Power Management Device Using Shared Inductor for Low Voltage Startup
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Solution Overview
Problem
Thermoelectric energy harvesting systems face challenges in generating sufficient electrical energy due to low output voltage and power from thermoelectric elements, requiring high-efficiency power management devices that can operate at low input voltages and reduce manufacturing costs.
Innovation Solution
A power management device incorporating a self-startup circuit with a Colpitts oscillator and a boost converter, utilizing a shared inductor and voltage multiplier to generate and manage start-up and output voltages efficiently, allowing for simplified configuration and reduced manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional startup circuit and boost converter are used separately, then the power management device can start up at low input voltage, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines the startup circuit and boost converter into a single integrated power management device. The startup circuit includes a startup capacitor, startup transistor, and startup resistor that work together with the boost converter circuit sharing common components. This integration reduces the number of separate components while maintaining the ability to start up at low input voltages from thermoelectric elements.
Solution Approach 2:
The power management device is designed to perform multiple functions: the boost converter operates both as a startup circuit when input voltage is low and as a power conversion circuit when input voltage is sufficient. The controller manages different operating modes (startup mode and normal operation mode) using the same hardware components, making the device universal and reducing complexity.
2Power
If a traditional power management device is used, then power conversion can be achieved, but the output efficiency at low input voltage is insufficient
Solution Approach 1:
The controller dynamically adjusts the operating mode of the power management device based on the input voltage level. When the input voltage from the thermoelectric element is below a threshold, the device operates in startup mode with enhanced efficiency. When the input voltage exceeds the threshold, it switches to normal boost converter operation. This dynamic adaptation optimizes energy conversion efficiency across varying input conditions.
Solution Approach 2:
The device changes its operational parameters based on input voltage conditions. The controller monitors the input voltage and adjusts the duty cycle and switching frequency of the boost converter to maintain optimal efficiency. The startup circuit parameters (capacitor charging/discharging) are specifically optimized for low-voltage operation to minimize energy losses during the startup phase.
3Reliability
If multiple separate components are used for startup and power conversion, then reliable operation is achieved, but the manufacturing cost increases
Solution Approach 1:
The patent integrates multiple functions into a single power management device chip or module. The startup circuit components (startup capacitor Cst, startup transistor Qst, startup resistor Rst) and the boost converter components (inductor L, capacitor Cout, transistor Q, diode D) are designed to work together in one unified circuit, reducing the number of separate components that need to be manufactured and assembled.
Solution Approach 2:
The power management device is designed as a universal solution that handles both startup and normal operation functions. The controller manages different operating modes using the same hardware, eliminating the need for separate dedicated startup and power conversion circuits, thereby reducing manufacturing complexity and cost while maintaining reliable operation.
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 enhances the output efficiency of the power management device by amplifying low input voltages and stabilizing output voltages, improving the overall performance and reducing manufacturing costs.
Implementation Method 1
a self-startup circuit including an oscillator and a voltage multiplier to generate a start-up voltage for starting up the power management device
Implementation Method 2
a boost converter to alternately charge the start-up voltage and an output voltage within a predetermined start-up voltage range
Implementation Method 3
Thermoelectric energy harvesting produces electrical energy using the thermoelectric effect, in which a temperature difference of an object is converted to a potential difference
Data Source
AI summary
A power management device according to example embodiments includes a self-startup circuit including an oscillator and a voltage multiplier to generate a start-up voltage in a first start-up period based on an input voltage, a boost converter to alternately charge the start-up voltage and an output voltage within a start-up voltage range during a second start-up period and to charge only the output voltage during an operation period, a controller to control the self-startup circuit and the boost converter based on a magnitude of the start-up voltage, a voltage charger including a start-up voltage capacitor and an output voltage capacitor, and a shared inductor connected between the input node and a common input node. The shared inductor operates as a part of the oscillator during the first start-up period and a part of the boost converter during the second start-up and operation periods.