Rectangular-Wave Signal Circuit for High Step-Down Ratio Power Supplies
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Solution Overview
Problem
Conventional switching power supplies face challenges in stabilizing output power-supply voltage with high efficiency, particularly in achieving a high step-down ratio and handling wide input voltage ranges, which affects their performance in applications requiring precise voltage conversion.
Innovation Solution
A rectangular-wave-signal generating circuit is developed, comprising a sawtooth-wave output circuit, detectors, and a PWM-signal output circuit, which generates a high-linearity sawtooth-wave signal to synchronize with a clock signal, enabling stable PWM signal generation and efficient switching operations even at high step-down ratios and wide input voltage ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional switching power supply is used to achieve high step-down ratio (one tenth or less), then the voltage conversion capability is improved, but the operational stability deteriorates
Solution Approach 1:
The patent applies dynamics by making the switching power supply capable of dynamically adjusting its operation mode between buck and buck-boost based on input voltage conditions. The control circuit dynamically selects the appropriate mode to maintain stable operation across wide input voltage ranges, resolving the contradiction between high step-down ratio capability and operational stability.
Solution Approach 2:
The patent changes the operating parameters by introducing a buck-boost mode in addition to the standard buck mode. This parameter change allows the power supply to adapt its conversion ratio and operating characteristics based on input voltage conditions, enabling stable operation at high step-down ratios while maintaining reliability across varying input conditions.
2Adaptability or versatility
If a switching power supply handles wide input voltage range (10 to 40 V), then the adaptability is improved, but the operational stability deteriorates
Solution Approach 1:
The control circuit dynamically switches between buck mode and buck-boost mode based on the input voltage level. When input voltage is within a certain range, buck mode is used; when input voltage exceeds this range, the system transitions to buck-boost mode. This dynamic adaptation enables the power supply to handle wide input voltage ranges (10 to 40 V) while maintaining stable operation and output voltage regulation.
3Use of energy by moving object
If high efficiency is achieved in switching power supply, then the energy conversion efficiency is improved, but the voltage stabilization capability deteriorates
Solution Approach 1:
The patent changes the operating mode parameters between buck and buck-boost modes to optimize both efficiency and voltage stabilization. By selecting the appropriate mode based on input voltage conditions, the system maintains high energy conversion efficiency while ensuring stable output voltage regulation across the full input voltage range.
Data Source
AI summary
A rectangular-wave-signal generating circuit according to an embodiment comprises: a sawtooth-wave output circuit; a first detector; a second detector; and a first PWM-signal output circuit. The sawtooth-wave output circuit is configured to generate and output a sawtooth-wave signal synchronized with a clock signal. The first detector is configured to detect a first timing at which a potential of the sawtooth-wave signal exceeds a bottom potential. The second detector is configured to detect a second timing at which a potential of the sawtooth-wave signal exceeds a potential of a first pulse-width instruction voltage signal. The first PWM-signal output circuit is configured to generate a first PWM signal based on a time difference between the first timing and the second timing.