DC-DC Voltage Reducing Converter Test Mode
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Solution Overview
Problem
Existing DC-DC converters, such as buck converters, face inefficiencies in voltage reduction due to heat dissipation in potential divider networks and material costs in synchronous buck converters, and struggle to measure DC output current, especially in burst mode.
Innovation Solution
A voltage reducing circuit that automatically switches between PWM and burst modes based on falltime duration, using a controller to compare the falltime to a threshold duration and adjust operation modes for improved efficiency, and includes a test mechanism to determine optimal mode operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If burst mode is used for lower output currents, then efficiency is improved, but measurement of DC output current becomes difficult
Solution Approach 1:
The patent applies periodic action by implementing a test mode that periodically switches the converter to burst mode for a predetermined time interval, then returns to PWM mode. This periodic testing allows the system to measure the falltime of the output voltage during burst mode operation, thereby indirectly measuring the DC output current while maintaining the efficiency benefits of burst mode for extended periods.
Solution Approach 2:
The system uses its own output voltage characteristics (the natural falltime when switching from on-state to off-state) as the measurement signal. By monitoring how long it takes for the output voltage to fall from an initial value to a threshold value during burst mode, the system self-measures the DC output current without requiring external measurement equipment, thus maintaining efficiency while enabling measurement.
2Loss of energy
If PWM mode is used for higher output currents, then efficiency is improved, but adaptability to varying load conditions decreases
Solution Approach 1:
The patent implements dynamics by making the operating mode adjustable and testable. The controller can dynamically switch between PWM mode and burst mode based on measured DC output current levels. A test mode is provided that allows the system to temporarily switch to burst mode, measure the output characteristics, and then return to PWM mode, enabling the system to adapt to varying load conditions while maintaining efficiency through informed mode selection.
Solution Approach 2:
The system changes operational parameters by switching between different operating modes (PWM and burst) based on load conditions. The controller measures the DC output current and adjusts the operating mode accordingly, changing the duty cycle and switching characteristics to optimize efficiency for the current load level while maintaining adaptability to varying conditions.
3Loss of energy
If automatic mode switching is implemented, then efficiency is optimized, but device complexity increases
Solution Approach 1:
The patent implements feedback by measuring the falltime of the output voltage during burst mode operation and using this measurement to determine the DC output current level. The controller uses this feedback information to automatically switch between PWM and burst modes, optimizing efficiency. The feedback mechanism relies on timing measurements rather than complex current sensing circuits, thereby limiting the increase in device complexity while achieving mode optimization.
4Measurement precision
If test mode operation is added, then measurement capability is improved, but device complexity increases
Solution Approach 1:
The controller serves multiple functions: it controls the power switch circuit, manages energy storage circuit operation, measures output voltage falltime, determines DC output current, and switches between operating modes. By making the controller universal and multi-functional, the patent improves measurement precision without requiring separate dedicated measurement circuits, thereby limiting the increase in device complexity while achieving accurate DC output current measurement capability.
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 circuit achieves increased efficiency by dynamically switching between PWM and burst modes, optimizing energy usage and allowing for efficient operation across varying load currents, while enabling efficient mode testing to maintain optimal performance.
Implementation Method 1
A buck converter circuit utilises an inductor-capacitor or 'LC' circuit which is periodically connected to and disconnected from the power supply
Implementation Method 2
an energy storage circuit portion comprising an inductor, said energy storage circuit portion being connected to the switch node and arranged to provide an output voltage
Data Source
AI summary
A voltage reducing circuit includes a power switch circuit portion having high-side and low-side field-effect-transistors connected at a switch node. The power switch circuit portion has an on-state wherein the high-side transistor is enabled and the low-side transistor is disabled and, vice versa, an off-state. An energy storage circuit portion including an inductor connected to the switch node is arranged to provide an output voltage. A timer determines a falltime duration required for the output voltage to fall to a threshold value. A controller switches the voltage reducing circuit between a first mode of operation in which a periodic pulse width modulated drive signal is applied to the high-side and low-side field-effect-transistors; and a second mode of operation in which a pulse is applied to the high-side and low-side field-effect-transistors only if the output voltage reaches the threshold value.