Regulator Circuit Overcurrent Protection Buffer Stage
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Solution Overview
Problem
Conventional regulator circuits face challenges in accurately controlling overcurrent, especially when power voltage varies due to signal superimposition in Power Line Communication (PLC), and they often require high-voltage resistance elements, which increase circuit size and complexity.
Innovation Solution
A regulator circuit configuration that includes a buffer stage between the operational amplifier and output transistor, with an overcurrent controlling circuit using a current mirror to detect and manage overcurrent without high-voltage resistance elements, ensuring accurate overcurrent control and stability across varying power voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-voltage resistance elements are used in the overcurrent controlling circuit to ensure accurate overcurrent control, then overcurrent protection reliability is improved, but circuit area and device complexity increase
Solution Approach 1:
The patent introduces a buffer stage as an intermediary component between the operational amplifier and the output transistor. This buffer stage includes transistors that isolate the overcurrent controlling circuit from high-voltage nodes, allowing standard low-voltage transistors to be used instead of high-voltage resistance elements. The buffer stage mediates the control signal transmission while protecting the overcurrent controlling circuit from high-voltage stress, thus achieving accurate overcurrent control without requiring high-voltage resistance elements.
Solution Approach 2:
The patent employs a current mirror circuit to copy the output current and feed it to the overcurrent detecting transistor. This allows the overcurrent control function to be implemented using standard transistors operating at lower voltages, eliminating the need for high-voltage resistance elements. The current mirror creates a replicated version of the main power transistor's current, enabling accurate overcurrent detection with conventional components.
2Reliability
If high-voltage resistance elements are used in the overcurrent controlling circuit, then overcurrent protection reliability is improved, but circuit area increases
Solution Approach 1:
The buffer stage acts as an intermediary that shields the overcurrent controlling circuit from high-voltage nodes. By placing the buffer stage between the operational amplifier and the output transistor, the patent enables the use of compact standard transistors instead of large high-voltage resistance elements, significantly reducing the overall circuit area while maintaining overcurrent protection reliability.
Solution Approach 2:
The current mirror circuit copies the output current to the overcurrent detecting transistor, enabling overcurrent detection using standard-sized transistors. This copying mechanism allows the overcurrent controlling circuit to be implemented with compact components rather than requiring large high-voltage resistance elements, thereby reducing circuit area.
3Adaptability or versatility
If power voltage varies due to signal superimposition in PLC, then adaptability to different operating conditions is improved, but overcurrent control accuracy deteriorates
Solution Approach 1:
The buffer stage serves as an intermediary that stabilizes the control signal transmission even when power voltage varies due to PLC signal superimposition. By isolating the overcurrent controlling circuit from high-voltage fluctuations, the buffer stage ensures that the overcurrent detection and control functions maintain high accuracy across different operating conditions, including varying power voltages.
Solution Approach 2:
The patent implements a feedback mechanism where the overcurrent detecting transistor monitors the output current and feeds back control signals to the operational amplifier through the buffer stage. This feedback loop continuously adjusts the output transistor's operation to maintain accurate overcurrent control, even when power voltage varies due to external signal superimposition in PLC environments.
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 proposed solution effectively protects the regulator circuit from overcurrent by accurately controlling output voltage, maintaining stability and reducing circuit area, even under conditions of varying power voltage, thus enhancing operational reliability and efficiency.
Implementation Method 1
The operational amplifier compares a reference voltage generated by a reference voltage generating circuit and a feedback voltage feeding back an output voltage of the output terminal
Implementation Method 2
The protection circuit of the patent literature 1 folds back a sense current by a current mirror circuit and compares the sense current and a reference current
Implementation Method 3
The regulator circuit includes a buffer stage between the operational amplifier and the output transistor
Data Source
AI summary
A buffer stage includes a first transistor having a control terminal connected to an output terminal of an operational amplifier and a second transistor connected in series to a main energization path of the first transistor. An overcurrent controlling circuit is configured to apply an output voltage of the operational amplifier to the control terminal of the first transistor and allow a normal operation of the first transistor when an energization current of a main energization path of an output transistor detected by an overcurrent detection transistor is less than a predetermined value, and is configured to control the output voltage of the operational amplifier to a predetermined control voltage according to a current flowing in a main energization path of the overcurrent detection transistor when the energization current of the main energization path of the output transistor is equal to or greater than the predetermined value.