A novel synchronous rectification driving circuit

Abstract

The application discloses a novel synchronous rectification driving circuit in the field of switching power supply, which comprises a current transformer, an I / V conversion circuit and a driving circuit, the current transformer comprises a winding TR1 on the primary side and windings TR2-TR4 on the secondary side, the winding TR1 samples current pulse signals from the drain current of the synchronous rectification tube on the secondary side of the main transformer, the windings TR2 and TR3 are connected in series and then connected to the input of the I / V conversion circuit, and the I / V conversion circuit converts the current pulse signals into voltage pulse signals with the amplitude between 0V and voltage amplitude Vo; the current pulse signals in the windings TR2 and TR3 are coupled to the winding TR4, and the winding TR4 is connected to the input of the driving circuit. The application can avoid the common phenomenon of the synchronous rectification tube and the MOS tube on the circular edge of the main transformer, the driving circuit chops through the MOS tube Q3, and the synchronous rectification tube is protected, so that the application has the characteristics of simple circuit structure, small loss, high efficiency and the like, and can be widely applied to various high-temperature switching power supplies.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of switching power supply, in particular to a novel synchronous rectification driving circuit. BACKGROUND

[0002] At present, the conventional thick film hybrid integrated DC / DC converter with high reliability, long service life, wide operating temperature range (-55-125 DEG C), and strong environmental stress resistance is widely used in aerospace, aviation, weapons, ships and other application fields. With the progress of science and technology, the whole system has higher and higher requirements for the DC / DC converter, and the development direction is mainly high frequency, miniaturization, high power density and the like. However, the demand for DC / DC converters that can withstand special environments including radiation resistance, extreme high temperature resistance, and extreme low temperature resistance is also becoming stronger and stronger.

[0003] High temperature environments exist in deep space exploration, deep well exploration, aircraft engine control systems, and internal combustion engine tank control systems. For example, the high temperature on the surface of the moon can reach above 127 DEG C; deep well logging instruments need to work at an ambient temperature of above 168 DEG C; the maximum working temperature of the aircraft engine control system can be above 93 DEG C; and the maximum working temperature of the internal combustion engine tank control system can be above 90 DEG C. The conventional DC / DC converter with a maximum shell temperature of 125 DEG C cannot work at an ambient temperature of 90 DEG C, considering the temperature rise of the shell, which has reached the limit of the existing product capability and cannot meet the temperature derating requirement, so the power supply products that can withstand high temperature are needed in these special occasions.

[0004] The existing conventional synchronous rectification driving circuit is divided into self-driving and driven two ways, wherein the driven adopts a driving chip to provide a driving signal, which can completely avoid the common of the primary and secondary power tubes and has a protection function for the synchronous rectification tube, but the existing synchronous rectification driving chip cannot be applied in the high temperature environments as described above. Although the self-driving can be applied in the high temperature environment by selecting components, it has the problems of common of the primary and secondary power tubes and no protection function for the synchronous rectification tube. SUMMARY

[0005] The present application aims to provide a novel synchronous rectification driving circuit to solve the problems in the background art.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] The application relates to a novel synchronous rectification driving circuit, which comprises a current transformer, an I / V conversion circuit and a driving circuit, wherein the current transformer comprises a winding TR1 on the primary side and windings TR2-TR4 on the secondary side; the winding TR1 samples a current pulse signal from the drain current of a synchronous rectification tube on the secondary side of a main transformer; the windings TR2 and TR3 are connected in series and then connected to the input of the I / V conversion circuit; the I / V conversion circuit converts the current pulse signal into a voltage pulse signal with an amplitude between 0V and a voltage amplitude Vo; the current pulse signals in the windings TR2 and TR3 are coupled to the winding TR4, the winding TR4 is connected to the input of the driving circuit, the driving circuit limits the current pulse signal, separates the direct current and chops the wave, and outputs a driving voltage to control the on-off of the synchronous rectification tube; the I / V converter and the driving circuit adopt an electronic switching element with a melting point of at least 200 DEG C.

[0008] In some embodiments, the same name end of the winding TR1 is connected to the output end of the secondary side of the main transformer, and the different name end is connected to the source of the synchronous rectification tube on the secondary side of the main transformer; the I / V conversion circuit comprises a capacitor C1, MOS tubes V1 and V2, the first end of the capacitor C1 is connected to the same name end of the winding TR2, the second end is connected to the gate and source of the MOS tube V1 and the drain of the MOS tube V2, the drain of the MOS tube V1 is connected to the output end of the DC / DC converter, and the gate and source of the MOS tube V2 and the different name end of the winding TR3 are connected to the output ground of the DC / DC converter.

[0009] In some embodiments, the driving circuit comprises resistors R1 and R2, a capacitor C2 and a MOS tube V3, the first end of the resistor R1 is connected to the same name end of the winding TR3, the second end is connected to the first end of the capacitor C2, the second end of the capacitor C2 is connected to the first end of the resistor R2, the drain of the MOS tube V3 and the gate of the synchronous rectification tube, and the different name end of the winding TR4, the second end of the resistor R2, the gate and drain of the MOS tube V3 are all connected to the output ground of the DC / DC converter.

[0010] Beneficial effects: the novel synchronous rectification driving circuit disclosed by the application adopts the high-temperature-resistant electronic switching element, breaks through the limitation of the conventional semiconductor 175 DEG C junction temperature, and can be used in the high-temperature DC / DC converter with the highest shell temperature of 185 DEG C. In addition, the application can avoid the common phenomenon of the synchronous rectification tube and the MOS tube on the circular edge of the main transformer, the driving circuit chops the wave through the MOS tube Q3, and the synchronous rectification tube is protected, and the novel synchronous rectification driving circuit has the characteristics of simple circuit structure, small loss, high efficiency and the like. BRIEF DESCRIPTION OF DRAWINGS

[0011] Fig. 1 It is the circuit block diagram of the application;

[0012] Fig. 2 It is the circuit schematic diagram of the application. DETAILED DESCRIPTION

[0013] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0014] Reference Figs. 1-2 A novel synchronous rectification driving circuit includes a current transformer 1, an I / V conversion circuit 2 and a driving circuit 3. The current transformer 1 includes a primary winding TR1 and secondary windings TR2-TR4. The same name end of the winding TR1 is connected to the output end of the secondary of the main transformer, and the different name end is connected to the source of the synchronous rectification tube of the secondary of the main transformer. The winding TR2 is connected in series with the winding TR3, and the series connection is connected to the input of the I / V conversion circuit 2. The output of the I / V conversion circuit 2 is connected to the output end of the DC / DC converter. The winding TR4 is connected to the input of the driving circuit 3, and the output of the driving circuit 3 controls the on-off of the synchronous rectification tube. The current transformer 1 samples the current from the drain of the synchronous rectification tube of the secondary of the main transformer, and the signal is used to synchronize the driving signal of the synchronous rectification tube, so that the common phenomenon of the synchronous rectification tube and the MOS tube of the primary of the main transformer can be avoided.

[0015] The I / V conversion circuit includes a capacitor C1, MOS tubes V1 and V2. The first end of the capacitor C1 is connected to the same name end of the winding TR2, the second end is connected to the gate and source of the MOS tube V1 and the drain of the MOS tube V2, the drain of the MOS tube V1 is connected to the output end of the DC / DC converter, and the gate and source of the MOS tube V2 and the different name end of the winding TR3 are connected to the output ground of the DC / DC converter. The winding TR1 collects the pulse signal of the output current from the secondary of the main transformer, and the pulse signal is coupled to the windings TR2 and TR3 through the current transformer 1. After the pulse signal is transmitted to the MOS tubes V1 and V2 after being isolated by the capacitor C1, the pulse signal is chopped by the MOS tubes V1 and V2 and is corrected to a pulse wave with an amplitude of 0V to the output voltage amplitude. The circuit can convert the current signal obtained by the current transformer into a voltage signal with an amplitude of 0V to the output voltage amplitude Vo.

[0016] The driving circuit includes resistors R1 and R2, a capacitor C2 and a MOS tube V3. The first end of the resistor R1 is connected to the same name end of the winding TR3, the second end is connected to the first end of the capacitor C2, the second end of the capacitor C2 is connected to the first end of the resistor R2, the drain of the MOS tube V3 and the gate of the synchronous rectification tube, the different name end of the winding TR4, the second end of the resistor R2, the gate and drain of the MOS tube V3 are all connected to the output ground of the DC / DC converter.

[0017] The current pulse signal in the windings TR2-TR3 is coupled to the winding TR4 through the current transformer 1, is current limited through the resistor R1, is direct current isolated through the capacitor C2, and is converted into the required driving voltage through the resistor R2. The pulse signal of the driving voltage is in phase with the pulse signal of the output current of the main transformer, and thus can be used to drive the synchronous rectifier tube of the output stage to realize the synchronous rectification function. The MOS tube V3 in the driving circuit plays a chopper role to correct the negative voltage value in the pulse signal of the driving voltage to 0V, and chops the negative voltage part in the pulse signal. After the pulse signal is direct current isolated through C2 and current limited through R1, the impact of the direct current on the gate of the MOS tube is avoided, and the synchronous rectifier tube is protected.

[0018] The amplitude of the driving signal of the circuit can be determined by the turn ratio of each winding, and the amplitude can be limited to , wherein N TR2 , N TR3 , and N TR4 are the number of turns of the windings TR2, TR3, and TR4. The parameters of each winding can be adjusted according to the selection of the MOS tube to protect the gate of the synchronous rectifier tube. The driving circuit can release energy through the MOS tubes V1 and V2 to the output stage, and thus has low loss and high efficiency.

[0019] The electronic switching elements such as the MOS tubes V1, V2, and V3 are high-temperature-resistant MOS tubes, and the model number can be WM1A060065B or the like. The melting point is at least 200℃, and different high-temperature-resistant MOS tubes with different voltage resistance and power can be selected according to the requirements of the project in actual application. Therefore, the application environment can be improved from the conventional -55-125℃ to -55-185℃, and a stable synchronous rectification driving signal is provided for the high-temperature DC / DC converter. In addition, the present application can avoid the common phenomenon of the synchronous rectifier tube and the MOS tube of the circular edge of the main transformer. The driving circuit chops through the MOS tube Q3 to protect the synchronous rectifier tube, has the characteristics of simple circuit structure, low loss, and high efficiency, and can be widely applied to various high-temperature switching power supplies.

[0020] Although the present specification is described in terms of embodiments, not every embodiment contains only one independent technical solution. The description of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0021] Therefore, the above description is only a preferred embodiment of the present application, and is not intended to limit the scope of the present application; that is, any equivalent transformation made within the scope of the claims of the present application is within the protection scope of the claims of the present application.

Claims

1. A novel synchronous rectification drive circuit, characterized by, The current transformer, I / V conversion circuit and driving circuit, the current transformer includes primary winding TR1 and secondary winding TR2-TR4, the winding TR1 obtains current pulse signal from the drain current of the synchronous rectifier tube of the secondary of the main transformer, the winding TR2 and winding TR3 are connected in series and the input of the I / V conversion circuit, I / V conversion circuit converts current pulse signal to voltage pulse signal with amplitude between 0V and voltage amplitude Vo; the current pulse signal in winding TR2, TR3 is coupled to winding TR4, winding TR4 connects the input of the driving circuit, the driving circuit limits current, separates direct current, chops wave, and outputs driving voltage to control the on-off of the synchronous rectifier tube, the I / V conversion circuit and driving circuit use electronic switching element with melting point of at least 200℃; The same name end of winding TR1 is connected to the output end of the secondary of the main transformer, and the opposite name end is connected to the source of the synchronous rectifier tube of the secondary of the main transformer; The I / V conversion circuit includes capacitor C1, MOS tube V1 and V2, the first end of capacitor C1 is connected to the same name end of winding TR2, the second end is connected to the gate and source of MOS tube V1 and the drain of MOS tube V2, the drain of MOS tube V1 is connected to the output end of DC / DC converter, the gate and source of MOS tube V2 and the opposite name end of winding TR3 are connected to the output ground of DC / DC converter; the opposite name end of winding TR2 is connected to the same name end of winding TR3; The DC / DC converter is a direct current converter device including a new type of synchronous rectification driving circuit.

2. A novel synchronous rectification driving circuit according to claim 1, characterized in that, The driving circuit includes resistance R1, R2, capacitor C2 and MOS tube V3, the first end of resistance R1 is connected to the same name end of winding TR4, the second end is connected to the first end of capacitor C2, the second end of capacitor C2 is connected to the first end of resistance R2, the drain of MOS tube V3 and the gate of synchronous rectifier tube, the opposite name end of winding TR4, the second end of resistance R2, the gate and source of MOS tube V3 are all connected to the output ground of DC / DC converter.

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