Voltage Converter Feedforward Circuit Transient Response
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Solution Overview
Problem
Existing voltage converters face challenges in maintaining stable output voltage when input voltage fluctuates, particularly due to parasitic resistance in electronic devices like mobile phones and tablets, which affects their transient response characteristic and bandwidth, making it difficult to improve stability and frequency compensation.
Innovation Solution
Incorporating a feedforward circuit that generates a signal opposite to the input voltage change, allowing the drive control circuit to adjust the charging and discharging operations of the voltage conversion circuit, thereby enhancing the transient response characteristic and maintaining a favorable linear output voltage state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the bandwidth of the voltage converter is increased to improve transient response characteristic, then the transient response characteristic is improved, but the parasitic zero pole at high frequency is included within the bandwidth, making frequency compensation design complex and difficult
Solution Approach 1:
The patent applies preliminary action by detecting the input voltage before it changes and generating a feedforward compensation signal in advance. The feedforward circuit monitors the input voltage Vin and generates a compensation signal that is added to the feedback signal before the error amplifier, allowing the system to proactively compensate for upcoming voltage changes rather than reacting after the disturbance occurs. This preliminary detection and compensation mechanism improves transient response without requiring increased bandwidth that would include parasitic poles.
2Speed
If the bandwidth of the voltage converter is increased to improve transient response characteristic, then the transient response characteristic is improved, but the design becomes more difficult due to right-half-plane zero point constraints in boost converters
Solution Approach 1:
The patent implements feedback by introducing a feedforward compensation path that works in conjunction with the existing feedback loop. The feedforward circuit provides a compensation signal based on input voltage changes, which is added to the feedback signal from the output voltage sensing. This dual-path approach (feedback + feedforward) allows the system to maintain stability while improving transient response, as the feedforward path anticipates disturbances before they affect the output, reducing the need to increase bandwidth beyond the right-half-plane zero point constraint.
3Speed
If a feedforward circuit is added to improve transient response characteristic, then the transient response characteristic is improved, but the device complexity increases
Solution Approach 1:
The patent uses an intermediary approach by introducing a dedicated feedforward compensation circuit that acts as a mediator between the input voltage source and the error amplifier. This intermediary circuit detects input voltage changes and generates compensation signals that are injected into the control path, allowing the system to handle transient disturbances without requiring major redesign of the core voltage conversion architecture. The intermediary feedforward circuit isolates the complexity from the main power conversion path.
Data Source
AI summary
Circuits and devices related to voltage conversion. In some embodiments, a voltage converter can include a voltage conversion circuit configured to convert an input voltage to an output voltage based on a drive signal, and a feedback circuit configured to generate an error signal based on the output voltage and a reference voltage. The voltage converter can further include a feedforward circuit configured to generate a feedforward signal indicative of a change opposite to that of a change in the input voltage. The voltage converter can further include a drive control circuit configured to generate the drive signal based on the feedforward signal and the error signal.