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US 5,844,786 AGranted
DC-DC converter circuit and inductive load driver using it
AssigneeKomatsu Ltd.
InventorsDaisuke Yoshida, Masao Hagiwara, Yasushi Kawaji
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AssigneeKomatsu Ltd.
InventorsDaisuke Yoshida, Masao Hagiwara, Yasushi Kawaji
Estimating the term…
An inductive load drive device comprising a DC--DC converter circuit which has a coil (L) and switch (Sw) in series with a power source (E) and a capacitor (C) provided in parallel with the switch (Sw). The DC--DC converter produces a high voltage by a procedure in which the switch (Sw) is closed to apply the power source voltage to the coil (L) and then the switch (Sw) is opened to transfer the magnetic energy stored in the coil (L) to the capacitor (C). Using a permanent magnet (Mg), a bias in the direction opposite to that of the magnetic flux induced by the current is applied to the magnetic core of the coil (L) so as to increase the magnetic energy stored in the coil (L). Thus, a DC--DC converter circuit in which a capacitor is efficiently charged through a small-sized coil is realized, and an inductive load drive device having a small size and a light weight is also realized.
A DC--DC converter circuit having a power source and a coil provided with a magnetic core connected to the power source, in which a process that energy is accumulated on the magnetic core by applying the power source voltage to the coil and the energy accumulated on the magnetic core is then discharged to a load, is performed repeatedly, characterized in that the magnetic core of the coil is magnetically biased in a direction opposite to a direction of magnetization induced by an electric current supplied from the power source so that the magnetic energy accumulated on the coil is increased.
A DC--DC converter circuit comprising the power source, a first coil connected to the power source and having a magnetic core, switching means that opens and closes a closed circuit including the power source and an entire winding or a partial winding of the first coil, first rectifying means connected to one end of the entire winding or partial winding of the coil, for preventing reverse current, first capacitors connected in parallel with the entire winding or partial winding of the coil through the first rectifying means, a second coil connected to at least one of the first capacitors, second rectifying means preventing reverse current of the current flowing through the second coil, and second capacitors connected to the second coil through the second rectifying means, wherein closure of the switching means applies the power source voltage to the entire winding or partial winding of the coil, causing energy to be accumulated on the magnetic core of the coil, and wherein the energy accumulated on the magnetic core by opening of the switching means with an arbitrarily determined timing is accumulated on at least one of the first capacitors as electrical energy induced in the entire winding or at least one location of the partial winding of the first coil through the first rectifying means, and the energy that is output from the first coil, including the charge of the first capacitors, through the second coil and second rectifying means, is accumulated on the second capacitors and output, characterized in that the magnetic core of the first coil is magnetically biased in the opposite direction to the magnetic field induced by the current supplied from the power source so that the magnetic energy accumulated on the first coil is increased.
An inductive load drive device comprising a monitor circuit that inputs the drive-side terminal voltage of an inductive load and, when a drive current of the inductive load is cut off or rapidly decreased, outputs an operation confirmation signal by detecting a surge current generated by self-induction of the inductive load, wherein the monitor circuit outputs a confirmation signal that detects a surge produced when a large current flowing in the load due to high voltage applied in an initial period of drive of the load is rapidly decreased, characterized in that, in order to prevent confusion of the surge with a surge produced when the load drive is terminated, the operating confirmation signal is masked by using a control signal indicative of the termination of drive of the inductive load.
A DC--DC converter circuit having a power source and a coil provided with a magnetic core connected to the power source, in which a process that energy is accumulated on the magnetic core by applying the power source voltage to the coil and the energy accumulated on the magnetic core is then discharged to a load, is performed repeatedly, characterized in that the magnetic core of the coil is magnetically biased in a direction opposite to a direction of magnetization induced by an electric current supplied from the power source so that the magnetic energy accumulated on the coil is increased,
Dependencies are inferred from the claim text.