Sequential Power-On Circuit for Low Current Solar Devices
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Solution Overview
Problem
Solar-powered products face start-up malfunctions and prolonged start-up times due to high current consumption, especially under low power conditions, leading to frequent voltage drops and device lockouts.
Innovation Solution
Implementing a method that uses time division multiplexing to sequentially enable circuit modules with different power consumptions, rather than increasing energy storage capacity, allowing for rapid and successful start-up by converting the low voltage reset signal to logic high only when necessary and enabling each module after predetermined periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If all function blocks are enabled simultaneously upon power-on, then the device can start up quickly, but the power voltage drops too quickly causing low voltage reset and device lockout
Solution Approach 1:
The patent segments the power-on process into distinct phases by dividing function blocks into different groups (first group and second group). Each group is enabled sequentially rather than simultaneously, with the first group enabled after a first preset period and the second group enabled after a second preset period. This segmentation prevents excessive simultaneous current draw while maintaining relatively quick start-up, resolving the contradiction between start-up speed and power voltage stability.
2Reliability
If the capacitance of the capacitor is greatly increased to 20 uF, then the voltage drop issue is solved, but the start-up time becomes too long (about 10 seconds)
Solution Approach 1:
The patent applies preliminary action by enabling the first group of function blocks before the second group, allowing critical functions to operate while power is being built up. The low voltage reset signal is converted to logic high only when necessary (when power voltage reaches threshold), and predetermined periods are set in advance to control the sequencing. This approach maintains power voltage stability without requiring excessive capacitance, thereby reducing start-up time significantly compared to the conventional 10-second start-up.
3Use of energy by moving object
If a low current power source (5 uA) is used, then the device achieves low power consumption, but the power voltage drops too quickly when function blocks are enabled
Solution Approach 1:
The patent implements periodic action through time-division multiplexing, where function blocks are enabled in periodic intervals rather than continuously or simultaneously. The first group of function blocks is enabled after a first preset period, and the second group is enabled after a second preset period. This periodic enabling strategy matches the low current supply capability (5 uA) while ensuring power voltage stability, allowing the device to maintain low power consumption without sacrificing reliability.
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
This approach reduces product size, eliminates start-up malfunctions, and significantly shortens start-up time without the need for increased capacitance, ensuring stable power delivery.
Implementation Method 1
the solar cell 101 receives the sun light, the charges would store in the capacitor 102
Data Source
AI summary
A method for power-on sequence and a device with a low current power source are provided in the present invention. The method is used for enabling a device including a low current power source, a first circuit module and a second circuit module, wherein the low current power source is used for providing a power voltage. The method includes: switching a low voltage reset signal from a first logic voltage to a second logic voltage when the power voltage rise to a threshold voltage; enabling the first circuit module after a first preset time from the time when the low voltage reset signal switches from the first logic voltage to the second logic voltage; and enabling the second circuit module after a second preset time from the time when the first circuit module is enabled.