Bandgap Reference Voltage Circuit Startup Current Generator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bandgap reference voltage generators often fail to start up properly, resulting in unstable or fluctuating output voltages that are temperature-dependent, rather than generating a constant output voltage over a wide temperature range.
Innovation Solution
Incorporating a startup current generator with a voltage comparator and switch to facilitate the transition of the bandgap reference voltage generator from an unstable state to a stable state by comparing the output voltage with an offset voltage and selectively connecting or disconnecting the supply voltage, ensuring the generator operates stably and generates a constant output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a bandgap reference voltage generator is designed to operate without a startup current generator, then the device complexity is reduced, but the generator fails to start up properly and produces fluctuating or temperature-dependent output voltage
Solution Approach 1:
The startup current generator is activated before the main bandgap reference voltage generator begins normal operation. It provides an initial current impulse that forces the generator into its correct operating state, ensuring proper startup before the startup circuit is deactivated. This preliminary action prevents startup failures without requiring continuous complexity.
Solution Approach 2:
The startup current generator is designed as a separate, extractable module from the main bandgap reference voltage generator. It operates independently during startup and can be disconnected once normal operation is achieved, reducing the overall complexity of the system while maintaining reliability during the critical startup phase.
2Reliability
If a startup current generator is added to ensure proper startup, then the startup reliability is improved, but the device complexity increases due to additional components
Solution Approach 1:
The startup current generator is merged with the main bandgap reference voltage generator as an integrated circuit block. Both circuits share common power supplies, substrate, and packaging, allowing the startup functionality to be added without proportionally increasing overall device complexity. The merged design enables seamless coordination between startup and normal operation modes.
3Ease of operation
If the bandgap reference voltage generator operates without proper startup control, then the ease of operation is maintained, but the output voltage becomes unstable and temperature-dependent
Solution Approach 1:
The startup current generator incorporates feedback mechanisms that monitor the operating state of the bandgap reference voltage generator. Based on this feedback, the startup circuit automatically adjusts its current output to ensure the generator reaches and maintains its correct operating point, providing stable output voltage without requiring manual intervention or complex external control.
Data Source
AI summary
A bandgap reference voltage circuit includes a bandgap reference voltage generator and a startup current generator. The bandgap reference voltage generator is configured to generate a first voltage and a second voltage. The startup current generator includes a voltage comparator and a switch. The voltage comparator is connected to the bandgap reference voltage generator and is configured to compare the first voltage with the sum of the second voltage and an offset voltage and to generate a comparison result. The switch is connected between the voltage comparator and the bandgap reference voltage generator and is configured to selectively connect a supply voltage to the bandgap reference voltage generator based on the comparison result. A device that includes the circuit is also disclosed. A method of operating the circuit is also disclosed.