CN213305260U

CN213305260U - Boost circuit for sampling current by using MOS (metal oxide semiconductor) tube

Info

Publication number: CN213305260U
Application number: CN202022404691.5U
Authority: CN
Inventors: 朱立山; 傅军团; 朱浩; 黄少雄; 卢庭
Original assignee: Hefei Tongzhi Electrical Control Technology Co ltd
Current assignee: Hefei Tongzhi Electrical Control Technology Co ltd
Priority date: 2020-10-26
Filing date: 2020-10-26
Publication date: 2021-05-28
Anticipated expiration: 2030-10-26

Abstract

The utility model relates to an utilize MOS pipe to carry out Boost circuit of current sampling, include: the temperature sensor comprises an inductor, a diode, a first capacitor and a temperature sensor, wherein the output end of the inductor is connected with the anode of the diode, the cathode of the diode is connected with the input end of the first capacitor, and the input end of the inductor and the output end of the first capacitor are connected with a power supply; the output end of the inductor is further connected with a drain electrode of a first MOS tube and a drain electrode of a second MOS tube, a source electrode of the first MOS tube is connected with the output end of the first capacitor, a source electrode of the second MOS tube is connected with a source electrode of a third MOS tube, the drain electrode of the third MOS tube is connected with one input end of a differential amplifier, and the other input end of the differential amplifier is connected with the source electrode of the first MOS tube. The utility model discloses reduce Boost circuit's volume and cost, can let the overcurrent protection action more timely.

Description

Boost circuit for sampling current by using MOS (metal oxide semiconductor) tube

Technical Field

The utility model relates to a Boost circuit technical field especially relates to an utilize MOS pipe to carry out Boost circuit of current sampling.

Background

The Boost circuit is also called a Boost chopper circuit, and is a direct current conversion circuit used for converting a direct current power supply voltage into a direct current voltage higher than the direct current voltage, so that energy is transferred from a low-voltage side power supply to a high-voltage side load. Boost circuits have been developed for a long time and are widely used in various power supply devices.

With the development of various industries on the switch power supply industry, especially the development of the digital control switch power supply, the requirements of the various industries on the volume and the cost of a Boost circuit are higher and higher. Because the Boost circuit topology is one of basic topologies in switching power supply conversion, the structure is simple, and few measures for reducing the cost and the volume are provided.

The current commonly used Boost circuit with medium and small power, especially within 10kW, as shown in fig. 1, is mainly characterized in that a first MOS transistor is used as a main switching transistor, and a hall current sensor (H1) is used for current sampling. The current sampling value output by a Hall current sensor (H1) is used as the current inner loop input, and the current closed-loop control is realized by controlling the on-off of a main switching tube through a loop.

In the middle and small power occasions, the volume and the cost are difficult to reduce due to the heating limit of the magnetic element and the switching tube. The Hall current sensor adopts a threading type or a PCB welding type, which can influence the layout of other components, the volume is difficult to further reduce, and the proportion of the cost of the Hall current sensor to the total cost is also large.

SUMMERY OF THE UTILITY MODEL

(1) Technical problem to be solved

The embodiment of the utility model provides an utilize MOS pipe to carry out Boost circuit of current sampling, including temperature sensor, digital control module etc. The volume and the cost of the Boost circuit are reduced, and the over-current protection action is more timely.

(2) Technical scheme

The utility model provides an utilize MOS pipe to carry out Boost circuit of current sampling, include: the temperature sensor comprises an inductor, a diode, a first capacitor and a temperature sensor, wherein the output end of the inductor is connected with the anode of the diode, the cathode of the diode is connected with the input end of the first capacitor, and the input end of the inductor and the output end of the first capacitor are connected with a power supply; the output end of the inductor is further connected with a drain electrode of a first MOS tube and a drain electrode of a second MOS tube, a source electrode of the first MOS tube is connected with the output end of the first capacitor, a source electrode of the second MOS tube is connected with a source electrode of a third MOS tube, a drain electrode of the third MOS tube is connected with one input end of a differential amplifier, and the other input end of the differential amplifier is connected with the source electrode of the first MOS tube; the grid electrodes of the first MOS tube, the second MOS tube and the third MOS tube are connected with a digital control module, and the output end of the differential amplifier is also connected with the digital control module; the temperature sensor is arranged on the first MOS tube and used for detecting the shell temperature of the first MOS tube, and the temperature sensor is connected with the digital control module.

Furthermore, the Boost circuit further comprises a second capacitor, one end of the second capacitor is connected to the input end of the inductor, and the other end of the second capacitor is connected to the output end of the first capacitor.

Further, the digital control module comprises one of a single chip microcomputer, an MCU or a PLC.

Further, the first MOS transistor and the second MOS transistor are N-channel transistors.

Further, the third MOS transistor is an N-channel transistor.

Furthermore, two ends of the first capacitor are connected with a load resistor in parallel.

(3) Advantageous effects

The utility model provides a circuit which utilizes the on resistance RDS (on) of an MOS tube as a current sampling resistor, firstly, a Hall current sensor in the traditional Boost circuit can be saved, and the volume and the cost of the Boost circuit are reduced;secondly, what traditional hall current sensor utilized is the electromagnetic induction principle, has certain response time, has certain hysteresis quality to the current sampling, and is based on the utility model discloses an on-resistance RDS of MOS pipe_(on)The current sampling is similar to the sampling resistance sampling current, so that the time delay of the Hall current sensor is reduced, the dynamic response of the system can be improved, and the overcurrent protection action can be more timely.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments of the present invention will be briefly described below, and it is obvious that the drawings described below are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic diagram of a Boost circuit commonly used for small power in the prior art.

Fig. 2 is a circuit diagram of the Boost circuit in an embodiment of the present invention.

Fig. 3 is a schematic diagram of a Boost circuit in an embodiment of the present invention.

Detailed Description

The following describes embodiments of the present invention in further detail with reference to the accompanying drawings and examples. The following detailed description of the embodiments and the accompanying drawings are provided to illustrate the principles of the invention, but are not intended to limit the scope of the invention, i.e., the invention is not limited to the embodiments described, but covers any modifications, substitutions and improvements in the parts, components and connections without departing from the spirit of the invention.

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

The present application will be described in detail with reference to the accompanying drawings 1-3, in conjunction with an embodiment.

Referring to fig. 1 to fig. 3, a Boost circuit for current sampling using a MOS transistor according to an embodiment of the present invention includes: an inductor L1, a diode D1, a first capacitor C2 and a temperature sensor NTC, wherein the output end of the inductor L1 is connected with the anode of the diode D1, the cathode of the diode D1 is connected with the input end of the first capacitor C2, and the input end of the inductor L1 and the output end of the first capacitor C2 are connected with a power supply; the output end of the inductor L1 is further connected to the drain of a first MOS transistor Q1 and the drain of a second MOS transistor Q2, the source of the first MOS transistor Q1 is connected to the output end of the second capacitor C2, the source of the second MOS transistor Q2 is connected to the source of a third MOS transistor Q3, the drain of the third MOS transistor Q3 is connected to one input end of a differential amplifier, and the other input end of the differential amplifier is connected to the source of the first MOS transistor Q1; the gates of the first MOS transistor Q1, the second MOS transistor Q2 and the third MOS transistor Q3 are connected with a digital control module, and the output end of the differential amplifier is also connected with the digital control module; the temperature sensor NTC is arranged on the first MOS tube Q1 and used for detecting the shell temperature of the first MOS tube Q1, and the temperature sensor NTC is connected with the digital control module.

The embodiment of the utility model discloses on the basis of Boost circuit commonly used of miniwatt among the prior art as shown in figure 1, reduce hall current sensor H1, increase second MOS pipe Q2, third MOS pipe Q3 increases differential amplifier circuit and temperature sensor NTC. The circuit of the present invention is shown in fig. 2.

Referring to fig. 2 and 3, in the embodiment of the present invention, the digital control module can send out PWM1 pulse signals, and when the first MOS transistor Q1 is in the on state, the digital control module sends out PWM2 pulse signals to control the second MOS transistor Q2, the third MOS transistor Q3 is turned on, and the digital control module reads the current sampling value I at this time₁(ii) a Then, the digital control module reads the shell temperature of the main switching tube acquired by the temperature sensor NTC, namely the first MOS tube Q1, according to the MOS tube RDS_(on)Obtaining a temperature compensation correction coefficient K according to a relation curve of the temperature of the shell; then, the current sampling value I₁Multiplying by the temperature compensation correction coefficient K to obtain a feedback current I, and setting the current I_refThe difference with the feedback current I is used as the input of a PI regulator, and PWM1 is sent out to control the second phaseA MOS transistor Q1 is turned on to complete a current closed loop regulation. Finally, the above steps may be repeated to form a complete closed loop current regulation process.

Since the drain of the first MOS transistor Q1 has a higher voltage when it is turned off, the sampling in this time is invalid and cannot directly enter the sampling circuit. Therefore, when the first MOS transistor Q1 operates, the two signal MOS transistors, i.e., the second MOS transistor Q2 and the third MOS transistor Q3, need to be synchronously controlled, and at this time, the RDS of the real first MOS transistor Q1 is sampled_(on)Pressure drop over; because the internal resistance of first MOS pipe Q1 changes along with temperature variation the utility model discloses in, gather first MOS pipe Q1 shell temperature, through the relation curve of shell temperature and MOS pipe RDS (on), revise the current sampling of first MOS pipe Q1 by digital control module to guarantee that current sampling precision can accord with system design requirement.

To sum up, the embodiment of the utility model provides an utilize digital processing module's sampling and computational element of high accuracy, provide an on resistance RDS who utilizes MOS pipe_(on)As a circuit of the current sampling resistor, a Hall current sensor in the traditional Boost circuit can be omitted, and the volume and the cost of the Boost circuit are reduced. Secondly, the traditional Hall current sensor utilizes the electromagnetic induction principle, has certain response time and certain hysteresis for current sampling, and is based on the RDS of the MOS tube_(on)The current sampling is similar to the sampling resistance sampling current, so that the time delay of the Hall current sensor is reduced, the dynamic response of the system can be improved, and the overcurrent protection action can be more timely.

Specifically, the Boost circuit further includes a second capacitor C1, one end of the second capacitor C1 is connected to the input end of the inductor L1, and the other end of the second capacitor C1 is connected to the output end of the first capacitor C2. Digital control module includes one in singlechip, MCU or the PLC, for example in the utility model provides an embodiment digital control module can select to the singlechip, and specific model is AT89S51, and of course, digital control module also can select MCU or PLC in other embodiments. Meanwhile, the first MOS transistor Q1 and the second MOS transistor Q2 are N-channel transistors, the third MOS transistor Q3 is an N-channel transistor, and two ends of the first capacitor C2 are connected in parallel with a load resistor R. Besides, in the embodiment of the present invention, the differential amplifier may be selected from suitable models, such as INA143U, etc., as needed, which should not be construed as limiting the present application.

It should be clear that the embodiments in this specification are described in a progressive manner, and the same or similar parts in the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. For embodiments of the method, reference is made to the description of the apparatus embodiments in part. The present invention is not limited to the specific steps and structures described above and shown in the drawings. Also, a detailed description of known process techniques is omitted herein for the sake of brevity.

The above description is only an example of the present application and is not limited to the present application. Various modifications and alterations to this application will become apparent to those skilled in the art without departing from the scope of this invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A Boost circuit for sampling current by using a MOS tube is characterized by comprising: the temperature sensor comprises an inductor, a diode, a first capacitor and a temperature sensor, wherein the output end of the inductor is connected with the anode of the diode, the cathode of the diode is connected with the input end of the first capacitor, and the input end of the inductor and the output end of the first capacitor are connected with a power supply; the output end of the inductor is further connected with a drain electrode of a first MOS tube and a drain electrode of a second MOS tube, a source electrode of the first MOS tube is connected with the output end of the first capacitor, a source electrode of the second MOS tube is connected with a source electrode of a third MOS tube, a drain electrode of the third MOS tube is connected with one input end of a differential amplifier, and the other input end of the differential amplifier is connected with the source electrode of the first MOS tube; the grid electrodes of the first MOS tube, the second MOS tube and the third MOS tube are connected with a digital control module, and the output end of the differential amplifier is also connected with the digital control module; the temperature sensor is arranged on the first MOS tube and used for detecting the shell temperature of the first MOS tube, and the temperature sensor is connected with the digital control module.

2. A Boost circuit for sampling current by using MOS transistors as claimed in claim 1, further comprising a second capacitor, wherein one end of the second capacitor is connected to the input terminal of the inductor, and the other end of the second capacitor is connected to the output terminal of the first capacitor.

3. The Boost circuit for sampling current by using the MOS transistor as claimed in claim 1, wherein the digital control module comprises one of a single chip, an MCU, or a PLC.

4. The Boost circuit for sampling current by using MOS transistor as claimed in claim 1, wherein said first MOS transistor and said second MOS transistor are N-channel transistors.

5. The Boost circuit for sampling current by using MOS transistor as claimed in claim 1 or 4, wherein the third MOS transistor is an N-channel transistor.

6. The Boost circuit for sampling current by using a MOS transistor as claimed in claim 1, wherein a load resistor is connected in parallel to two ends of the first capacitor.