Charge Pump Frequency Synchronization for Power Converter Noise Reduction
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Solution Overview
Problem
The frequency of a charge pump in power converters is often not synchronized with the switching frequency, particularly at light loads, leading to noise issues that do not meet customer requirements.
Innovation Solution
A control circuit and method that synchronize the frequency of the charge pump circuit with the switching frequency of the power converter using a synchronous oscillator, which generates a synchronization signal to control a switch and produce a voltage source, thereby reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the charge pump frequency is not synchronized with the switching frequency, then the charge pump can operate independently without complex synchronization control, but noise problems occur and customer requirements are not met
Solution Approach 1:
The patent implements frequency synchronization by using the switching frequency as a reference to control the charge pump frequency. A feedback mechanism compares the switching frequency with the charge pump frequency and adjusts the charge pump oscillator accordingly, ensuring they remain synchronized. This feedback control eliminates noise while maintaining manageable system complexity through automated frequency matching.
Solution Approach 2:
The patent changes the operating parameter (frequency) of the charge pump to match the switching frequency dynamically. By adjusting the charge pump frequency parameter based on the switching frequency, the system achieves noise reduction without requiring complex additional hardware, as it leverages existing frequency information from the switching circuit.
2Object-affected harmful factors
If frequency synchronization is implemented, then noise is reduced and customer requirements are met, but the control circuit complexity increases
Solution Approach 1:
The patent makes the control circuit multi-functional by having it perform both switching control and charge pump frequency synchronization functions. The same control circuit that generates switching signals also generates synchronization signals for the charge pump, eliminating the need for separate synchronization hardware and reducing overall system complexity despite adding the synchronization capability.
Solution Approach 2:
The patent introduces a synchronization signal as an intermediary between the switching circuit and the charge pump circuit. This intermediary signal carries frequency information from the switching circuit to the charge pump, enabling noise reduction without direct complex interaction between the two circuits, thus managing complexity through a simple mediating mechanism.
Data Source
AI summary
A control circuit of a power converter is provided. The control circuit includes a switching circuit and a charge pump circuit. The switching circuit generates a switching signal for controlling the power converter. The charge pump circuit includes an oscillator for generating an oscillation signal synchronized with the switching signal. The oscillation signal is coupled to control a switch of the charge pump circuit for generating a voltage source.