DC Load Interconnection Circuit With Quiescent Current Switching
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Solution Overview
Problem
Existing connection circuits in vehicles fail to efficiently manage low quiescent current supply to electrical energy consumers while ensuring safety against fault conditions such as overcurrent and short circuits, without significant energy consumption.
Innovation Solution
A connection circuit with switching transistors and diodes that detect increased current demand, switching to direct DC voltage supply and bypassing control circuits to prevent overload, while incorporating a safety circuit to monitor and interrupt connections if critical conditions are detected.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the connecting switch control circuit continuously monitors current to detect fault conditions, then safety against overcurrent and short circuits is improved, but energy consumption increases
Solution Approach 1:
The patent implements periodic current monitoring through the switching transistor that only activates during specific operational phases rather than continuous monitoring. The control circuit periodically checks current levels by activating the switching transistor in response to voltage changes at the collector terminal, thereby maintaining fault detection capability while minimizing energy consumption during normal operation.
Solution Approach 2:
The circuit uses the existing voltage fluctuations and current flow during normal operation to trigger monitoring actions. When the voltage at the collector terminal exceeds the threshold, the circuit automatically activates the switching transistor to check for fault conditions, utilizing the system's own operational characteristics to perform safety checks without requiring dedicated continuous monitoring power.
2Reliability
If the connecting switch control circuit supplies sufficient current to reliably detect fault conditions, then detection reliability is improved, but the control circuit becomes overloaded and energy consumption increases
Solution Approach 1:
The switching transistor serves as an intermediary element between the control circuit and the load. It amplifies the control signal from the base terminal to the collector terminal, allowing the control circuit to detect fault conditions through voltage changes at the collector terminal without requiring the control circuit itself to supply high current directly to the load.
Solution Approach 2:
The patent replaces direct mechanical current measurement with an electrical field-based detection method. Instead of physically measuring current flow through the control circuit, the system detects voltage changes at the collector terminal of the switching transistor, which indirectly indicate current conditions, thereby avoiding direct current exposure and potential overload of the control circuit.
3Reliability
If the connecting switch remains open to protect the control circuit from overload, then control circuit safety is improved, but the electrical energy consumer cannot receive sufficient power
Solution Approach 1:
The circuit is segmented into two distinct current paths: a control path through the switching transistor for fault detection, and a power path through the connecting switch for delivering power to the load. This segmentation allows the control circuit to monitor conditions without being exposed to high currents, while the connecting switch can independently handle the full power delivery to the electrical energy consumer.
Solution Approach 2:
The switching transistor acts as an intermediary control element that regulates the state of the connecting switch based on detected fault conditions. It translates small control signals into actions that control the main power flow through the connecting switch, allowing the control circuit to safely manage high-power operations without direct exposure to overload conditions.
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 efficiently supplies quiescent current to consumers with minimal energy consumption and promptly responds to increased demand or fault conditions, preventing overload and ensuring system safety.
Implementation Method 1
a base-emitter voltage of the switching transistor depends on the current supplied to the respective associated consumer of electrical energy via the connecting switch control circuit
Implementation Method 2
The voltage drop across a diode generally depends on the current flowing through it in the forward direction. As the forward current increases, the voltage drop across the diode also increases.
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A connecting circuit for connecting a plurality of electrical energy consumers (V1, V2, V3) to a DC voltage source (12) comprises, for each electrical energy consumer (V1, V2, V3) of a plurality of electrical energy consumers (V1, V2, V3), a connecting switch (14, 16, 18) for establishing a connection of the electrical energy consumer (V1, V2, V3) to a DC voltage source (12), and for each electrical energy consumer (V1, V2, V3) of the plurality of electrical energy consumers (V1, V2, V3), a connecting switch control circuit (24, 26, 28) for supplying current to the respective electrical energy consumer (V1, V2, V3) and for controlling the connecting switch (14, 16, 18) assigned to the respective electrical energy consumer (V1, V2, V3) to establish the connection. of the respective consumer (V1, V2, V3) electrical energy with the DC voltage source (24,26, 28), wherein the connecting switch control circuit comprises a switching transistor (32), wherein a base-emitter voltage of the switching transistor (32) depends on the current supplied to the respective associated consumer of electrical energy via the connecting switch control circuit (24, 26, 28), and wherein, when the base-emitter voltage exceeds a threshold voltage, a switching signal is generated at a collector terminal (46) of the switching transistor (32) to switch the respective associated connecting switch (14, 16, 18) into a closed state, thereby establishing a connection between the respective associated consumer (V1, V2, V3) of electrical energy and the DC voltage source (12).