Switching Transistor Drive Circuit With Dynamic Short-Circuit Voltage
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Solution Overview
Problem
Existing driving circuits for switching transistors face inefficiencies and short-circuit protection challenges due to varying driving voltages, leading to high power loss and potential damage from rapid short-circuit currents.
Innovation Solution
A driving circuit with a power amplifier, voltage regulating devices, and a transistor control circuit that adjusts the driving voltage based on the switching transistor's state, using a push-pull circuit and voltage dividing devices to manage the PWM signal and provide efficient power amplification while enabling rapid short-circuit protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a high driving voltage (18V) is applied to the switching transistor, then the power loss is reduced and efficiency is improved, but the short-circuit current rises rapidly causing damage to the transistor
Solution Approach 1:
The driving voltage is made dynamic rather than fixed. The circuit automatically adjusts the driving voltage between two levels (first driving voltage and second driving voltage) based on the working state of the switching transistor. When the transistor is in a short-circuit state, the circuit switches to the second driving voltage (lower voltage) to limit short-circuit current. When the transistor is in normal working state, the circuit uses the first driving voltage (higher voltage) to reduce power loss and improve efficiency.
Solution Approach 2:
The circuit changes the voltage parameter of the driving signal based on the detected working state. By detecting whether the switching transistor is in a short-circuit state or normal working state, the circuit changes the driving voltage parameter between two discrete values, thereby optimizing both power efficiency and short-circuit protection.
2Reliability
If a low driving voltage (15V) is applied to the switching transistor, then the short-circuit protection time is extended, but the power loss increases and efficiency decreases
Solution Approach 1:
The driving voltage is made dynamic rather than fixed. The circuit automatically adjusts the driving voltage between two levels (first driving voltage and second driving voltage) based on the working state of the switching transistor. When the transistor is in a short-circuit state, the circuit switches to the second driving voltage (lower voltage) to limit short-circuit current. When the transistor is in normal working state, the circuit uses the first driving voltage (higher voltage) to reduce power loss and improve efficiency.
Solution Approach 2:
The circuit changes the voltage parameter of the driving signal based on the detected working state. By detecting whether the switching transistor is in a short-circuit state or normal working state, the circuit changes the driving voltage parameter between two discrete values, thereby optimizing both power efficiency and short-circuit protection.
3Device complexity
If a fixed driving voltage is used, then the circuit structure is simple, but the circuit cannot adapt to different working states (short-circuit vs normal operation)
Solution Approach 1:
The circuit incorporates a feedback mechanism that detects the working state of the switching transistor and uses this information to control the voltage switching. The detection circuit monitors parameters such as voltage or current to determine whether the transistor is in a short-circuit state or normal working state, and this detection result feeds back to control the selection between the first and second driving voltages, enabling adaptive operation.
Solution Approach 2:
The driving circuit is designed to perform multiple functions: it can provide high driving voltage for normal operation to reduce power loss, switch to low driving voltage for short-circuit protection, and automatically detect and respond to different working states. This multi-functionality is achieved through the combination of voltage switching circuit and detection circuit within a single integrated system.
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
The solution reduces power loss, improves efficiency, and extends the time for short-circuit protection of the switching transistor by dynamically adjusting the driving voltage in response to the transistor's state, ensuring both low power consumption and high efficiency.
Implementation Method 1
a power amplifier, including a first power transistor and a second power transistor that are connected between a first direct current voltage terminal and a second direct current voltage terminal and are arranged in a push-pull circuit, where an input terminal of the power amplifier is configured to receive a pulse-width modulation (PWM) signal, an output terminal of the power amplifier outputs a PWM drive signal with amplified power
Implementation Method 2
a first voltage regulating device, connected between the input terminal of the power amplifier and a control terminal of the first power transistor, where a first predetermined voltage is applied across the first voltage regulating device
Implementation Method 3
a power amplifier, including a first power transistor and a second power transistor that are connected between a first direct current voltage terminal and a second direct current voltage terminal and are arranged in a push-pull circuit
Data Source
AI summary
The present invention provides a driving circuit for a switching transistor and a driving device including the same. The driving circuit includes: a power amplifier, including a first power transistor and a second power transistor that are connected between a first direct current voltage terminal and a second direct current voltage terminal and are arranged in a push-pull circuit; a first voltage regulating device, connected between an input terminal of the power amplifier and a control terminal of the first power transistor; a third power transistor, connected between an output terminal of the power amplifier and the second direct current voltage terminal or a grounding terminal; a first voltage dividing device, connected between the input terminal and the output terminal of the power amplifier; and a transistor control circuit, configured to: control the third power transistor to be turned on when the switching transistor is located in a short-circuit path, and control the third power transistor to be turned off when the switching transistor is controlled to be turned on and is not located in the short-circuit path. The driving circuit of the present invention reduces the power consumption of the switching transistor and extends the time for short-circuit protection.