Feedforward Circuit for DC-to-DC Converters with Digital Voltage Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional digital voltage control loops in power converters lack robust line rejection capabilities, leading to inefficiencies and increased complexity, particularly when dealing with abrupt changes in input voltage.
Innovation Solution
Incorporating a feedforward circuit that modifies the minimum resolution of the digital pulse width modulation (DPWM) signal based on an analog input voltage, allowing the digital voltage control loop to react to input voltage changes without requiring additional ADCs or complex algorithms, similar to sawtooth waveform compensation in analog control loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ADCs are used to improve the accuracy and control of the voltage or current level, then the accuracy and control are improved, but the overall efficiency decreases and the physical size, complexity, and cost increase
Solution Approach 1:
The patent extracts the voltage measurement function from the main control path, using a separate feedforward circuit that directly processes the input voltage signal. This allows the main ADC to focus on feedback control while the feedforward path handles input voltage compensation, reducing the overall system complexity while maintaining accuracy.
Solution Approach 2:
The feedforward circuit performs preliminary processing of the input voltage signal before it reaches the main control loop. By pre-compensating for input voltage variations through the feedforward path, the system reduces the burden on the main ADC and controller, thereby reducing complexity while maintaining control accuracy.
2Measurement precision
If ADCs are used to improve the accuracy and control of the voltage or current level, then the accuracy and control are improved, but the overall efficiency decreases
Solution Approach 1:
The feedforward circuit performs preliminary compensation for input voltage variations before they affect the output. This allows the main control loop to operate with reduced precision requirements, enabling the use of lower-resolution ADCs that consume less power while still achieving the required control accuracy.
Solution Approach 2:
The system uses partial ADC resolution in the main control path combined with analog feedforward compensation. This partial use of digital processing combined with analog preprocessing reduces the power consumption of the ADC while maintaining overall control accuracy through the complementary feedforward path.
3Device complexity
If conventional digital voltage control loops are used, then the system is simpler, but the line rejection capabilities are insufficient and the system cannot react robustly to abrupt input voltage changes
Solution Approach 1:
The patent introduces an intermediary feedforward circuit that acts as a mediator between the input voltage and the control loop. This feedforward path provides direct compensation for input voltage variations, enhancing line rejection capabilities without requiring significant increases to the main control loop complexity.
Solution Approach 2:
The feedforward circuit performs preliminary compensation for input voltage changes before they propagate through the main control loop. This proactive compensation mechanism enhances the system's ability to reject line disturbances while maintaining relatively simple control loop architecture.
Data Source
AI summary
A method may comprise receiving a first clock signal; receiving a digital duty cycle value; using the first clock signal and digital duty cycle value to generate a digital pulse width modulation (DPWM) signal having a plurality of discrete steps to control a switch of a switched-mode power supply; and using a voltage control circuit to modify a duration of each of the plurality of discrete steps of the DPWM signal, wherein the voltage control circuit is configured to receive an analog voltage input.