Digital LDO Regulator Transient Response via Push-Pull Logic
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LDO regulators face challenges in rapidly responding to peak load current variations and managing supply voltages efficiently for core processor systems, with limitations in generating different voltage levels and high power efficiency, especially when used in conjunction with switching regulators.
Innovation Solution
A digital LDO regulator employing a push-pull scheme and calibration circuit to rapidly respond to peak load current variations and adjust recovery speed, featuring a reference voltage comparison circuit, push-pull logic circuit, transient load voltage comparison circuit, transient current switching circuit, current mirroring circuit, and a capacitor for improved transient characteristics and load current management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional analog LDO regulator is used, then the supply voltage can be regulated, but the response speed to load current variations is slow and the area occupied is large
Solution Approach 1:
The patent replaces the analog amplifier-based voltage regulation system with a digital control system comprising a comparator, shift register, and switching elements. This substitution eliminates the need for large analog components while achieving faster response speeds through digital logic operations and programmable control sequences.
Solution Approach 2:
The voltage regulation process is divided into discrete digital control steps using a shift register that sequences switching operations. The load current supply is segmented into multiple switching elements controlled individually, enabling precise and rapid response to load variations without requiring large analog components.
2Area of stationary object
If a digital LDO regulator without amplifier is used, then the area is reduced, but the output voltage reaches target voltage over multiple steps causing slow recovery
Solution Approach 1:
The patent stores control signals in advance within a shift register, enabling the regulator to execute pre-planned switching sequences rapidly when load changes occur. This preliminary preparation of control signals allows the output voltage to reach the target voltage faster without requiring an amplifier, resolving the contradiction between reduced area and improved recovery speed.
3Speed
If a high-current transistor is used for transient control, then the response to load current variation is fast, but the switching time delay increases
Solution Approach 1:
The patent divides the high-current supply into multiple parallel switching elements instead of using a single high-current transistor. This segmentation allows simultaneous switching of multiple smaller transistors, achieving the same transient current capability while reducing individual switching delays and enabling more precise control of the transient response.
Data Source
AI summary
A digital LDO regulator includes a first comparison circuit to compare an output voltage with a reference voltage and to output a reference load switching signal when the output voltage rises above the reference voltage, a logic circuit to output a control current in response to the reference load switching signal, a second comparison circuit to compare the output voltage with a transient reference voltage and to output a transient load switching signal when the output voltage rises above the transient reference voltage, a switching circuit to control the logic circuit to pass a transient current in response to the transient load switching signal, a circuit to provide a mirroring current to the logic circuit after a transient state, a load current supply circuit to switch in response to the control current and to supply a load current, and a capacitor coupled to the load current supply circuit.