Switching Regulator Current Ripple Reduction via Intermediary Source
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Solution Overview
Problem
Conventional switching regulators with power factor correction (PFC) function suffer from current ripple issues, leading to unstable current flow through load circuits, particularly in LED applications, causing flicker and inefficiencies.
Innovation Solution
A switching regulator with a buck power stage circuit and a control circuit that includes an operation signal generation circuit and a current source circuit to reduce current ripple by generating operation signals based on current and voltage sense signals, effectively converting rectified voltage to a stable load voltage and current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a PFC circuit is used to improve power factor, then power factor is improved, but current ripple increases causing LED flicker
Solution Approach 1:
A current source circuit is introduced as an intermediary between the PFC circuit and LED circuit. This current source circuit generates a stable current signal that superimposes on the PFC output current, effectively canceling the ripple component and providing stable current to the LED circuit while maintaining the PFC function.
Solution Approach 2:
The invention changes the current parameter by generating a compensating current signal with specific amplitude and phase characteristics. The current source circuit produces a current that is precisely controlled to counteract the ripple frequency and amplitude, transforming the unstable PFC current into stable LED driving current.
2Use of energy by moving object
If a rectifier circuit with PFC is used, then power factor is improved, but the output current contains low frequency ripple that cannot be filtered by typical capacitors
Solution Approach 1:
The current source circuit serves as an intermediary that actively compensates for the harmful ripple current. Instead of passively filtering with capacitors, the system introduces an active current source that generates a counter-ripple signal to neutralize the low frequency ripple generated by the PFC circuit.
Solution Approach 2:
The invention employs feedback control where the current source circuit continuously monitors and adjusts its output current based on the PFC circuit operation. This feedback mechanism ensures that the compensating current precisely matches the ripple characteristics, effectively eliminating the harmful current ripple while maintaining high power factor.
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 current ripple, providing a stable load current to LED circuits, enhancing power utilization efficiency and eliminating flicker, thereby improving the quality of the output current.
Implementation Method 1
a buck power stage circuit, which is configured to operably control at least one power switch therein according to a first operation signal, so as to convert a rectified voltage to an output voltage
Implementation Method 2
a current source circuit for reducing current ripple, which is coupled to the operation signal generation circuit and the buck power stage circuit, and is configured to operably control a ripple reduction switch therein according to the second operation signal, to convert the output voltage to a load voltage
Data Source
AI summary
The present invention discloses a switching regulator capable of reducing current ripple and a control circuit thereof. The switching regulator includes a buck power stage circuit and a control circuit. The control circuit includes an operation signal generation circuit and a current source circuit for reducing current ripple. The current source circuit is coupled to the operation signal generation circuit and the buck power stage circuit, for operating a ripple reduction switch therein according to an operation signal, to convert the output voltage to a load voltage between a load node and a reference node, and to reduce a current ripple of the output current, so as to generate a load current which is supplied to a load circuit, wherein the load circuit is coupled between the load node and the reference node, and the current source circuit is coupled between the output node and the load node.