17)
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10. A power-supply device provided with plural power supply device units of a step-down type DC-DC converter provided with a power semiconductor switching device, driving means of the power semiconductor switching device, a pulse-width modulation oscillator that supplies a driving signal to the driving means and an error amplifier that supplies an error signal with reference voltage to the oscillator, wherein:
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the plural power supply device units are respectively provided with a power output filter that passes output power and first and second filters provided separately from the power output filter;
the first filter and one input terminal of the error amplifier are connected;
differential voltage between the output of the second filter and the output of the power output filter is added to the reference voltage; and
voltage acquired by the addition is input to the error amplifier. - View Dependent Claims (11, 12, 13)
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15. A hard disk drive provided with a magnetic storage disk, a magnetic head, a magnetic-disk rotating device, a magnetic-head drive, a magnetic-head position controller, an input/output signal controller and a power-supply device that supplies power, wherein:
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the power-supply device is a step-down type DC-DC converter power-supply device provided with a power semiconductor switching device, driving means of the power semiconductor switching device, a pulse-width modulation oscillator that supplies a driving signal to the driving means and an error amplifier that supplies an error signal with reference voltage to the oscillator; and
the power-supply device provided with a power output filter that passes output power and first and second filters provided separately from the power output filter wherein the first filter and one input terminal of the error amplifier are connected, differential voltage between the output of the second filter and the output of the power output filter is added to the reference voltage, voltage acquired by the addition is input to the error amplifier, the power output filter is an LC filter composed of an inductor and a capacitor, the first and second filters are a CR filter composed of a capacitor and a resistor, the first and second filters are provided in parallel with the power output filter, when frequencies of the first and second filters are fCR, fCR2 and a frequency of the power output filter is fLC, fLC<
fCR and relation that fCR2 is smaller than fCR by one digit or more is met and output is fed back to the error amplifier via the first and second filters is provided.
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Specification