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US 4,864,482 AGranted
Conversion circuit for limiting inrush current
AssigneeEtta Industries, Inc.
InventorsFazie S. Quazi, Ira S. Faberman
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AssigneeEtta Industries, Inc.
InventorsFazie S. Quazi, Ira S. Faberman
Estimating the term…
A conversion circuit is provided which includes a negative temperature coefficient resistance between a rectifier and a storage capacitor to limit inrush current when power is applied to the circuit after a power interruption of a relatively long duration. When power is resumed after a short term power interruption and the resistance of the negative temperature coefficient resistance is still low, inrush current is limited by disconnecting a load from the conversion circuit immediately upon the occurrence of the power interruption to maintain the charge on the storage capacitor for the duration of the interruption. A boost regulator unit is provied between the negative temperature coefficient resistance and the storage capacitor to provide a regulated direct current potential across the capacitor which is not responsive to input power variations.
A conversion unit for converting an alternating current signal from a power source and providing a converted signal to a load while operating to limit inrush current from the power source under all conditions comprising rectifier means connected to receive the alternating current signal from said power source and to convert said alternating current signal to a pulsating direct current signal, storage capacitor means connected to said rectifier means to receive said pulsating direct current signal and to charge in response thereto, said storage capacitor means operating to provide a filtered output direct current signal, and boost switching regulator means connected between said rectifier means and said storage capacitor means, said boost switching regulator means including inductor means connected to receive the pulsating direct current signal from said rectifier means and to raise said pulsating direct current signal to provide an inductor output signal of a higher potential, switch means connected to said inductor means, said switch means operating in a first state to cause the inductor means to store a potential and in a second state to permit said inductor output signal to charge said storage capacitor means, drive means operative in response to said pulsating direct current signal to drive said switch means repetitively between said first and second states, and an inverter means connected between said storage capacitor means and said load, said inverter means operating to change said filtered output direct current signal to an alternating current signal wherein said inverter means includes inverter switching means connected to receive the filtered output direct current signal from said storage capacitor means, and inverter switching control means operative in response to said pulsating direct current signal to drive said switching means, said inverter switching control means operating upon the discontinuance of said pulsating direct current signal to cause said inverter switching means to open and disconnect said load from the storage capacitor means.
A conversion unit for converting an alternating current signal from a power source and providing a converted signal to a load while operating to limit inrush current from the power source under all conditions comprising rectifier means connected to receive the alternating current signal from said power source and to convert said alternating current signal to a pulsating direct current signal, storage capacitor means connected to said rectifier means to receive said pulsating direct current signal and to charge in response thereto, said storage capacitor means operating to provide a filtered and regulated output direct current signal and inverter means connected to said load and to receive said filtered output direct current signal from said storage capacitor means and operative to convert said filtered output direct current signal to an alternating current signal for said load, said inverter means including switching means for selectively making and breaking a circuit to said storage capacitor means, and switch control means operative in response to said pulsating direct current signal to control said switching means, said switch control means operating upon the loss of said pulsating direct current signal to cause said switching means to break the circuit to said storage capacitor means to disconnect the load from said storage capacitor means.
Dependencies are inferred from the claim text.