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Short-circuit detection method, short-circuit detection circuit and short-circuit detection chip when power MOS is started

A technology of short-circuit detection and MOS tubes, which is applied in the field of circuits and chips, can solve problems such as high current and danger, and achieve the effects of low trigger current, low cost, and low power loss

Pending Publication Date: 2021-04-30
江苏应能微电子有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The short-circuit detection does not require high accuracy, but requires a quick response, otherwise the current may be too high when the short-circuit state is detected, causing danger.

Method used

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  • Short-circuit detection method, short-circuit detection circuit and short-circuit detection chip when power MOS is started
  • Short-circuit detection method, short-circuit detection circuit and short-circuit detection chip when power MOS is started
  • Short-circuit detection method, short-circuit detection circuit and short-circuit detection chip when power MOS is started

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] This embodiment provides a short-circuit detection method when the power MOS is turned on, and the method specifically includes:

[0033] Connect the gate of the power MOS to the gate of the sampling MOS; wherein, the power MOS and the sampling MOS use the same type of MOS transistor, that is, both are N-channel MOS transistors or both are P-channel MOS transistors, Moreover, the power MOS and the sampling MOS are preferably MOS transistors having the same electrical characteristics, and the difference between the two is only in size.

[0034] Connect the sampling MOS to a current-limiting resistor, connect the voltage on the current-limiting resistor and the output voltage of the power MOS to the two inputs of the comparator, and compare them. The result of the comparison represents the state of the load , if the load resistance is less than the allowable minimum load resistance value, and the voltage on the current-limiting resistor is higher than the voltage on the l...

Embodiment 2

[0071] Based on the short-circuit detection method when the power MOS is turned on in the first embodiment above, this embodiment provides a short-circuit detection circuit when the power MOS is turned on, the circuit includes a power MOS, a sampling MOS, and a current limiting resistor; the power MOS The gate is connected to the gate of the sampling MOS, the sampling MOS is connected to the current limiting resistor, the output of the power MOS is connected to the load resistor, and the voltage of the current limiting resistor is connected to the output terminal voltage of the load resistor for comparison The positive and negative inputs of the comparator, the output of the comparator is connected to the control circuit, the control circuit is connected to the driving circuit, and the driving circuit is connected to the gate of the power MOS. Wherein, the power MOS and the sampling MOS adopt the same type of MOS transistor, that is, both are N-channel MOS transistors or both a...

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PUM

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Abstract

The embodiment of the invention discloses a short-circuit detection method, a short-circuit detection circuit and a short-circuit detection chip when a power MOS is started. The method comprises the following steps of: connecting a grid of the power MOS with a grid of a sampling MOS; connecting the sampling MOS with the current-limiting resistor, connecting the voltage on the current-limiting resistor and the output voltage of the power MOS to two inputs of the comparator respectively and compared, wherein the comparison result represents the state of the load, and if the load resistance is smaller than the allowable minimum load resistance value and the voltage on the current-limiting resistor is higher than the voltage on the load, it is judged that a short circuit occurs, and the power MOS is controlled to be turned off, otherwise, it is judged that the power MOS is normal. According to the invention, the state of the output load can be judged when the current is small, and if the current is short-circuited, the output load is immediately turned off without the need to act when the current is increased to a great extent, so that the safety level of the system is increased. The short-circuit detection method, the short-circuit detection circuit and the short-circuit detection chip are high in response speed, low in trigger current, high in accuracy, low in power loss, low in cost and suitable for popularization and application.

Description

technical field [0001] Embodiments of the present invention relate to the field of electronic circuits, in particular to a short circuit detection method, circuit and chip when power MOS is turned on. Background technique [0002] The power management chip is responsible for the conversion, distribution and protection of electric energy. The realization of these functions is inseparable from a power field-effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET), that is, a power MOSFET (hereinafter referred to as a power MOS). Under the action of the control circuit, the power MOS is used to provide electric energy for the load at the output end. For example: the chip provides safe and reliable power for the output terminal through the power MOS. Chips are mainly used in mobile devices. Mobile devices require frequent charging. When charging, it needs to be connected to the external environment, and at this time it may be impacted by the surge. Surg...

Claims

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Application Information

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IPC IPC(8): G01R31/52
CPCG01R31/52
Inventor 李征
Owner 江苏应能微电子有限公司