Parallel Power Semiconductor Current Balance via Gate Feedback
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Solution Overview
Problem
Conventional semiconductor devices face challenges in maintaining current balance and preventing thermal breakdown when multiple power semiconductor elements are connected in parallel, leading to inefficiencies and increased costs due to temperature variations and manufacturing imbalances.
Innovation Solution
A semiconductor device configuration that includes a control circuit, a power semiconductor element, and a gate driving circuit with a resistor exhibiting a positive temperature characteristic and a diode with a negative temperature characteristic, allowing for negative feedback to achieve current balance without dedicated temperature-cancelling elements, and utilizing a charge pump circuit to manage voltage and switching times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple power semiconductor elements are connected in parallel to increase current carrying capacity, then the current capacity is improved, but temperature variations and manufacturing imbalances cause current distribution unevenness leading to thermal breakdown
Solution Approach 1:
The patent introduces a feedback mechanism where the gate driving circuit monitors the actual gate voltage and adjusts the driving signal accordingly. This feedback loop compensates for temperature variations and manufacturing imbalances by dynamically adjusting the gate voltage to maintain equal current distribution among parallel-connected power semiconductor elements, preventing thermal breakdown while preserving current carrying capacity
Solution Approach 2:
The patent changes the gate voltage parameter dynamically based on temperature and operating conditions. By adjusting the gate voltage through the gate driving circuit, the system compensates for parameter variations in parallel-connected elements, ensuring uniform current distribution across different temperature ranges and maintaining reliability while utilizing the full current capacity
2Temperature
If the effective area for current flow is reduced to prevent thermal breakdown, then temperature control is improved, but the current carrying capacity and power handling ability deteriorate
Solution Approach 1:
The feedback mechanism in the gate driving circuit enables real-time monitoring and adjustment of gate voltage based on temperature conditions. This allows the system to maintain lower temperatures through precise voltage control without requiring reduced device area, thereby preserving full current carrying capacity while achieving effective temperature management
Solution Approach 2:
The system transitions from a static design where area must be reduced for temperature control to a dynamic system where gate voltage is continuously adjusted based on operating conditions. This dynamic control allows the full device area to be utilized for current conduction while maintaining temperature within safe limits through adaptive voltage regulation
3Temperature
If dedicated temperature-cancelling elements are added to compensate for temperature variations, then temperature stability is improved, but device complexity and cost increase
Solution Approach 1:
The gate driving circuit is designed to perform multiple functions: it provides the primary gate drive signal, monitors gate voltage through feedback, compensates for temperature variations, and ensures uniform current distribution among parallel elements. By making the gate driving circuit multi-functional, the patent achieves temperature stability without adding separate dedicated temperature-cancelling elements, thereby avoiding increased device complexity
Solution Approach 2:
The patent merges the temperature compensation function with the existing gate driving circuit rather than adding separate compensation elements. The feedback mechanism and voltage adjustment capabilities are integrated into the gate driving circuit, combining temperature stabilization and current control functions in a single circuit block, thus maintaining simplicity while achieving temperature stability
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
This configuration effectively compensates for temperature-related imbalances between semiconductor elements, maintaining current balance and preventing thermal breakdown, allowing for flexible response to changes in current carrying capacity without redesigning the semiconductor device or increasing its size.
Implementation Method 1
a resistor exhibiting a positive temperature characteristic
Implementation Method 2
a diode exhibiting a negative temperature characteristic
Implementation Method 3
a charge pump (CP) circuit 120, which raises a voltage up to a value higher than the power supply voltage VCC voltage
Data Source
AI summary
A semiconductor device that compensates for imbalance between a plurality of semiconductor elements connected in parallel by negative feedback to achieve current balance utilizing reversed temperature characteristics without providing any dedicated element just for cancelling temperature characteristics. A gate driving circuit turns ON a power semiconductor element by applying a voltage elevated by a charge pump (CP) circuit to a gate through a resistor connected between the CP circuit and the gate. The power semiconductor element is turned OFF by control circuit that gives a control signal to turn ON a MOS switch in the gate driving circuit and discharges the gate through a diode.