Current-Feedback Power Supply Circuit for Low-Voltage Differential Drivers
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Solution Overview
Problem
Conventional voltage feedback type LDO regulators require multiple stages between the power supply and ground, limiting the reduction of power supply voltage and making it difficult to achieve low power consumption for high-speed interface differential drivers.
Innovation Solution
A power supply circuit with a current feedback unit comprising two p-type MOS transistors and a control element, which configures a current turnback circuit, allowing the output voltage to be determined by the product of the resistance value of a first resistor and the reference current, thereby reducing the power supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a voltage feedback type LDO regulator is used, then the regulator can provide stable voltage output, but the power supply voltage cannot be reduced due to multiple transistor stages required
Solution Approach 1:
The patent employs current feedback mechanism where a portion of the output current is fed back to the input through a feedback resistor network. This current feedback approach replaces the traditional voltage feedback with multiple transistor stages, enabling the regulator to maintain stable output voltage while reducing the number of voltage stages to just one p-type MOS transistor, thereby lowering the power supply voltage requirement
Solution Approach 2:
The patent changes the feedback parameter from voltage to current. By using current feedback instead of voltage feedback, the regulator architecture is fundamentally altered to use a single p-type MOS transistor with current sensing and feedback, which reduces the voltage headroom requirement while maintaining regulation stability through current-based control
2Reliability
If multiple transistor stages are used in the LDO regulator, then voltage regulation can be achieved, but the device complexity increases and power consumption rises
Solution Approach 1:
The patent extracts and eliminates the unnecessary multiple voltage regulation stages from the traditional LDO architecture. By taking out the redundant transistor stages and replacing them with a streamlined current feedback mechanism using a single p-type MOS transistor, the design achieves voltage regulation with reduced device complexity
Solution Approach 2:
The patent substitutes the mechanical voltage-stage-based regulation mechanism with an electrical current feedback mechanism. Instead of using multiple voltage stages (mechanical approach), the system uses current sensing and feedback through resistors and a single transistor (electrical approach), simplifying the overall device structure
Data Source
AI summary
Provided are a power supply circuit and a transmitting device that can achieve lowering of power supply voltage. Provided is a power supply circuit including a current feedback unit, in which the current feedback unit has two p-type MOS transistors, a control element, and a first resistor, the two p-type MOS transistors and the control element configure a current turnback circuit that turns back the current, current substantially the same as the reference current in the circuit flows through the control element and the first resistor, and the output voltage is determined at least depending on the first resistor and the reference current.