Low-Voltage Detection Circuit With Delayed Current Cutoff
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Solution Overview
Problem
Conventional low voltage detection circuits with delays face issues of increased electric current consumption due to constant current flow in the constant current source, especially when the power supply voltage is above a predetermined level, leading to inefficiencies and higher power usage.
Innovation Solution
A low voltage detection circuit that includes a voltage comparison circuit, an output stage, a constant current circuit for charging a condenser to set a delay time, and a judgment circuit to control the electric current flow, allowing the electric current to be cut off after a predetermined delay when the voltage is stable, thereby reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a constant current source is continuously operated in a low voltage detection circuit with delay, then a stable delay time can be achieved, but electric current consumption increases
Solution Approach 1:
The constant current source is operated periodically rather than continuously. A control circuit activates the constant current source only during the delay period after voltage recovery, then deactivates it. This periodic operation maintains the necessary delay function while significantly reducing overall current consumption compared to continuous operation.
Solution Approach 2:
The circuit uses the voltage recovery detection signal itself to control the activation of the constant current source. When the detection circuit detects voltage recovery, it automatically triggers the constant current source to operate for the delay period, then automatically shuts it off. This self-service mechanism eliminates the need for continuous external control while ensuring proper timing.
2Use of energy by moving object
If a switch is added to control current flow in the constant current source, then current consumption can be reduced, but device complexity increases
Solution Approach 1:
The control circuit is integrated with the existing detection circuit components. The same detection circuit that monitors voltage recovery is used to control the switch, and the control signals are generated within the existing circuit architecture. This merging approach adds minimal complexity while achieving current reduction.
Solution Approach 2:
The detection circuit serves dual functions: it detects voltage recovery status and simultaneously controls the constant current source operation. By making the detection circuit multi-functional, the patent avoids adding separate control circuitry, thereby minimizing the increase in device complexity while still achieving current consumption reduction.
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 circuit effectively suppresses electric current consumption by cutting off the constant current source after a delay when the power supply voltage is stable, reducing power usage and minimizing the influence of element variations and temperature attributes on delay time.
Implementation Method 1
a voltage comparison circuit that compares a voltage in proportion to a voltage of a detection target with a predetermined reference voltage
Implementation Method 2
an electric current circuit that includes a constant current source and that obtains a predetermined delay time by charging a condenser with a constant current
Data Source
AI summary
Disclosed is a low voltage detection circuit. The low voltage detection circuit includes, a voltage comparison circuit, an output stage, an electric current circuit, and a judgment circuit. When the voltage comparison circuit detects that the voltage of the detection target is a predetermined voltage value or less, an output state of the output stage is promptly changed. When the voltage comparison circuit detects that the voltage of the detection target is a predetermined voltage value or more, the output state of the output stage is changed after a delay time obtained by the electric current circuit.