ESR Compensation Circuit for Constant Ramp Amplitude Control
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Solution Overview
Problem
The existing constant-frequency turn-on circuits in voltage conversion devices face challenges in maintaining a constant average and maximum amplitude of the ramp voltage signal, leading to instability due to changes with input voltage and turn-on time, making it difficult to control the compensation value.
Innovation Solution
An equivalent series resistance compensation circuit comprising a low-pass filter, voltage divider, and compensator is introduced to generate a ramp voltage signal with constant average and maximum amplitudes, using hardware circuits to stabilize the system by ensuring the amplitudes are independent of input voltage and turn-on time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a comparator is used to compare the ramp voltage signal with the average amplitude, then the constant-frequency turn-on circuit can generate turn-on time signals, but the average amplitude and maximum amplitude of the ramp voltage signal are not constant and change with input voltage and turn-on time, making the compensation value difficult to control
Solution Approach 1:
The patent changes the parameters of the ramp voltage signal generation by using a current source to charge a capacitor, where the charging current is controlled to be constant. This ensures that the ramp voltage signal has a constant slope and constant amplitudes regardless of input voltage variations, thereby stabilizing the compensation value and improving system reliability
Solution Approach 2:
The patent uses a replica of the equivalent series resistance compensation circuit to generate a reference ramp voltage signal. This reference signal is used to compare with the actual ramp voltage signal, allowing the system to maintain constant amplitudes through feedback control without directly measuring the changing input voltage
2Adaptability or versatility
If the ramp voltage signal amplitudes are allowed to change with input voltage and turn-on time, then the circuit can adapt to different operating conditions, but the compensation value becomes difficult to control and system stability deteriorates
Solution Approach 1:
The patent implements a feedback mechanism where the ramp voltage signal is compared with a reference ramp voltage signal generated by a replica circuit. The comparison result is used to adjust the charging current, ensuring that the amplitudes remain constant across different operating conditions while maintaining system stability through closed-loop control
Data Source
AI summary
A ramp voltage signal generated by an equivalent series resistance compensation circuit in prior art is not linear, and average amplitude and maximum amplitude of the ramp voltage signal changes with an input voltage and a turn-on time. It results in a comparison result or compensation value generated by a comparator of the constant-frequency turn-on circuit will change accordingly and is difficult to control. Thus, it is difficult to design the stability of the system. The embodiments of the present disclosure design an equivalent series resistance compensation circuit including hardware circuits. Through functions of these hardware circuits, a ramp voltage signal of which average amplitude and a maximum amplitude are constant is generated, thereby solving problems encountered in the prior art.