Circuit system capable of reducing working heat of MOS (Metal Oxide Semiconductor) tube switch

Abstract

The invention relates to a circuit system capable of reducing work heat of an MOS tube switch. The circuit system comprises a pulse width modulation control module, a power switch driving module, a conversion isolation transformation module, a first power switch module and a second power switch module. Two paths of complementary PWM signals generated by the pulse width modulation control module are alternately output, the signals are amplified by the power switch driving module and then are input to a primary winding of the conversion isolation transformation module, and two groups of secondary windings of the transformer respectively control MOS tubes in the two power switch modules to alternately conduct work. The output frequency of the two MOS tubes to the rear stage is two times of the working frequency of the MOS tubes, and the working frequency and the working time of the MOS tubes of the circuit are only half of those of the MOS tubes of a traditional circuit structure under the same frequency state, so that the heat productivity is reduced, the problem caused by overheating aging in the using process of the MOS tubes of the traditional circuit structure is solved, and the product stability is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of DC-DC power supply voltage reduction, and particularly relates to a circuit system capable of reducing MOS tube switch working heat. BACKGROUND

[0002] In the prior art, in order to improve output efficiency and reduce the size of filter inductors and capacitors used in the later stage, the conventional method is to increase the switching frequency of MOS tube working, and output high-frequency PWM waves to the later stage. However, the increase will also bring disadvantages, the switching loss of the MOS tube will increase when the MOS tube works at high frequency, especially when the current is large, the heat is more serious, and even the MOS tube will be damaged. The traditional method can only strengthen heat dissipation, and the requirement for circuit heat dissipation is increased and a special MOS tube is selected. In addition, when the MOS tube is selected, the type and model of the MOS tube that can be used are limited, and the price is correspondingly increased. SUMMARY

[0003] Therefore, the application provides a circuit system capable of reducing MOS tube switch working heat, to solve the problem that the MOS tube generates a large amount of heat when working at high frequency in the prior art.

[0004] The technical scheme adopted by the application is as follows: a circuit system capable of reducing MOS tube switch working heat, comprising: a pulse width modulation control module, a power switch driving module, a conversion isolation transformer module, a first power switch module and a second power switch module, the output end of the pulse width modulation control module is connected to the input end of the power switch driving module, the output end of the power switch driving module is connected to the primary side of the conversion isolation transformer module, the secondary side of the conversion isolation transformer module is connected to the control end of the first power switch module and the control end of the second power switch module respectively, the input end of the first power switch module and the input end of the second power switch module are connected to a power supply voltage, and the output end of the first power switch module and the output end of the second power switch module are connected to each other. The pulse width modulation control module is used to generate a first PWM signal and a second PWM signal, and the first PWM signal and the second PWM signal are complementary. The power switch driving module is used to improve the driving capability of the first PWM signal and the second PWM signal. The conversion isolation transformer module is used to input the first PWM signal with improved driving capability to the control end of the first power switch module, and input the second PWM signal with improved driving capability to the control end of the second power switch module. The first power switch module is used to output power according to the first PWM signal, and the second power switch module is used to output power according to the second PWM signal.

[0005] Further, the conversion isolation transformer module comprises a primary winding, a first secondary winding and a second secondary winding, an A1 end of the first secondary winding is connected to a control end of the first power switch module, a B1 end of the first secondary winding is connected to an A2 end of the second secondary winding and an output end of the first power switch module, a B2 end of the second secondary winding is connected to a control end of the second power switch module, an A end of the primary winding is connected to the first PWM signal with improved driving capability, and a B end of the primary winding is connected to the second PWM signal with improved driving capability.

[0006] Further, the turns ratio of the first secondary winding and the second secondary winding to the primary winding is 1:1.

[0007] Further, the B end of the primary winding is connected to one output end of the power switch driving module through a capacitor C1.

[0008] Further, the first power switch module comprises a first diode D1, a third resistor R3, a first MOS tube Q1 and a first zener diode D2, a negative electrode of the first diode D1 is connected to one end of the third resistor R3 and a secondary side of the conversion isolation transformer module, a positive electrode of the first diode D1 is connected to the other end of the third resistor R3, a gate of the first MOS tube Q1 and a negative electrode of the first zener diode D2, a drain of the first MOS tube Q1 is connected to a power supply voltage, and a source of the first MOS tube Q1 is connected to a positive electrode of the first zener diode D2 and an output end of the second power switch module.

[0009] Further, the second power switch module comprises a second diode D3, a fourth resistor R4, a second MOS tube Q2 and a second zener diode D4, a negative electrode of the second diode D3 is connected to one end of the fourth resistor R4 and a secondary side of the conversion isolation transformer module, a positive electrode of the second diode D3 is connected to the other end of the fourth resistor R4, a gate of the second MOS tube Q2 and a negative electrode of the second zener diode D4, a drain of the second MOS tube Q2 is connected to a power supply voltage, and a source of the second MOS tube Q2 is connected to a positive electrode of the second zener diode D4 and an output end of the first power switch module.

[0010] Further, the pulse width modulation control module comprises a pulse width modulation controller U1, a first resistor R1 and a second resistor R2, an E1 output end of the pulse width modulation controller U1 outputs the first PWM signal and is connected to one end of the first resistor R1, an E2 output end outputs the second PWM signal and is connected to one end of the second resistor R2, and the other end of the first resistor R1 and the other end of the second resistor R2 are respectively connected to input ends of the power switch driving module.

[0011] Further, the power switch driving module adopts a power switch driving chip U2.

[0012] The present application has the following advantages: the present application generates two complementary PWM signals by using a pulse width modulation control module, amplifies the signals by a power switch driving module, and inputs the signals to the primary winding of a conversion isolation transformer module, and the two groups of secondary windings of the transformer control the MOS tubes in the two power switch modules to work alternately, the output frequency of the two MOS tubes is twice the working frequency of the MOS tubes, and in the same frequency state, the working frequency and working time of the MOS tubes of the present application circuit are only half of those of the traditional circuit structure, so the heat generation is reduced, and the safety of the MOS tubes is ensured in the large current state, the problems caused by the overheating aging of the MOS tubes in the high frequency use process of the traditional circuit structure are overcome, the product stability is improved, the price of the MOS tubes with low working frequency is relatively reduced, and the selection is very wide.

[0013] The present application circuit structure has the advantages of low frequency work of the MOS tubes: lower switching frequency means lower switching loss, and in the case where switching loss is dominant, the efficiency is usually higher, and the system output has the advantage of high frequency: the higher the switching frequency, the smaller the inductance and capacitance of the energy storage elements inductor and capacitor in the later stage can be used, and the two advantages are combined, further improving the efficiency, and the isolation transformer is used to drive the MOS tube, ensuring safety and stability.

[0014] The present application circuit system has high output frequency, the MOS tubes work alternately in low frequency state, and the MOS tubes generate small heat. The circuit heat is reduced, and there is no need to strengthen heat dissipation, the product stability is improved. The MOS tubes have wide selection range and low cost. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 is a circuit system structure block diagram of the present application capable of reducing the switching heat of the MOS tubes.

[0016] Figure 2 is a circuit system circuit diagram of the present application capable of reducing the switching heat of the MOS tubes.

[0017] Figure 3 is a schematic diagram of the first PWM signal and the second PWM signal in the present application.

[0018] Figure 4 is a schematic diagram of the primary winding side signal of the transformer.

[0019] Figure 5 is a schematic diagram of the two-way signal of the secondary winding side of the transformer.

[0020] Figure 6 is a schematic diagram of the output voltage. DETAILED DESCRIPTION

[0021] In order for those skilled in the art to better understand the technical scheme of the present application, the technical scheme in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application, and the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should belong to the scope of protection of the present application.

[0022] In the technical scheme of the present application, Figure 1 is a structural diagram of a circuit system capable of reducing the heat generated by the MOS switch operation according to the specific structure of the present application, as Figure 1 shown, the present application specifically includes: a pulse width modulation control module 1, a power switch driving module 2, a conversion isolation transformer module 3, a first power switch module 4 and a second power switch module 5, the output end of the pulse width modulation control module 1 is connected to the input end of the power switch driving module 2, the output end of the power switch driving module 2 is connected to the primary side of the conversion isolation transformer module 3, the secondary side of the conversion isolation transformer module 3 is connected to the control end of the first power switch module 4 and the control end of the second power switch module 5 respectively, the input end of the first power switch module 4 and the input end of the second power switch module 5 are both connected to the power supply voltage, and the output end of the first power switch module 4 and the output end of the second power switch module 5 are connected to each other. The pulse width modulation control module 1 is used to generate a first PWM signal and a second PWM signal, and the first PWM signal and the second PWM signal are complementary, and it should be noted that the first PWM signal and the second PWM signal have a dead time.

[0023] The power switch driving module 2 is used to improve the driving capability of the first PWM signal and the second PWM signal. The conversion isolation transformer module 3 is used to input the first PWM signal with improved driving capability to the control end of the first power switch module 4 and input the second PWM signal with improved driving capability to the control end of the second power switch module 5. The first power switch module 4 is used to output power according to the first PWM signal, and the second power switch module 5 is used to output power according to the second PWM signal.

[0024] As Figure 2As shown, the pulse width modulation control module 1 in the application includes a pulse width modulation controller U1, a first resistor R1 and a second resistor R2, the E1 output end of the pulse width modulation controller U1 outputs a first PWM signal and connects one end of the first resistor R1, the E2 output end outputs a second PWM signal and connects one end of the second resistor R2, the other end of the first resistor R1 and the other end of the second resistor R2 are connected to the input end of the power switch driving module 2. Among them, the pulse width modulation controller U1 can specifically adopt TL494 pulse width modulation chip, TL494 is a mature PWM controller, stable performance and cheap, widely used.

[0025] As shown in the figure, Figure 2 The power switch driving module 2 adopts a power switch driving chip U2. Specifically, TC4424 chip can be used. TC4424 is a high cost-effective super-speed driving chip specially designed for MOSFET, which has strong anti-interference ability and will not cause logic confusion. The combination of the two can improve the driving reliability, faster switching speed and stronger anti-interference ability.

[0026] The 2-pin INA port of the power switch driving chip U2 is connected to the first resistor R1, the 3-pin of the power switch driving chip U2 is grounded, the 4-pin INB port of the power switch driving chip U2 is connected to the second resistor R2, the 5-pin OUTB port of the power switch driving chip U2 is connected to the B end of the primary winding of the transformer T1 through the first capacitor C1, the 6-pin of the power switch driving chip U2 is connected to +12V, and the 7-pin OUTA port of the power switch driving chip U2 is connected to the A end of the primary winding of the transformer T1.

[0027] As shown in the figure, Figure 2 The conversion isolation transformer module 3 includes a primary winding, a first secondary winding and a second secondary winding, the A1 end of the first secondary winding is connected to the control end of the first power switch module 4, the B1 end of the first secondary winding is connected to the A2 end of the second secondary winding and the output end of the first power switch module 4, the B2 end of the second secondary winding is connected to the control end of the second power switch module 5, the A end of the primary winding is connected to the first PWM signal with improved driving capability, and the B end of the primary winding is connected to the second PWM signal with improved driving capability.

[0028] Among them, the turns ratio of the first secondary winding and the second secondary winding to the primary winding is 1:1.

[0029] The B end of the primary winding is connected to one output end of the power switch driving module 2 through the first capacitor C1. The first capacitor C1 functions to isolate direct current and couple signals, avoiding the influence of direct current components on the operation of the transformer.

[0030] Specifically, the conversion isolation transformer module 3 is a transformer T1, which has a primary winding, a first secondary winding and a second secondary winding, the A end of the primary winding is connected to the 7-pin OUTA port of the power switch driving chip U2, the B end of the primary winding is connected to the first capacitor C1, the A1 end of the first secondary winding is connected to the first diode D1 and the third resistor R3, the B1 end of the first secondary winding is respectively connected to the A2 end of the second secondary winding, the first voltage stabilizing diode D2, the S pole of the first MOS tube Q1, the second voltage stabilizing diode D4 and the S pole of the second MOS tube Q2, and the B2 end of the second secondary winding is connected to the second diode D3 and the fourth resistor R4.

[0031] The conversion isolation transformer is used in the application, so that the driving chip is highly isolated from the MOS tube, the driving chip is safer, the working voltage of the MOS tube can be increased to the highest voltage of the MOS tube without damaging the driving chip, and the GS opening voltage of the MOS tube does not need an additional voltage boosting circuit, so that the circuit is simple and stable.

[0032] As shown in Figure 2 The first power switch module 4 includes: a first diode D1, a third resistor R3, a first MOS tube Q1, a first voltage stabilizing diode D2, the negative pole of the first diode D1 is connected to one end of the third resistor R3 and the secondary side of the conversion isolation transformer module 3, the positive pole of the first diode D1 is connected to the other end of the third resistor R3, the gate of the first MOS tube Q1 and the negative pole of the first voltage stabilizing diode D2, the drain level of the first MOS tube Q1 is connected to the power supply voltage, and the source of the first MOS tube Q1 is connected to the positive pole of the first voltage stabilizing diode D2 and the output end of the second power switch module 5. The second power switch module 5 includes: a second diode D3, a fourth resistor R4, a second MOS tube Q2 and a second voltage stabilizing diode D4, the negative pole of the second diode D3 is connected to one end of the fourth resistor R4 and the secondary side of the conversion isolation transformer module 3, the positive pole of the second diode D3 is connected to the other end of the fourth resistor R4, the gate of the second MOS tube Q2 and the negative pole of the second voltage stabilizing diode D4, the drain level of the second MOS tube Q2 is connected to the power supply voltage, and the source of the second MOS tube Q2 is connected to the positive pole of the second voltage stabilizing diode D4 and the output end of the first power switch module 4.

[0033] Specifically, the D pole of the first MOS Q1 is connected to the VCC input, the G pole of the first MOS Q1 is connected to the A1 end of the first secondary winding of the transformer T1 through the first diode D1 and the third resistor R3, the first stabilizing diode D2 is connected between the G pole and the S pole of the first MOS Q1, and the S pole of the first MOS Q1 is connected to the B1 end of the first secondary winding of the transformer T1, the A2 end of the second secondary winding of the transformer T1 and the S pole of the second MOS Q2 respectively. The D pole of the second MOS Q2 is connected to the VCC input, the G pole of the second MOS Q2 is connected to the B2 end of the second secondary winding of the transformer T1 through the second diode D3 and the fourth resistor R4, the second stabilizing diode D4 is connected between the G pole and the S pole of the second MOS Q2, and the S pole of the second MOS Q2 is connected to the power output of the subsequent filter circuit. The third resistor R3, the fourth resistor R4, the first diode D1 and the second diode D3 in the circuit are current limiting and switching speed adjusting, and the first stabilizing diode D2 and the second stabilizing diode D4 are 12V stabilizing voltage, which protects the MOS.

[0034] Figure 3 、 Figure 4 、 Figure 5 and Figure 6 are respectively 2-way PWM signal schematic diagram, 2-way complementary PWM signal has certain dead time, transformer primary winding side signal schematic diagram, transformer secondary winding side 2-way signal schematic diagram and output voltage schematic diagram.

[0035] The present application generates 2-way complementary PWM signals by using a pulse width modulation control module 1, and alternately outputs the signals, for example, when the E1 port outputs a high level and the E2 port outputs a low level. The present application is amplified by a power switch driver, the power switch driver is 12V power supply, the 7-pin OUTA port and the 5-pin OUTB port output corresponding 12V high and low levels, drive the A end and the B end of the conversion isolation transformer primary winding, the turn ratio of the conversion isolation transformer primary winding and the secondary winding is 1:1, the A1 of the first secondary winding 1 is the same direction end for high level, the B1 is low level, the G level and the S level of the MOS Q1 reach the opening voltage, the D level and the S level of the MOS Q1 are turned on, the A2 of the second secondary winding 2 is the same direction end for high level, the B2 is low level, the G level and the S level of the second MOS Q2 have no opening voltage, the D level and the S level of the second MOS Q2 are closed, when the E1 port outputs a low level and the E2 port outputs a high level, the levels are opposite, the first MOS Q1 is closed, the second MOS Q2 is turned on, and the 2-way MOS alternately works and outputs to the subsequent filter circuit.

[0036] The application alternately outputs two-way complementary PWM signals, controls MOS tubes in two power switch modules to alternately conduct, and the frequency of the two MOS tubes output to the next stage is twice the working frequency of the MOS tubes.

[0037] Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present application and are not limiting. Although the present application has been described in detail with reference to the examples, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application, and they should be covered in the scope of the claims of the present application.

Claims

1. A circuit system capable of reducing heat generated by MOS switch operation, characterized by, The application relates to a power supply device, which comprises a pulse width modulation control module (1), a power switch driving module (2), a conversion isolation transformer module (3), a first power switch module (4) and a second power switch module (5), wherein the output end of the pulse width modulation control module (1) is connected with the input end of the power switch driving module (2), the output end of the power switch driving module (2) is connected with the primary side of the conversion isolation transformer module (3), the secondary side of the conversion isolation transformer module (3) is respectively connected with the control end of the first power switch module (4) and the control end of the second power switch module (5), the input end of the first power switch module (4) and the input end of the second power switch module (5) are connected with a power supply voltage, and the output end of the first power switch module (4) and the output end of the second power switch module (5) are connected with each other. The pulse width modulation control module (1) is used for generating a first PWM signal and a second PWM signal, and the first PWM signal and the second PWM signal are complementary. The power switch driving module (2) is used for improving the driving capacity of the first PWM signal and the second PWM signal. The conversion isolation transformer module (3) is used for inputting the first PWM signal with improved driving capacity to the control end of the first power switch module (4) and inputting the second PWM signal with improved driving capacity to the control end of the second power switch module (5). The first power switch module (4) is used for outputting power according to the first PWM signal, and the second power switch module (5) is used for outputting power according to the second PWM signal. The conversion isolation transformer module (3) comprises a primary winding, a first secondary winding and a second secondary winding, the A1 end of the first secondary winding is connected with the control end of the first power switch module (4), the B1 end of the first secondary winding is connected with the A2 end of the second secondary winding and the output end of the first power switch module (4), the B2 end of the second secondary winding is connected with the control end of the second power switch module (5), the A end of the primary winding is connected with the first PWM signal with improved driving capacity, and the B end of the primary winding is connected with the second PWM signal with improved driving capacity.

2. The circuit system capable of reducing heat generated by MOS switch operation according to claim 1, wherein, The turns ratio of the first secondary winding and the second secondary winding to the primary winding is 1:

1.

3. The circuit system capable of reducing heat generated by MOS switch operation according to claim 2, wherein, The B end of the primary winding is connected with one output end of the power switch driving module (2) through a first capacitor C1.

4. The circuit system capable of reducing heat generated by MOS switch operation according to claim 2, wherein, The first power switch module (4) comprises a first diode D1, a third resistor R3, a first MOS tube Q1 and a first voltage stabilizing diode D2, the negative pole of the first diode D1 is connected with one end of the third resistor R3 and the secondary side of the conversion isolation transformer module (3), the positive pole of the first diode D1 is connected with the other end of the third resistor R3, the gate of the first MOS tube Q1 and the negative pole of the first voltage stabilizing diode D2, the drain of the first MOS tube Q1 is connected with a power supply voltage, and the source of the first MOS tube Q1 is connected with the positive pole of the first voltage stabilizing diode D2 and the output end of the second power switch module (5).

5. The circuit system capable of reducing heat generated by MOS switch operation according to claim 1, wherein, ​ 6. The circuit system capable of reducing heat generated by MOS switch operation according to claim 1, wherein, The second power switch module (5) comprises a second diode D3, a fourth resistor R4, a second MOS tube Q2 and a second voltage stabilizing diode D4. The negative pole of the second diode D3 is connected to one end of the fourth resistor R4 and the secondary side of the conversion isolation transformer module (3). The positive pole of the second diode D3 is connected to the other end of the fourth resistor R4, the gate of the second MOS tube Q2 and the negative pole of the second voltage stabilizing diode D4. The drain of the second MOS tube Q2 is connected to the power supply voltage. The source of the second MOS tube Q2 is connected to the positive pole of the second voltage stabilizing diode D4 and the output end of the first power switch module (4).

7. The circuit system capable of reducing heat generated by MOS switch operation according to claim 1, wherein, The pulse width modulation control module (1) comprises a pulse width modulation controller U1, a first resistor R1 and a second resistor R2. The E1 output end of the pulse width modulation controller U1 outputs a first PWM signal and is connected to one end of the first resistor R1. The E2 output end outputs a second PWM signal and is connected to one end of the second resistor R2. The other end of the first resistor R1 and the other end of the second resistor R2 are respectively connected to the input end of the power switch driving module (2).

8. The circuit system capable of reducing heat generated by MOS switch operation according to claim 1, wherein, The power switch driving module (2) adopts a power switch driving chip U2.

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