Bandgap Reference Circuit Startup Control for Low Voltage Stability
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Solution Overview
Problem
Bandgap reference circuits face challenges in generating a stable output reference voltage independent of temperature and power voltage, particularly in low voltage large scale integrated circuits, where they often fail to rise the output reference voltage once it reaches nearly zero, requiring external devices for power-up detection and signal generation.
Innovation Solution
The proposed solution involves a bandgap circuit configuration with a bandgap core circuit, differential amplifier circuit, and start control circuit, where the start control circuit supplies a start signal to the differential amplifier until it starts up and then discontinues it, ensuring the bandgap core circuit operates stably without external power-up detection signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a bandgap reference circuit is designed to operate in low voltage large scale integrated circuits, then the output reference voltage can be adjusted to match the power voltage requirements, but the circuit fails to rise the output reference voltage once it reaches nearly zero, requiring external power-up detection devices
Solution Approach 1:
The start control circuit proactively generates a start signal before the differential amplifier circuit can naturally start up on its own. This preliminary action ensures that the circuit transitions smoothly from the zero voltage state to the operational state, preventing the reliability issue of voltage failure while maintaining low voltage compatibility.
Solution Approach 2:
The start control circuit acts as an intermediary between the power supply and the differential amplifier circuit. It mediates the power-up process by detecting when power is applied and providing the necessary start signal, thereby eliminating the need for external power-up detection devices while ensuring reliable voltage rise.
2Reliability
If external devices are added for power-up detection and signal generation, then the output reference voltage stability is improved, but the device complexity increases
Solution Approach 1:
The start control circuit merges the power-up detection function and the start signal generation function into a single integrated circuit block. This combination eliminates the need for separate external power-up detection devices, thereby maintaining output voltage stability while reducing overall device complexity.
Solution Approach 2:
The start control circuit performs multiple functions: it detects power-up conditions, generates the start signal, and controls the differential amplifier circuit startup. This multi-functionality consolidates what would otherwise require multiple separate components, reducing device complexity while ensuring reliable operation.
3Reliability
If the start control circuit continuously supplies start signal, then the differential amplifier circuit remains operational, but power consumption increases
Solution Approach 1:
The start control circuit provides the start signal in a periodic or pulsed manner rather than continuously. It activates the start signal during the startup phase and then discontinues it once the differential amplifier circuit is operational, thereby maintaining circuit reliability while minimizing unnecessary power consumption during steady-state operation.
Solution Approach 2:
The differential amplifier circuit, once started by the start control circuit, maintains its own operation without requiring continuous external start signals. The circuit becomes self-sustaining, allowing the start control circuit to discontinue the start signal and thereby reducing power consumption while preserving operational reliability.
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
This configuration allows the bandgap reference circuit to maintain a stable output reference voltage and prevent the phenomenon of failing to rise the output voltage, ensuring consistent operation without relying on external power-up detection signals.
Implementation Method 1
a first diode having a first junction area and a first forward voltage, a second diode having a second junction area larger than the first junction area and a second forward voltage
Data Source
AI summary
In accordance with a bandgap circuit and a method of starting the bandgap circuit, a start signal is continuously supplied to a differential amplifier circuit to start up the differential amplifier circuit that controls a bandgap core circuit until the differential amplifier circuit has started up, and then the supply of the start signal to the differential amplifier circuit is discontinued after the differential amplifier circuit has started up.