Voltage Regulator Diode Isolation for Supply Glitch Tolerance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Voltage regulators fail to maintain a constant voltage level during power supply glitches, leading to brownout resets and corruption of digital circuit states due to parasitic inductance causing ringing and voltage drops.
Innovation Solution
A supply-glitch-tolerant voltage regulator is designed with a diode and resistor configuration that prevents reverse current flow from bypass capacitance, ensuring the regulated voltage remains above a minimum level during glitches, using a diode to block reverse current and a limiting resistor to manage compensation capacitor discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional voltage regulator is used, then the circuit is simple and current consumption is low, but the regulated voltage drops during power supply glitches causing brownout resets
Solution Approach 1:
The patent introduces a diode as an intermediary component between the bypass capacitance and the regulated output. This diode acts as a one-way valve that allows current to charge the bypass capacitance during normal operation but blocks reverse current flow during power supply glitches, preventing the regulated voltage from dropping below the minimum level and avoiding brownout resets.
Solution Approach 2:
The patent pre-charges the bypass capacitance during normal operation so that when a power supply glitch occurs, the stored energy in the capacitance can immediately support the regulated output voltage. This preliminary energy storage action ensures the voltage remains above the minimum threshold during the glitch duration without requiring complex active control circuits.
2Reliability
If large external capacitance is used to maintain voltage during glitches, then voltage stability improves, but the device size and cost increase
Solution Approach 1:
The diode serves as a protective intermediary that enables a small bypass capacitance to effectively protect against glitches. By blocking reverse current discharge, the diode allows the capacitance to maintain voltage unidirectionally, achieving glitch protection with minimal capacitance value and avoiding the need for large external capacitors.
Solution Approach 2:
The patent changes the operational parameters of the bypass capacitance by introducing the diode, transforming it from a bidirectional energy storage element to a unidirectional voltage support element. This parameter change allows the use of smaller capacitance values while maintaining voltage stability during glitches, as the diode prevents the capacitance from discharging during supply disturbances.
3Speed
If fast switching of large currents is performed, then power delivery speed improves, but parasitic inductance causes ringing and voltage glitches
Solution Approach 1:
The diode acts as a protective intermediary that isolates the regulated output from the harmful effects of parasitic inductance during fast switching. By blocking reverse current flow that would otherwise cause voltage drops and ringing, the diode allows aggressive fast switching of large currents while maintaining voltage stability and preventing glitches at the output.
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
The solution effectively maintains the regulated voltage above a specified minimum level during power supply glitches, preventing resets and ensuring seamless operation of analog and digital circuits without increasing current consumption or requiring large external capacitance.
Implementation Method 1
A diode is coupled between the drain terminal and the first power supply node
Implementation Method 2
a resistor coupled between the gate terminal and the first node
Data Source
AI summary
A supply-glitch-tolerant voltage regulator includes a regulated voltage node and an output transistor having a source terminal, a gate terminal, and a drain terminal. The source terminal is coupled to the regulated voltage node. The supply-glitch-tolerant voltage regulator includes a first current generator coupled between a first node and a first power supply node. The supply-glitch-tolerant voltage regulator includes a second current generator coupled between the first node and a second power supply node. The supply-glitch-tolerant voltage regulator includes a feedback circuit coupled to the first current generator and the second current generator and is configured to adjust a voltage on the first node based on a reference voltage and a voltage level on the regulated voltage node. The supply-glitch-tolerant voltage regulator includes a diode coupled between the drain terminal and the first power supply node and a resistor coupled between the gate terminal and the first node.