DC-DC Converter LC Filter Control for Light Load Efficiency
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Solution Overview
Problem
Conventional power management chips and DC-DC converters face issues with erroneous protection modes and frequent mode switching, leading to inefficiencies in power conversion, especially during light loads.
Innovation Solution
A DC-DC converter design that directly charges and discharges an LC filter to adjust output voltage, using a system control circuit, driver circuit, and output voltage adjusting circuit to generate switch control signals and adjust voltages based on reference and detecting voltages, reducing switch losses and preventing erroneous protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the power management chip enters power-saving mode with diode emulation mode to reduce power consumption, then power consumption is reduced, but the response time to adjust output voltage becomes too slow causing erroneous protection mode
Solution Approach 1:
The patent applies preliminary action by pre-configuring a fast response pathway through the output voltage adjusting circuit that can immediately charge or discharge the LC filter when voltage adjustment is needed. This preliminary setup allows the system to quickly transition from the slow diode emulation mode to a fast adjustment mode when reference voltage changes occur, preventing erroneous protection mode while maintaining power-saving operation.
2Speed
If the control circuit frequently switches between continuous current mode and discontinuous current mode to adjust output voltage, then output voltage adjustment responsiveness is improved, but switching loss increases reducing conversion efficiency
Solution Approach 1:
The patent introduces an intermediary mechanism - the output voltage adjusting circuit that directly charges or discharges the LC filter - to achieve fast voltage adjustment without relying on frequent mode switching. This intermediary pathway provides a direct control route that responds quickly to voltage changes while avoiding the high switching losses associated with frequent transitions between continuous and discontinuous current modes.
3Use of energy by moving object
If the power management chip uses diode emulation mode to operate under light load, then power consumption is reduced, but the ability to timely respond to reference voltage changes is lost causing over-voltage protection errors
Solution Approach 1:
The patent applies dynamics by creating a hybrid operational mode where the system dynamically switches between diode emulation operation and active voltage adjustment based on real-time conditions. The output voltage adjusting circuit continuously monitors and can activate fast adjustment when reference voltage changes are detected, ensuring reliable over-voltage protection while maintaining power-saving diode emulation mode during stable light-load operation.
Data Source
AI summary
A DC-DC converter, adapted to control a converting circuit to convert an input voltage into an output voltage, is disclosed. The converting circuit comprises a switch module and an LC filter, the switch module is coupled to the input voltage, and the LC filter is coupled to the switch module and provides the output voltage. The DC-DC converter comprises a system control circuit, a driver circuit, and an output voltage adjusting circuit. The system control circuit generates a switch control signal according to a reference voltage and a state of the LC filter. The driver circuit controls the switch module according to the switch control signal for adjusting the output voltage in response to the reference voltage. The output voltage adjusting circuit determines whether adjusting the output voltage toward a predetermined adjusting voltage according to an adjusting reference voltage and a detecting voltage indicative of the output voltage.