DC-DC Converter Pulse Frequency Modulation with Discontinuous Voltage Sensing
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Solution Overview
Problem
DC-DC converters with discontinuous output voltage sensing face challenges in achieving light-load efficiency similar to systems with continuous output voltage sensing, as existing solutions either require large capacitors for low input power or prioritize low total Bill Of Materials (BOM) cost over efficiency.
Innovation Solution
A pulse frequency modulation (PFM) control method for DC-DC regulators that adjusts input power in standby and no-load modes by varying characteristics of electrical components such as capacitors, resistors, and sensors, including a controller, timer, and inductive charger, to manage charging and discharging pulses effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If discontinuous output voltage sensing is used in DC-DC converters, then device complexity is reduced and ease of manufacture is improved, but light-load efficiency deteriorates and minimum input power consumption increases
Solution Approach 1:
The patent implements dynamic switching between different control modes (PFM and CCM) based on load conditions. The controller dynamically adjusts the operating mode to optimize efficiency across different load ranges, allowing the system to achieve both discontinuous sensing simplicity and light-load efficiency through adaptive control
Solution Approach 2:
The patent changes key operating parameters including switching frequency, duty cycle, and control mode based on load conditions. By dynamically adjusting these parameters, the system maintains high efficiency at light loads while preserving the benefits of discontinuous output voltage sensing
2Use of energy by moving object
If large COUT is used to achieve low PIN,min in discontinuous sensing systems, then minimum input power is reduced, but device size and cost increase
Solution Approach 1:
The patent uses dynamic control strategies that adjust switching frequency and duty cycle in real-time based on load conditions, eliminating the need for oversized capacitors. The adaptive control maintains stability and efficiency across different load ranges without requiring large COUT values
Solution Approach 2:
The patent changes operating parameters including switching frequency and duty cycle to optimize performance for different load conditions. This parameter adjustment allows the system to achieve low minimum input power with standard capacitor values rather than requiring enlarged COUT
3Use of energy by moving object
If PFM operation is implemented with continuous VOUT sensing, then light-load efficiency is improved, but compatibility with discontinuous VOUT sensing is lost
Solution Approach 1:
The patent creates a universal control architecture that can operate with both continuous and discontinuous output voltage sensing methods. The controller is designed to accommodate different sensing topologies (high-side buck, primary sensing flyback) while maintaining PFM functionality and light-load efficiency across all configurations
Solution Approach 2:
The patent implements dynamic adaptation of the control algorithm based on the sensing method being used. The system dynamically adjusts its operation to be compatible with either continuous or discontinuous sensing while preserving PFM benefits, achieving both efficiency and versatility
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
Enables efficient low minimum input power consumption without additional external components, allowing for adjustable input power settings in DC-DC converters, thereby enhancing light-load efficiency in discontinuous output voltage sensing systems.
Implementation Method 1
a sensor with a sampling capacitor has a first terminal coupled to the output node and a second terminal coupled to the controller and the inductive charger
Data Source
AI summary
Exemplary embodiments may include a method of applying a charging pulse to an output capacitor, detecting satisfaction of a charging threshold, ending the charging pulse in response to the detecting the satisfaction of the charging threshold, and discharging the sampling capacitor in response to the detecting the satisfaction of the charging threshold. In some embodiments, once a sampling capacitor voltage drops below a discharging threshold, a charging pulse is applied. Exemplary embodiments may also include an apparatus with a controller coupled to an input node, a timer coupled to the controller, an inductive charger coupled to the controller, to an input node, and to an output node, and a sensor coupled to the controller and the output node. Exemplary embodiments may further include an apparatus where a sensor with a sampling capacitor has a first terminal coupled to the output node and a second terminal coupled to the controller and the inductive charger.