LDO Output Noise Filter for Chip Area Reduction
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Solution Overview
Problem
Conventional voltage regulators face challenges in maintaining ultra-low output noise while managing multiple output voltages efficiently, especially in systems on chip, where the use of reference amplifiers and filters consumes significant chip area and introduces noise.
Innovation Solution
The proposed linear regulator incorporates an output noise filter and voltage divider with a shared control voltage source, utilizing on-chip components like capacitors and resistive devices to suppress noise and reduce chip area, allowing for multiple output possibilities with individual DC level settings and low quiescent current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If reference amplifiers and filters are used to achieve ultra-low output noise, then output noise is reduced, but chip area consumption increases significantly
Solution Approach 1:
The patent combines the reference amplifier and output noise filter into a single integrated circuit block, sharing common components such as the bandgap reference voltage source and compensation capacitors. This merging eliminates the need for separate discrete reference amplifiers and filters, achieving ultra-low output noise performance while significantly reducing chip area consumption through component sharing and integration.
2Adaptability or versatility
If multiple output voltages are supported with individual regulation, then versatility is improved, but device complexity increases
Solution Approach 1:
The patent implements a universal reference amplifier circuit that can serve multiple output voltage regulations simultaneously. The single reference amplifier with shared bandgap reference and compensation network can regulate multiple output voltages by switching different feedback dividers, eliminating the need for separate reference amplifiers for each output. This multi-functional design reduces circuit complexity while maintaining the capability to support multiple output voltages.
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 configuration achieves ultra-low output noise with reduced chip area consumption, effectively managing noise and power supply stability across multiple outputs, enhancing the performance of power management units.
Implementation Method 1
an output noise filter arranged to provide a filtered output signal by filtering the feedback signal such that noise associated with the voltage divider is filtered out
Data Source
AI summary
A low-drop out (LDO) regulator is provided. In one embodiment, the LDO regulator includes an error amplifier, a pass transistor, a reference voltage circuit, an output noise filter, and a voltage divider. The voltage divider provides a feedback voltage based on the output voltage. Further, the feedback voltage is provided at a feedback node. The output of the error amplifier is coupled to the pass transistor. The reference voltage circuit is coupled to a first input of the error amplifier. The output noise filter is coupled between the feedback node and the second input of the error amplifier.