Half-bridge drive circuit

Abstract

The utility model discloses a half-bridge driving circuit, and relates to the technical field of power device driving. When the transformer driving module outputs a square signal, the polarities of driving voltages output to the rear by the two secondary windings of the isolation transformer are opposite, and one secondary winding drives the corresponding MOS tube to be switched off. The gate source capacitor of one switching tube in the half-bridge circuit is charged through the corresponding charging loop module, the charging and discharging loop module, the voltage clamping module and the voltage stabilizing diode module in sequence, and the switching tube of the half-bridge circuit is driven to be switched on; the other secondary winding drives the corresponding MOS tube to be conducted, so that a gate-source capacitor of the other switching tube in the half-bridge circuit discharges through the charging and discharging loop module, the corresponding MOS tube and the voltage clamping module in sequence, and the switching tube of the other half-bridge circuit is driven to be conducted; therefore, only one of the two switching tubes in the half-bridge circuit can be switched on at any time, and the half-bridge circuit is prevented from being directly connected.

Description

Technical Field

[0001] The utility model relates to the technical field of power device driving, in particular to a half-bridge driving circuit. Background Art

[0002] SIC power devices (such as IGBT) have a high switching frequency, and their drive circuits need to be able to support high-frequency characteristics, including fast switching and fast shutdown. For a half-bridge circuit composed of two SIC power devices, its drive circuit may drive the two switch tubes of the half-bridge circuit to turn on at the same time due to electromagnetic interference, that is, direct conduction, which is easy to damage the SIC power device. Utility Model Content

[0003] The utility model solves the technical problem of how to avoid the direct conduction of the half-bridge circuit by providing a half-bridge driving circuit.

[0004] The utility model provides the following technical solutions:

[0005] A half-bridge drive circuit includes a transformer drive module, an isolation transformer and two charging circuit modules, two charging and discharging circuit modules, two voltage clamping modules, two voltage stabilizing diode modules, two resistor modules and two MOS tubes;

[0006] The output end of the transformer driving module is connected to the primary winding of the isolation transformer, and the transformer driving module is used to output a square wave signal to drive the isolation transformer;

[0007] The opposite-name end of the first secondary winding of the isolation transformer is connected to the gate of the first switch tube in the half-bridge circuit via the first charging circuit module and the first charging and discharging circuit module in sequence, the common end of the first charging circuit module and the first charging and discharging circuit module is connected to the drain of the first MOS tube and connected to the gate of the first MOS tube via the first resistor module, the gate of the first MOS tube is also connected to the negative electrode of the first voltage zener diode module and the same-name end of the first secondary winding, the source of the first MOS tube is connected to the positive electrode of the first voltage zener diode module and connected to the source of the first switch tube in the half-bridge circuit via the first voltage clamping module;

[0008] The same-name end of the second secondary winding of the isolation transformer is connected to the gate of the second switch tube in the half-bridge circuit via the second charging circuit module and the second charging and discharging circuit module in sequence; the common end of the second charging circuit module and the second charging and discharging circuit module is connected to the drain of the second MOS tube and connected to the gate of the second MOS tube via the second resistor module; the gate of the second MOS tube is also connected to the negative electrode of the second voltage stabilizing diode module and the opposite-name end of the second secondary winding, respectively; the source of the second MOS tube is connected to the positive electrode of the second voltage stabilizing diode module and connected to the source of the second switch tube in the half-bridge circuit via the second voltage clamping module.

[0009] Optionally, the transformer driving module includes a driving chip and its peripheral circuits;

[0010] The first output end of the driver chip is connected to one end of the primary winding of the isolation transformer, the second output end of the driver chip is connected to the other end of the primary winding of the isolation transformer, and the output signals of the first output end and the second output end of the driver chip have opposite polarities.

[0011] Optionally, the model of the driver chip is NSD1025.

[0012] Optionally, the isolation transformer includes a transformer T9, a capacitor C85 and a diode D9;

[0013] The capacitor C85 is connected in series with the primary winding of the transformer T9, and the diode D9 is connected in parallel with the capacitor C85.

[0014] Optionally, the charging circuit module includes a first resistor, a second resistor and a first diode;

[0015] The first resistor is connected in series with the first diode and then in parallel with the second resistor. The common end of the first resistor and the second resistor is connected to the secondary winding of the isolation transformer. The cathode of the first diode and the common end of the second resistor are respectively connected to the charge and discharge loop module, the resistor module, and the drain of the MOS tube.

[0016] Optionally, the charge-discharge circuit module includes a third resistor;

[0017] One end of the third resistor and the common end of the charging loop module are respectively connected to the resistor module and the drain of the MOS tube, and the other end of the third resistor is connected to the gate of the switch tube in the half-bridge circuit.

[0018] Optionally, the charge and discharge circuit module further includes a second diode;

[0019] The second diode is connected in parallel with the third resistor, and an anode of the second diode is connected to a gate of a switch tube in the half-bridge circuit.

[0020] Optionally, the voltage stabilizing diode module includes a first voltage stabilizing diode;

[0021] The cathode of the first voltage stabilizing diode is connected to the gate of the MOS tube, and the anode of the first voltage stabilizing diode is connected to the source of the MOS tube.

[0022] Optionally, the voltage stabilizing diode module further includes a third diode;

[0023] The third diode is connected in parallel with the first voltage regulator diode in the same direction.

[0024] Optionally, the voltage clamping module includes a first capacitor and a second voltage stabilizing diode;

[0025] The source of the MOS tube is connected to the source of the switch tube in the half-bridge circuit via the first capacitor, the second voltage regulator diode is connected in parallel with the first capacitor, and the cathode of the second voltage regulator diode is connected to the source of the switch tube in the half-bridge circuit.

[0026] The technical solution provided by the utility model has at least the following technical effects or advantages:

[0027] When the transformer driving module of the utility model outputs a square wave signal, the two secondary windings of the isolation transformer output driving voltages with opposite polarities to the rear, one of the secondary windings drives the corresponding MOS tube to turn off, and sequentially charges the gate-source capacitance of one of the switch tubes in the half-bridge circuit through the corresponding charging loop module, the charging and discharging loop module, the voltage clamping module, and the voltage stabilizing diode module, and drives the switch tube of the half-bridge circuit to turn on; the other secondary winding drives the corresponding MOS tube to turn on, so that the gate-source capacitance of the other switch tube in the half-bridge circuit is discharged sequentially through the charging and discharging loop module, the corresponding MOS tube, and the voltage clamping module, and drives the switch tube of the other half-bridge circuit to turn on; thereby, only one of the two switch tubes in the half-bridge circuit can be turned on at any time, and the half-bridge circuit is avoided from being directly connected. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0029] Figure 1 This is a structural block diagram of a half-bridge drive circuit in an embodiment of the utility model;

[0030] Figure 2 2 is a circuit diagram of a half-bridge driving circuit in an embodiment of the present utility model. DETAILED DESCRIPTION

[0031] The embodiment of the utility model solves the technical problem of how to avoid the direct conduction of the half-bridge circuit by providing a half-bridge driving circuit.

[0032] In order to better understand the technical solution of the present invention, the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0033] like Figure 1 As shown, the half-bridge driving circuit of the embodiment of the utility model includes a transformer driving module, an isolation transformer and two charging circuit modules, two charging and discharging circuit modules, two voltage clamping modules, two voltage stabilizing diode modules, two resistor modules and two MOS tubes;

[0034] The output end of the transformer driving module is connected to the primary winding of the isolation transformer, and the transformer driving module is used to output a square wave signal to drive the isolation transformer;

[0035] The opposite-name end of the first secondary winding of the isolation transformer is connected to the gate of the first switch tube in the half-bridge circuit via the first charging circuit module and the first charging and discharging circuit module in sequence, the common end of the first charging circuit module and the first charging and discharging circuit module is connected to the drain of the first MOS tube and connected to the gate of the first MOS tube via the first resistor module, the gate of the first MOS tube is also connected to the negative electrode of the first voltage zener diode module and the same-name end of the first secondary winding, the source of the first MOS tube is connected to the positive electrode of the first voltage zener diode module and connected to the source of the first switch tube in the half-bridge circuit via the first voltage clamping module;

[0036] The same-name end of the second secondary winding of the isolation transformer is connected to the gate of the second switch tube in the half-bridge circuit via the second charging circuit module and the second charging and discharging circuit module in sequence. The common end of the second charging circuit module and the second charging and discharging circuit module is connected to the drain of the second MOS tube and connected to the gate of the second MOS tube via the second resistor module. The gate of the second MOS tube is also connected to the negative electrode of the second voltage zener diode module and the opposite-name end of the second secondary winding, respectively. The source of the second MOS tube is connected to the positive electrode of the second voltage zener diode module and connected to the source of the second switch tube in the half-bridge circuit via the second voltage clamping module.

[0037] The isolation transformer has two secondary windings.

[0038] like Figure 2As shown, the transformer driving module of the embodiment of the utility model may include a driving chip U6 and its peripheral circuits; the first output end of the driving chip is connected to one end of the primary winding of the isolation transformer, the second output end of the driving chip is connected to the other end of the primary winding of the isolation transformer, and the output signal polarities of the first output end and the second output end of the driving chip are opposite.

[0039] Among them, the model of the driver chip U6 can be NSD1025, and the peripheral circuit of the NSD1025 chip U6 includes a 12V power supply, a resistor R39, a resistor R61, a resistor R37 and a transistor T12. The first output terminal and the second output terminal of the driver chip are the OUTA pin and the OUTB pin of the NSD1025 chip U6 respectively. When the INA pin of the NSD1025 chip U6 is at a high level, the OUTA pin outputs a +12V voltage, when the INA pin is at a low level, the OUTA pin outputs a -12V voltage, when the INB pin is at a high level, the OUTB pin outputs a +12V voltage, and when the INB pin is at a low level, the OUTB pin outputs a -12V voltage. The NV and NV pins of the NSD1025 chip U6 are enable pins. When LLC_DR_EN is at a low level, the transistor T12 is turned off, DR_EN is 12V, and the NSD1025 chip U6 is enabled to work; when LLC_DR_EN is at a high level, the transistor T12 is saturated and turned on, DR_EN is 0V, and the NSD1025 chip U6 is disabled.

[0040] When the NSD1025 chip U6 is enabled, complementary square wave signals with dead zones can be input to the INA pin and the INB pin. In this way, when the OUTA pin outputs a +12V voltage, the OUTB pin outputs a -12V voltage, and when the OUTA pin outputs a -12V voltage, the OUTB pin outputs a +12V voltage, thereby realizing the function of the transformer drive module outputting a square wave signal.

[0041] like Figure 2 As shown, the isolation transformer of the embodiment of the utility model may include a transformer T9, a capacitor C85 and a diode D9; the capacitor C85 is connected in series with the primary winding of the transformer T9, and the diode D9 is connected in parallel with the capacitor C85. Assuming that the number of turns of the two secondary windings of the transformer T9 is the same, and the turn ratio of the primary winding to the two secondary windings is 20:30:30, when the transformer driving module outputs a ±12V square wave signal to the primary winding of the transformer T9, the two secondary windings of the transformer T9 output a ±18V square wave signal. The capacitor C85 and the diode D9 play the role of isolating DC and buffering.

[0042] Depend on Figure 1 and Figure 2 It can be seen that the two driving circuits behind the two secondary windings of the isolation transformer have the same structure and therefore the same working principle.

[0043] The charging circuit module, the charge-discharge circuit module, the voltage clamping module and the voltage stabilizing diode module of the embodiment of the utility model are used to provide a circuit for charging the gate-source capacitor CD of the switch tube in the half-bridge circuit by the output voltage of the secondary winding of the transformer T9, and the charging-discharge circuit module, the MOS tube and the voltage clamping module are used to provide a circuit for discharging the gate-source capacitor CD of the switch tube in the half-bridge circuit.

[0044] Among them, the charging circuit module may include a first resistor, a second resistor and a first diode; the first resistor is connected in series with the first diode and then in parallel with the second resistor, the common end of the first resistor and the second resistor is connected to the secondary winding of the isolation transformer, and the negative electrode of the first diode and the common end of the second resistor are respectively connected to the charge and discharge circuit module, the resistor module, and the drain of the MOS tube. The charging and discharging circuit module may include a third resistor and a second diode; one end of the third resistor and the common end of the charging circuit module are respectively connected to the resistor module and the drain of the MOS tube, and the other end of the third resistor is connected to the gate of the switch tube in the half-bridge circuit; the second diode is connected in parallel with the third resistor, and the positive electrode of the second diode is connected to the gate of the switch tube in the half-bridge circuit. The voltage regulator diode module may include a first voltage regulator diode and a third diode; the negative electrode of the first voltage regulator diode is connected to the gate of the MOS tube, and the positive electrode of the first voltage regulator diode is connected to the source of the MOS tube; the third diode is connected in parallel with the first voltage regulator diode in the same direction. The voltage clamping module may include a first capacitor and a second zener diode; the source of the MOS tube is connected to the source of the switch tube in the half-bridge circuit via the first capacitor, the second zener diode is connected in parallel with the first capacitor, and the cathode of the second zener diode is connected to the source of the switch tube in the half-bridge circuit.

[0045] For the secondary winding 6-7 of the transformer T9, the MOS tube is the MOS tube T4, the first resistor is the resistor R43, the second resistor is the resistor R66, the first diode is the diode D12, the third resistor is the resistor R180, the second diode is the diode D41, the first voltage regulator diode is the voltage regulator diode D17, the third diode is the diode D20, the first capacitor is the capacitor C10, the second voltage regulator diode is the voltage regulator diode D19, and the resistor module includes the resistor R68.

[0046] For the secondary winding 9-10 of the transformer T9, the MOS tube is the MOS tube T11, the first resistor is the resistor R74, the second resistor is the resistor R78, the first diode is the diode D13, the third resistor is the resistor R181, the second diode is the diode D42, the first voltage regulator diode is the voltage regulator diode D31, the third diode is the diode D33, the first capacitor is the capacitor C14, the second voltage regulator diode is the voltage regulator diode D32, and the resistor module includes the resistor R79.

[0047] Taking the secondary winding 6-7 of the transformer T9 as an example, when the output voltage U67 of the secondary winding 6-7 of the transformer T9 is +18V, the gate of the MOS tube T4 is connected to the low voltage end 7 of the transformer T9, the gate voltage of the MOS tube T4 is less than the source voltage, the resistance between the drain and the source of the MOS tube T4 is infinite, and the secondary winding 6-7 charges the capacitor CD through the resistor R43, the diode D12, the resistor R44, the resistor R180, the capacitor C10 and the voltage regulator diode D19, the voltage regulator diode D17 and the diode D20 in sequence. Due to the voltage regulation effect of D19 (such as the voltage regulation value is 3.3V), the voltage across the capacitor CD will eventually reach about 14.7V, driving the first switch tube in the half-bridge circuit to turn on.

[0048] When the output voltage U67 of the secondary winding 6-7 of the transformer T9 is -18V, the gate voltage of the MOS tube T4 is 18V, and the source of the MOS tube T4 is connected between the two ends of the secondary winding 6-7 of the transformer T9 through the voltage regulator diode D17 and the resistor R66. Due to the voltage regulation effect of the voltage regulator diode D17 (such as the voltage regulation value is 12V), the source voltage of the MOS tube T4 is 6V relative to the 6th pin of the secondary winding 6-7, and the gate-source voltage of the MOS tube T4 is 12V. The MOS tube T4 is turned on, and the 14.7V voltage on the capacitor CD is discharged through the diode D41, the resistor R44, the MOS tube T4, the capacitor C10 and the voltage regulator diode D19 in sequence. Since the MOS tube T4 connects the capacitor CD to the two ends of the capacitor C10 and the voltage regulator diode D19 stabilizes the voltage across the two ends of the capacitor C10 at 3.3V, the capacitor CD will eventually discharge to -3.3V, driving the first switch tube in the half-bridge circuit to turn off.

[0049] Thus, the function of driving the first switch tube in the half-bridge driving circuit to turn on and off is realized. Among them, the resistor R43 is the current limiting resistor of the charging circuit; the resistor R44 and the resistor R180 are the current limiting resistors of the charging and discharging circuit; the diode D20 provides a fast charging circuit for the capacitor CD; the diode D41 is used to bypass the resistor R180 to speed up the discharge of the capacitor CD; the capacitance of the capacitor C10 is much larger than that of the capacitor CD, and the voltage across the capacitor C10 will basically not change during the discharge process.

[0050] Since the connection method of the secondary windings 9-10 and 6-7 of the transformer T9 is opposite to that of the rear driving circuit, when the gate-source capacitor CD voltage of the first switch tube in the half-bridge circuit is 14.7V, the gate-source capacitor CD voltage of the second switch tube in the half-bridge circuit is -3.3V, the first switch tube is turned on and the second switch tube is turned off; when the gate-source capacitor CD voltage of the first switch tube in the half-bridge circuit is -3.3V, the gate-source capacitor CD voltage of the second switch tube in the half-bridge circuit is 14.7V, the first switch tube is turned off and the second switch tube is turned on.

[0051] It can be seen from the above that when the transformer driving module of the half-bridge driving circuit of the embodiment of the utility model outputs a square wave signal, the two secondary windings of the isolation transformer output the driving voltage with opposite polarity to the rear, and one of the secondary windings drives the corresponding MOS tube to turn off, and the gate-source capacitance of one of the switching tubes in the half-bridge circuit is charged through the corresponding charging loop module, the charging and discharging loop module, the voltage clamping module, and the voltage zener diode module in sequence, driving the switching tube of the half-bridge circuit to turn on; the other secondary winding drives the corresponding MOS tube to turn on, so that the gate-source capacitance of the other switching tube in the half-bridge circuit is discharged through the charging and discharging loop module, the corresponding MOS tube, and the voltage clamping module in sequence, driving the other half-bridge circuit switching tube to turn off; thereby, only one of the two switching tubes in the half-bridge circuit can be turned on at any time, avoiding the half-bridge circuit from being directly turned on.

[0052] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0053] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A half-bridge driving circuit, characterized in that: It includes a transformer drive module, an isolation transformer and two charging circuit modules, two charging and discharging circuit modules, two voltage clamping modules, two voltage stabilizing diode modules, two resistor modules and two MOS tubes; The output end of the transformer driving module is connected to the primary winding of the isolation transformer, and the transformer driving module is used to output a square wave signal to drive the isolation transformer; The opposite-name end of the first secondary winding of the isolation transformer is connected to the gate of the first switch tube in the half-bridge circuit via the first charging circuit module and the first charging and discharging circuit module in sequence, the common end of the first charging circuit module and the first charging and discharging circuit module is connected to the drain of the first MOS tube and connected to the gate of the first MOS tube via the first resistor module, the gate of the first MOS tube is also connected to the negative electrode of the first voltage zener diode module and the same-name end of the first secondary winding, the source of the first MOS tube is connected to the positive electrode of the first voltage zener diode module and connected to the source of the first switch tube in the half-bridge circuit via the first voltage clamping module; The same-name end of the second secondary winding of the isolation transformer is connected to the gate of the second switch tube in the half-bridge circuit via the second charging circuit module and the second charging and discharging circuit module in sequence; the common end of the second charging circuit module and the second charging and discharging circuit module is connected to the drain of the second MOS tube and connected to the gate of the second MOS tube via the second resistor module; the gate of the second MOS tube is also connected to the negative electrode of the second voltage stabilizing diode module and the opposite-name end of the second secondary winding, respectively; the source of the second MOS tube is connected to the positive electrode of the second voltage stabilizing diode module and connected to the source of the second switch tube in the half-bridge circuit via the second voltage clamping module.

2. The half-bridge driving circuit according to claim 1, characterized in that: The transformer driving module includes a driving chip and its peripheral circuits; The first output end of the driver chip is connected to one end of the primary winding of the isolation transformer, the second output end of the driver chip is connected to the other end of the primary winding of the isolation transformer, and the output signals of the first output end and the second output end of the driver chip have opposite polarities.

3. The half-bridge driving circuit according to claim 2, characterized in that: The model of the driver chip is NSD1025.

4. The half-bridge driving circuit according to claim 1, characterized in that: The isolation transformer includes a transformer T9, a capacitor C85 and a diode D9; The capacitor C85 is connected in series with the primary winding of the transformer T9, and the diode D9 is connected in parallel with the capacitor C85.

5. The half-bridge driving circuit according to claim 1, characterized in that: The charging circuit module includes a first resistor, a second resistor and a first diode; The first resistor is connected in series with the first diode and then in parallel with the second resistor. The common end of the first resistor and the second resistor is connected to the secondary winding of the isolation transformer. The cathode of the first diode and the common end of the second resistor are respectively connected to the charge and discharge loop module, the resistor module, and the drain of the MOS tube.

6. The half-bridge driving circuit according to claim 1, characterized in that: The charge-discharge circuit module includes a third resistor; One end of the third resistor and the common end of the charging loop module are respectively connected to the resistor module and the drain of the MOS tube, and the other end of the third resistor is connected to the gate of the switch tube in the half-bridge circuit.

7. The half-bridge driving circuit according to claim 6, characterized in that: The charging and discharging circuit module also includes a second diode; The second diode is connected in parallel with the third resistor, and an anode of the second diode is connected to a gate of a switch tube in the half-bridge circuit.

8. The half-bridge driving circuit according to claim 1, characterized in that: The voltage stabilizing diode module comprises a first voltage stabilizing diode; The cathode of the first voltage stabilizing diode is connected to the gate of the MOS tube, and the anode of the first voltage stabilizing diode is connected to the source of the MOS tube.

9. The half-bridge driving circuit according to claim 8, characterized in that: The voltage stabilizing diode module further includes a third diode; The third diode is connected in parallel with the first voltage regulator diode in the same direction.

10. The half-bridge driving circuit according to claim 1, characterized in that: The voltage clamping module includes a first capacitor and a second voltage stabilizing diode; The source of the MOS tube is connected to the source of the switch tube in the half-bridge circuit via the first capacitor, the second voltage regulator diode is connected in parallel with the first capacitor, and the cathode of the second voltage regulator diode is connected to the source of the switch tube in the half-bridge circuit.

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