High-Voltage Switch Driving Circuit for Fast Symmetric Transients
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High voltage switch configurations face challenges in achieving quick switch transients with reasonable control current values, as existing designs require a small resistive element to manage parasitic capacitances, leading to long turn-off times and inefficiencies.
Innovation Solution
A driving circuit with a latch circuit between the gate and source terminals of transistors, utilizing latch transistors and clamp circuits to manage current values and ensure correct switch states, including flip-flops and activation circuits to dynamically short-circuit resistances during signal edges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a small resistive element is used to manage parasitic capacitances, then the switch can be turned on quickly, but the turn-off time becomes long
Solution Approach 1:
The patent segments the resistive element into two distinct paths: a first resistive element for charging the parasitic capacitance during turn-on, and a second resistive element for discharging during turn-off. This segmentation allows each resistive element to be optimized independently for its specific function, resolving the contradiction between fast turn-on and fast turn-off
Solution Approach 2:
The patent introduces dynamic control through a control circuit that actively manages the charging and discharging paths. The control circuit dynamically switches between different resistive elements based on the switch state, enabling rapid turn-on when needed and rapid turn-off when needed, making the system adaptive to different operational requirements
2Speed
If a resistive element is used to control parasitic capacitances, then switching speed improves, but power dissipation increases
Solution Approach 1:
The patent applies different resistive values to different parts of the circuit based on local requirements: a first resistive element with optimized value for charging during turn-on, and a second resistive element with optimized value for discharging during turn-off. This local optimization minimizes power dissipation in each path while maintaining fast switching performance
Solution Approach 2:
The control circuit dynamically activates only the necessary resistive element for the current operation mode, avoiding continuous power dissipation. During turn-on, only the charging path is active; during turn-off, only the discharging path is active, significantly reducing overall power consumption compared to having both paths continuously active
3Strength
If the switch uses two transistors in series with intrinsic diodes in antiseries, then voltage handling capability improves, but device complexity increases
Solution Approach 1:
The patent combines the voltage handling function and the parasitic capacitance control function into a single integrated circuit structure. The control circuit is directly coupled to the gate terminals of both transistors, and the resistive elements are strategically placed to simultaneously manage voltage distribution and capacitance discharge, eliminating the need for separate control mechanisms and reducing overall complexity
Solution Approach 2:
The control circuit serves multiple functions simultaneously: it controls the gate voltages of both transistors, manages the discharge of parasitic capacitances through the second resistive element, and ensures proper voltage distribution across the series-connected transistors. This multi-functionality reduces the need for additional dedicated circuits, maintaining simplicity despite the enhanced voltage handling capability
Data Source
AI summary
A driving circuit of a switch includes first and second transistors connected in series to each other and to relative intrinsic diodes in antiseries and driven by a driving device that includes at least one first and one second output terminal connected to the switch to supply it with a first control signal for driving the switch in a first working state and a second control signal for driving the switch in a second working state. At least one latch circuit coupled between respective common gate and source terminals of the first and second transistors supplies the common gate terminal with the first and second control signals, respectively, according to the working state to turn off and turn on the first and second transistors. The latch circuit comprises at least one flip-flop coupled to the common source terminal and having a reset terminal coupled to the first output terminal of the driving device and to the common source terminal by means of a reset resistance, a set terminal coupled to the second output terminal of the driving device and to the common source terminal by means of a set resistance and an output terminal coupled to the common gate terminal. The latch circuit further includes an activation circuit connected to the set and reset terminals of the flip-flop and to the common source terminal in order to dynamically short-circuit the set and reset resistances during the falling edges of the signal applied to the switch.