Bandgap Reference Circuit Trim Code Retrieval
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Solution Overview
Problem
Existing bandgap reference circuits are not suitable for applications requiring low power voltage due to instability in the reference voltage level caused by threshold voltage variations of MOS transistors.
Innovation Solution
A method and system for retrieving a preset trim code stored in a memory block to trim a bandgap reference circuit, involving setting an input trim code, generating a read bias voltage, reading the memory block, and determining if the output trim code matches the input trim code, with the trim code being used to stabilize the reference signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an existing bandgap reference circuit is used to generate a reference voltage level, then the circuit can provide a reference voltage, but the reference voltage level is unstable due to threshold voltage variations of MOS transistors
Solution Approach 1:
The patent applies preliminary action by pre-storing the correct trim code in a memory block before the circuit operates. During power-up, the circuit automatically retrieves this pre-stored trim code and applies it to compensate for threshold voltage variations, eliminating the need for real-time calibration and ensuring stable reference voltage from the start.
Solution Approach 2:
The patent implements feedback by comparing the output trim code read from memory with the input trim code applied to the bandgap reference circuit. This verification feedback loop ensures that the correct trim code is successfully retrieved and applied, confirming that the threshold voltage compensation is properly established before normal operation begins.
2Reliability
If a trim code is stored in memory and automatically retrieved at power-up, then the reference voltage stability is improved, but the circuit complexity increases due to additional components
Solution Approach 1:
The patent applies self-service by designing the circuit to automatically retrieve and apply the trim code from memory without requiring external intervention or complex calibration procedures. The power-up sequence autonomously completes the trim code retrieval and application, simplifying the overall system interface while maintaining high reliability.
3Reliability
If the trim code retrieval process is made robust with verification steps, then the reliability is improved, but the power consumption increases
Solution Approach 1:
The patent applies periodic action by confining the high-power trim code retrieval and verification operations to a brief power-up interval. Once the trim code is successfully retrieved and verified, the circuit transitions to low-power normal operation, avoiding continuous high power consumption while ensuring reliable trim code establishment.
Data Source
AI summary
The present disclosure provides a method and a trim code reloading system. The method is for retrieving a preset trim code, wherein the preset trim code is for trimming a bandgap reference circuit and is stored in a memory block. The method includes: setting a first input trim code for the bandgap reference circuit, wherein a read bias voltage is generated according to the first input trim code; reading the memory block biased by the read bias voltage, to obtain an output trim code; determining if the output trim code is the same as the first input trim code; and using the first input trim code or the output trim code as a retrieved preset trim code when the output trim code is the same as the first input trim code.