Semiconductor Device Overvoltage Protection Circuit
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Solution Overview
Problem
Existing semiconductor devices face challenges in protecting load circuits from overvoltage while maintaining steady electrical power supply, particularly in vehicle-mounted applications, where they must operate under varying voltage conditions from 3.9 V to 40 V, and increasing the size of circuitry to achieve this protection is undesirable.
Innovation Solution
A semiconductor device incorporating an N-channel MOS transistor and a control voltage generation circuit that clips the gate voltage of the N-channel MOS transistor to a predetermined level, combined with a P-channel MOS transistor and a current mirror circuit to manage power supply voltage, along with an overvoltage detection and delay circuit to prevent overvoltage propagation to the load circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection circuit is added to protect the load circuit from overvoltage, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The patent combines the overvoltage protection function with the existing power supply voltage management circuitry. The N-channel MOS transistor and control voltage generation circuit are integrated into the power supply system, allowing the same circuit structure to perform both power supply control and overvoltage protection functions, thereby avoiding additional circuit complexity.
Solution Approach 2:
The control voltage generation circuit serves multiple purposes: it controls the power supply voltage to the load circuit and simultaneously provides overvoltage protection. By making the circuit multi-functional, the patent avoids adding separate protection circuits, thus maintaining simplicity while improving reliability.
2Adaptability or versatility
If the circuit is designed to operate under varying voltage conditions (3.9 V to 40 V), then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The patent uses parameter changes to achieve wide voltage range operation. The N-channel MOS transistor's gate voltage is controlled by a control voltage generation circuit that adjusts the transistor's on-resistance based on the input voltage level. This allows the circuit to adapt to varying voltage conditions (3.9V to 40V) by dynamically changing the electrical parameters of the MOS transistor rather than using complex switching circuits.
3Adaptability or versatility
If a step-down circuit is used to operate low-voltage circuit on high voltage, then the adaptability is improved, but the loss of energy increases
Solution Approach 1:
The patent employs dynamic control of the N-channel MOS transistor to minimize energy loss. Instead of using a static step-down circuit with fixed voltage conversion, the MOS transistor's on-resistance is dynamically adjusted based on the input voltage conditions. This dynamic adaptation allows the circuit to operate efficiently across a wide voltage range without the continuous energy loss associated with traditional step-down converters.
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 effectively protects the load circuit from overvoltage while maintaining a steady power supply, suppressing the increase in circuit size and preventing instantaneous power interruption due to noise or voltage fluctuations.
Implementation Method 1
an N-channel MOS transistor that controls a supply of a power supply voltage in accordance with a control voltage
Implementation Method 2
a control voltage generation circuit that clips the gate voltage of the N-channel MOS transistor at a control voltage not higher than a predetermined voltage
Implementation Method 3
a P-channel MOS transistor and a current mirror circuit to manage power supply voltage
Implementation Method 4
an overvoltage detection and delay circuit to prevent overvoltage propagation to the load circuit
Data Source
AI summary
Disclosed is a semiconductor device that includes an N-channel MOS transistor and a control voltage generation circuit. The N-channel MOS transistor controls the supply of a power supply voltage obtained by stepping down a DC voltage. The control voltage generation circuit clips the gate voltage of the N-channel MOS transistor at a control voltage not higher than a predetermined voltage in accordance with the DC voltage.