Level Shifter ESD Protection Leak Current Reduction
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Solution Overview
Problem
In signal transmission between circuits with different supply voltages, existing technologies face issues with leak currents through protection circuits during Electro-Static Discharge (ESD) countermeasures, which can lead to circuit damage and malfunction, especially when the high potential side is not continuously powered.
Innovation Solution
A level shifter with a combination circuit and level shift circuit that applies an enable signal to manage signal levels, reducing leak currents by keeping both signals at low levels when the high potential side is not powered, and using protection circuits with diodes and resistors to direct ESD currents effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protection circuits are provided for ESD countermeasures in signal transmission between circuits with different supply voltages, then gate destruction is prevented, but leak currents flow through the protection circuits when the high potential side is not powered
Solution Approach 1:
The enable signal is activated in advance before the high potential side is powered on, and deactivated before it is powered off. This preliminary action ensures that the protection circuits are only active when needed, preventing leak currents from flowing when the high potential side is not powered, while still providing gate protection during operation
Solution Approach 2:
The protection circuit's activation state is made dynamic by controlling the enable signal. The enable signal transitions between active and inactive states based on the power status of the high potential side, allowing the protection circuit to adaptively enable or disable itself to prevent unnecessary leak currents while maintaining gate protection when required
2Reliability
If switches are disposed on the low potential side for ESD protection, then high voltage pulses are blocked, but the switches may be damaged by ESD and cause system failure
Solution Approach 1:
The enable signal acts as an intermediary control mechanism between the ESD protection function and the actual protection circuit activation. Instead of directly exposing switches to ESD risks, the enable signal mediates by selectively activating protection circuits only when the high potential side is powered, reducing switch exposure to damaging ESD events while maintaining protection capability
3Use of energy by moving object
If the high potential side circuit operates intermittently, then power consumption is reduced, but leak currents flow through protection circuits during idle periods
Solution Approach 1:
The enable signal is deactivated in advance when the high potential side is powered off, preventing protection circuits from remaining active during idle periods. This preliminary deactivation eliminates leak currents during intermittent operation while still providing protection when the high potential side is powered on
Solution Approach 2:
The enable signal creates a periodic activation pattern that matches the intermittent operation of the high potential side circuit. Protection circuits are activated only during periods when the high potential side is powered and deactivated during idle periods, creating a rhythmic on-off pattern that reduces both power consumption and leak currents
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces leak currents through protection circuits during ESD events, prevents gate damage in the level shift circuit, and allows intermittent operation of the high potential side circuit without significant current flow, ensuring system reliability.
Implementation Method 1
a high voltage pulse, which is generated along with Electro-Static Discharge (ESD) (hereinafter, referred to as "ESD"), is prevented from destructing an inside circuit of a semiconductor chip
Implementation Method 2
a protection circuit including a protection element 260 and a protection circuit including a protection element 270
Data Source
AI summary
A first circuit and a second circuit, which have different operating voltages, are connected through a level shifter, and a combination circuit below is provided in the level shifter. An enable signal, which is switched between active and inactive states according to whether or not a potential is supplied to a second high potential power line, is applied to the combination circuit. The combination circuit outputs a first signal and a second signal, which is acquired by logically inverting the first signal, to a level shift circuit according to an output signal of the first circuit, in a case where the enable signal is active, and causes both the first signal and the second signal to be at a low level in a case where the enable signal is inactive.