Synchronous VCC Generator Eliminates Auxiliary Winding
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Solution Overview
Problem
Existing switching voltage regulators require an auxiliary winding to power the controller IC, which increases complexity and reduces efficiency due to the need for high voltage isolation across the transformer.
Innovation Solution
A method and apparatus that charge a capacitor during the ON portion of a pulse width modulated signal using the primary side inductor current, providing a supply voltage to the control circuitry without relying on the auxiliary winding, with charging controlled by threshold comparisons to optimize voltage and current levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an auxiliary winding is used to power the controller IC, then the controller can be powered reliably, but the device complexity increases and efficiency decreases
Solution Approach 1:
The patent extracts the VCC generation function from the auxiliary winding and implements it using the primary side inductor and a dedicated charging circuit. This removes the need for the auxiliary winding while maintaining reliable controller power supply, directly resolving the contradiction between reliability and device complexity
Solution Approach 2:
The primary side inductor serves dual functions: it performs its main power conversion function and simultaneously charges the VCC capacitor to power the controller. This multi-functionality eliminates the need for separate auxiliary winding, reducing device complexity while maintaining reliability
2Reliability
If an auxiliary winding is used to power the controller IC, then the controller can be powered reliably, but energy efficiency is reduced
Solution Approach 1:
By extracting the VCC charging function from the auxiliary winding pathway and implementing it through the primary side inductor, the patent eliminates the energy losses associated with the auxiliary winding, thereby improving overall power conversion efficiency while maintaining reliable controller power supply
Solution Approach 2:
The primary side inductor charges the VCC capacitor using its own stored energy during the switching cycle, creating a self-service mechanism that eliminates the need for separate auxiliary power winding and reduces energy losses in the power conversion process
3Productivity
If the capacitor is charged synchronously with the PWM signal, then charging efficiency is improved, but voltage regulation complexity increases
Solution Approach 1:
The patent implements periodic charging action by synchronizing the VCC capacitor charging with the PWM switching cycles. The charging occurs during specific phases of the PWM cycle, improving charging efficiency while using simple threshold-based control logic to manage the synchronization, thus balancing productivity and complexity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach eliminates the need for an auxiliary winding, simplifies the power supply, and enhances efficiency by using the primary side inductor current to charge the capacitor synchronously or asynchronously with the PWM signal, ensuring stable voltage regulation.
Implementation Method 1
charging a capacitor during a beginning of an ON portion of a pulse width modulated signal to generate a voltage across the capacitor using charging current sourced from an inductor on a primary side of a transformer
Data Source
AI summary
A capacitor is charged synchronously with the beginning of an ON portion of a pulse width modulated (PWM) signal to generate a voltage across the capacitor using charging current sourced from an inductor on a primary side of a transformer. The voltage is supplied as a supply voltage to control circuitry in an integrated circuit used to generate the pulse width modulated signal. The charging is stopped when either the charging current goes above a predetermined charging current level or when the capacitor voltage goes above a predetermined capacitor voltage.