LDO Startup Switching for Stable Bandgap Reference Power-On
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Solution Overview
Problem
The existing power supply powering-on structures face challenges in ensuring stable powering-on and starting of the bandgap reference module, particularly in low-power-consumption designs where internal power supply voltage restricts the operation, leading to contradictions and potential start failures.
Innovation Solution
A power supply powering-on structure comprising an LDO module, a bandgap reference module, a voltage detection module, a bias module, and a switch module, where the LDO module's output voltage is used to supply power to the bandgap reference module, with the voltage detection module controlling the switch module to switch between connection states to provide necessary reference voltage and bias current, allowing the bandgap reference module to stabilize and enable the LDO module's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the bandgap reference module is directly connected to external power supply voltage to ensure stable powering-on, then the powering-on stability is improved, but the output variation of the bandgap reference module increases due to ripple from DCDC
Solution Approach 1:
The power supply system is segmented into two separate power supply paths: one for the LDO module connected to external power supply voltage, and another for the bandgap reference module connected to internal power supply voltage. This segmentation allows each module to operate in its optimal power environment, resolving the contradiction between powering-on stability and output variation.
2Manufacturing precision
If the bandgap reference module uses internal power supply voltage to reduce output variation, then the output accuracy is improved, but the module cannot start because the internal power supply voltage is not yet available during powering-on
Solution Approach 1:
The LDO module is designed to operate in advance during the powering-on phase, generating the internal power supply voltage before the bandgap reference module needs it. This preliminary action ensures that when the bandgap reference module starts up, the clean internal power supply voltage is already available, enabling both accurate operation and successful starting.
3Manufacturing precision
If the LDO module uses the bandgap reference module for reference voltage, then the LDO output accuracy is improved, but the LDO cannot start because the bandgap reference module requires power that the LDO has not yet generated
Solution Approach 1:
The bandgap reference module is designed to operate in advance during the powering-on phase, generating the reference voltage and bias current before the LDO module needs them for accurate operation. This preliminary action ensures that when the LDO module starts up, the accurate reference voltage is already available, enabling both accurate operation and successful starting.
Data Source
AI summary
The present invention discloses a power supply powering-on structure, which comprises an LDO module, a bandgap reference module, a voltage detection module, a bias module and a switch module; the working voltage of the LDO module, the voltage detection module and the bias module adopts external power supply voltage; the working voltage of the bandgap reference module adopts LDO output voltage; the switch module provides switching connection between the output of the bias module and the output of the bandgap reference module for a reference voltage input end and a bias current input end of the LDO module. The present invention can adopt internal power supply voltage to supply power to the bandgap reference module and can also solve the problem that the internal power supply voltage restricts the powering-on and starting of the bandgap reference module.