Digital Compensator Adaptive Feedforward DC-DC Converter
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Solution Overview
Problem
Existing DC-DC converters face challenges in maintaining effective control over varying operating conditions, particularly in response to input voltage transients, due to fixed compensation circuitry that is not adaptable.
Innovation Solution
A digital compensator with adaptive feedforward compensation is introduced, responsive to feedback and feedforward control signals, which includes a register to store input voltage values and a feedforward gain unit to generate feedforward gain values based on these inputs, allowing for dynamic adjustment of control parameters such as proportional, integral, and derivative gains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed compensation circuitry is used in digital control, then the control parameters can be determined for a particular set of operating conditions, but the converter cannot effectively respond to varying operating conditions such as input voltage transients
Solution Approach 1:
The patent implements dynamic compensation by making the feedforward gain variable rather than fixed. The feedforward gain is scaled based on the square of the input voltage through a gain scaling unit, allowing the compensation characteristics to adapt dynamically to changing operating conditions. This resolves the contradiction by enabling the system to respond effectively to varying conditions while maintaining a relatively simple circuit structure through mathematical scaling relationships.
Solution Approach 2:
The patent changes the parameter of feedforward gain dynamically based on input voltage levels. By scaling the feedforward gain with the square of the input voltage, the system adjusts its compensation behavior to match operating conditions. This parameter change approach allows the converter to maintain effective control across different operating points without requiring completely different circuit configurations for each condition.
2Reliability
If control parameters are optimized for one operating frequency and voltage, then performance is maximized at that point, but performance degrades when operating conditions change
Solution Approach 1:
The patent incorporates feedforward control that uses information about input voltage transients to proactively adjust the control signal. The feedforward path processes the input voltage signal and generates a compensating signal that is added to the feedback control signal. This feedback mechanism ensures that the converter maintains reliable control effectiveness across varying operating conditions by continuously adapting to changes in input voltage and operating frequency.
Data Source
AI summary
A control circuit for a voltage regulator includes a divider coupled to the regulated output voltage to generate a divided voltage having a value that is a fraction of the regulated output voltage, an ADC responsive to the divided voltage to generate a feedback control signal, a digital compensator responsive to the feedback control signal and to a feedforward control signal scaled by a feedforward gain value to generate a compensator signal, and a pulse width modulator responsive to the compensator signal to generate a voltage control signal to control a switch of the voltage regulator. The digital compensator includes a register configured to store a value indicative of the input voltage and a feedforward gain unit configured to generate the feedforward gain value in response to the value indicative of the input voltage. In embodiments, the feedforward gain value is generated in response to the square of the value indicative of the input voltage. The feedforward gain value can be updated each time the value indicative of the input voltage is updated.