High Side Switch Under-Voltage Protection Circuit
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Solution Overview
Problem
Smart power switches in automotive applications face challenges in withstanding transient electrical disturbances like ISO7 pulses, which can cause malfunctions due to negative voltage swings on supply lines, especially when capacitance values are reduced to minimize costs.
Innovation Solution
A semiconductor chip with integrated power semiconductor switches and control circuitry that monitors unstabilized supply voltages, short-circuiting the supply and ground terminals when an under-voltage is detected to prevent activation of parasitic transistors and maintain stable logic states, along with additional protection using zener diodes and capacitors to absorb transient peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If capacitance values are reduced to minimize costs, then manufacturing cost is reduced, but immunity to transient electrical disturbances deteriorates
Solution Approach 1:
The monitoring circuit continuously monitors the supply voltage before transient disturbances can cause damage. When a disturbance is detected (voltage drops below threshold), the circuit proactively activates the short-circuiting switch to protect the semiconductor switch, preventing damage before it occurs rather than reacting after damage happens.
Solution Approach 2:
The invention introduces an intermediary protection circuit between the supply line and the semiconductor switch. This intermediary circuit includes the monitoring circuit that detects voltage disturbances and the switch that short-circuits the supply and ground terminals, acting as a mediator to protect the main semiconductor switch from transient disturbances.
2Device complexity
If capacitance values are reduced to minimize costs, then device complexity is reduced, but susceptibility to transient disturbances increases
Solution Approach 1:
The monitoring circuit continuously monitors the supply voltage before transient disturbances can cause damage. When a disturbance is detected (voltage drops below threshold), the circuit proactively activates the short-circuiting switch to protect the semiconductor switch, preventing damage before it occurs rather than reacting after damage happens.
Solution Approach 2:
The invention introduces an intermediary protection circuit between the supply line and the semiconductor switch. This intermediary circuit includes the monitoring circuit that detects voltage disturbances and the switch that short-circuits the supply and ground terminals, acting as a mediator to protect the main semiconductor switch from transient disturbances.
3Reliability
If monitoring and protection circuitry is added to withstand transient disturbances, then immunity to transient disturbances is improved, but device complexity increases
Solution Approach 1:
The protection circuit is self-regulating and automatically responds to transient disturbances without external intervention. The monitoring circuit detects voltage drops and automatically activates the short-circuiting switch, making the system self-protecting and eliminating the need for external control or complex protection mechanisms.
Solution Approach 2:
The invention changes the operational parameters of the semiconductor switch by dynamically adjusting its state based on supply voltage conditions. When voltage drops below a threshold, the switch transitions from normal operation to short-circuit mode, changing its electrical parameters to protect against transient disturbances.
4Reliability
If monitoring circuitry is added to detect under-voltage conditions, then reliability during transient disturbances is improved, but manufacturing cost increases
Solution Approach 1:
The protection circuit is self-regulating and automatically responds to transient disturbances without external intervention. The monitoring circuit detects voltage drops and automatically activates the short-circuiting switch, making the system self-protecting and eliminating the need for external control or complex protection mechanisms.
Solution Approach 2:
The invention changes the operational parameters of the semiconductor switch by dynamically adjusting its state based on supply voltage conditions. When voltage drops below a threshold, the switch transitions from normal operation to short-circuit mode, changing its electrical parameters to protect against transient disturbances.
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
Enhances the immunity of smart switches to ISO7 pulses by preventing ground shifts and unintended resets, ensuring reliable operation during transient disturbances and maintaining internal logic states without external resets.
Implementation Method 1
A monitoring circuit supplied by the stabilized second supply voltage and configured to monitor the unstabilized first supply voltage. The unstabilized first supply voltage including signaling an under-voltage when the unstabilized first supply voltage falls below a first threshold value is monitored.
Implementation Method 2
A switch configured to short circuit the first supply terminal and the third terminal when the monitoring circuit signals an under-voltage.
Implementation Method 3
along with additional protection using zener diodes and capacitors to absorb transient peaks
Implementation Method 4
along with additional protection using zener diodes and capacitors to absorb transient peaks
Data Source
AI summary
A semiconductor chip includes at least one power semiconductor switch configured to activate and deactivate current conduction from a first supply terminal, which is connected to a first supply line that provides an unstabilized first supply voltage, to the at least one output terminal in accordance with a respective control signal. In operation, the unstabilized first supply voltage is monitored and an under-voltage is signaled when the unstabilized first supply voltage falls below a first threshold value. The first supply terminal is short circuited with a third terminal when the an under-voltage is signaled.