Self-Regulating Relay Charging Circuit to Prevent MCU Brownouts
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Solution Overview
Problem
The sharing of a common voltage source between a microcontroller and a switching device in relay circuitry can lead to inefficiencies, including brownouts or loss of power, as the voltage required by the charging circuit reduces the voltage available to the microcontroller, potentially falling below the operational threshold.
Innovation Solution
Incorporating a charge circuit with a switching element, such as a MOSFET, that is controlled by the microcontroller to regulate the voltage supplied to both the microcontroller and the charging circuit, ensuring the microcontroller receives a voltage above the threshold by automatically disconnecting when the voltage falls below a certain level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a common voltage source is shared between the microcontroller and the charging circuit, then the device complexity is reduced, but the reliability of power supply deteriorates due to voltage drops causing brownouts
Solution Approach 1:
The patent divides the power supply system into two separate voltage sources: a main voltage source for the charging circuit and a secondary voltage source (voltage regulator) for the microcontroller. This segmentation isolates the microcontroller from voltage drops caused by charging operations, resolving the contradiction between simplified design and reliable operation.
Solution Approach 2:
A voltage regulator is introduced as an intermediary component between the main voltage source and the microcontroller. This mediator ensures stable voltage supply to the microcontroller regardless of fluctuations in the main voltage source during charging, thereby maintaining reliability without significantly increasing overall system complexity.
2Productivity
If the charging circuit draws high current to charge the capacitor quickly, then the productivity is improved, but the voltage available to the microcontroller deteriorates causing operational failures
Solution Approach 1:
The patent segments the current draw paths by providing separate voltage sources for charging and microcontroller operation. The main voltage source can supply high current for rapid charging without affecting the microcontroller, which receives regulated voltage from its dedicated source, thus resolving the contradiction between fast charging and operational reliability.
Solution Approach 2:
The voltage regulator is configured to maintain adequate voltage levels for the microcontroller before charging operations begin. This preliminary voltage stabilization ensures that the microcontroller remains operational throughout the charging process, even when high currents are drawn by the charging circuit.
3Reliability
If the voltage is regulated to maintain stable supply to the microcontroller, then the reliability is improved, but the use of energy deteriorates due to additional regulation losses
Solution Approach 1:
The patent applies voltage regulation locally only where needed (at the microcontroller supply line) rather than regulating the entire system. The main charging circuit operates without regulation, allowing efficient energy transfer, while the microcontroller receives regulated voltage only from its dedicated regulator, minimizing total energy loss while maintaining reliability.
Data Source
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AI summary
A system may include a power source. The power source supplies a first voltage. The system may also include a voltage regulator that receives the first voltage and supply a second voltage. Additionally, the system may include a microcontroller that receives the second voltage and output the second voltage via an output pin. Further, the system may include a switching element that receives the second voltage from the output pin of the controller at a first terminal and receives the first voltage from the power supply at a second terminal. The switching element selectively charges a first capacitor based on a difference between the first voltage and the second voltage.