DC-DC Converter Hysteresis Control Circuit
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Solution Overview
Problem
Conventional DC-DC converters with hysteresis control face challenges in achieving high-speed transient response and output stability without increasing output ripple voltage, as they rely on delay times and equivalent series resistance, leading to degraded stability and lower switching frequencies.
Innovation Solution
A DC-DC converter design that uses a comparison circuit to control the output DC voltage between two reference voltages, without an error amplifier, by employing a switch element, reference voltage source, capacitive element, charge/discharge circuit, and switch circuit to manage the differential voltage and current flow, enabling high-speed response and precision stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If hysteresis control is used to achieve rapid transient response, then transient response time is improved, but output ripple voltage increases and switching frequency decreases
Solution Approach 1:
The patent introduces a feedback mechanism where the output voltage is fed back to the hysteresis comparison circuit. This feedback loop allows the system to dynamically adjust the switching control based on actual output conditions, enabling rapid transient response while maintaining stable output voltage and controlling output ripple voltage through continuous monitoring and adjustment.
2Object-generated harmful factors
If output capacitor with low ESR is used to reduce output ripple voltage, then output ripple voltage is reduced, but switching frequency decreases
Solution Approach 1:
The patent changes the control parameter from relying solely on ESR-based voltage detection to using a hysteresis comparison circuit with adjustable hysteresis voltage. This allows independent optimization of switching frequency and output ripple voltage by adjusting the hysteresis width parameter, decoupling the relationship between ESR, ripple voltage, and switching frequency.
3Loss of time
If hysteresis comparison circuit is used to control switching, then transient response is improved, but output voltage stability decreases
Solution Approach 1:
The feedback of output voltage to the hysteresis comparison circuit enables the system to maintain stability by continuously comparing actual output with reference voltage. The hysteresis mechanism provides noise immunity while the feedback ensures accurate voltage regulation, achieving both rapid response and stable output voltage simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution allows for high-speed response and high-precision output stability without increasing output ripple voltage, effectively stabilizing the output DC voltage within a controlled range between reference voltages, suppressing fluctuations in switching frequency.
Implementation Method 1
a capacitive element (51) having one terminal connected to the reference voltage source (50)
Implementation Method 2
a switch element (1) which is turned ON/OFF by a drive signal
Implementation Method 3
an inductor (3) connected between the output of the DC-DC converter and the connecting point between the switch element (1) and the diode (2)
Data Source
AI summary
A DC-DC converter for converting an input DC voltage to an output DC voltage has a switch element which is turned ON/OFF by a drive signal, a reference voltage source for outputting a first reference voltage when the switch element is ON or outputting a second reference voltage when the switch element is OFF, a capacitive element having one terminal connected to the reference voltage source, a charge/discharge circuit for discharging the capacitive element when the switch element is ON and charging the capacitive element when the switch element is OFF, a switch circuit for short-circuiting the capacitive element when the switch element is turned ON and OFF, and a comparison circuit for comparing the output DC voltage or a voltage at which the output DC voltage is detected with a voltage at the other terminal of the capacitive element and generating the drive signal.