Voltage Regulator Noise Replica Buffer for High-Frequency PSRR
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Solution Overview
Problem
Existing voltage regulators struggle to achieve a high power supply rejection ratio (PSRR) characteristic, especially in high-frequency power supply scenarios, while maintaining a simple structure and efficient operation.
Innovation Solution
The proposed voltage regulator incorporates a power noise replica buffer unit that generates a bias signal including a high-frequency component of the power supply voltage, which is then used to improve the PSRR characteristic through a comparison unit and pass transistor configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex power noise replica buffer unit is added to improve PSRR characteristic, then the power supply rejection ratio is improved, but the device complexity increases
Solution Approach 1:
The patent uses a power noise replica buffer unit that creates a copy of the power supply noise signal. This copied noise signal is then subtracted from the output voltage to cancel out the harmful power supply ripple, thereby improving PSRR without requiring complete redesign of the regulator architecture
Solution Approach 2:
The patent introduces an intermediary buffer unit that processes the power supply noise signal separately and then combines it with the main output. This intermediary approach allows noise cancellation without directly modifying the core voltage regulation path, maintaining structural simplicity while achieving high PSRR
2Reliability
If high-frequency noise filtering is implemented to improve PSRR at high frequencies, then the power supply rejection ratio is improved, but the device complexity and component count increase
Solution Approach 1:
The patent changes the frequency response parameters of the buffer unit to specifically target high-frequency noise components. By adjusting the buffer's gain and frequency characteristics, the system achieves high-frequency noise cancellation without adding complex filtering stages or multiple components
3Reliability
If additional buffer units and transistors are added to improve noise cancellation, then the power supply rejection ratio is improved, but the manufacturing cost and device area increase
Solution Approach 1:
The patent merges the power noise replica buffer unit with the existing feedback control loop of the voltage regulator. By combining these functions into a unified structure, the patent achieves effective noise cancellation without requiring separate discrete components, thereby reducing manufacturing complexity and device area
Data Source
AI summary
A voltage regulator configured to generate an output voltage includes a comparison unit configured to generate a second voltage based on a reference voltage and a first voltage generated by a feedback of the output voltage, a power noise replica buffer unit configured to generate a third voltage including a power noise copied based on the second voltage, and a pass transistor configured to generate the output voltage in response to the third voltage.