Floating Gate Driver Circuit Noise Immunity via Dynamic Load Control
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Solution Overview
Problem
Existing floating gate driver circuits face noise immunity issues due to dv/dt noise, leading to incorrect switching of high-voltage power switches, especially in high-voltage applications, where fixed resistances and RC response times limit dynamic control and flexibility in circuit design.
Innovation Solution
A floating gate driver circuit with a level shifter, pass element, and control logic circuit using current sources or programmable impedance devices as loads, allowing dynamic control of voltage speeds at the bistable circuit terminals to minimize dv/dt noise influence and prevent erroneous triggering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If resistor-based level shifting is used, then the circuit structure is simple, but the RC response time is fixed and noise immunity is poor
Solution Approach 1:
The patent replaces fixed resistors with dynamically controllable current sources that can adjust their impedance based on circuit state. The control logic circuit dynamically switches between different current source configurations to optimize both response time and noise immunity during different operating phases, transforming a static resistor-based design into a dynamic adaptive system.
Solution Approach 2:
The invention changes the fundamental parameter from fixed resistance to variable current output. By using current sources with controllable magnitude and timing, the circuit can adjust its effective impedance and response characteristics dynamically, improving noise immunity while maintaining manufacturing simplicity through integrated circuit implementation.
2Use of energy by moving object
If dv/dt noise is present at the floating node, then the bootstrap capacitor maintains power supply, but noise couples to the power supply terminal causing incorrect switching
Solution Approach 1:
The patent introduces an intermediate filtering stage between the bootstrap capacitor and the power supply terminal. The control logic circuit acts as a mediator that detects noise conditions and activates filtering current sources to block dv/dt noise coupling while allowing legitimate power supply current to pass through, thus protecting the sensitive input terminals from noise-induced incorrect switching.
Solution Approach 2:
The invention converts the harmful dv/dt noise effect into a useful signaling mechanism. By detecting the noise-induced current through the bootstrap capacitor, the control logic identifies when noise is present and activates compensatory measures, such as adjusting current source outputs or enabling additional filtering, thereby turning the noise presence into a trigger for protective action.
3Ease of operation
If parasitic capacitors at the level shifter output are present, then the circuit functions normally, but transient voltage changes induce currents that charge/discharge parasitic capacitors causing logic state changes
Solution Approach 1:
The patent applies preliminary action by pre-charging or pre-discharging the parasitic capacitors through controlled current sources before the main switching event occurs. The control logic circuit anticipates the voltage transient and prepares the parasitic capacitors in advance, ensuring they are in a known state that prevents erroneous logic transitions when the actual switching occurs.
Solution Approach 2:
The invention implements preliminary anti-action by applying counteracting currents through the controllable current sources before the dv/dt transient affects the parasitic capacitors. The control logic detects impending voltage changes and activates current sources that oppose the noise-induced charging/discharging of parasitic capacitors, preventing logic state changes before they can occur.
Data Source
AI summary
A floating gate driver circuit includes a level shifter, a pass element, a bistable circuit and a control logic circuit, to shift the voltage level of a control signal from a lower one to a higher one. The level shifter or the pass element has loads dynamically controlled by the control logic circuit to filter malfunction caused by dv/dt noise induced by a floating node.