Switching Regulator Control Circuit High-Speed Transistor Turn-Off
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Solution Overview
Problem
Existing switching regulators using MOS transistors face challenges in switching off the transistor at high speed due to the difficulty in controlling the gate voltage to be lower than the source voltage, leading to inefficiencies and potential instability in output voltage.
Innovation Solution
A control circuit for switching regulators that includes a signal generation circuit and an output circuit capable of outputting a voltage lower than the source voltage as an off-voltage level to the gate of the N-type transistor, utilizing a boosting circuit or external voltage supply to achieve high-speed switching off, and for P-type transistors, outputting a voltage higher than the source voltage for efficient switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the gate voltage is set to the same electric potential as the source voltage to switch off the MOS transistor, then the transistor can be turned off, but the switching speed is slow
Solution Approach 1:
Instead of setting the gate voltage to the same potential as the source voltage (conventional method), the patent inverts the approach by generating a voltage that is actually lower than the source voltage. This is achieved by using a boosting circuit that produces a negative voltage relative to the source voltage, thereby enabling fast turn-off of the MOS transistor by creating a sufficient voltage difference between gate and source.
2Speed
If a voltage lower than the source voltage is output to switch off the N-type transistor, then high-speed switching is achieved, but the device complexity increases due to the boosting circuit
Solution Approach 1:
The boosting circuit is designed to serve multiple functions within the switching regulator system. It not only generates the negative voltage required for fast turn-off of the N-type MOS transistor but also provides voltage boosting functionality for the overall regulator operation. This multi-functionality reduces the need for separate dedicated circuits, thereby mitigating the increase in device complexity.
3Loss of energy
If the transistor switching speed is increased, then power efficiency is improved, but the stability of output voltage may be compromised
Solution Approach 1:
The patent incorporates feedback mechanisms that monitor the output voltage and adjust the switching control accordingly. The control circuit receives feedback about the output voltage status and modifies the switching signals to maintain stability. This feedback loop ensures that even with high-speed switching, the output voltage remains stable and within acceptable ranges, preventing oscillations or instability that could arise from rapid switching transitions.
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
Enables high-speed switching off of transistors, improving power efficiency and stability of the output voltage by steepening the drive signal waveform and preventing unintended reactivation of the transistor, thus enhancing the overall performance of the switching regulator.
Implementation Method 1
the boosting circuit is a charge pump type boosting circuit that converts voltage using a switched capacitor circuit
Data Source
AI summary
Provided are a control circuit for a switching regulator that can switch off a transistor that drives an inductor at high speed, an integrated circuit device, the switching regulator, an electronic device, and the like. A control circuit (100) includes a signal generation circuit (10) and an output circuit (20). The signal generation circuit (10) generates a control signal (SG) for a switching regulator. Upon receiving the control signal (SG), the output circuit (20) outputs a drive signal (GD) to a gate of an N-type transistor (30) that drives an inductor (40). The output circuit (20) outputs a voltage level lower than a source voltage of the N-type transistor (30) as an off-voltage level of the drive signal (GD) for switching off the N-type transistor (30).