Over-current detection and protection circuit for power MOS tube, and power MOS tube assembly
A MOS tube and overcurrent detection technology, applied in emergency protection circuit devices, overcurrent protection, electrical components, etc., can solve problems such as overcurrent detection point deviation, and achieve the effect of avoiding early protection or protection failure
Pending Publication Date: 2021-04-23
SHANGHAI EASTSOFT MICROELECTRONICS
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However, since R S The voltage drop, M 2 and M 1 The gate-source voltages are not exactly equal, therefore, M 2 cannot exactly reproduce the flow through the M 1 The output current I O , making the output current I O There is a deviation in the relevant overcurrent detection point
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[0030] In the prior art, the sampling MOS tube cannot accurately replicate the output current flowing through the power MOS tube, so that there is a deviation in the set overcurrent detection point (ie, the current threshold); and the body effect, ambient temperature and Factors such as resistor manufacturing precision can also introduce further deviations in the current threshold. If the deviation makes the current threshold set too low, it will lead to early protection when the load is small; if the deviation makes the current threshold set too high, it will cause protection failure, which may cause damage to the power MOS tube.
[0031] In an embodiment of the present invention, the overcurrent detection and protection circuit includes a gate control module, whose input terminal is coupled to the source of the power MOS tube, and whose output terminal is coupled to the gate of the power MOS tube to provide the power MOS tube with a gate Driving voltage, so that the current ...
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Abstract
The embodiment of the invention provides an over-current detection and protection circuit for a power MOS transistor, and a power MOS transistor assembly. The over-current detection and protection circuit comprises a current sampling module and a grid control module. The current sampling module is suitable for sampling current flowing through the source electrode of the power MOS tube. The input end of the grid control module is coupled with the source electrode of the power MOS tube, and the output end of the grid control module is coupled with the grid electrode of the power MOS tube to provide grid driving voltage for the power MOS tube, so that the current does not exceed the current threshold value of the power MOS tube. Therefore, the current flowing through the power MOS tube does not have overcurrent, and the current threshold value is accurately calculated without deviation of the current threshold value, so that advanced protection or protection failure of the power MOS tube caused by the deviation can be avoided.
Description
technical field [0001] The invention relates to the field of current detection, in particular to an overcurrent detection and protection circuit for a power MOS tube and a power MOS tube assembly. Background technique [0002] A power metal oxide semiconductor field effect transistor (Metal Oxide Semiconductor Effect Transistor) is also called a power MOS transistor, and a large current usually flows when it is turned on. If the load is accidentally short-circuited, or the current exceeds the limit value of the power MOS tube switch, it may be permanently damaged. In order to ensure the reliability of the long-term operation of the device, the load current must be detected; and, when the current is too large, the power MOS tube can be protected to avoid damage to the device due to overheating. [0003] figure 1 It shows a typical circuit structure diagram for detecting the current flowing through the power MOS tube, wherein the sampling MOS tube M 2 will flow through the ...
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Login to View More IPC IPC(8): H02H7/20H02H3/08H02H1/00
CPCH02H7/205H02H3/08H02H1/0007
Inventor 夏钊张旭陈光胜
Owner SHANGHAI EASTSOFT MICROELECTRONICS