阅读说明：本技术 一种外置普通电阻功率mosfet控制方法及控制器 (External common resistance power MOSFET control method and controller ) 是由 刘若曦 田泽 郎静 邵刚 邓广真 陈智 李潇 于 2020-12-05 设计创作，主要内容包括：本发明涉及一种外置普通电阻功率MOSFET控制方法及控制器。本发明的方法包括以下步骤：1)检测功率MOSFET的功率管源漏两端的电压；2)计算出功率MOSFET的功率管的源漏电压差；3)通过内部电流基准输出电流至外部低温漂普通电阻,从而转化为基准电压；4)通过比较基准电压同功率MOSFET的功率管源漏之间的压差,从而判断功率MOSFET的功率管所处状态；5)通过设置不同阻值的电阻,实现对不同功率的功率MOSFET的功率管的控制。本发明具有缩小功率MOSFET控制电路面积的优点。(The invention relates to a control method and a controller of an external common resistance power MOSFET. The method of the invention comprises the following steps: 1) detecting the voltage at the source and drain ends of a power tube of a power MOSFET; 2) calculating the source-drain voltage difference of a power tube of the power MOSFET; 3) outputting current to an external low-temperature drift common resistor through an internal current reference so as to convert the current into reference voltage; 4) comparing the reference voltage with the voltage difference between the source and the drain of the power tube of the power MOSFET so as to judge the state of the power tube of the power MOSFET; 5) the power MOSFET power tube with different powers is controlled by setting resistors with different resistance values. The invention has the advantage of reducing the area of the power MOSFET control circuit.)

1. A control method of an external common resistance power MOSFET is characterized in that: the method comprises the following steps:

1) detecting the voltage at the source and drain ends of a power tube of a power MOSFET;

2) calculating the source-drain voltage difference of a power tube of the power MOSFET;

3) outputting current to an external low-temperature drift common resistor through an internal current reference so as to convert the current into reference voltage;

4) comparing the reference voltage with the voltage difference between the source and the drain of the power tube of the power MOSFET so as to judge the state of the power tube of the power MOSFET;

5) the power MOSFET power tube with different powers is controlled by setting resistors with different resistance values.

2. The external common resistance power MOSFET of claim 1 further comprising: and in the step 4), when the voltage difference is larger than the threshold value, the load can be judged to be short-circuited, and when the voltage difference is smaller than the threshold value, the load can be judged to be open-circuited.

3. A controller for realizing the external common resistance power MOSFET control method of claim 1, the controller comprising a power tube, a voltage source, a charge pump voltage-boosting circuit and a logic control unit, wherein the voltage source and the charge pump voltage-boosting circuit are respectively connected to the power tube, the logic control unit is connected to the charge pump voltage-boosting circuit, and the controller is characterized in that: the controller further comprises a voltage detection unit, a subtracter, a comparator, a fixed current source and a control resistor Rctrl, wherein the source end and the drain end of the power tube are connected to the positive input end of the comparator through the subtracter, the negative input end of the comparator is connected with the fixed current source and the control resistor Rctrl, the output end of the comparator is connected with the logic control unit, and the voltage detection unit is connected with the logic control unit.

4. The external common resistance power MOSFET controller of claim 3, wherein: and the voltage source is connected into the subtracter.

Technical Field

The invention relates to the fields of aviation, navigation, aerospace and the like, in particular to a control method and a controller of an external common resistance power MOSFET.

Background

In the prior art, a power MOSFET (MOS transistor) uses a current sampling resistor with a small resistance to be connected in series with a load terminal, thereby realizing current monitoring of a power tube branch. Although the current sampling resistor can be used for accurately measuring the current of the load branch of the power tube so as to detect the power, in some circuits requiring high-power MOSFET, a current sampling resistor which can bear high current needs to be selected, and the sampling resistor is usually overlarge in size and usually needs an additional heat dissipation device, so that the defect that the size of a finished product is overlarge is caused.

Disclosure of Invention

The invention provides a control method and a controller of an external common resistance power MOSFET (metal oxide semiconductor field effect transistor) for solving the technical problems in the background art, the difference is calculated between the source and the drain of a power tube of the power MOSFET, the working state of the power tube of the external power MOSFET is judged, the power MOSFET is controlled, and the control method and the controller have the advantage of reducing the area of a control circuit of the power MOSFET.

The technical solution of the invention is as follows: the invention relates to a control method of an external common resistance power MOSFET, which is characterized in that: the method comprises the following steps:

1) detecting the voltage at the source and drain ends of a power tube of a power MOSFET;

2) calculating the source-drain voltage difference of a power tube of the power MOSFET;

3) outputting current to an external low-temperature drift common resistor through an internal current reference so as to convert the current into reference voltage;

4) comparing the reference voltage with the voltage difference between the source and the drain of the power tube of the power MOSFET so as to judge the state of the power tube of the power MOSFET;

5) the power MOSFET power tube with different powers is controlled by setting resistors with different resistance values.

Preferably, in step 4), when the voltage difference is greater than the threshold value, it may be determined that the load is short-circuited, and when the voltage difference is less than the threshold value, it may be determined that the load is open-circuited.

A controller for realizing the external common resistance power MOSFET control method comprises a power tube, a voltage source, a charge pump booster circuit and a logic control unit, wherein the voltage source and the charge pump booster circuit are respectively connected with the power tube, and the logic control unit is connected with the charge pump booster circuit, and is characterized in that: the controller also comprises a voltage detection unit, a subtracter, a comparator, a fixed current source and a control resistor Rctrl, wherein the source end and the drain end of the power tube are connected to the positive input end of the comparator through the subtracter, the negative input end of the comparator is connected with the fixed current source and the control resistor Rctrl, the output end of the comparator is connected with the logic control unit, and the voltage detection unit is connected with the logic control unit.

Preferably, the voltage source is connected to the subtractor.

The external common resistance power MOSFET control method and the controller provided by the invention are characterized in that a voltage detection unit, a subtracter, a comparator, a fixed current source and a control resistor Rctrl are added in the existing power MOSFET control circuit, the source-drain voltage difference of the external power MOSFET is sampled, current is led out from an internal high-precision current source and converted into voltage with an external common resistor, and the voltage is compared with the voltage of an internal current reference output current on an external common low-temperature drift resistor, so that the state of a power tube is judged and the on-off of the power tube is controlled, and different power MOSFETs can be controlled simply by replacing different resistors, such as overvoltage turn-off, undervoltage turn-on, load short-circuit detection, load open-circuit detection and the like. Therefore, the invention has the advantage of reducing the area of the control circuit of the power MOSFET.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

Detailed Description

The technical solution of the present invention is further described in detail with reference to the accompanying drawings and specific embodiments.

The invention provides a control method of an external common resistance power MOSFET, which comprises the following steps:

1) introducing a detection port, and detecting the voltage at two ends of a source and a drain of a power tube of the power MOSFET;

2) calculating the source-drain voltage difference of a power tube of the power MOSFET;

3) outputting current to an external low-temperature drift common resistor (control resistor Rctrl) through an internal current reference (fixed current source I), and converting the current into reference voltage;

4) comparing the reference voltage with the voltage difference between the source and the drain of the power tube so as to judge the state of the power MOSFET, wherein when the voltage difference is greater than a threshold value, the power MOSFET can be judged as a load short circuit, and when the voltage is smaller than the threshold value, the power MOSFET can be judged as a load open circuit;

5) the control of the power tubes of the power MOSFETs with different powers can be realized by setting resistors with different resistance values.

Referring to fig. 1, the control of the power MOSFET mainly controls the GATE voltage of the power tube P, and the structure of the specific embodiment of the present invention includes a power tube P, a charge pump boost circuit, an output circuit limiting unit, an inductive load degaussing unit, a logic control unit, an overvoltage protection unit, a voltage source, a GATE protection unit, an electrostatic protection unit, a voltage detection unit, a subtractor, a comparator, a control resistor Rctrl, and a fixed current source I; wherein the charge pump booster circuit, the output circuit limiting unit, the inductive load degaussing unit, the logic control unit, the overvoltage protection unit, the voltage source, the grid protection unit and the static protection unit are all structures in a power MOSFET control circuit in the prior art, the voltage source, the charge pump booster circuit, the output circuit limiting unit, the inductive load degaussing unit, the overvoltage protection unit and the grid protection unit are respectively connected to the GATE voltage of the power tube P, inside the chip, the source end and the drain end of the power tube P are connected to the positive input end of the comparator through the subtracter, the negative input end of the comparator is connected with the fixed current source I and the control resistor Rctrl, the control resistor Rctrl is located outside the chip, the output end of the comparator is connected with the logic control unit, the logic control unit is connected with the charge pump booster circuit, the electrostatic protection unit and the voltage detection unit are respectively connected to the logic control unit, and the voltage source is connected to the subtracter.

When the controller works, the voltage at the two ends of the source drain of the power MOSFET is detected through the voltage detection unit; calculating the source-drain voltage difference of a power tube P of the power MOSFET through a subtracter; outputting current to an external low-temperature drift common resistor (control resistor Rctrl) through an internal current reference I (fixed current source I), and converting the current into reference voltage; comparing the reference voltage with the voltage difference between the source and the drain of the power tube by a comparator so as to judge the state of the power MOSFET power tube P, wherein the power MOSFET power tube P can be judged to be in a load short circuit when the voltage difference is greater than a threshold value, and can be judged to be in a load open circuit when the voltage is smaller than the threshold value; the control of the power transistors P of the power MOSFETs with different powers can be realized by setting the control resistors Rctrl with different resistance values.

Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.