Linear Regulator Ripple Rejection via Dual Voltage Reference Switching
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Solution Overview
Problem
Conventional linear regulators do not provide sufficient rejection of ripple voltage, which can affect circuit operation and require additional efforts to control the remaining ripple in the power supply output.
Innovation Solution
A modified linear regulator design that includes a first and second voltage reference generator and a reference and power switcher, which switches the voltage reference from the initial power supply to the regulator output after startup, improving the power supply ripple rejection ratio (PSRR) by using the generated output with reduced ripple voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional linear regulator is used, then the circuit structure is simple, but the power supply ripple rejection ratio (PSRR) is insufficient
Solution Approach 1:
The voltage reference generation function is segmented into two separate generators: a first voltage reference generator connected to the input power supply and a second voltage reference generator connected to the regulated output. This segmentation allows each reference generator to operate from a different power source, enabling the regulator to reject input power supply ripple while maintaining a stable reference voltage throughout operation.
Solution Approach 2:
The patent implements dynamic switching between the first and second voltage reference generators based on operating conditions. A switch controller dynamically selects which reference generator to use, allowing the regulator to adapt to different power supply conditions and load requirements, thereby improving PSRR across a wide frequency range while maintaining circuit simplicity through automated control.
2Reliability
If the voltage reference is switched from the initial power supply to the regulator output, then the ripple rejection is improved, but the switching control complexity increases
Solution Approach 1:
The first voltage reference generator is prepared and ready to provide reference voltage during the startup phase before the regulator output is stable. The switch controller is pre-configured to automatically select the first reference generator during startup and transition to the second reference generator once the output stabilizes, eliminating the need for complex manual switching control and reducing switching complexity.
Solution Approach 2:
The switch controller monitors the stability of the regulated output voltage and uses this feedback to determine when to switch from the first voltage reference generator to the second. This feedback mechanism automates the switching decision process, simplifying the control logic while ensuring optimal PSRR performance throughout the regulator's operation.
Data Source
AI summary
Embodiments of the invention are generally directed to a linear regulator with improved power supply ripple rejection. An embodiment of an apparatus includes an linear regulator to receive a system power supply and to generate a regulated power supply; a first voltage reference generator to generate a first voltage reference for the linear regulator; a second voltage reference generator to generate a second voltage reference for the linear regulator; and a voltage reference and power switcher. In some embodiments, the voltage reference and power switcher is to switch a voltage reference for the linear regulator from the first voltage reference to the second voltage reference and is to switch a part of a power supply for the linear regulator from the system power supply to the regulated power supply.