Semiconductor Circuit Breakdown Voltage Enhancement
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Solution Overview
Problem
Semiconductor level shift circuits with SOI RESURF structures are limited to a breakdown voltage of around 500 to 600 V, which is insufficient for higher voltage applications, and existing solutions with high breakdown voltage MOSFETs require larger circuit areas.
Innovation Solution
A semiconductor circuit configuration that includes resistors and a MOSFET connected in series and parallel, with an inverter connected between the resistors, satisfying specific resistance and voltage threshold conditions to reduce the voltage applied to the MOSFET, thereby enhancing the breakdown voltage without increasing circuit size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SOI RESURF structure is used to achieve high breakdown voltage, then breakdown voltage is improved to 500-600V, but breakdown voltage cannot be enhanced further beyond this limit
Solution Approach 1:
The voltage blocking function is segmented between two components: the SOI RESURF MOSFET handles the majority of the voltage (V1 - V3 - Vinvth), while the added series resistor R1 handles the remaining voltage (V3 + Vinvth). This segmentation allows the MOSFET to operate within its safe breakdown voltage range while the circuit as a whole achieves higher voltage capability through the resistor's voltage bearing capacity.
Solution Approach 2:
Resistor R1 acts as an intermediary element that bears the high voltage stress (V3 + Vinvth) and protects the MOSFET from exceeding its breakdown voltage limit. The resistor serves as a voltage mediator that allows the circuit to operate at voltages higher than the MOSFET's inherent breakdown capability without damaging the semiconductor device.
2Reliability
If high breakdown voltage MOSFETs are used to achieve higher breakdown voltage, then breakdown voltage is improved, but circuit area increases
Solution Approach 1:
The invention changes the circuit configuration by adding external resistors R1 and R2 in series with the MOSFET, transforming the voltage bearing mechanism from relying solely on the MOSFET's inherent breakdown voltage to a combined system where resistors bear portion of the voltage stress. This parameter change allows achieving higher voltage capability without increasing MOSFET size or requiring larger area devices.
Data Source
AI summary
An object is to provide a technique for enhancing the breakdown voltage of a semiconductor device. A semiconductor circuit includes a first resistor, a second resistor, a third resistor, a MOSFET, and an inverter. The first resistor, the second resistor, and the third resistor are connected in series between a power supply and a ground corresponding to the reference voltage of a low-side circuit. The MOSFET is connected to the third resistor in parallel between the second resistor and the ground, and has a gate electrically connected to the low-side circuit. The inverter is electrically connected between a connection point and the high-side circuit, the connection point being located between the first resistor and the second resistor.