PFC Converter Switch-Voltage Sensing for Low-Standby Operation
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Solution Overview
Problem
Existing power factor correction converters face challenges in reducing circuit size and standby power consumption, particularly when operating at high voltages, due to the need for complex voltage detection using multiple dividers.
Innovation Solution
A power factor correction converter design that utilizes a single voltage divider to detect the switch voltage, approximating it to the output voltage, thereby reducing the number of required dividers and minimizing circuit area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple voltage dividers are used to detect voltage at high voltage, then measurement precision is improved, but device complexity increases and standby power consumption increases
Solution Approach 1:
The patent combines the functions of multiple voltage dividers into a single voltage divider by utilizing the inherent voltage relationship between the switch node and output node. The controller calculates output voltage by combining the switch voltage detected by one voltage divider with the known duty cycle, eliminating the need for separate voltage dividers while maintaining detection precision.
Solution Approach 2:
The single voltage divider is designed to detect switch voltage, which then serves multiple purposes: determining output voltage through calculation, monitoring for overvoltage conditions, and enabling duty cycle measurement. This multi-functional approach replaces multiple specialized voltage dividers.
2Measurement precision
If multiple voltage dividers are used to detect voltage at high voltage, then measurement precision is improved, but standby power consumption increases
Solution Approach 1:
The patent merges multiple voltage divider circuits into a single voltage divider, directly reducing the number of active components that consume standby power. The single voltage divider serves all detection needs through computational processing in the controller.
Solution Approach 2:
The patent replaces physical voltage divider circuits with a computational approach. Instead of using multiple physical dividers to directly provide scaled-down voltage signals, the system uses one voltage divider and performs calculations in the controller to derive all necessary voltage information, reducing hardware power consumption.
3Measurement precision
If multiple voltage dividers are used to detect voltage at high voltage, then measurement precision is improved, but circuit layout area increases
Solution Approach 1:
The patent consolidates multiple voltage divider circuits into a single voltage divider, significantly reducing the physical space required for voltage detection components. The controller processes the single detected voltage signal to derive all necessary voltage information computationally.
Solution Approach 2:
The patent creates a virtual representation of multiple voltage detection points through computational processing. Instead of physically placing multiple voltage dividers at different circuit nodes, the system uses one physical voltage divider and mathematically derives equivalent detection data for all required points, eliminating redundant physical components.
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
The solution significantly reduces circuit layout area and standby power consumption while maintaining accurate output voltage regulation, even at high voltages, by using a single voltage divider to detect switch voltage, thus enhancing efficiency.
Implementation Method 1
the voltage divider is configured to perform a voltage-division operation on the switch voltage to generate a divided voltage which is lower than the switch voltage
Implementation Method 2
the main switch is coupled between a second end of the inductor and a ground end and configured to control the inductor to perform a magnetization operation and a demagnetization operation
Data Source
AI summary
A power factor correction (PFC) converter comprises an inductor, a main switch, a voltage divider, a diode, and a controller. The main switch controls the inductor performing magnetization and demagnetization, wherein a voltage difference between two ends of the main switch is a switch voltage. The voltage divider divides the switch voltage and generates a division voltage. The controller performs the following operations periodically in general mode: turning on the main switch; turning off the main switch after the main switch is turned on for a period of time; obtaining the switch voltage according to the division voltage, and determining the period of time for which the main switch is turned on next time according to the switch voltage and a predetermined output voltage of the PFC converter; and obtaining an output voltage according to the switch voltage during a period of time after the main switch is turned off.