Voltage Conversion Circuit Fixed Frequency Hysteresis Control
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Solution Overview
Problem
Current DC-DC converters, particularly hysteresis-mode controlled ones, face challenges in maintaining a fixed operating frequency, which is essential for frequency-sensitive loads, and have poor load transient response and antinoise capabilities, limiting their suitability for multiphase parallel connections.
Innovation Solution
A voltage conversion circuit with a feedback loop that includes a sampling and amplification circuit, a feedback circuit, and a comparator circuit, generating a frequency-controllable PWM signal to control the power transistor, allowing for a fixed operating frequency and improved load transient response without the need for internal compensation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If hysteresis-mode control is used in DC-DC converter, then structure is simplified and load transient response is improved, but operating frequency cannot be fixed
Solution Approach 1:
The patent introduces a feedback loop that samples the output voltage, compares it with a reference voltage, and adjusts the switching duty cycle accordingly. This feedback mechanism enables the hysteresis-mode converter to maintain a fixed operating frequency while retaining the simplicity of hysteresis control and fast transient response.
Solution Approach 2:
The patent dynamically adjusts the switching duty cycle based on the difference between sampled output voltage and reference voltage. This dynamic adjustment allows the converter to maintain stable operating frequency while adapting to load changes, resolving the contradiction between fixed frequency requirement and hysteresis-mode flexibility.
2Stability of the object's composition
If current-mode control is used in DC-DC converter, then operating frequency can be fixed, but structure becomes complex and antinoise capability deteriorates
Solution Approach 1:
The patent extracts only the essential feedback function needed to fix the operating frequency, removing the complex current-mode control circuitry. By taking out only the necessary voltage sampling and comparison components, the design achieves fixed frequency operation without inheriting the complexity and poor antinoise capability of full current-mode control.
3Stability of the object's composition
If voltage-mode control is used in DC-DC converter, then operating frequency can be fixed, but internal compensation circuit becomes complex and area is wasted
Solution Approach 1:
The patent removes the complex internal compensation circuits typically required in voltage-mode control by using a simplified feedback approach. The design achieves stable fixed-frequency operation without needing extensive compensation networks, thereby reducing circuit area and complexity while maintaining the benefits of voltage-mode control.
Data Source
AI summary
A voltage conversion circuit and method, and a multiphase parallel power system, where in the voltage conversion circuit, a feedback circuit provides a frequency-controllable feedback ripple signal. Therefore, the voltage conversion circuit has a controllable operating frequency, and a frequency requirement of a load may be met. Compensation does not need to be performed in a hysteresis mode, and therefore the hysteresis mode has a fast-speed response. The operating frequency is fixed. Therefore, the voltage conversion circuit in the embodiments may be applied to the multiphase parallel power system such that the multiphase parallel power system is applicable to an application scenario with a large load current.