HV Level Shifting Circuit With Switch Timing to Cut Static Current
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Solution Overview
Problem
Conventional High Voltage Level Shifting (HVLS) circuits in Non-Volatile Memory (NVM) devices consume substantial power and time due to high threshold voltages of HVNMOS transistors, resulting in significant static current during voltage conversion.
Innovation Solution
A novel HVLS circuit design incorporating a level conversion circuit with specific transistor configurations and switch control mechanisms, including a first and second switch controlled by a switch control circuit to prevent simultaneous conduction, reducing static current and accelerating the voltage conversion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional HVLS circuit uses a current mirror circuit with HVNMOS and HVPMOS transistors, then voltage conversion can be achieved, but substantial power consumption and long conversion time occur due to high threshold voltage
Solution Approach 1:
The circuit is divided into two separate paths: a first path with a first transistor for fast charging and a second path with a second transistor for discharge, allowing independent optimization of each path's characteristics rather than using a single current mirror circuit
Solution Approach 2:
The invention changes the threshold voltage parameter by using different transistor types (first conductivity type vs second conductivity type) with different threshold voltage characteristics, enabling one transistor to have low threshold voltage for fast switching while the other handles the voltage conversion
2Loss of energy
If a conventional HVLS circuit uses a current mirror circuit, then voltage conversion is possible, but a large amount of conversion current (static current) is generated
Solution Approach 1:
The circuit separates the charging and discharge functions into different transistors with different conductivity types, allowing each transistor to operate in its optimal region and reducing overall static current consumption
Solution Approach 2:
A control circuit acts as an intermediary to manage the switching between the first and second transistors, ensuring they do not conduct simultaneously and thereby reducing static current while maintaining conversion efficiency
3Speed
If a conventional HVLS circuit uses HVNMOS transistor with high threshold voltage, then voltage conversion can be performed, but changing from blocking state to conducting state takes relatively long time
Solution Approach 1:
The invention changes the threshold voltage parameter by selecting transistors with different conductivity types, where the first transistor has low threshold voltage for fast switching and the second transistor handles the voltage conversion function
Solution Approach 2:
The circuit separates the fast switching function and voltage conversion function into different transistors, allowing each to be optimized for its specific function without compromise
Data Source
AI summary
A high voltage level shifting circuit and related semiconductor devices are presented. The circuit comprises: a level conversion circuit that converts an input signal with a first high voltage to an output signal with a second high voltage; a first switch having a first node connected to a first power source and a second node connected to a control node of a first transistor; a second switch having a first node connected to the control node of the first transistor and a second node connected to a first connection node; and a switch control circuit connected to the first switch and the second switch and controls them not to be close at the same time. By adding these two switches to the level conversion circuit, this inventive concept substantially lowers the static current generated during a high voltage level conversion process.