Systems and methods for frequency control of a voltage converter

A voltage converter, the voltage converter comprising:

• a transformer, wherein the transformer includes a first winding and a second winding;
• an operational detector, wherein the operational detector provides an electrical output corresponding to an operational characteristic of the transformer;
• a controllable oscillator, wherein the controllable oscillator provides a clock output with a frequency corresponding to the electrical output, wherein the clock output at least in part controls application of a voltage input to the first winding;
• a first transistor, wherein a first leg of the first transistor is electrically coupled to the first winding, wherein a second leg of the first transistor is electrically coupled to the voltage input;
• a second transistor, wherein a first leg of the second transistor is electrically coupled to the first winding, wherein a second leg of the second transistor is electrically coupled to the voltage input;
• a clock generator that receives the clock output and provides a first duty cycle controlled clock signal to a gate of the first transistor and a second duty cycle controlled clock signal to a gate of the second transistor;
• and
• wherein the operational detector includes a frequency controller, wherein the frequency controller includes a logic function that logically combines the first duty cycle controlled clock signal with the second duty cycle controlled clock signal, wherein an output of the logic function is filtered to create a first average voltage, wherein the output of the logic function is inverted and the inverted output is filtered to create a second average voltage, and wherein the first average voltage and the second average voltage are multiplied to create the electrical output.

A voltage converter, comprising:

• a transformer, wherein the transformer includes a first winding and a second winding;
• an operational detector, wherein the operational detector provides an electrical output signal as a predetermined function of a voltage input signal applied to the transformer, wherein the operational detector includes a frequency controller, wherein the frequency controller includes a logic function that logically combines the first duty cycle controlled clock signal with the second duty cycle controlled clock signal, wherein an output of the logic function is filtered to create an average voltage, wherein the frequency controller includes a multiplexer, wherein a selector input of the multiplexer is an inverted version of the output of the logic function, wherein one input of the multiplexer is the average voltage, and wherein another input of the multiplexer is a reference voltage;
• a controllable oscillator, wherein the controllable oscillator provides a clock output with a frequency corresponding to the electrical output;
• and
• further comprising a first transistor, wherein a first leg of the first transistor is electrically coupled to the first winding, wherein a second leg of the first transistor is electrically coupled to the voltage input;
• a second transistor, wherein a first leg of the second transistor is electrically coupled to the first winding, wherein a second leg of the second transistor is electrically coupled to the voltage input;
• a clock generator that receives the clock output and provides a first duty cycle controlled clock signal to a gate of the first transistor and a second duty cycle controlled clock signal to a gate of the second transistor;
• wherein the clock output at least in part controls application of the voltage input signal applied to the first winding to control ripple in an output of the voltage converter.

A method for providing voltage conversion having reduced ripple current, the method comprising:

• providing a transformer, wherein the transformer includes a first winding and a second winding;
• applying a periodically gated voltage input to the first winding, wherein the periodic gating has a time varying duty cycle and a time varying frequency;
• and
• maintaining a mathematical combination of the time varying duty cycle and the time varying frequency defined by:
• (time varying duty cycle)(1-time varying duty cycle)/(time varying frequency), substantially constant.

A power distribution system, wherein the power distribution system comprises:

• at least one unregulated voltage converter, wherein the unregulated voltage converter has an unregulated output voltage and includes:
• a transformer, wherein the transformer includes a first winding and a second winding;
• an operational detector, wherein the operational detector provides an electrical output signal as a predetermined function of a voltage input signal applied to of the transformer;
• a controllable oscillator, wherein the controllable oscillator provides a duty cycle clock output with a frequency corresponding to the electrical output;
• wherein the clock output at least in part controls application of the voltage input signal applied to the first winding to control ripple in an output of the unregulated voltage converter during times of low duty cycle operation including start-up of the unregulated converter and current limit, wherein the frequency of the clock is determined by the equation:
• Frequency=k*D*(1−D),
• where D is the duty cycle of duty cycle controlled clock signal and k is a constant;
• and
• wherein a voltage output is electrically coupled to the second winding.