Semiconductor Switch Driver Circuit With Short-Pulse Blanking
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Solution Overview
Problem
Existing control circuits for semiconductor switches experience unwanted power dissipation due to short transient pulses in the input signal, which are not long enough to affect the switching state of the semiconductor switch, leading to inefficiency in low-power applications.
Innovation Solution
A control circuit comprising a driver circuit, an observer circuit, and a gate circuit that detects the pulse length of input signals and blanks out pulses shorter than a critical pulse length, ensuring only sufficient pulses trigger the semiconductor switch, thereby reducing power dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the control circuit responds to all input pulses including short transient pulses, then the control circuit is highly responsive to input signals, but power dissipation increases due to cross-conduction and internal switching without affecting the semiconductor switch
Solution Approach 1:
The control circuit measures the pulse width of incoming input signals before generating the driver signal. By preliminarily assessing whether the pulse width exceeds a threshold value, the control circuit avoids unnecessary switching operations that would cause power dissipation, thus resolving the contradiction between responsiveness and energy loss.
Solution Approach 2:
The control circuit introduces an intermediate measurement step that acts as a mediator between the input signal and the driver signal generation. This intermediate pulse width measurement filters out short transient pulses before they can cause harmful cross-conduction and internal switching, reducing power dissipation while maintaining proper response to valid signals.
2Loss of energy
If the control circuit filters out short pulses to reduce power dissipation, then power efficiency improves, but the control circuit may miss legitimate short-duration switching commands
Solution Approach 1:
The control circuit dynamically adjusts the pulse width threshold parameter based on the specific application requirements and semiconductor switch characteristics. By optimizing this threshold parameter, the circuit achieves the right balance between filtering harmful short pulses and preserving legitimate switching commands, thus resolving the contradiction between power efficiency and signal response accuracy.
3Ease of operation
If the control circuit generates driver signals for every input pulse, then the control circuit maintains simple operation, but electromagnetic emissions increase during switching
Solution Approach 1:
The control circuit performs a preliminary pulse width measurement before generating driver signals. This preliminary action filters out short transient pulses that would cause unnecessary electromagnetic emissions during switching, thereby reducing harmful emissions while maintaining simple operation for valid signals.
4Productivity
If the control circuit responds to all input signals including transient pulses, then the system achieves maximum productivity in terms of switching operations, but power dissipation from cross-conduction increases
Solution Approach 1:
The control circuit implements a preliminary pulse width measurement step that filters out short transient pulses before they can trigger switching operations. This preliminary filtering reduces power dissipation from cross-conduction while maintaining high productivity by ensuring rapid response to all valid, sufficiently long input signals.
Data Source
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AI summary
The invention relates to a control circuit for driving at least one semiconductor switch having a control terminal for receiving a driver signal. The control circuit comprises: a driver circuit adapted for generating the driver signal for the semiconductor switch, the driver signal being dependent on an input signal received by the control circuit, the input signal comprising pulses having a pulse length; an observer circuit receiving the input signal, being adapted for detecting whether the pulse length of a received pulse of the input signal exceeds a critical pulse length; a gate circuit receiving the input signal, connected to the observer circuit, and adapted for gating the input signal to the driver circuit dependent on the detection result of the observer circuit.