Gate Control Circuit With Voltage Boosting During Supply Transitions
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Solution Overview
Problem
In high-side and low-side transistor control circuits for power semiconductor devices, existing technologies face challenges in maintaining stable operation and preventing simultaneous turn-on during power supply voltage fluctuations, especially at low voltages and temperatures, leading to potential through currents and uncontrollable gate voltages.
Innovation Solution
A gate control circuit with a voltage adjustment mechanism that temporarily increases the potential difference between reference voltage nodes during specific voltage transitions, ensuring stable operation and preventing simultaneous turn-on of high-side and low-side transistors, even at low voltages and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the power supply voltage VCC is temporarily decreased during power supply or power blocking, then the level shift circuits cannot be normally operated and monitor signals cannot be correctly transmitted, but using conventional monitoring circuits requires two separate systems (VCC-Hs_GND and VCC-GND) which increases device complexity
Solution Approach 1:
The patent combines the VCC-Hs_GND monitoring function and VCC-GND monitoring function into a single integrated monitoring circuit. The circuit uses a single comparator to monitor both the potential difference between VCC and Hs_GND and the potential difference between VCC and GND, thereby reducing device complexity while maintaining reliable monitor signal transmission during power supply fluctuations.
Solution Approach 2:
The monitoring circuit is designed to perform multiple functions simultaneously: it monitors the high-side floating power supply potential difference (VCC-Hs_GND) and the main power supply potential difference (VCC-GND) using a single circuit structure. This multi-functional approach eliminates the need for separate monitoring systems and reduces overall circuit complexity.
2Reliability
If the buck level shift circuit is not operated when VCC is low, then the low side transistor is maintained in turn-off state and the output terminal becomes high impedance, causing uncontrollable current flow in external MOS transistors, but adding protection circuits increases device complexity
Solution Approach 1:
The patent integrates the output terminal voltage stabilization function into the existing monitoring circuit. The same monitoring circuit that detects power supply voltage abnormalities also controls the stabilization of the output terminal voltage, eliminating the need for separate protection circuits and reducing device complexity while ensuring gate voltage stability.
Solution Approach 2:
The monitoring circuit provides feedback control for the output terminal voltage stabilization. When the comparator detects abnormal power supply voltage, it generates a monitoring signal that feeds back to control the stabilization circuit, which in turn regulates the output terminal voltage to prevent uncontrollable current flow in external MOS transistors.
3Reliability
If the potential difference (VCC-Hs_GND) is not maintained at low voltage (2.4V) and low temperature, then the high side transistor turn-on state cannot be maintained during lightning surge interruptions, but using conventional circuits leads to simultaneous turn-on of high side and low side transistors causing through current
Solution Approach 1:
The monitoring circuit performs preliminary detection of power supply voltage abnormalities before they cause harmful effects. When the comparator detects that VCC drops below the threshold (2.4V), it generates a monitoring signal in advance that prevents the simultaneous turn-on of high side and low side transistors, thereby preventing through current flow before it can occur.
Solution Approach 2:
The circuit uses feedback control to maintain proper transistor states during voltage fluctuations. The monitoring signal generated by the comparator feeds back to the transistor control logic, ensuring that the high side transistor turn-on state is maintained or properly terminated based on the actual power supply conditions, preventing through current while maintaining reliable operation.
Data Source
AI summary
A gate control circuit has a first gate controller that controls a gate voltage of a first transistor connected between a first reference voltage node and an output node on the basis of a potential difference between the first reference voltage node and a second reference voltage node, a second gate controller that controls a gate voltage of a second transistor connected between the output node and a fourth reference voltage node. and a voltage adjustment circuit that temporarily increases the potential difference between the first reference voltage node and the second reference voltage node in a first period in which the voltage of the first reference voltage node is rising from an initial voltage and a second period in which the voltage of the first reference voltage node is falling from a normal voltage.