Signal Clamping Control Module for Power Transistor Protection
Solution Overview
Problem
The high cost and complexity of insulated gate bipolar transistors (IGBTs) in ignition systems are due to their design requirements for withstanding high voltages, which necessitate internal self-protection voltage clamping mechanisms, making them expensive and complicated.
Innovation Solution
Incorporating a signal clamping control module with a signal reference module and a feedback control module to clamp the voltage difference across power transistors at a lower voltage, allowing for the use of simpler and less expensive transistors by generating a feedback signal that represents the voltage at the power transistor's anode, thereby reducing the design complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an insulated gate bipolar transistor is designed with an internal self-protection voltage clamp to withstand high voltages (400V or higher), then the transistor can operate in high-voltage ignition systems, but the design becomes relatively complicated and costly
Solution Approach 1:
The patent introduces an external voltage clamp circuit as an intermediary component between the power transistor and the high-voltage environment. This external clamp circuit absorbs the voltage clamping function, allowing the power transistor itself to be designed without complex internal protection mechanisms. The intermediary circuit handles the harmful high-voltage spikes, enabling the transistor to remain simpler while still providing reliable high-voltage operation.
2Reliability
If the voltage rating and energy rating of the insulated gate bipolar transistor are increased to handle high-voltage operation, then the transistor can withstand higher voltages during normal operation, but the cost of the transistor increases significantly
Solution Approach 1:
The patent segments the voltage protection function from the power transistor itself and places it in a separate external circuit. Instead of requiring the transistor to handle the full burden of high-voltage protection internally, the system divides the protection function into external components (voltage clamp circuit) that are optimized for this specific task. This segmentation allows the transistor to be manufactured with lower voltage ratings, reducing cost, while the external circuit handles the high-voltage protection requirements.
3Reliability
If the insulated gate bipolar transistor is designed to allow up to 400 volts between collector and emitter with internal high-voltage clamping, then the transistor can protect itself during high-voltage operation, but the design becomes relatively complicated
Solution Approach 1:
The patent extracts the high-voltage clamping function from the internal structure of the power transistor and relocates it to an external circuit. By taking out this protective function, the transistor design is simplified and can focus on optimal power switching performance without the burden of complex internal protection mechanisms. The external voltage clamp circuit provides the necessary protection, achieving the same self-protection capability without the complexity.
Data Source
AI summary
An electronic device can be used with a system, such as an ignition system, that operates a relatively high voltage. The device can include a signal clamping control module that can include a signal reference module and a feedback control module. The signal reference module is operable to provide a reference signal to the feedback control module. The feedback control can be configured to receive a scaled signal from a signal scaling module, wherein the scaled signal is representative of a signal at a current carrying electrode of a power transistor. Based on the comparison of the reference signal to the scaled signal, the measurement module provides one or more signals to a control signal drive module. The feedback control module provides a control electrode signal to a control electrode of the power transistor.