Bandgap Startup Circuit Using Replica Comparator Across PVT Corners
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Solution Overview
Problem
Startup circuits for bandgap reference circuits often fail to operate consistently across various process, voltage, and temperature (PVT) conditions, leading to incorrect initialization and inefficient operation of semiconductor devices.
Innovation Solution
Incorporating a comparator circuit that is a scaled-down replica of the amplifier circuit in the bandgap circuit within the startup circuit, allowing it to mimic the operation of the bandgap circuit and ensure consistent initialization across PVT corners, with a high voltage gate signal disconnecting the voltage source once the bandgap circuit reaches a stable operational state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a startup circuit is used to initialize the bandgap reference circuit, then the bandgap circuit can ramp its output voltage to a stable value, but the startup circuit may fail to operate consistently across different process, voltage, and temperature conditions
Solution Approach 1:
The patent creates a scaled-down replica of the bandgap amplifier circuit as a comparator within the startup circuit. This replica circuit copies the essential characteristics and electrical properties of the main bandgap circuit, allowing the startup circuit to predict and adapt to the bandgap circuit's behavior under different PVT conditions. By using this copied model, the startup circuit can consistently initialize the bandgap circuit across process, voltage, and temperature variations without requiring separate calibration for each condition.
2Ease of manufacture
If different manufacturers and processes are used to produce startup circuit components, then component availability and manufacturing flexibility improve, but the electrical properties (input voltage, threshold voltage) vary导致 inconsistent operation
Solution Approach 1:
The patent designs the startup circuit with a scaled-down replica that inherently scales with process variations. When manufacturing conditions change, both the main bandgap circuit and its replica copy experience similar parameter shifts proportionally. This parameter scaling approach allows the startup circuit to maintain correct relative relationships between voltages and thresholds even when absolute values change due to different manufacturers or processes, ensuring operational consistency despite manufacturing flexibility.
Data Source
AI summary
A semiconductor device may include a bandgap circuit that outputs a reference voltage. The semiconductor device may also include a startup circuit coupled to the bandgap circuit. The startup circuit may connect a voltage source to a node that corresponds to an output of the bandgap circuit in response to the bandgap circuit being initialized. The startup circuit may also disconnect the voltage source from the node in response to the reference voltage being greater than a threshold.