IC Power Supply Selection Using OTP Bits and XOR Configuration
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Solution Overview
Problem
Existing integrated circuits (ICs) lack flexibility in selecting power supply voltages due to the one-time programmable (OTP) memory's inability to change programmed values, limiting the ability to adapt to changing user requirements.
Innovation Solution
The ICs utilize a configuration engine with two programmable bits in an OTP memory to allow switching between multiple power supplies by performing XOR operations, enabling up to two changes in power supply selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If OTP memory is used to specify power supply voltages, then voltage selection is determined at manufacturing, but flexibility to change voltage selection later is lost
Solution Approach 1:
The voltage selection function is segmented into two independent parts: OTP memory bits (volt-sel[1:0]) that remain fixed and provide stable baseline selection, and configuration register bits (volt-sel[3:0]) that can be modified and provide flexible overrides. This segmentation allows both reliability and adaptability to coexist by assigning different functions to different memory segments.
Solution Approach 2:
A configuration engine acts as an intermediary between the OTP memory and the voltage selection logic. It reads both the fixed OTP bits and the modifiable configuration register bits, performs logical operations (XOR) on them, and generates the final voltage selection signal. This intermediary enables the system to combine the stability of OTP with the flexibility of reconfigurable registers.
2Ease of manufacture
If OTP bits are programmed to a non-default value, then initial voltage selection is set, but ability to change selection later is prevented
Solution Approach 1:
The OTP memory is programmed during manufacturing with default voltage selection values, establishing a preliminary configuration that works for most applications. However, the system also provides configuration registers that allow users to perform preliminary actions themselves (programming the registers before operation) if different voltage selections are needed, thus maintaining ease of manufacture while enabling post-manufacturing reconfiguration.
3Device complexity
If a single bit is used for voltage selection, then simple programming is achieved, but only one voltage change is possible
Solution Approach 1:
The system transitions from a single-dimensional voltage selection (one OTP bit) to a two-dimensional selection space by combining OTP memory bits (volt-sel[1:0]) with configuration register bits (volt-sel[3:0]). This creates a 4-bit virtual address space that can represent 16 different voltage selection states, effectively adding another dimension to the selection capability while maintaining relatively simple hardware structure.
Solution Approach 2:
The invention merges two separate memory structures (OTP memory and configuration registers) into a unified voltage selection system. The configuration engine combines the contents of both memory structures through logical operations, creating a unified selection mechanism that leverages the permanent storage of OTP and the reconfigurability of registers, thereby increasing adaptability without proportionally increasing complexity.
Data Source
AI summary
An integrated circuit (IC) containing a circuit to be operable using one of multiple unequal power supplies during normal operation of the IC. The IC contains a one time programmable (OTP) memory containing a first bit and a second bit, with each of the bit having an initial value and being programmable to a programmed value. A configuration engine contained in the IC operates the circuit with a first selection with respect to using one of the unequal power supplies during normal operation of the IC if both of the first bit and the second bit have an equal value comprising one of the initial value and the programmed value. The configuration engine operates the circuit with a second selection with respect to using one of the unequal power supplies during normal operation of the IC if the first bit and the second bit have unequal values.