Power Supply Circuit Trimming Using Enable and Feedback Pads
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Solution Overview
Problem
Conventional power supplies require extra trim pads to adjust electrical characteristics of integrated circuits, leading to increased chip area and cost, and existing methods still necessitate at least one trim pad.
Innovation Solution
A power supply circuit design that includes a voltage regulator, a trim circuit with a variable resistor, and a test mode to adjust the output voltage without additional trim pads by using existing pads for enable and feedback signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a trimmer is used to trim the circuit to reduce output voltage error, then the electrical characteristic precision is improved, but extra trim pads are required which increases chip area and cost
Solution Approach 1:
The enable pad and feedback pad are made to serve dual functions: their original functions plus the additional function of trimming the output voltage. The enable pad can activate either the power supply or the trim circuit, and the feedback pad is used for both feedback signaling and as a trim terminal, eliminating the need for dedicated trim pads.
Solution Approach 2:
The trimming function is merged with the existing enable and feedback circuits. The trim circuit shares the enable pad for activation and the feedback pad for voltage reference, combining multiple functions into existing pad structures rather than adding separate trim pads.
2Manufacturing precision
If a trimmer is used to trim the circuit to reduce output voltage error, then the electrical characteristic precision is improved, but the cost increases due to extra trim pads
Solution Approach 1:
The enable pad and feedback pad are made to serve dual functions: their original functions plus the additional function of trimming the output voltage. The enable pad can activate either the power supply or the trim circuit, and the feedback pad is used for both feedback signaling and as a trim terminal, eliminating the need for dedicated trim pads.
Solution Approach 2:
The patent uses simple, easily manufacturable trim circuit elements such as resistors and transistors that can be implemented using standard semiconductor fabrication processes, avoiding costly custom trim pad structures while achieving the desired trimming precision.
3Area of stationary object
If existing pads are used for trim circuit to eliminate extra trim pads, then the chip area is reduced, but the circuit complexity increases
Solution Approach 1:
The trim circuit is divided into distinct functional blocks: an enable circuit that responds to the enable pad signal, a comparison circuit that compares voltages, and a control circuit that adjusts the variable resistor. This segmentation allows the complex trimming function to be implemented in a structured, manageable way using existing pads.
Solution Approach 2:
The patent introduces intermediate control circuits that mediate between the simple enable/feedback signals and the complex trimming operation. The enable circuit and comparison circuit act as intermediaries that translate pad signals into precise control of the variable resistor, managing complexity through layered control.
Data Source
AI summary
A power supply circuit and a control method are provided, in which the original enable pad and output pad, or the enable pad and feedback pad are used to trim the output voltage of the power supply circuit without extra trim pads.