Current Control Circuit with Transistor Array for Precision Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current current sensing and control circuits in switch-mode power converters and linear regulators face challenges in accurately measuring input current, leading to sensing errors that can affect voltage regulation and overcurrent protection.
Innovation Solution
A current control circuit utilizing an array of control transistors, including a reference transistor and a controller, adjusts the load current by selecting transistors to achieve a target current level with reduced error, where the transistors operate in their linear regions and are configured to provide resistive behavior, allowing for precise control of the load current relative to a reference current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional current sensing circuits are used in switch-mode power converters, then the circuit structure is simple, but the measurement precision of input current deteriorates due to sensing errors
Solution Approach 1:
The current control circuit is segmented into multiple functional blocks: an array of control transistors for current adjustment, a reference transistor for comparison, a current source for reference current generation, and a controller for selection and coordination. This segmentation allows each component to perform its specific function with high precision while maintaining overall system manageability despite increased complexity.
2Reliability
If the measurement accuracy depends on input current level, then the circuit operation is simple, but the reliability of current indication deteriorates across different current levels
Solution Approach 1:
The controller dynamically changes the configuration parameters of the transistor array by selecting different combinations of control transistors based on the target current level. This parameter adjustment ensures that the ratio between reference current and load current remains accurate across the full range of operating conditions, maintaining reliability regardless of input current level.
Solution Approach 2:
The current control circuit employs dynamic selection of control transistors based on real-time current level requirements. The controller activates specific transistors from the array to match the desired current ratio, enabling the circuit to adapt its configuration dynamically rather than relying on a fixed structure, thereby maintaining accuracy across varying operating conditions.
3Measurement precision
If a single control transistor is used for current control, then the device complexity is low, but the measurement precision and current control accuracy deteriorate
Solution Approach 1:
Instead of using a single control transistor, the invention segments the control function across multiple transistors arranged in an array. Each transistor can be independently controlled to contribute to the total load current, allowing for finer granularity in current adjustment and higher precision control while distributing the complexity across multiple identical components.
Solution Approach 2:
Multiple control transistors are merged in parallel to form a composite current control element. The combined effect of selected transistors provides the desired load current with higher accuracy than a single transistor could achieve alone, while the controller intelligently selects which transistors to activate based on the target current level.
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
This solution enables accurate and precise control of the load current, reducing sensing errors and maintaining accuracy regardless of the input current level, thereby enhancing voltage regulation and overcurrent protection in electronic devices.
Implementation Method 1
The transistors operate in their linear regions and are configured to provide resistive behavior, allowing for precise control of the load current
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present document relates to current conveyers. In particular, the present document relates to a current sensing and/or control circuit with reduced sensing errors. A current control circuit (301) for controlling a load current (136) into an electronic device (103) is described. The current control circuit (301) comprises an array of control transistors (311-1, ..., 311-n) configured to adjust the load current (136) provided at an output of the array of control transistors (311-1, ..., 311-n). The load current (136) is drawn from a power supply at an input voltage (131). Furthermore, the power supply is coupled to an input of the array of control transistors (311-1, ..., 311-n). The circuit (301) further comprises a reference transistor (110) coupled to the power supply at an input of the reference transistor (110) and a reference current source (112) configured to draw a reference current (137) at an output of the reference transistor (110). In addition, the circuit (301) comprises a controller (340) configured to select one or more control transistors from the array of control transistors (311-1, ..., 311-n), and transistor control units (120, 321-1, ..., 321-n) configured to control the reference transistor (110) to provide a reference on-resistance and to control the selected one or more control transistors to provide an array on-resistance. The controller (340) is configured to select the one or more control transistors such that a ratio of a target level of the load current (136) and the reference current (137) corresponds to a ratio of the reference on-resistance and the array on-resistance.