OVERVIEW

High-voltage (e.g., 10-100 kilovolts) low-current (1-100 milliampere) power supply can be beneficial in many applications, among others, including the medical, environmental, security, and aerospace fields. Further, enhanced portability of a high-voltage device can lead to new usages of the technology, better performance, and/or new applications.

The above issues as well as others have presented challenges to power conversion for a variety of applications.

SUMMARY

Aspects of various embodiments are directed to apparatuses and/or methods involving power conversion using multiple rectifier circuits. In the following discussion, various implementations and applications are disclosed to provide an understanding of the instant disclosure by way of non-limiting example embodiments.

Various aspects are directed to and/or involve power conversion provided by a plurality of stacked rectifier circuits, at least one of the rectifier circuits having inductive isolation between a front-end portion and a back-end portion to enable use of the back-end portion for delivering power-converted output-stage signals with a steady-state voltage that is significantly greater than a voltage stress/breakdown rating associated with one or more components of the front-end portion.

A number of aspects are directed to a power converter having a class-DE resonant rectifier with capacitive direct current (DC) isolation that generates several hundreds of volts. As the rectifier diodes and output terminals are DC-isolated from the input, tens of units of the rectifier can be stacked such that the signals output by the units are in series to generate an output voltage of several kilovolts. In this configuration, the output voltage can be up to twice the voltage rating of DC-isolation capacitors as the voltage stress on capacitors of top and bottom rectifiers is half of the total output voltage, provided that the isolated total output voltage diverges symmetrically toward positive and negative directions. To achieve a higher output voltage, various embodiments include an air-core transformer which acts as an additional DC-isolation barrier. Multiple units of the multi-stage class-DE rectifiers can be cascaded, as described above. Using such an example configuration, a high output voltage can be generated because the limit of the achievable voltage is now the breakdown voltage of the inductive isolation barrier between the transformer's primary and secondary windings.

More specific aspects are directed to an apparatus that includes DC-alternating-current (AC) inverter circuitry, first and second circuits, and output circuitry. The DC-AC inverter circuitry inverts at least one DC input signal corresponding to an input voltage to at least one AC signal. The first circuit includes a first inductive isolation circuit to be driven in response to power from the at least one AC signal and a first rectifier circuit. The first rectifier circuit responds to the first inductive isolation circuit by outputting a first rectified signal at a first pair of output terminals. The second circuit includes a second inductive isolation circuit to be driven in response to power from the at least one AC signal and includes a second rectifier circuit. The second rectifier circuit responds to the second inductive isolation circuit by outputting a second rectified signal at a second pair of output terminals. At least one of the first and second rectifier circuits are characterized as being limited by a voltage breakdown rating. The output circuit provides a DC output voltage signal between voltage source terminals and cascades a plurality of signals, including the first and second rectified signals, by one of the output terminals of one of the pairs of output terminals being a source of supply to one of the output terminals of the other of the pairs of output terminals. The voltage source terminals provide a voltage source that is dependent on the first and second rectified signals and is greater than the voltage breakdown rating of the at least one of the first and second rectifier circuits.

In related and mores specific aspects, each of the first and second rectifier circuits includes or is configured as a Class DE rectifier and/or each of the rectifier circuits is one of multiple rectifier stages connected in parallel. The voltage breakdown rating is defined by a DC-blocking capacitor used in a signal path in one of the first and second circuits, between an output terminal of the inductive isolation circuit and a diode in the rectifier circuit. In specific embodiments, the at least one of the first and second rectifier circuits delivers in the associated rectified signal, a DC output voltage signal that is greater than twice the voltage breakdown rating of the at least one of the first and second rectifier circuits. In more specific and related embodiments, the DC output voltage signal that is greater than three times, four times, five times, six time or more of the voltage breakdown rating.

At least one of the first and second inductive isolation circuits is associated with another voltage breakdown rating which is greater than the voltage breakdown rating of the at least one of the first and second rectifier circuits. For example, each of the first and second inductive isolation circuits includes an air-core transformer having an associated voltage breakdown rating that is greater than the voltage breakdown rating of the at least one of the first and second rectifier circuits and defines a minimum overall voltage breakdown rating for circuitry included in the inductive isolation circuit.

In a number of related aspects, the apparatus further includes additional rectifier circuits having outputs cascaded with the first and second rectifier circuits. Each of the rectifier circuits includes or is configured as a Class DE rectifier, is DC-isolated from the input voltage, and/or is rated at not less than 300 volts. For example, the apparatus further includes at least one additional circuit including a third circuit having a third inductive isolation circuit to be driven in response to power from the at least one AC signal, and including a third rectifier circuit to respond to the third inductive isolation circuit by outputting a third rectified signal at a third pair of output terminals. The output circuitry provides a DC output voltage signal between voltage source terminals and cascades a plurality of signals, including the first, second and third rectified signals, by coupling selected ones of the output terminals of the first, second and third pairs of output terminals as being a cascaded source of supply, with the first, second and third voltage source terminals collectively arranged to provide a voltage source that is dependent on the first, second and third rectified signals and that is greater than the voltage breakdown rating. In such a configuration, the input terminals to the multiple rectifier circuits are in parallel and the output terminals are in series.

Other aspects are directed to a DC power source for providing a DC voltage in response to at least one AC signal associated with an input voltage signal. The DC power source includes a first circuit, a second circuit, and output circuitry. The first circuit includes a first inductive isolation circuit to be driven in response to power from the at least one AC signal, and including a first rectifier circuit to respond to the first inductive isolation circuit by outputting a first rectified signal at a first pair of output terminals. The second circuit includes a second inductive isolation circuit to be driven in response to power from the at least one AC signal, and including a second rectifier circuit to respond to the second inductive isolation circuit by outputting a second rectified signal at a second pair of output terminals, and at least one of the first and second rectifier circuits characterized as being limited by a voltage breakdown rating. The output circuitry provides a DC output voltage signal between voltage source terminals and cascades a plurality of signals, including the first and second rectified signals, by one of the output terminals of one of the pairs of output terminals being a source of supply to one of the output terminals of the other of the pairs of output terminals, with the voltage source terminals to provide a voltage source that is dependent on the first and second rectified signals and is greater than the voltage breakdown rating of the at least one of the first and second rectifier circuits.

As described above, each of the first and second inductive isolation circuits includes an air-core transformer having another voltage breakdown rating associated with material between the windings of the air-core transformer and which is greater than the voltage breakdown rating of the at least one of the first and second rectifier circuits. The at least one of the first and second rectifier circuits includes a DC-blocking capacitor used in a signal path in one of the first and second circuits, between an output terminal of the inductive isolation circuit and a diode in the rectifier circuit. The DC-blocking capacitor is characterized as being limited by the voltage breakdown rating. The apparatus can further include a plurality of circuits, including the first and second circuits, cascaded in an arrangement between voltage rails, and the at least one of the first and second rectifier circuits is respectively situated closet to one of the voltage rails.

In a number of related and more specific aspects, the DC power source and/or an apparatus that includes the DC power source further includes front-end driver circuitry that provides the at least one AC signal to the first inductive isolation circuit and the second inductive isolation circuit. In more specific aspects, the front-end driver circuitry includes one or more DC-AC inverter circuits configured and arranged to invert at least one DC input signal corresponding to the input voltage signal to the at least one AC signal and to drive the first inductive isolation circuit and the second inductive isolation circuit via the at least one AC signal. In other aspects, the front-end driver circuitry includes one or more AC-AC inverter circuits configured and arranged to invert at least one AC input signal, corresponding to the input voltage signal and a first frequency, to the at least one AC signal corresponding to a second frequency and to drive the first inductive isolation circuit and the second inductive isolation circuit via the at least one AC signal at the second frequency.

A number of aspects are directed to methods of converting power using one or more of the above-described apparatuses. The method includes providing from a direct-current (DC) voltage input signal at least one alternating-current (AC) signal, and using a first circuit and a second circuit in parallel, each providing inductive isolation and each driven in response to power from the at least one AC signal, and each rectifying in response to the inductive isolation by outputting a rectified signal at an associated pair of output terminals. The rectifying associated with at least one of the first circuit and second circuits is associated with circuitry characterized as being limited by a voltage breakdown rating. The method further includes providing a DC output voltage signal between voltage source terminals by cascading a plurality of signals, including the rectified signals, with the DC output voltage signal being dependent on the rectified signals and being greater than the voltage breakdown rating.

Accordingly, various embodiments are directed to addressing challenges relating to the above aspects and others, as may benefit a variety of power converters and/or multi-stage rectifiers. The above discussion/summary is not intended to describe each embodiment or every implementation of the present disclosure. The figures and detailed description that follow also exemplify various embodiments.

