DC-DC Converter Cold Start Below 100 mV Using Self-Oscillating Charge Pump
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Solution Overview
Problem
Existing DC-DC converters face challenges in starting up with extremely low input voltages, typically below 100 mV, and require complex and costly transformer solutions to step up low voltage power sources efficiently.
Innovation Solution
A DC-DC converter design utilizing a self-oscillating charge pump with an array of interconnected ring oscillators and a single inductor, capable of cold starting with input voltages below 100 mV, eliminating the need for transformers and providing a scalable solution for low voltage power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a transformer is used to step up low voltage power sources, then the output voltage can be increased to practical levels, but the device becomes expensive, bulky and significantly complicates the production process
Solution Approach 1:
The patent replaces the mechanical/physical transformer system with an electronic DC-DC converter circuit. The converter uses an inductor, switch, diode, and capacitor arranged in a boost topology to achieve voltage step-up without the mechanical complexity of a transformer. This substitution eliminates the need for magnetic coupling and complex winding structures, simplifying production while maintaining voltage transformation capability.
Solution Approach 2:
The patent changes the operating parameters of the power conversion system by using a DC-DC converter operating in discontinuous conduction mode. By controlling the switch duty cycle and timing, the converter can achieve variable voltage step-up ratios without changing the physical structure of the components. This allows the same circuit to adapt to different input voltages and power requirements.
2Loss of energy
If a DC-DC converter with multiple components (switches, transistors, diodes, battery, charger, oscillator) is used to maximize efficiency, then the converter can regulate input loading conditions and ensure energy storage, but the device complexity increases and cold start becomes difficult when energy storages are empty
Solution Approach 1:
The patent extracts and removes unnecessary components from the conventional DC-DC converter design. Specifically, it eliminates the need for separate battery, battery charger, and complex oscillator circuits by designing a simplified converter that can cold-start directly from photovoltaic input. The design keeps only the essential components: inductor, switch, diode, and capacitor, while achieving the same energy storage and regulation functions through different circuit topology and control methodology.
Solution Approach 2:
The patent implements self-service functionality where the converter automatically regulates its own operation and cold-starts without external assistance. The discontinuous conduction mode operation allows the converter to build up energy in its inductor and capacitor during each switching cycle, enabling it to start up from zero energy state without requiring pre-charged batteries or external energy sources. The controller automatically adjusts switching parameters to maximize efficiency across different operating conditions.
3Adaptability or versatility
If the converter is designed to cold start with extremely low input voltages below 100 mV, then the adaptability to low voltage power sources is improved, but the device complexity increases to achieve such low voltage operation
Solution Approach 1:
The patent implements dynamic control where the switching frequency and duty cycle are continuously adjusted based on the input voltage level. The controller adapts its operation in real-time to maintain optimal efficiency across the wide input voltage range from below 100 mV to higher voltages. This dynamic adaptation allows the same converter circuit to handle extremely low voltage photovoltaic inputs without requiring different hardware configurations.
Solution Approach 2:
The patent employs periodic switching action in discontinuous conduction mode, where the switch operates in rhythmic on-off cycles that allow energy accumulation in the inductor during the on-period and energy transfer to the output during the off-period. This periodic operation enables the converter to build up output voltage even from extremely low input voltages by accumulating energy over multiple switching cycles, rather than requiring high instantaneous input power.
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 converter efficiently steps up low input voltages to 1.5 V, enabling power to conventional electronic circuits with reduced power consumption and cost, while maintaining scalability and efficiency across different CMOS manufacturing processes.
Implementation Method 1
an inductor LX connected between an input of the power source 2 through a resistor Rin, which supplies a Vin voltage
Implementation Method 2
a diode element 12, switches 11, 13 and transistors 14, 15 are also included in the circuit 1
Data Source
AI summary
The invention relates to a DC-DC converter (1) for a power source (2) generating extremely low voltage, the converter (1) operating in discontinuous mode, wherein the converter (1) comprises a self-oscillating charge pump (3a) having an array of interconnected ring oscillators (RO1-RON) for successively stepping up an input voltage (Vin) so as to result in the accumulated voltage (XN) at the last ring oscillator (RON), an amplifier (3b) and a pulse signal generator (3c) that generates a pulse signal that actuates a switch (11) so that the stepped-up, output voltage may be provided via a diode (12). The invention further relates to a method for actuating the DC-DC converter (1) for a power source (2) generating extremely low voltage.