Voltage-Glitch Reset Latch for Secure Memory Protection
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Solution Overview
Problem
Existing secure chips are vulnerable to side channel voltage-glitch attacks due to the slow response of conventional reset circuits, which fail to detect rapid voltage glitches, and are unreliable under extreme voltage changes, compromising the detection of side channel voltage-glitch attacks.
Innovation Solution
A voltage-glitch detection and protection circuit that includes a voltage-glitch detector coupled with a latch and a system-reset block, generating a system-reset signal to reset on-chip circuits when a voltage glitch is detected, using a voltage-glitch-isolated latch and sample and hold circuit to ensure reliable detection and protection against voltage glitches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional reset circuits are used, then the circuit complexity is low, but the response speed is slow and cannot detect rapid voltage glitches
Solution Approach 1:
The reset circuit is divided into multiple specialized detection blocks: a voltage-glitch detection block for rapid glitch detection, a brown-out detection block for sustained low-voltage conditions, and a reset control block for coordinated response. Each block is optimized for its specific function, enabling fast response to voltage glitches while maintaining manageable overall complexity through functional segmentation.
Solution Approach 2:
The voltage-glitch detection block uses a latch circuit that is pre-configured to immediately capture and hold voltage-glitch detection pulses when glitches occur. This preliminary action ensures that even extremely rapid glitches are captured before the system can respond, enabling detection speeds that exceed conventional circuit response times.
2Reliability
If conventional detection circuits are used, then the device reliability is high under normal conditions, but the detection reliability fails under extreme voltage changes
Solution Approach 1:
The detection circuit incorporates protection mechanisms that are activated before extreme voltage conditions can cause failure. The latch circuit is designed to capture glitch signals even when supply voltage drops rapidly, and the reset control block coordinates responses to ensure detection reliability is maintained throughout the voltage transient, cushioning against the harmful effects of extreme voltage changes.
Solution Approach 2:
The reset control block serves as an intermediary that receives inputs from both the voltage-glitch detection block and the brown-out detection block, coordinates their responses, and generates the final reset signal. This intermediary function ensures that detection reliability is maintained by properly integrating signals from multiple detection pathways and generating appropriate reset responses even under extreme voltage conditions.
3Measurement precision
If the detection threshold is set to detect rapid glitches, then the measurement precision for voltage glitches improves, but false detection of normal voltage variations increases
Solution Approach 1:
The detection system employs different detection thresholds and response characteristics for different detection blocks. The voltage-glitch detection block uses a latch-based mechanism with optimized timing to detect only extremely rapid voltage changes, while the brown-out detection block uses different parameters for sustained low-voltage detection. This local differentiation of detection characteristics enables precise glitch detection without false triggering from normal voltage variations.
Solution Approach 2:
The detection system dynamically adapts its response based on the characteristics of the detected voltage event. The latch circuit responds immediately to rapid voltage-glitch detection pulses with a fixed-duration output pulse, while the brown-out detection block responds to sustained low-voltage conditions with a different timing characteristic. The reset control block coordinates these dynamic responses to generate appropriate reset signals while avoiding false detection of normal voltage variations.
Data Source
AI summary
A voltage-glitch detection and protection circuit and method are provided. Generally, circuit includes a voltage-glitch-detection-block (GDB) and a system-reset-block coupled to the GDB to generate a reset-signal to cause devices in a chip including the circuit to be reset when a voltage-glitch in a supply voltage (VDD) is detected. The GDB includes a voltage-glitch-detector coupled to a latch. The voltage-glitch-detector detects the voltage-glitch and generates a PULSE to the system-reset-block and latch. The latch receives the PULSE and generates a PULSE_LATCHED signal to the system-reset-block to ensure the reset-signal is generated no matter a width of the PULSE. In one embodiment, the latch includes a filter and a sample and hold circuit to power the latch, and ensure the PULSE_LATCHED signal is coupled to the system-reset-block when a voltage to the GDB or to the latch drops below a minimum voltage due to the voltage-glitch.