Hybrid linear-switching power supply
First Claim
1. A power supply system comprising a switching power supply serially cascaded after a linear power supply;
- the linear power supply including a linear regulating device, said linear regulating device presenting a linearly variable impedance through which energy is controllably passed and dissipated as heat to effect regulation;
the switching power supply including a switching element and a reactive element, said elements cooperating to store energy in association with the reactive element during a first part of a switching cycle, and to deliver energy from the reactive element during a second part of the switching cycle;
the linear power supply being connected to a power supply system input;
the switching power supply being cascaded between the linear power supply and a power supply system output;
the system further including a control loop for controlling the linear power supply from a feedback signal derived from the switching power supply output.
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Accused Products
Abstract
A hybrid regulator incorporates both linear and switching-type regulator circuits. While such a combination may at first be thought undesirable as simply compounding the flaws of one design with the flaws of the other, in fact the present design is well suited for many applications. In the preferred embodiment, the linear and switching circuits are cascaded. The switching circuit runs in open-loop fashion--without adaptive control. However, a feedback signal is derived from the output of the switching circuit and is used to control the linear regulator, effecting net control of the entire circuit. In this manner, a simple, low cost power supply is provided that provides the excellent regulation and simple over-current protection characteristic of a linear supply, together with the boost capabilities of switching topologies.
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Citations
11 Claims
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1. A power supply system comprising a switching power supply serially cascaded after a linear power supply;
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the linear power supply including a linear regulating device, said linear regulating device presenting a linearly variable impedance through which energy is controllably passed and dissipated as heat to effect regulation; the switching power supply including a switching element and a reactive element, said elements cooperating to store energy in association with the reactive element during a first part of a switching cycle, and to deliver energy from the reactive element during a second part of the switching cycle; the linear power supply being connected to a power supply system input; the switching power supply being cascaded between the linear power supply and a power supply system output; the system further including a control loop for controlling the linear power supply from a feedback signal derived from the switching power supply output. - View Dependent Claims (2, 3, 4)
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5. A hybrid method of providing a regulated output power signal from an unregulated input power signal, the method comprising:
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coupling the unregulated input power signal through serially cascaded first and second semiconductor circuits to produce the regulated output signal; operating the second of said semiconductor circuits non-linearly to switch energy into and out of a reactive element; operating the first of said semiconductor circuits linearly to present a linearly variable impedance through which energy is controllably dissipated; deriving a feedback signal from an output signal produced by the second, non-linearly operated semiconductor circuit; and controlling operation of the first, linearly operated semiconductor circuit from said feedback signal. - View Dependent Claims (6, 8, 9, 10, 11)
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7. A hybrid power supply system comprising:
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a linear power supply for producing a controlled output signal; a switching power supply serially cascaded after the linear power supply, the switching power supply having an input coupled to an output of the linear power supply; and a control loop for controlling the linear power supply in response to a feedback signal derived from an output of the switching power supply.
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Specification