Native Transistor Startup Circuit for Bandgap Voltage
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Solution Overview
Problem
Existing startup circuits in integrated circuits (ICs) face challenges in efficiently initializing and stabilizing bandgap voltage references, particularly in terms of power consumption and response speed, especially when the output voltage is below a predetermined trigger level.
Innovation Solution
The implementation of startup circuits utilizing native transistors with zero or near-zero threshold voltage, which operate by providing a signal to boost the bandgap circuit's output when it falls below a trigger voltage and automatically rearming to stabilize it, thereby minimizing power consumption and enhancing response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional startup circuits are used to initialize bandgap voltage references, then the circuit can provide startup functionality, but power consumption increases and response speed decreases
Solution Approach 1:
The patent changes the threshold voltage parameter of the transistor to near-zero (native transistor), which fundamentally alters the operating characteristics. This parameter change enables the circuit to achieve both low power consumption and fast response by allowing the transistor to turn on at minimal voltage differences while maintaining high switching speed
Solution Approach 2:
The startup circuit dynamically adjusts its operation based on the voltage difference between nodes. The native transistor automatically transitions between conductive and non-conductive states as the bandgap voltage approaches the trigger level, providing adaptive response that optimizes both speed and power efficiency
2Measurement precision
If conventional transistors with non-zero threshold voltage are used, then the transistor can operate in standard modes, but the startup circuit cannot efficiently detect small voltage differences below the trigger level
Solution Approach 1:
By changing the threshold voltage parameter to near-zero, the native transistor can detect and respond to minimal voltage differences that conventional transistors would miss. This enables precise detection of when the bandgap voltage reaches the trigger level without requiring additional comparison circuits or increased complexity
3Reliability
If the startup circuit operates continuously to ensure stability, then reliability improves, but power consumption increases during idle states
Solution Approach 1:
The startup circuit operates periodically rather than continuously. The native transistor automatically activates when voltage differences exist (during startup or recovery) and remains inactive when the system is stable, providing reliability only when needed and minimizing power consumption during normal operation
Solution Approach 2:
The circuit monitors its own state through the voltage difference detection and automatically activates or deactivates the startup function. The native transistor serves as both the detection element and the correction element, eliminating the need for separate control logic and enabling self-regulating operation
Data Source
AI summary
Startup circuits with native transistors. In some embodiments, a startup circuit may include a first inverter configured to receive a bandgap voltage (Vbg) from a bandgap reference circuit and to produce an output voltage (VOUT), and a second inverter operably coupled to the first inverter to form a latch, the latch configured to maintain a value of VOUT, the second inverter including a native transistor, the native transistor having a gate terminal coupled to VOUT and a source terminal coupled to Vbg. In other embodiments, a method may include receiving Vbg at a startup circuit and outputting VOUT configured to change in response to Vbg rising above Vtrig or falling below Vtrig, where the power consumption of the startup circuit is based at least in part upon a voltage value applied to a source terminal of a native transistor within the startup circuit.