Capacitor Discharge Circuit for Predictable Power-Down States
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Solution Overview
Problem
In power supply systems, when the power converter is disabled, the capacitor may remain charged, leading to an unknown or unexpected power state for the load, causing unpredictability and potential issues in transitioning to a low power or disabled state.
Innovation Solution
A discharge circuit is introduced, which includes a discharge control circuit coupled with a transistor and a rectifying device, enabling the capacitor to be discharged efficiently by controlling the LS transistor, reducing the time the load is in an unknown power state and ensuring predictable discharge times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the power supply system is disabled to transition the load to a low power state, then power consumption is reduced, but the capacitor remains charged causing the load to stay in an unexpected power state
Solution Approach 1:
The discharge circuit is activated in advance when the power supply system is disabled, proactively discharging the capacitor before the load can enter an unexpected power state. This preliminary action ensures the capacitor is fully discharged within a predetermined time, making the power state transition predictable and reliable.
Solution Approach 2:
A dedicated discharge circuit is introduced as an intermediary component between the power supply system and the capacitor. This discharge circuit includes a discharge control circuit and a switch device that mediates the discharge process, controlling the capacitor discharge independently from the main power supply system to ensure predictable power state transitions.
2Device complexity
If the capacitor is discharged naturally without a discharge circuit, then device complexity is reduced, but the discharge time becomes uncontrolled and unpredictable
Solution Approach 1:
A discharge control circuit acts as an intermediary between the power supply system and the discharge switch, providing controlled activation of the discharge path. The control circuit receives signals from the power supply system and activates the switch device at the appropriate moment, ensuring the capacitor discharges within a predetermined time without requiring complex continuous control mechanisms.
Solution Approach 2:
The discharge circuit is designed to activate automatically when the power supply system is disabled, using the existing system signals to trigger the discharge process. The circuit self-regulates the discharge timing based on the power supply state, eliminating the need for external control mechanisms while maintaining predictable discharge timing.
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 discharge circuit speeds up the discharge of the capacitor, reducing the time the load is in an unknown power state and ensuring more predictable discharge times, thereby reducing unpredictability during the transition to a low power or disabled state.
Implementation Method 1
A rectifying device is coupled between the resistor and the second transistor
Data Source
AI summary
A circuit includes a first transistor coupled between a discharge terminal and a ground terminal. The first transistor has a first control terminal. A resistor is coupled between a power terminal and the first control terminal. A second transistor has a second control terminal coupled to the discharge terminal. A rectifying device is coupled between the resistor and the second transistor.