Method and apparatus for providing an initial bias and enable signal for a power converter
Assigneedi/dt, Inc.
InventorMilivoje S. Brkovic
Life of this patent
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Abstract
The invention employs a coreless isolated transformer, with associated electronic circuitry, for providing an initial bias and enable signal for control and drive circuitry that is referenced to the output of a converter. The improvement is accomplished by embedding the transformer primary and secondary windings into a multi-layer PCB so that the transformer does not occupy space on the top and bottom surfaces of the PCB The initial bias voltage is used to initialize operation of the control circuit when referenced to the output side of the converter. Thus, complete regulation and drive signals are generated on the output side.
Claims31
A bias circuit used in a switch-mode power converters having an input and an output side, the bias circuit providing initial bias power to a control circuit located on the output side of the switch-mode power converter, the bias circuit comprising:
- an isolated coreless transformer, the transformer having windings, the windings formed in or on layers of a printed circuit board (PCB);
- a driver coupled to the transformer, wherein the driver, when enabled by an enable signal, drives the coreless transformer with high frequency pulses of short duration;
- a rectifier coupled to the output of the transformer to provide pulses;
- a capacitor coupled to the rectifier to smooth the rectified pulses into a voltage, and providing the power to the control circuit located on the output side of said of the converter during startup.
A bias circuit used in switch-mode power converters having an input and an output side, the bias circuit providing initial power to a control circuit located on the output side of the switch-mode power converter, the bias circuit comprising:
- an isolated coreless transformer, the transformer having windings, the windings formed on layers of a printed circuit board (PCB), wherein the driver, when enabled by an enable signal, drives the coreless transformer with high frequency pulses of short duration;
- driving means for driving said coreless transformer;
- rectifier means for providing pulses at the output of said coreless transformer;
- capacitor means for smoothing the rectified, the smoothed rectified pulses generating a voltage for powering said control circuit located on the output side of said switch-mode power converter at startup.
A method to provide an initial bias and an enable signal for a control circuit (controller) on the output side of a power converter having an input side, by use of a coreless transformer, the method comprising:
- providing the coreless transformer fabricated in or on the layers of a printed circuit board;
- providing the controller, the controller controlled from output side of the converter;
- providing a controller transformer to transmit control power to power the input (primary) side of the power converter;
- driving the coreless transformer using high frequency pulses of short duration;
- and
- powering the controller using the coreless transformer.
A bias circuit used in a switch-mode power converter having an input and an output side, the bias circuit providing an initial bias and an enable signal for a control circuit (controller) located on the output side of the switch-mode power converter, the bias circuit comprising:
- an isolated coreless transformer, the transformer having windings formed in or on layers of a printed circuit board (PCB);
- a driver coupled to the transformer to drive said coreless transformer, the driver comprising an oscillator that generates high frequency pulses, the driver to drive the careless transformer in response to the output of the oscillator, to generate pulses of predetermined duration followed by a relatively long inactive period;
- a rectifier coupled to the rectifier to provide positive pulses at the output of said coreless transformer;
- a capacitor coupled to the rectifier to smooth the rectified positive pulses into the enable signal, and providing the smoothed rectified pulses as the enable signal to generate a voltage to enable the controller located on the output side of said switch-mode power converter.
A bias circuit used in switch-mode power converters having an input and an output side, the bias circuit providing an initial bias and an enable signal for a control circuit (controller) located on the output side of the switch-mode power converter, the bias circuit comprising:
- an isolated coreless transformer, the transformer having windings formed in or on layers of a printed circuit board (PCB);
- driving means for generating high frequency pulses of predetermined duration followed by a relatively long inactive period for driving the coreless transformer, the driving means comprising an oscillator means for generating the pulses, wherein the pulses are of short duration;
- rectifier means for providing positive pulses at the output of said coreless transformer;
- capacitor means for smoothing the rectified positive pulses, the smoothed rectified pulses for enabling the controller located on the output side of said switch-mode power converter.
Dependencies are inferred from the claim text.