Supply-Detecting Level Shifters for Low Leakage Output Control
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Solution Overview
Problem
Conventional level-shifter circuits experience high current leakage and unpredictable output when the power supply voltage in one domain is insufficient, leading to inefficiencies and battery life issues in mobile devices.
Innovation Solution
A low-leakage level-shifter circuit with supply detection, featuring a supply detector, disabler, and leakage reducer, which generates a detection signal to set the output to a predetermined state and electrically disconnect transistors when an invalid power supply voltage is detected, preventing current leakage and ensuring a predictable output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional level-shifter circuit is used to pass digital signals between power supply domains, then signal level shifting is achieved, but high current leakage occurs when the input power supply voltage is insufficient
Solution Approach 1:
The supply detector performs preliminary detection of the input power supply voltage before the level-shifter operates. When insufficient voltage is detected, the disabler component preemptively disables the level-shifter circuit, preventing the high current leakage that would otherwise occur during operation with invalid input voltage
Solution Approach 2:
The supply detector acts as an intermediary between the input power supply and the level-shifter circuit. It monitors the input voltage and controls the disabler, which in turn controls the operation of the level-shifter, creating a protective intermediary layer that prevents harmful operation
2Productivity
If a conventional level-shifter circuit operates with insufficient input power supply voltage, then the circuit remains operational, but the output becomes unpredictable
Solution Approach 1:
The supply detector continuously monitors the input power supply voltage and provides feedback control to the disabler. When the input voltage falls below the threshold, the feedback mechanism triggers the disabler to shut down the level-shifter, ensuring predictable output behavior by preventing operation under invalid conditions
Solution Approach 2:
The disabler component performs preliminary anti-action by shutting down the level-shifter circuit before unpredictable operation can occur. This protective action is triggered by the supply detector when insufficient voltage is detected, preventing the harmful effect of unpredictable output signals
Data Source
AI summary
Low-leakage level-shifters with reduced leakage are disclosed. In one example, a level-shifter circuit to reduce leakage when there is an invalid supply voltage is described, including a level-shifter configured to shift a voltage of an digital input signal based on a first supply voltage to a digital output signal based on a second supply voltage, comprising a first transistor and a second transistor configured to set the digital output signal based on the digital input signal, a supply detector configured to generate a detection signal based on the first supply voltage, a disabler configured to, based on the detection signal, set the digital output signal of the level-shifter to a predetermined state, and a leakage reducer configured to, based on the detection signal, electrically disconnect the first and second transistors from the level-shifter.