Voltage Regulator Circuit for Supply Glitch Tolerance
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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 and limits discharge of bypass capacitance, ensuring the regulated voltage remains above a minimum level during glitches, using a feedback circuit and current generators to adjust the voltage based on a reference level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional voltage regulator design 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 pre-charges bypass capacitance to a voltage higher than the normal regulated voltage before a glitch occurs. This preliminary action ensures that when a power supply glitch happens, the pre-charged capacitance can immediately supply current to maintain the regulated voltage above the minimum level, preventing brownout resets without requiring complex real-time response mechanisms
Solution Approach 2:
The patent uses pre-charged bypass capacitance as an energy buffer or cushion that is prepared in advance. This cushion absorbs the voltage drop during glitches by discharging its stored energy to maintain the regulated output voltage, protecting the load from voltage sags without adding complex active compensation circuits
2Reliability
If larger bypass capacitance is used to maintain voltage during glitches, then glitch tolerance improves, but the regulator requires large external capacitance increasing device size and cost
Solution Approach 1:
The patent changes the voltage parameter of the bypass capacitance by charging it to a voltage higher than the normal regulated voltage. This parameter change allows a smaller capacitance value to provide the same energy buffer during glitches, reducing the quantity of external capacitance required while maintaining or improving glitch tolerance
3Speed
If faster switching of large currents is implemented, then power delivery improves, but parasitic inductance causes ringing and voltage glitches
Solution Approach 1:
The patent converts the harmful effect of parasitic inductance and ringing into a benefit by using the resulting voltage variation to trigger pre-charging of the bypass capacitance. The ringing that would normally cause glitches is instead used as a signal to prepare the energy buffer, which then protects against actual supply glitches, turning a harmful phenomenon into a useful triggering mechanism
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 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 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
Implementation Method 3
maintaining the output voltage on the regulated voltage node above a predetermined voltage level during a glitch of a power supply voltage
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.