Charge Discharge Control Circuit for Low Power Electronic Devices
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Solution Overview
Problem
Conventional electronic devices with charge/discharge control circuits face challenges in supplying desired electric power to loads due to low voltage increase rates and minute generated power from downsized generators, leading to incomplete operation of electronic devices.
Innovation Solution
The electronic device incorporates a charge/discharge control circuit with a PMOS and NMOS transistor configuration that monitors voltage levels and controls power flow to charge a capacitor efficiently, ensuring the load operates reliably even with low input power by disconnecting the capacitor when a predetermined voltage is reached and managing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the generator is downsized for improving portability and cutting costs, then the portability and cost are improved, but the generated power becomes minute and less than the consumption power of the electronic device
Solution Approach 1:
The system performs preliminary charging of the capacitor during periods when the generated power exceeds consumption power, storing energy in advance. The charge/discharge control circuit accumulates electric charge in the capacitor before the load requires it, enabling the load to operate when generated power is insufficient.
2Use of energy by moving object
If a charge/discharge control circuit is used to charge a capacitor with generated power, then the capacitor can be charged with minute power, but during the delay time after voltage detection the voltage must increase by several mV which stops voltage increase and causes indefinite operation state
Solution Approach 1:
The voltage detection circuit continuously monitors the capacitor voltage and provides feedback to the charge/discharge control circuit. When the voltage reaches the predetermined threshold, the feedback signal immediately triggers the discharge phase, eliminating delay and preventing the voltage stagnation problem that causes indefinite operation states.
3Extent of automation
If the voltage of the capacitor needs to increase by several mV during delay time for latch circuit inversion or hysteresis circuit operation, then the control circuits can operate, but the voltage increase stops when charged power equals consumption power and the electronic device cannot perform desired operation
Solution Approach 1:
The capacitor is charged in advance during periods when generated power exceeds consumption, storing sufficient energy before the load requires operation. This preliminary energy accumulation ensures that when the load activates, there is already enough stored energy to support desired operations without being constrained by real-time power balance limitations.
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 configuration allows for the reliable operation of more functional loads using compact power sources by efficiently managing power flow and maintaining voltage detection states, ensuring consistent operation despite low input power and high capacitance values.
Implementation Method 1
The thermoelectric conversion element 402 converts a temperature, such as a body temperature and an outside air temperature, into generated power and outputs the generated power
Implementation Method 2
a capacitor 405, a control circuit 406 for controlling charge/discharge
Data Source
AI summary
Provided is an electronic device capable of supplying desired electric power to a load so as to operate the load even in a case where charged power is minute and a voltage increase rate of a capacitor, which increases by charge, is low. The electronic device includes: a power source which has supply power less than consumption power of the load; a capacitor to be charged with the supply power; and a charge/discharge control circuit which controls charging of the capacitor and consumption of charged power of the capacitor by the load, and the charge/discharge control circuit includes: a first node to which the supply power of the power source is supplied; and a circuit which charges the capacitor with the supply power from the first node.