Bipolar Gate Driver Charge Pump Negative Voltage
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Solution Overview
Problem
Advanced power semiconductor devices with low gate threshold voltages and high switching rates lead to oscillations in gate voltage, causing shoot-through faults in converters/inverters due to the lack of negative gate voltage control.
Innovation Solution
A bipolar gate driver utilizing charge pump circuits to generate negative supply voltages from a single positive power supply, allowing for the provision of bipolar control signals to semiconductor devices, preventing oscillations and ensuring reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If advanced power semiconductor devices with low gate threshold voltages and high switching rates are used, then productivity and power efficiency are improved, but gate voltage oscillations occur causing shoot-through faults
Solution Approach 1:
The bipolar gate driver proactively applies a negative voltage offset to the gate control signal before switching events occur. This preliminary anti-action ensures that even if oscillations occur during switching, the gate voltage remains below the threshold voltage, preventing false turn-on and shoot-through faults while maintaining high switching rates.
Solution Approach 2:
The invention changes the parameter of gate voltage from unipolar (0V to Vcc) to bipolar (negative voltage to positive voltage). By introducing a negative voltage component, the gate driver creates a voltage margin that prevents oscillations from exceeding the threshold voltage, thereby resolving the reliability issue while preserving high switching performance.
2Ease of operation
If unipolar control signals are used with low gate threshold voltage devices, then device operation is simplified, but gate voltage oscillations cause loss of control and shoot-through faults
Solution Approach 1:
The gate driver transforms the control signal from a simple unipolar waveform to a bipolar waveform with a negative voltage offset. This parameter change maintains the simplicity of the control interface while adding the necessary voltage margin to prevent oscillations from causing loss of control, thereby improving reliability without significantly complicating operation.
3Productivity
If high switching rates are implemented, then productivity increases, but gate voltage oscillations increase causing shoot-through faults
Solution Approach 1:
The bipolar gate driver applies a negative voltage offset in advance to counteract the harmful oscillations that occur during high-speed switching. This preliminary anti-action creates a voltage buffer that prevents oscillations from reaching the threshold voltage, enabling high switching frequencies without the harmful effects of shoot-through faults.
Solution Approach 2:
By changing the gate voltage parameter to include a negative component, the invention creates sufficient voltage headroom to absorb the oscillations generated during high-rate switching. This parameter modification eliminates the harmful oscillation effects while preserving the benefits of high switching frequency operation.
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 use of bipolar gate drivers effectively prevents shoot-through faults by maintaining gate voltages below the threshold voltage, enhancing the reliability and efficiency of converter/inverter operations.
Implementation Method 1
A bipolar gate driver utilizing charge pump circuits to generate negative supply voltages from a single positive power supply
Data Source
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AI summary
According to one aspect, embodiments of the invention provide a gate driver comprising a level shifter circuit configured to be coupled to a controller, to receive control signals from the controller, each control signal having a voltage with respect to a control ground, and to redefine the voltage of each control signal with respect to a chip ground to generate redefined control signals, a gate driver chip coupled to the level shifter circuit and configured to be coupled to at least one semiconductor device, the gate driver chip further configured to provide bipolar control signals to the at least one semiconductor device based on the redefined control signals, and at least one power source configured to provide at least one positive supply voltage to the gate driver chip and at least one negative supply voltage to the gate driver chip and to the chip ground.