Reconfigurable Series-Shunt LDO for PSRR and Reverse Isolation
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Solution Overview
Problem
Conventional low-dropout regulators (LDOs) face a trade-off between achieving high power-supply rejection ratio (PSRR) and good reverse isolation, often sacrificing one performance for the other, and may consume excessive power.
Innovation Solution
The design incorporates a core circuitry with high PSRR and a reverse isolation circuitry that is configurable and reconfigurable to adjust current flow in response to output node ripples, allowing for simultaneous high PSRR and good reverse isolation, with the reverse isolation circuitry operating at a higher bandwidth than the core circuitry to effectively mitigate noise and ripple-induced currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reverse isolation circuitry is added to improve reverse isolation, then reverse isolation is improved, but power consumption increases
Solution Approach 1:
The reverse isolation circuitry employs dynamic current adjustment where the current flowing through the reverse isolation circuitry is configurable and reconfigurable based on operating conditions. This allows the circuit to provide adequate reverse isolation only when needed, reducing unnecessary power consumption during normal operation
Solution Approach 2:
The current parameter of the reverse isolation circuitry is made adjustable through reconfiguration capabilities. By changing the current parameter dynamically based on ripple conditions and power requirements, the system achieves good reverse isolation performance while minimizing power consumption
2Reliability
If reverse isolation circuitry responds faster to ripples, then reverse isolation is improved, but bandwidth requirements increase
Solution Approach 1:
The reverse isolation circuitry is designed with higher bandwidth specifically at the output node where ripples occur, while the core circuitry maintains its original bandwidth characteristics. This localized bandwidth enhancement provides fast response to ripples for improved reverse isolation without requiring the entire LDO system to operate at higher bandwidth
Data Source
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AI summary
A low-dropout regulator (LDO) capable of providing high power-supply rejection ratio (PSRR) and good reverse isolation. The LDO may include a core circuitry and a reverse isolation circuitry. The core circuitry may include a PSRR circuitry coupled to an output node and configured to provide high PSRR at the output node. The reverse isolation circuitry may be configured to provide good reverse isolation at the output node by, for example, providing current in response to ripples at the output node. The reverse isolation circuitry may be configured with bandwidth higher than that of the core circuitry such that it can provide fast transient response. The reverse isolation circuitry may be configurable and/or reconfigurable for a desirable reverse isolation performance. The reverse isolation circuitry may be configurable and/or reconfigurable to trade off between power consumed by the reverse isolation circuitry and a leakage current flowing through the core circuitry.