Switching Circuit Charge Pump Segmentation for Speed and Loss
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Solution Overview
Problem
The existing switching circuits with charge pump units experience a decrease in switching speed and an increase in switching loss due to the flow of electric charges through resistors during turn-on and turn-off operations of voltage-driven switching elements.
Innovation Solution
A switching circuit configuration that includes a charge pump unit with a first and second capacitor, where the first capacitor is charged through a first wiring when the first switching element is turned on and discharged through a second wiring when the second switching element is turned on, minimizing the flow of electric charges through resistors and thereby reducing switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a charge pump unit is added to generate negative voltage for driving voltage-driven switching elements, then the switching element can be properly driven with appropriate gate voltages, but the switching speed decreases and switching loss increases due to charge flow through resistors
Solution Approach 1:
The patent segments the charging and discharging paths for the first capacitor C1 by introducing separate first and second wirings. The first wiring connects to the gate turn-on wiring at a point between the first switching element S1 and first resistor R1, while the second wiring connects to the gate turn-off wiring at a point between the second switching element S2 and second resistor R2. This segmentation allows independent optimization of charge and discharge paths, enabling fast charging through the first wiring without affecting discharge speed through the second wiring, thereby resolving the contradiction between reliable driving and high switching speed.
2Speed
If the first capacitor is connected to the gate turn-on wiring at a point between the first switching element and first resistor, then turn-on speed is maintained, but during turn-off the capacitor discharges through both resistors causing increased loss and reduced turn-off speed
Solution Approach 1:
The patent extracts the discharging path for the first capacitor C1 from the conventional path that goes through both resistors R1 and R2. By introducing a dedicated second wiring that connects the first capacitor to the gate turn-off wiring at a point between the second switching element S2 and second resistor R2, the discharge current is taken out directly without flowing through the resistors. This eliminates the energy loss that would occur during discharge while maintaining fast turn-off speed, resolving the contradiction between turn-on speed maintenance and switching loss reduction.
3Productivity
If separate charging and discharging paths for the first capacitor are implemented using first and second wirings, then switching speed is maintained and switching loss is reduced, but the circuit complexity increases
Solution Approach 1:
The patent applies multi-functionality to the first capacitor C1 and its associated wirings. The first capacitor serves dual purposes: it is charged through the first wiring during the turn-on phase and discharged through the second wiring during the turn-off phase. The first and second wirings are integrated into the existing gate drive circuitry, connecting at strategic points between switching elements and resistors. This multi-functional design achieves fast switching and low loss without requiring completely separate independent circuits, thereby minimizing the increase in overall circuit complexity while maintaining high productivity.
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 suppresses the decrease in switching speed and increase in switching loss by optimizing the charging and discharging paths for the capacitors, allowing for efficient operation of voltage-driven switching elements.
Implementation Method 1
a first capacitor C1... In a case of turning on the voltage-driven switching element SM, an electric charge is also charged in the first capacitor C1 of the charge pump unit
Data Source
AI summary
A first switching element and a gate of a voltage-driven switching element are connected by a gate turn-on wiring through a first resistor. The gate of the voltage-driven switching element and a second switching element are connected by a gate turn-off wiring through a second resistor. A charge pump unit has a first capacitor, and a second capacitor configured to output a negative voltage. A resistor unit is arranged in at least one of a first wiring configured to connect the gate turn-on wiring and the first capacitor and a second wiring configured to connect the gate turn-off wiring and the first capacitor, and is configured to charge the first capacitor through the first wiring when the first switching element is turned on and to discharge the first capacitor through the second wiring when the second switching element is turned on.