Opportunity
Current control circuits are essential for regulating electric current between a power source and an external circuit, ensuring high dynamic response, low noise, and energy efficiency. However, existing solutions face significant limitations. Linear-type series-pass devices, such as bipolar junction transistors (BJTs), offer fast dynamic response and low output ripple but suffer from low energy efficiency and unidirectional power flow. Conversely, switched-mode power supplies (SMPS) provide high efficiency and bidirectional operation but introduce slow dynamic response, large output ripple, and high switching noise, often requiring bulky output filters. These trade-offs create a gap in the market for a current control apparatus that combines the best of both worlds: the precision and speed of linear devices with the efficiency and flexibility of SMPS. This patent addresses this unmet need by proposing a hybrid solution that integrates both technologies to optimize performance.
Technology
The patent introduces a hybrid current control apparatus comprising two key loops: a current control loop and a voltage control loop. The current control loop uses a linear-type series-pass device (e.g., a BJT) to precisely regulate the current flow between a load (e.g., a battery or resistor) and an external circuit. The voltage control loop employs a switched-mode voltage converter (e.g., a buck converter) to minimize the voltage across the series-pass device, thereby reducing power dissipation.
The innovation lies in the synergistic operation of these loops. The current control loop ensures accurate current regulation by adjusting the base current of the BJT to match a reference current value. Simultaneously, the voltage control loop dynamically adjusts the output voltage of the SMPS to keep the voltage across the BJT at a minimal level (e.g., near the saturation voltage). This dual-loop design achieves high efficiency (by minimizing power loss in the BJT) while maintaining fast response and low noise (inherited from the linear regulator). For bidirectional applications, the apparatus can integrate two BJTs in parallel and a bidirectional SMPS to enable energy flow in both directions.
Advantages
- High Efficiency: Minimizes power loss in the series-pass device by regulating voltage across it.
- Fast Dynamic Response: Leverages the linear regulator’s speed for precise current control.
- Low Noise/Ripple: Avoids the high switching noise of traditional SMPS.
- Bidirectional Operation: Supports both current sourcing and sinking when configured with bidirectional components.
- Compact Design: Eliminates the need for large output filters.
- Flexibility: Compatible with various loads (e.g., batteries, resistive components).
Applications
- Battery Management Systems: For charging/discharging with minimal energy loss.
- Renewable Energy Systems: Regulating current in solar/wind power inverters.
- Industrial Automation: Precision current control in motor drives and actuators.
- Consumer Electronics: Power supplies for devices requiring low-noise, efficient current regulation.
- Electric Vehicles: Bidirectional energy transfer in charging stations.
