Voltage Adjusting Circuit Reduces Chip Area and Testing Time
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional voltage adjusting circuits in integrated circuits require multiple pads and pins, leading to increased chip area and testing time, and are inefficient for precise voltage adjustments, especially for sensitive voltage sources like bandgap reference voltage generators.
Innovation Solution
A voltage adjusting circuit utilizing a test control device, multiplexer, comparator, and built-in self-test (BIST) device, which selects and compares voltage sources, adjusts output voltages through a single pad, reducing chip area and testing time while providing precise adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If each voltage source uses a separate pad for output, then voltage adjustment can be performed, but chip area increases and pin count increases
Solution Approach 1:
The patent combines multiple voltage source outputs into a single pad by using a multiplexer. The multiplexer sequentially connects different voltage sources to the same pad, allowing multiple voltage sources to share one pad for both output and trimming operations. This merging approach reduces the number of pads and pins required while maintaining the ability to adjust each voltage source independently.
Solution Approach 2:
The single pad serves multiple functions: it outputs voltages from different voltage sources at different times, and it also receives trimming values for adjusting those voltage sources. The multiplexer enables the pad to be universally used for both voltage output and trimming control, eliminating the need for separate dedicated pads for each voltage source.
2Reliability
If external testing machine adjusts voltage sources sequentially via pads, then voltage adjustment is achieved, but testing time increases
Solution Approach 1:
The built-in self-test (BIST) device enables the voltage sources to perform their own trimming operations internally without requiring external testing machine intervention. The BIST device generates trimming values and adjusts the voltage sources automatically, significantly reducing testing time while maintaining adjustment accuracy. This self-service mechanism eliminates the time-consuming sequential external adjustment process.
Solution Approach 2:
The BIST device performs voltage source trimming in advance during the manufacturing test process, storing the trimming values in non-volatile memory. This preliminary action ensures that voltage sources are pre-adjusted to their optimal values before the IC device is shipped, eliminating the need for time-consuming field adjustments and ensuring consistent voltage accuracy.
3Reliability
If weak and sensitive voltage signals are coupled to pads, then voltage adjustment can be performed, but signal integrity deteriorates
Solution Approach 1:
The multiplexer acts as an intermediary between the weak voltage sources and the external pad interface. By providing a controlled, high-impedance connection path, the multiplexer protects sensitive voltage signals from external interference and loading effects that would occur if they were directly connected to pads. This intermediary structure enables safe external access while preserving signal integrity.
Data Source
AI summary
A voltage adjusting circuit is provided. The voltage adjusting circuit for adjusting the output voltages supplied by voltage sources includes a test control device, a multiplexer, a comparator, and a built in self test (BIST) device. The test control device selects one of the voltage sources as a testing voltage source, and outputs a selecting command for selecting the testing voltage source and a target voltage corresponding to the testing voltage source. The multiplexer is coupled to the voltage sources, receives an enablement signal, and outputs a voltage supplied by the testing voltage source as a testing voltage according to the enablement signal. The comparator compares the voltage levels of the testing voltage and the target voltage, and outputs a comparison result. The BIST device receives the selecting command, outputs the enablement signal for enabling the testing voltage source according to the selecting command, and adjusts the voltage supplied by the testing voltage source to a predetermined voltage according to the comparison result.