Power Supply Mode Switching via Frequency Comparison
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Solution Overview
Problem
Conventional power supply apparatuses face significant response time delays when switching between pulse-width modulation (PWM) and pulse-frequency modulation (PFM) modes due to the requirement of a hysteretic counter for mode determination, impacting their ability to quickly adapt to changing load states.
Innovation Solution
The implementation of an operation-mode determining unit that includes a frequency comparator, a zero current detector, and a mode controller, which compares the operation frequency with a reference frequency and detects the inductor current to determine the switching signal, allowing for rapid mode switching without the need for a hysteretic counter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hysteretic counter is used to determine operation mode switching, then the mode switching decision is made, but the response time is significantly delayed
Solution Approach 1:
The patent extracts and removes the hysteretic counter from the mode determination system. Instead of using a counter to delay switching decisions, the invention directly compares the operating frequency with a reference frequency to determine mode switching, eliminating the time delay caused by counting operations while maintaining accurate mode determination
Solution Approach 2:
The patent establishes a reference frequency in advance that corresponds to the boundary between PWM and PFM modes. By pre-setting this reference value, the system can immediately determine mode switching conditions without needing to count cycles or wait for predetermined conditions, thus achieving rapid response
2Ease of operation
If the counter counts the time since load state changes, then the delay switching mechanism is provided, but the response time of the power supply apparatus is impacted significantly
Solution Approach 1:
The patent replaces the mechanical counting mechanism with a frequency comparison mechanism. Instead of using a counter to track time cycles, the system uses a frequency comparator to directly compare the current operating frequency with the reference frequency, substituting a time-based mechanical counting approach with an instantaneous electrical comparison approach that achieves both control and speed
Data Source
AI summary
A power supply apparatus and an operation-mode determining unit and a method thereof are provided. The power supply apparatus includes first and second control units, a switching unit, a power output unit, and an operation-mode determining unit. The first and second control units provide first and second control signals respectively. The switching unit selects to output the first or second control signal according to a switching signal. The power output unit adjusts its output power in accordance with the control signal output from the switching unit. The operation-mode determining unit compares an operation frequency in the power output unit with a reference frequency, and detects an inductor current in the power output unit. The operation-mode determining unit determines the state of a switching signal and outputs it to the switching unit in accordance with the comparison result and the detection result.