Switching Power Supply Digital Control Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing switching power supply devices face challenges in stabilizing output voltage during sudden changes in input voltage or load, leading to overshoot and vibration, which can cause equipment malfunction, and require complex control circuits to achieve high-speed response, resulting in increased size and cost.
Innovation Solution
A digital control switching power supply device with a control circuit that uses a continuous function formula to determine the ON and OFF times of the main switching element based on output voltage and differential values, allowing for high-speed response with a simple and cost-effective control circuit, and incorporates state variable estimation to minimize operation delay and account for parasitic impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current-voltage conversion circuit is provided to measure capacitor current and digitize it to obtain output differential signal, then the output differential signal can be obtained, but the power supply device becomes large in size and loss increases
Solution Approach 1:
The patent extracts only the necessary information (output voltage signal) and uses mathematical differentiation to obtain the output differential signal, rather than measuring the physical capacitor current directly. This eliminates the need for current-voltage conversion circuitry while still providing the required differential signal for control.
Solution Approach 2:
The patent replaces the physical measurement system (current-voltage conversion circuit) with a computational approach (digital differentiation of voltage signal). This substitution eliminates additional hardware components and their associated power losses while achieving the same control objective.
2Measurement precision
If an output voltage signal digitized by an A/D converter is differentiated to obtain an output differential signal, then the output differential signal can be obtained, but a delay in control due to an increase in the number of times of calculation becomes a problem
Solution Approach 1:
The patent performs the differentiation calculation in advance within the control cycle, using the sampled voltage signal to compute the differential value before it is needed for control decisions. This preliminary computation ensures that the differential signal is ready when required, eliminating control delay.
3Measurement precision
If a highly intelligent digital control circuit with a digital processor is used to stabilize output voltage, then the output voltage control precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent changes the control approach from complex multi-variable optimization to a simpler differential-based control law. By focusing on the rate of change of output voltage rather than multiple simultaneous parameters, the control algorithm becomes less complex while maintaining precision.
4Device complexity
If the control circuit function is lowered to reduce the number of times of calculation, then the calculation complexity is reduced, but the high-speed operation capability is lost
Solution Approach 1:
The patent implements continuous differential calculation based on the sampled voltage signal, ensuring that the control circuit continuously processes information and responds to changes in real-time. This continuous action maintains high-speed response capability while using a relatively simple differentiation-based algorithm.
Data Source
AI summary
A control circuit (24) includes a calculation means (28) which determines ON time and OFF time of a main switching element (14) and a drive pulse generating means (30) which generates drive pulses that turn the main switching element (14) ON and OFF. A control function formula which prescribes a relationship between an output voltage (Vo) and an output differential value (Vd) by a negative linear function and the like is defined in the calculation means (28). The calculation means (28) samples an input voltage signal (Vi) and an output voltage signal (Vo) at a timing synchronized with a switching cycle of the main switching element (14), and calculates the ON time and OFF time of the main switching element (14) thereafter so as to satisfy the control function formula. The drive pulse generating means (30) generates drive pulses (V14) which turn the main switching element (14) ON and OFF on the basis of the ON and OFF time determined by the calculation means (28).