Voltage Supply Interface Segmented Switch Calibration
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Solution Overview
Problem
Conventional voltage supply interfaces face challenges in providing accurate current control to next stage circuit devices due to the need for large sense resistors, which result in power loss and difficulty in supplying adjustable currents, as they require a large voltage drop and inflexible switching.
Innovation Solution
A voltage supply interface with a segmented switch and calibration circuit that replaces the sense resistor, using a replica switch and digital controller to achieve both coarse and fine current control, eliminating the need for a sense resistor and reducing series resistance by forcing a common voltage drop across the switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a large sense resistor is used to monitor current accurately, then current monitoring precision is improved, but power loss increases and voltage drop increases
Solution Approach 1:
The patent creates a replica switch that copies the electrical characteristics of the actual switch. By measuring current through the replica switch instead of the actual switch, the system achieves accurate current monitoring without inserting a large sense resistor into the main current path, thereby eliminating the power loss and voltage drop associated with traditional sense resistors.
Solution Approach 2:
The replica switch acts as an intermediary element that allows indirect measurement of switch current. Instead of directly measuring current through the main switch (which would require a sense resistor causing power loss), the system uses the replica switch as a mediator to obtain current information without affecting the main power path.
2Device complexity
If a single inflexible switch is used to supply current, then device simplicity is maintained, but current adjustability deteriorates
Solution Approach 1:
The patent divides a single switch into multiple parallel switches (first switch, second switch, third switch, etc.). Each switch can be independently controlled to provide different current levels. This segmentation allows the system to achieve adjustable current supply while maintaining relative structural simplicity, as each parallel switch is a basic element similar to the original single switch.
Data Source
AI summary
A voltage supply interface provides both coarse and fine current control with reduced series resistance. The voltage supply interface has a segmented switch having N component switches that are digitally controlled. The voltage supply interface replaces a conventional sense resistor with a calibration circuit that has a replica switch that is a replica of the N component switches. The calibration circuit includes a reference current IREF that is sourced through the replica switch. A voltage comparator forces a common voltage drop across the replica switch and the n-of-N activated component switches so that the cumulative current draw through the segmented switch is n·IREF. The current control of the voltage interface can be coarsely tuned by activating or deactivating component switches, and can be finely tuned by adjusting the reference current. The current sense resistor is eliminated so that the overall series resistance is lower.