Single-Supply Gate Driver Circuit for Accidental Turn-On Prevention
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Solution Overview
Problem
Existing power semiconductor modules face issues with accidental turn-on during transient phenomena due to positive threshold characteristics of enhancement elements, requiring negative bias application, which complicates system design and increases size, and struggle with reliable operation at high temperatures and voltages.
Innovation Solution
A driving circuit integrated on an IC chip that generates a second voltage from a single power supply, allowing for negative bias application without the need for a negative power supply, using a buffer amplifier to sink or source current for the control terminal of the semiconductor switching element, eliminating the requirement for large-capacity capacitors and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a negative bias is applied to the gate terminal to prevent accidental turn-on during transient phenomena, then reliability is improved, but device complexity increases due to requiring a negative power supply
Solution Approach 1:
Instead of applying negative bias to the gate terminal as in conventional approaches, this invention applies positive bias to the emitter terminal. The emitter terminal, which is normally at reference potential, is shifted to a positive potential during off-state. This inverted approach achieves the same safety margin against accidental turn-on without requiring negative voltage generation circuitry.
Solution Approach 2:
The single power supply serves multiple functions: it provides the positive voltage for normal gate drive operations and, through the voltage division circuit, generates the positive bias for the emitter terminal. This eliminates the need for separate negative power supply circuits while maintaining all necessary voltage levels for reliable switching operation.
2Reliability
If a negative power supply is added to apply negative bias, then reliability is improved, but the system size increases
Solution Approach 1:
The single power supply unit is designed to perform multiple functions: providing the main positive voltage for gate drive, generating the divided positive voltage for emitter bias through voltage division circuitry, and enabling normal reference potential operations. This consolidation eliminates the need for separate negative power supply components and reduces overall system footprint.
Solution Approach 2:
The voltage division circuit integrates the generation of emitter bias voltage directly into the existing power supply architecture. By combining the positive voltage generation and division functions within the single power supply block, the design merges multiple voltage generation tasks into one unified circuit, reducing component count and system area.
3Area of stationary object
If the control IC and IGBT are arranged close to each other to reduce interconnect impedance, then the system size is reduced, but reliability deteriorates in high-temperature and high-voltage environments
Solution Approach 1:
The patent applies preliminary anti-action by pre-shifting the emitter potential to a positive level before transient phenomena occur. This creates a safety margin that counteracts the harmful effects of voltage spikes and feedback capacitor charging that would otherwise cause accidental turn-on. The protective bias is established in advance, preventing the reliability issue rather than reacting to it.
Solution Approach 2:
The invention changes the voltage parameter at the emitter terminal from the conventional 0V reference potential to a positive potential during off-state. This parameter change fundamentally alters the voltage relationship between gate and emitter, ensuring that even with reduced interconnect impedance, the switching element maintains reliable off-state operation in high-temperature and high-voltage environments.
4Device complexity
If a single power supply is used instead of dual power supplies, then device complexity is reduced, but the ability to provide negative bias is lost
Solution Approach 1:
The invention inverts the conventional approach by applying positive bias to the emitter terminal instead of negative bias to the gate terminal. This allows the use of a single power supply while achieving the same reliability effect, as the positive emitter bias creates the necessary voltage margin without requiring negative voltage generation.
Solution Approach 2:
By changing the reference potential parameter at the emitter terminal to a positive value during off-state, the system achieves reliable switching control with a single power supply. This parameter change transforms the voltage relationship to eliminate the need for negative bias while maintaining all necessary control capabilities.
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
Enables reliable operation of semiconductor switching elements with negative bias using a single power supply, reducing system size and preventing capacitor-related issues, while maintaining efficient power consumption and extending the lifespan of the semiconductor device.
Implementation Method 1
The power supply circuit includes a buffer amplifier for sinking or sourcing a current for driving the control terminal of the semiconductor switching element
Data Source
AI summary
A driving circuit is placed on an IC chip, and which drives a semiconductor switching element. The driving circuit includes: a power supply circuit for receiving a first voltage supplied from a single power supply provided outside the IC chip, generating a second voltage based on the first voltage, and applying the second voltage to a reference terminal of the semiconductor switching element; and a driving part for driving the semiconductor switching element by applying the first voltage or stopping application of the first voltage to a control terminal of the semiconductor switching element in response to an input signal given from outside the IC chip.