PFC Converter Control Device Eliminates Resistive Divider
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power factor correction (PFC) converter control devices consume significant power due to the use of resistive dividers for output voltage detection, increasing power consumption and manufacturing costs, and require additional pins for voltage reading.
Innovation Solution
The control device estimates the output voltage using the input voltage and duty cycle, eliminating the need for a resistive divider and associated pins, and corrects for time errors in zero-current detection using specific algorithms based on the oscillation period and voltage relationships.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If resistive dividers are used for output voltage detection, then voltage measurement is achieved, but power consumption increases
Solution Approach 1:
The patent extracts and eliminates the resistive divider component from the voltage detection circuit. Instead of using a traditional resistive divider to sense the output voltage, the invention uses an alternative detection method that does not require this power-consuming component, thereby removing the source of excessive power consumption while maintaining voltage measurement capability
Solution Approach 2:
The patent uses an auxiliary winding on the inductor to generate a voltage signal that is proportional to the output voltage. This auxiliary voltage serves as a copy or representation of the actual output voltage, allowing the control device to monitor the output voltage without directly connecting high-impedance resistive dividers to the output node, thus avoiding the power consumption issue
2Measurement precision
If resistive dividers are used for output voltage detection, then voltage measurement is achieved, but device complexity increases
Solution Approach 1:
The auxiliary winding on the inductor serves multiple functions: it provides magnetic coupling for energy transfer in the PFC converter operation and simultaneously generates a voltage signal proportional to the output voltage for detection purposes. This multi-functionality eliminates the need for separate resistive divider circuits, reducing overall device complexity
Solution Approach 2:
The patent merges the voltage detection function with the existing auxiliary winding structure of the PFC converter. By combining these functions, the invention eliminates separate detection components (resistive dividers and associated pins) and integrates voltage sensing into the existing magnetic coupling structure, thereby simplifying the overall device
3Measurement precision
If additional pins are added for voltage reading, then measurement capability is improved, but manufacturing cost increases
Solution Approach 1:
The auxiliary winding serves dual purposes: enabling PFC converter operation through magnetic coupling and providing voltage sensing capability. This eliminates the need for additional dedicated sensing pins, reducing the pin count on the control device and thereby lowering manufacturing costs associated with higher-pin-count packages
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 solution reduces power consumption, simplifies the device by eliminating unnecessary pins, and maintains control performance with improved precision in estimating the output voltage, thereby reducing overall power converter power consumption and manufacturing costs.
Implementation Method 1
an auxiliary winding 9, which is magnetically coupled to the inductor 5 and on which a control voltage VZCD is present
Data Source
AI summary
A control device for a converter of the switched-mode type provided with an inductor element and a switch element generates a driving signal for controlling switching of the switch element and determining alternately a phase of storage of energy in the inductor element as a function of an input quantity and a phase of transfer of the energy stored in the inductor element to an output element on which an output quantity is present; the control device generates the driving signal by means of a control based on the value of the output quantity in order to regulate the same output quantity. In particular, an estimation block determines an estimated value of the output quantity, and a driving block generates the driving signal as a function of said estimated value.