High-Side Intelligent Power Switch Low Voltage Detection Circuit
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Solution Overview
Problem
Conventional high-side intelligent power switches (IPS) face challenges in maintaining drive circuit operation when the power supply voltage drops, as the voltage required for the drive circuit to function properly is not guaranteed, leading to potential malfunction.
Innovation Solution
Incorporating a low voltage detection circuit that turns on an N-channel MOSFET to set the internal ground voltage to ground potential when the power supply voltage drops, ensuring the drive circuit can operate with reduced voltage, thereby extending the operational range of the power supply voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the drive circuit uses the power supply voltage directly without local ground generation, then the chip area is reduced, but the drive circuit cannot operate when the power supply voltage drops below the required threshold
Solution Approach 1:
The patent introduces an N-channel MOSFET as an intermediary component between the power supply terminal and the internal ground generation circuit. This MOSFET acts as a voltage regulator that ensures the internal ground voltage remains stable even when the power supply voltage drops, thereby maintaining drive circuit operation without requiring additional chip area for complex voltage regulation structures.
Solution Approach 2:
The patent changes the voltage parameter relationship by using the MOSFET to dynamically adjust the internal ground voltage based on the power supply voltage. When the power supply voltage drops, the MOSFET adjusts its channel resistance to maintain the internal ground voltage at a level sufficient for drive circuit operation, effectively decoupling the drive circuit's voltage requirements from the fluctuating power supply voltage.
2Device complexity
If the internal ground voltage is generated using conventional methods, then the circuit structure is simple, but the internal ground voltage becomes unstable when the power supply voltage drops
Solution Approach 1:
The N-channel MOSFET serves as a voltage stabilization intermediary that sits between the power supply terminal and the internal ground generation circuit. It monitors the power supply voltage and adjusts the internal ground voltage accordingly, preventing instability without requiring complex feedback control circuits.
Solution Approach 2:
The MOSFET is configured to automatically adjust its operation based on the power supply voltage conditions. When the power supply voltage drops, the MOSFET self-adjusts its channel resistance to maintain the internal ground voltage, eliminating the need for external control mechanisms while ensuring voltage stability.
3Area of stationary object
If the drive circuit is designed to operate at low voltage, then the chip area is reduced, but the power supply voltage range is limited
Solution Approach 1:
The patent enables the drive circuit to adapt to varying power supply voltages by introducing a controllable voltage reference (the MOSFET-adjusted internal ground). This allows the drive circuit to maintain low-voltage operation for area efficiency while the system can accommodate a wider power supply voltage range through dynamic voltage adjustment.
Solution Approach 2:
The patent makes the internal ground voltage dynamic rather than fixed. The MOSFET continuously adjusts the internal ground voltage based on the power supply voltage, allowing the drive circuit to operate efficiently across a wide voltage range while maintaining the benefits of low-voltage design.
Data Source
AI summary
A semiconductor device, including a power supply terminal, an output terminal, a ground terminal, an N-channel main MOSFET connected between the power supply terminal and the output terminal, a drive circuit which operates to drive the main MOSFET, using a potential difference, between the power supply terminal and an internal ground, as a power supply thereof, an internal ground generation circuit which is provided between the power supply terminal and the ground terminal and which generates the internal ground, an N-channel first MOSFET provided between an output terminal of the internal ground generation circuit and the ground terminal, and a low voltage detection circuit which is provided between the power supply terminal and the ground terminal, and which turns on the first MOSFET upon detecting that a voltage between the power supply terminal and the ground terminal drops below a prescribed voltage.