A circuit for improving performance of a MOS transistor based on NTC sampling

Abstract

The utility model relates to a kind of circuit based on NTC sampling to promote the performance of MOS tube, comprising: NTC sampling unit, voltage following unit and filter unit;The NTC sampling unit is arranged at MOS tube side, the output of the NTC sampling unit is connected the input of the voltage following unit, and the input of the voltage following unit is sent to MOS tube control module after passing through the filter unit.The circuit based on NTC sampling to promote the performance of MOS tube provided by the utility model, with the characteristics of NTC, the temperature of MOS can be effectively detected and controlled, MOS tube can be effectively protected to improve its performance, and the performance of high-frequency electrotome is further improved.

Description

Technical Field

[0001] This utility model belongs to the field of medical device technology, specifically relating to a circuit that improves the performance of a MOS transistor based on NTC sampling. Background Technology

[0002] The working principle of a high-frequency electrosurgical unit is to use high-frequency, high-voltage current to heat human tissue, achieving tissue separation and coagulation, thereby achieving the purpose of cutting and hemostasis. MOSFETs are widely used in the hardware modules of high-frequency electrosurgical units. In power amplifier and power supply modules, MOSFETs are mainly used to amplify small input signals to the required amplitude. However, excessively high temperatures during operation can damage the performance of MOSFETs, severely affecting the normal use of the high-frequency electrosurgical unit. How to control the temperature of MOSFETs and improve their performance is an urgent problem to be solved.

[0003] The traditional method for controlling the temperature of a MOSFET is to use a heat sink. However, when the temperature is too high, relying solely on a heat sink is not ideal, and the performance of the MOSFET will still be damaged due to the high temperature. Summary of the Invention

[0004] The technical problem to be solved by this utility model is to overcome the shortcomings of the above-mentioned technologies and propose a circuit that uses NTC sampling to sample the precise temperature of the MOS transistor and send it to the microcontroller in real time. When the temperature is too high, the microcontroller turns off the MOS transistor to protect the MOS transistor and improve its performance.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this utility model is: a circuit for improving the performance of a MOSFET based on NTC sampling, comprising: an NTC sampling unit, a voltage follower unit, and a filtering unit; the NTC sampling unit is arranged next to the MOSFET, the output of the NTC sampling unit is connected to the input of the voltage follower unit, and the input of the voltage follower unit is sent to the MOSFET control module after passing through the filtering unit.

[0006] A further improvement to the above scheme is that: the NTC sampling unit includes a 1% accuracy NTC, a 1% accuracy first voltage divider resistor, a transient diode, and a first transfer resistor; the NTC and the first voltage divider resistor are connected in series between the power supply and ground, and the connection node between the two is connected to the input of the voltage follower unit through the first transfer resistor; the positive terminal of the transient diode is grounded, and the negative terminal is connected to the connection node between the NTC and the first voltage divider resistor; a first filter capacitor is also connected to one end of the first transfer resistor connected to the input of the voltage follower unit.

[0007] A further improvement to the above scheme is that: the voltage follower unit includes an operational amplifier and a second transfer resistor; the non-inverting input of the operational amplifier is connected to the NTC sampling unit as the input of the voltage follower unit; the output of the operational amplifier is connected to the filtering unit as the output of the voltage follower unit; and the output of the operational amplifier is also connected to the inverting input through the second transfer resistor.

[0008] A further improvement to the above scheme is that: the filtering unit is a π-type filter composed of a filtering resistor, a second filtering capacitor, and a third filtering capacitor; the input of the filtering unit is connected to the output of the voltage follower unit; the output of the filtering unit is grounded through a second voltage divider resistor and is also connected to a clamping power supply through a clamping diode group; the output of the filtering unit is connected to a MOS transistor control module.

[0009] The circuit provided by this invention, which improves the performance of MOSFETs based on NTC sampling, utilizes the characteristics of NTC to effectively detect and control the temperature of the MOSFET, thereby effectively protecting the MOSFET, improving its performance, and ultimately enhancing the performance of the high-frequency electrosurgical unit. Attached Figure Description

[0010] The present invention will be further described below with reference to the accompanying drawings.

[0011] Figure 1 This is a circuit diagram of a preferred embodiment of the present invention. Detailed Implementation

[0012] The circuit for improving MOSFET performance based on NTC sampling in this embodiment includes: an NTC sampling unit, a voltage follower unit, and a filtering unit; the NTC sampling unit is arranged next to the MOSFET, the output of the NTC sampling unit is connected to the input of the voltage follower unit, and the input of the voltage follower unit is sent to the MOSFET control module after passing through the filtering unit.

[0013] like Figure 1 As shown, the NTC sampling unit includes a 1% accuracy NTC, a 1% accuracy voltage divider resistor R142, a transient diode D52, and a transfer resistor R140. The NTC and voltage divider resistor R142 are connected in series between the power supply and ground, and their connection point is connected to the input of the voltage follower unit through the transfer resistor R140. The positive terminal of the transient diode D52 is grounded, and the negative terminal is connected to the connection point between the NTC and the voltage divider resistor R142. One end of the transfer resistor R140, which is connected to the input of the voltage follower unit, is also connected to a filter capacitor C137. The NTC sampling unit acquires the temperature of the MOS through the NTC. When the temperature of the MOS rises, the resistance of the NTC decreases, thus increasing the voltage division of the voltage divider resistor R142, and increasing the output voltage of the NTC sampling unit.

[0014] The voltage follower unit includes operational amplifier U26A and pass-through resistor R134. The non-inverting input of operational amplifier U26A is connected to the NTC sampling unit as the input of the voltage follower unit. The output of operational amplifier U26A is connected to the filtering unit as the output of the voltage follower unit. The output of operational amplifier U26A is also connected to the inverting input through pass-through resistor R134. Operational amplifier U26A is also connected to necessary power and ground. To ensure stable operation of operational amplifier U26A, capacitor C59 is used for filtering and stabilization of the power supply. The voltage follower unit serves to reduce interference and improve circuit stability and load-driving capability.

[0015] The filtering unit is a π-type filter composed of filter resistor R139, filter capacitor C133, and filter capacitor C134. The input of the filtering unit is connected to the output of the voltage follower unit. The output of the filtering unit is grounded through voltage divider resistor R141 and connected to the clamping power supply through clamping diode group D43. The output of the filtering unit is connected to the MOSFET control module. The voltage signal output by the voltage follower unit is filtered and then divided by resistor R141 to obtain the NTC ADC, which is sent to the MOSFET control module. The MOSFET control module judges the magnitude of the NTC ADC signal and outputs a control signal to turn off the MOSFET when the temperature is too high. The clamping power supply uses a 3.3V power supply that is 5V lower than the power supply. In this way, the clamping diode group D43 limits the maximum value of the signal to 3.3V, avoiding damage to the MOSFET control module in the event of a failure in the circuit based on NTC sampling to improve MOSFET performance in this embodiment.

[0016] This utility model is not limited to the above embodiments. All technical solutions formed by equivalent substitutions fall within the protection scope claimed by this utility model.

Claims

1. A circuit for improving MOSFET performance based on NTC sampling, characterized in that, include: The system comprises an NTC sampling unit, a voltage follower unit, and a filtering unit; the NTC sampling unit is located next to the MOS transistor, the output of the NTC sampling unit is connected to the input of the voltage follower unit, and the input of the voltage follower unit is sent to the MOS transistor control module after passing through the filtering unit.

2. The circuit for improving MOSFET performance based on NTC sampling according to claim 1, characterized in that: The NTC sampling unit includes a 1% precision NTC, a 1% precision first voltage divider resistor, a transient diode, and a first transfer resistor; the NTC and the first voltage divider resistor are connected in series between the power supply and ground, and their connection node is connected to the input of the voltage follower unit through the first transfer resistor; the positive terminal of the transient diode is grounded, and the negative terminal is connected to the connection node of the NTC and the first voltage divider resistor; a first filter capacitor is also connected to one end of the first transfer resistor connected to the input of the voltage follower unit.

3. The circuit for improving MOSFET performance based on NTC sampling according to claim 2, characterized in that: The voltage follower unit includes an operational amplifier and a second transfer resistor; the non-inverting input of the operational amplifier is connected to the NTC sampling unit as the input of the voltage follower unit; the output of the operational amplifier is connected to the filtering unit as the output of the voltage follower unit; the output of the operational amplifier is also connected to the inverting input through the second transfer resistor.

4. The circuit for improving MOSFET performance based on NTC sampling according to claim 3, characterized in that: The filtering unit is a π-type filter composed of a filtering resistor, a second filtering capacitor, and a third filtering capacitor; the input of the filtering unit is connected to the output of the voltage follower unit; the output of the filtering unit is grounded through a second voltage divider resistor and also connected to a clamping power supply through a clamping diode group; the output of the filtering unit is connected to a MOS transistor control module.

Images