Multi-phase Signal Control Circuit for PWM Stability
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Solution Overview
Problem
Conventional switched capacitor-based voltage converters experience abnormal operation and reliability issues when the on-off cycle controlled by the PWM signal becomes unstable, leading to abnormal working conditions in the power stage circuit.
Innovation Solution
A multi-phase signal control circuit that generates phase switch signals independently of the PWM signal, using a signal generation circuit to produce a triangular wave and phase switch signals, and a phase switch circuit to generate first and second phase signals, ensuring stable operation even when the on-off cycle is unstable, by performing frequency division and logical operations to control the power stage circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If frequency division is performed on the PWM signal to generate phase switch signals, then multi-phase signal generation is achieved, but the on-off cycle becomes unstable when PWM signal cycle is unstable
Solution Approach 1:
The circuit segments the unstable PWM signal into multiple phases using frequency division and logical operations. The frequency divider separates the PWM signal into multiple frequency-reduced signals, and AND gates further segment these into distinct phase signals (P1, P2, etc.), enabling multi-phase operation while isolating the instability propagation.
Solution Approach 2:
The patent introduces intermediate signals including frequency-reduced signals from the frequency divider and working allowed signals from AND gate operations. These intermediary signals act as buffers between the unstable PWM signal and the final phase signals, filtering and stabilizing the timing characteristics through multiple processing stages.
2Device complexity
If direct frequency division is used to generate working allowed signals, then circuit complexity is reduced, but the power stage circuit cannot meet normal working conditions when PWM cycle is unstable
Solution Approach 1:
The circuit dynamically adapts to unstable PWM cycles by using multiple processing stages. The frequency divider and AND gates dynamically adjust the phase signal generation based on the actual PWM signal characteristics, allowing the power stage circuit to maintain normal working conditions even when the input PWM cycle varies or becomes unstable.
Solution Approach 2:
The patent employs feedback control where the unstable PWM signal is continuously processed through the frequency divider and logical operations to generate stabilized phase signals. The system monitors the PWM signal characteristics and adjusts the phase signal generation accordingly, ensuring the power stage circuit receives stable control signals despite PWM instability.
Data Source
AI summary
A multi-phase signal control circuit includes: a comparator, configured to compare a triangular wave signal with a feedback control signal to output a first pulse width modulation signal, where the feedback control signal is a signal fed back by the power stage circuit; a phase switch circuit, configured to receive a phase switch signal and the first pulse width modulation signal to generate a first phase signal and a second phase signal, where the first phase signal and the second phase signal are used to control the power stage circuit to generate an output voltage signal.