Current Source for Voltage Regulator with Instant Current Adjustment
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Solution Overview
Problem
Modern voltage regulators face challenges in quickly adjusting output currents to meet large instantaneous current demands, leading to instability and malfunctions due to the limitations of complex circuit designs and parasitic resistances, especially as digital circuit densities increase.
Innovation Solution
A current source with a constant current generation module, a capacitor, and a trans-conductance amplifier, coupled with a control node and output terminal, allows for rapid adjustment of output currents by detecting instant current variations and generating corresponding voltage changes to stabilize the output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large voltage regulation capacitor is applied to support large current variations, then the voltage regulation capability is improved, but the response speed is reduced and cost increases
Solution Approach 1:
The patent segments the current supply function into two parts: the voltage regulation capacitor handles small current variations, while a separately controlled instant current source handles large current variations. This segmentation allows each component to be optimized for its specific function, achieving both good voltage regulation and fast response speed without requiring an excessively large capacitor.
Solution Approach 2:
The patent implements preliminary action by detecting output voltage variations before they become severe and proactively adjusting the instant current source accordingly. The detection circuit monitors voltage changes and triggers the current source adjustment in advance, preventing voltage instability before it occurs and enabling faster response compared to reactive correction.
2Speed
If voltage regulators without voltage regulation capacitors are designed using complex detection circuits, then the response speed is improved, but the circuit complexity and cost increase
Solution Approach 1:
The patent makes the voltage regulation capacitor serve multiple functions: it maintains output voltage stability during normal operation and simultaneously acts as a sensing element for detecting voltage variations. By removing the dedicated detection circuit and utilizing the capacitor's inherent voltage response, the design achieves fast response speed while reducing circuit complexity and component count.
Solution Approach 2:
The voltage regulation capacitor performs self-service by automatically responding to current variations through its voltage change (ΔV = ΔI × Z), which directly controls the gate voltage of the power supply transistor. This self-regulating mechanism eliminates the need for external detection circuits and complex control logic, simplifying the overall circuit design while maintaining fast response capability.
3Ease of manufacture
If NMOS is used as power supply transistor instead of PMOS, then the cost is reduced, but the tuning range of output voltage becomes smaller and response to rapid current changes deteriorates
Solution Approach 1:
The patent applies counterweight by introducing the instant current source to compensate for the NMOS transistor's limited current driving capability. When rapid current changes are detected, the instant current source provides additional current support that counteracts the NMOS's insufficient response, effectively extending the operational range and improving performance without changing the transistor type.
Solution Approach 2:
The patent applies asymmetry by using different transistor types for different functions: NMOS is used for the main power supply transistor where cost and integration are priorities, while a PMOS transistor is used for the instant current source where high current driving capability and fast response are critical. This asymmetric assignment optimizes overall system performance while maintaining cost effectiveness.
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 quick adjustment of output currents to match load requirements, preventing output voltage fluctuations and ensuring stable voltage regulation, even with increased current demands, while maintaining circuit stability and reducing redundant power consumption.
Implementation Method 1
A voltage regulation capacitor is disposed in the output terminal of the voltage regulator to assist in regulation capability of the voltage regulator. The voltage regulation capacitor is responsible for converting pre-stored charge into a driving current that can be provided to the load driven by the voltage regulator when its current requirement changes rapidly.
Implementation Method 2
a trans-conductance amplifier coupled between the control node and the output terminal, for changing a magnitude of the first output current of the output terminal when variation on the voltage of the control node is generated
Data Source
AI summary
A current source for quickly adjusting an output current includes a constant current generation module, coupled to a control node, for generating a predefined current flowing through the control node in order to determine a voltage of the control node; a capacitor, coupled to an output terminal of the current source; a current variation detection module, coupled between the control node and the capacitor, for generating a variation on the voltage of the control node via the capacitor when the output terminal of the current source receives an instant current variation; and a trans-conductance amplifier, coupled between the control node and the output terminal, for changing a magnitude of the output current of the output terminal when the variation on the voltage of the control node is generated.