Drive Signal Circuit for Power Factor Correction
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Solution Overview
Problem
Existing power factor correction circuits consume power due to resistors used for dividing rectified voltage, leading to increased power consumption even when not operating.
Innovation Solution
A drive signal generating circuit that uses an output voltage and inductor current to control a transistor, with a reference current output unit, command value output unit, and drive signal output unit to manage inductor current, reducing power consumption by eliminating the need for resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If resistors are used for dividing rectified voltage in PFC circuit, then voltage division function is achieved, but power consumption increases even when PFC circuit is not operating
Solution Approach 1:
The patent extracts and removes the resistor-based voltage division circuit from the PFC circuit. Instead of using resistors to divide the rectified voltage, the invention uses a capacitor connected between the rectified voltage line and ground, with a control circuit that switches the capacitor in and out based on voltage levels, thereby eliminating the continuous power consumption associated with resistor-based voltage division.
Solution Approach 2:
The patent implements periodic action by using a control circuit that periodically switches a capacitor into and out of the circuit based on detected voltage levels. This periodic switching replaces the continuous power consumption of resistor-based voltage division with intermittent capacitor charging/discharging cycles, significantly reducing average power consumption while maintaining voltage regulation functionality.
2Reliability
If resistors are used for voltage division in PFC circuit, then voltage reference is obtained, but power is consumed continuously even when not operating
Solution Approach 1:
The patent employs feedback control by using a control circuit that continuously monitors the rectified voltage level and adjusts the switching of the capacitor accordingly. When the voltage exceeds a predetermined threshold, the control circuit switches the capacitor to discharge, thereby maintaining voltage reference stability without the continuous power consumption of resistor-based division. This feedback mechanism ensures reliable voltage reference while minimizing energy waste.
Solution Approach 2:
The capacitor-based voltage regulation system is self-regulating through the control circuit that automatically switches the capacitor based on voltage levels. This self-service mechanism eliminates the need for continuous power consumption to maintain voltage reference, as the system autonomously charges and discharges the capacitor only when needed, rather than relying on continuously powered resistor-based division.
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 effectively reduces power consumption in power factor correction circuits by generating drive signals based on output voltage and inductor current, improving power factor without unnecessary power usage.
Implementation Method 1
an inductor current flowing through an inductor, the inductor being configured to be applied with a voltage from a rectifier circuit configured to rectify the AC voltage
Data Source
AI summary
A drive signal generating circuit that generates a drive signal for turning on and off a transistor based on an output voltage and an inductor current flowing through an inductor, includes: a reference current output unit that outputs a reference current serving as a reference for the inductor current; a command value output unit that outputs a command value for increasing and decreasing the inductor current when the inductor current is smaller and greater than the reference current, respectively; and a drive signal output unit that outputs the drive signal based on the command value such that the output voltage achieves a target level, the reference current output unit configured to output the reference current based on the command value output from the command value output unit and a value corresponding to a first error between a level of the output voltage and the target level.