Half-bridge DC-DC conversion circuit and electronic equipment

Abstract

The utility model provides a half-bridge DC-DC conversion circuit and electronic equipment, and belongs to the technical field of switches. The half-bridge DC-DC conversion circuit comprises a first HEMT, a second HEMT, an MOSFET and a DC-DC converter. The first HEMT is located on the upper half bridge, and the second HEMT is located on the lower half bridge. And the MOSFET is positioned on the upper half bridge or the lower half bridge.

Description

Technical Field

[0001] The present disclosure relates to the field of switch technology, and in particular to a half-bridge DC-DC conversion circuit and an electronic device. Background Art

[0002] The half-bridge direct current-direct current conversion circuit is composed of a half-bridge and a direct current-direct current converter. The half-bridge includes two upper and lower bridge arms, each of which is composed of a high electron mobility transistor (HEMT) and a metal oxide semiconductor field effect transistor (MOSFET) connected in series. The two bridge arms are connected in series, one input end of the direct current-direct current converter is connected to the midpoint of a series bridge arm, and the other input end of the direct current-direct current converter is grounded.

[0003] The control of the half-bridge DC-DC converter circuit is achieved by providing signals to the control terminals of the two MOSFETs. The HEMT is connected in series to the MOSFETs without the need for separate control. Limited by the switching characteristics of the MOSFET, the operating frequency of the half-bridge DC-DC converter circuit is usually lower than 150KHz. Utility Model Content

[0004] The embodiment of the present disclosure provides a half-bridge DC-DC conversion circuit and an electronic device, which can increase the frequency of the half-bridge DC-DC conversion circuit. The technical solution is as follows:

[0005] At least one embodiment of the present disclosure provides a half-bridge DC-DC conversion circuit, the half-bridge DC-DC conversion circuit comprising: a first HEMT, a second HEMT, a MOSFET, and a DC-DC converter;

[0006] The first terminal of the first HEMT is connected to the voltage supply terminal, and the control terminal of the first HEMT is connected to the first PWM signal supply terminal; the first terminal of the second HEMT is connected to the first input terminal of the DC-DC converter, and the control terminal of the second HEMT is connected to the second PWM signal supply terminal; the control terminal of the MOSFET is connected to the EN signal supply terminal; the second input terminal of the DC-DC converter is grounded;

[0007] The second end of the first HEMT is connected to the first end of the second HEMT; the second end of the second HEMT is connected to the first end of the MOSFET; the second end of the MOSFET is grounded; or, the second end of the first HEMT is connected to the first end of the MOSFET; the second end of the second HEMT is grounded; and the second end of the MOSFET is connected to the first end of the second HEMT.

[0008] That is, the first HEMT is located in the upper half bridge, the second HEMT is located in the lower half bridge, and the MOSFET is located in the upper half bridge or the lower half bridge.

[0009] Optionally, the first HEMT, the second HEMT and the MOSFET are three discrete components.

[0010] Optionally, the first HEMT is a discrete element, and the second HEMT and the MOSFET form a discrete element.

[0011] Optionally, the second HEMT is a discrete element, and the first HEMT and the MOSFET constitute a discrete element.

[0012] Optionally, the first HEMT and the second HEMT are normally-off gallium nitride HEMTs.

[0013] Optionally, the MOSFET is an enhancement mode MOSFET.

[0014] In some examples, the frequency range of the PWM signals provided by the first PWM signal providing terminal and the second PWM signal providing terminal is 100 KHz to 1 MHz.

[0015] In some other examples, the frequency range of the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end may also be outside the range of 100 KHz to 1 MHz, which is not limited in the present disclosure.

[0016] In some examples, the voltage range of the PWM signals provided by the first PWM signal providing terminal and the second PWM signal providing terminal is -18 to 0V.

[0017] In some other examples, the voltage range of the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end may also be outside the range of -18 to 0 V, which is not limited in the present disclosure.

[0018] In some examples, the voltage range of the EN signal provided by the EN signal providing terminal is 0 to 12V.

[0019] In some other examples, the voltage range of the EN signal provided by the EN signal providing end may be outside the range of 0 to 12V, which is not limited in the present disclosure.

[0020] At least one embodiment of the present disclosure provides an electronic device, comprising a half-bridge DC-DC conversion circuit as described in any of the preceding items.

[0021] The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

[0022] The half-bridge DC-DC conversion circuit provided by the embodiment of the present disclosure includes two HEMTs and one MOSFET, the control terminals of the two HEMTs are respectively connected to two PWM signal supply terminals, and the control terminal of one MOSFET is connected to one EN signal supply terminal. Therefore, the half-bridge DC-DC conversion circuit of this structure can be controlled by the signals provided by the two PWM signal supply terminals and one EN signal supply terminal when the half-bridge DC-DC conversion circuit is working. For example, the MOSFET can be controlled to be turned on by the EN signal provided by the EN signal supply terminal. Then, in the first timing cycle, the first HEMT is controlled to be turned on and the second HEMT is turned off by the PWM signals provided by the first PWM signal supply terminal and the second PWM signal supply terminal respectively; in the second timing cycle, the first HEMT is controlled to be turned off and the second HEMT is controlled to be turned on by the PWM signals provided by the first PWM signal supply terminal and the second PWM signal supply terminal respectively. By alternating the control of the above two timing cycles, the operation of the half-bridge DC-DC conversion circuit is realized. In the above working process, the MOSFET is continuously turned on, so the operating frequency of the half-bridge DC-DC conversion circuit will not be subject to the switching characteristics of the MOSFET, thereby increasing the frequency of the half-bridge DC-DC conversion circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 is a structural schematic diagram of a half-bridge DC-DC conversion circuit provided by some embodiments of the present disclosure;

[0025] Figure 2 is a structural schematic diagram of another half-bridge DC-DC conversion circuit provided in some embodiments of the present disclosure;

[0026] Figure 3is a structural schematic diagram of another half-bridge DC-DC conversion circuit provided in some embodiments of the present disclosure;

[0027] Figure 4 is a structural schematic diagram of another half-bridge DC-DC conversion circuit provided in some embodiments of the present disclosure;

[0028] Figure 5 is a flow chart of a control method of a half-bridge DC-DC conversion circuit provided by some embodiments of the present disclosure;

[0029] Figure 6 This is a flow chart of another control method for a half-bridge DC-DC conversion circuit provided in some embodiments of the present disclosure. DETAILED DESCRIPTION

[0030] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0031] Figure 1 is a schematic diagram of the structure of a half-bridge DC-DC conversion circuit provided by some embodiments of the present disclosure. Figure 1 The half-bridge DC-DC conversion circuit includes: a first HEMT 101, a second HEMT 102, a MOSFET 103 and a DC-DC converter 104.

[0032] The first terminal of the first HEMT 101 is connected to the voltage supply terminal VBUS, and the control terminal of the first HEMT 101 is connected to the first PWM signal supply terminal; the first terminal of the second HEMT 102 is connected to the first input terminal of the DC-DC converter 104, and the control terminal of the second HEMT 102 is connected to the second PWM signal supply terminal; the control terminal of the MOSFET 103 is connected to the EN signal supply terminal; and the second input terminal of the DC-DC converter 104 is grounded.

[0033] The second end of the first HEMT 101 is connected to the first end of the second HEMT 102 ; the second end of the second HEMT 102 is connected to the first end of the MOSFET 103 ; and the second end of the MOSFET 103 is grounded.

[0034] Figure 2 is a schematic diagram of the structure of another half-bridge DC-DC conversion circuit provided by some embodiments of the present disclosure. Figure 2 , Figure 2 The structure of the half-bridge DC-DC converter circuit shown in FIG. Figure 1 The difference is: Figure 1 The MOSFET is set in the lower half bridge. Figure 2The middle MOSFET is set in the upper half bridge.

[0035] See also Figure 2 The half-bridge DC-DC conversion circuit includes: a first HEMT 101, a second HEMT 102, a MOSFET 103 and a DC-DC converter 104.

[0036] The first terminal of the first HEMT 101 is connected to the voltage supply terminal VBUS, and the control terminal of the first HEMT 101 is connected to the first PWM signal supply terminal; the first terminal of the second HEMT 102 is connected to the first input terminal of the DC-DC converter 104, and the control terminal of the second HEMT 102 is connected to the second PWM signal supply terminal; the control terminal of the MOSFET 103 is connected to the EN signal supply terminal; and the second input terminal of the DC-DC converter 104 is grounded.

[0037] The second end of the first HEMT 101 is connected to the first end of the MOSFET 103 ; the second end of the second HEMT 102 is grounded; and the second end of the MOSFET 103 is connected to the first end of the second HEMT 102 .

[0038] The half-bridge DC-DC conversion circuit provided by the embodiment of the present disclosure includes two HEMTs and one MOSFET, the control ends of the two HEMTs are respectively connected to two PWM signal supply ends, and the control end of one MOSFET is connected to one EN signal supply end. Therefore, when the half-bridge DC-DC conversion circuit of this structure is working, it can be controlled by the signals provided by the two PWM signal supply ends and one EN signal supply end.

[0039] The half-bridge DC-DC conversion circuit provided by the embodiment of the present disclosure is adopted. When the half-bridge DC-DC conversion circuit is working, the MOSFET is controlled to be turned on by the EN signal (enable signal) provided by the EN signal providing end. Then, in the first timing cycle, the first HEMT is controlled to be turned on and the second HEMT is controlled to be turned off by the PWM signals (pulse width modulation signals) provided by the first PWM signal providing end and the second PWM signal providing end respectively; in the second timing cycle, the first HEMT is controlled to be turned off and the second HEMT is controlled to be turned on by the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end respectively. The operation of the half-bridge DC-DC conversion circuit is realized by alternating the control of the above two timing cycles. In the above working process, the MOSFET is continuously turned on, so the operating frequency of the half-bridge DC-DC conversion circuit will not be subject to the switching characteristics of the MOSFET, thereby increasing the frequency of the half-bridge DC-DC conversion circuit.

[0040] That is to say, in the embodiment of the present disclosure, when the half-bridge DC-DC conversion circuit is working, the MOSFET is continuously turned on.

[0041] In some possible implementations of the present disclosure, the first HEMT 101 and the second HEMT 102 are normally-off gallium nitride HEMTs.

[0042] Compared with the normally open GaN switch, the normally closed GaN switch has the advantages of simpler structure, lower manufacturing cost, higher switch toughness and reliability.

[0043] Normally closed HEMT cannot be used alone. When two MOSFETs are connected in series, they become a normally open switch. The use of this switch is to achieve control by switching MOSFET. Therefore, a MOSFET is set in the half-bridge. The MOSFET and two HEMTs can constitute the above switch, and the effect of the original two MOSFETs can be achieved by controlling the MOSFET and the two HEMTs respectively. Compared with the half-bridge DC-DC conversion circuit of the related art, it is not only no longer limited by the frequency of MOSFET, but also takes advantage of the operating frequency of the gallium nitride power switching device (HEMT) to improve the volume power density of the power supply product; it also saves a MOSFET and reduces the cost of the half-bridge DC-DC conversion circuit.

[0044] Exemplarily, the control terminal of the HEMT or MOSFET is a gate.

[0045] Exemplarily, the first end of the HEMT or MOSFET is a source, and the second end is a drain. Alternatively, the first end of the HEMT or MOSFET is a drain, and the second end is a source.

[0046] exist Figure 1 and Figure 2 In the half-bridge DC-DC conversion circuit structure shown, the first HEMT 101, the second HEMT 102 and the MOSFET 103 are three discrete components.

[0047] like Figure 1 and Figure 2 As shown, the three discrete components are Q1, Q2 and Q3 respectively.

[0048] Figure 3 It is a structural schematic diagram of another half-bridge DC-DC conversion circuit provided in some embodiments of the present disclosure. Figure 3 The structure of the half-bridge DC-DC converter circuit shown is similar to Figure 1 Compared with the structure of the half-bridge DC-DC converter circuit shown in FIG. 1 , the difference is: Figure 1There are three discrete components in Figure 3 There are only two discrete components in Figure 1 and Figure 3 In FIG. 1 , the black frame outside the HEMT and / or MOSFET represents a discrete component.

[0049] In conventional related technical designs, since the switch composed of HEMT and MOSFET is only controlled by MOSFET driving, in order to solve the matching problem between the two, HEMT and MOSFET are usually designed as a discrete component. However, since HEMT and MOSFET are controlled separately in the present application, they can be combined into a discrete component or separated into different discrete components.

[0050] See also Figure 3 , the first HEMT 101 is a discrete element, and the second HEMT 102 and the MOSFET 103 constitute a discrete element.

[0051] like Figure 3 As shown, the two discrete components are Q1 and Q2 respectively.

[0052] Figure 4 It is a structural schematic diagram of another half-bridge DC-DC conversion circuit provided in some embodiments of the present disclosure. Figure 4 The structure of the half-bridge DC-DC converter circuit shown is similar to Figure 2 Compared with the structure of the half-bridge DC-DC converter circuit shown in FIG. 1 , the difference is: Figure 2 There are three discrete components in Figure 4 The second HEMT 102 is a discrete component, and the first HEMT 101 and the MOSFET 103 form a discrete component.

[0053] In some other possible implementations of the present disclosure, the first HEMT 101 and the second HEMT 102 may also be other types of HEMTs, which is not limited in the present disclosure.

[0054] In the embodiments of the present disclosure, HEMT specifications include HEMTs of various specifications ranging from low to high voltage ranges and from low to high current ranges.

[0055] Exemplarily, the HEMT used in the embodiments of the present disclosure has a withstand voltage of 650V and a withstand current of 30A.

[0056] In some possible implementations of the present disclosure, the MOSFET 103 is an enhancement-mode MOSFET.

[0057] In some other possible implementations of the present disclosure, the MOSFET 103 may also be other types of MOSFETs, which is not limited in the present disclosure.

[0058] In the embodiments of the present disclosure, MOSFET specifications include MOSFETs of various specifications ranging from low to high voltage ranges and from low to high current ranges.

[0059] Exemplarily, the MOSFET used in the embodiments of the present disclosure has a withstand voltage of 30V and has an ultra-low impedance.

[0060] In the embodiment of the present disclosure, the frequency range of the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end is 100 KHz to 1 MHz.

[0061] The PWM signals provided by the first PWM signal providing end and the second PWM signal providing end are PWM1 and PWM2 in the figure respectively.

[0062] The PWM frequency refers to the frequency of high and low level switching in the PWM signal, that is, the frequency of controlling the switching of the HEMT switch.

[0063] In the embodiment of the present disclosure, the frequencies of the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end are the same.

[0064] Exemplarily, when the two HEMTs are of the same type, for example, both adopt a HEMT that is turned on by a high level and turned off by a low level, the high and low levels of the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end are set oppositely, that is, the high level of the PWM signal provided by the first PWM signal providing end corresponds to the low level of the PWM signal provided by the second PWM signal providing end, and the low level of the PWM signal provided by the first PWM signal providing end corresponds to the high level of the PWM signal provided by the second PWM signal providing end, thereby achieving an effect of turning one on and the other off.

[0065] In an example, the high level and the low level of the PWM signal provided by the first PWM signal providing end and the second PWM signal providing end may be respectively the same.

[0066] In another example, at least one of a high level and a low level of the PWM signal provided by the first PWM signal providing end and the second PWM signal providing end may be different.

[0067] Exemplarily, the voltage range of the PWM signals provided by the first PWM signal providing terminal and the second PWM signal providing terminal is -18 to 0V.

[0068] For example, the low level is -18V and the high level is 0V.

[0069] In the embodiment of the present disclosure, the high and low level waveforms of the EN signal provided by the EN signal providing end are designed according to needs.

[0070] The EN signal provided by the EN signal providing end is EN in the figure.

[0071] Exemplarily, the EN signal uses a MOSFET that is turned on when at a high level and turned off when at a low level.

[0072] Exemplarily, the voltage range of the EN signal provided by the EN signal providing terminal is 0 to 12V.

[0073] For example, a low level is 0V and a high level is 12V.

[0074] When the half-bridge DC-DC conversion circuit needs to work, the MOSFET is controlled to be turned on through the EN signal provided by the EN signal providing terminal.

[0075] At this time, respective PWM signals are input to the two HEMTs, and when the first HEMT is turned on, the second HEMT is turned off. When the first HEMT is turned off, the second HEMT is turned on. And under the action of PWM, the above two states are switched at a high speed.

[0076] When the half-bridge DC-DC conversion circuit stops working, the MOSFET is controlled to be turned off through the EN signal provided by the EN signal providing terminal.

[0077] See again Figures 1 to 4 The DC-DC converter 104 includes a capacitor Cr, an inductor Lr, a transformer Tr, a diode D1, a diode D2, a capacitor Co and a resistor RL.

[0078] One end of the capacitor Cr is connected to the second end of the first HEMT 101, the other end of the capacitor Cr is connected to one end of the inductor Lr, the other end of the inductor Lr is connected to one end of the primary coil of the transformer Tr, the other end of the primary coil of the transformer Tr is grounded, one end of the secondary coil of the transformer Tr is connected to the anode of the diode D1, the other end of the secondary coil of the transformer Tr is connected to the anode of the diode D2, the cathode of the diode D2 is connected to the cathode of the diode D1, the cathode of the diode D1 is also connected to one end of the capacitor Co and one end of the resistor RL, the cathode of the diode D1 is the output end Vout of the DC-DC converter 104, the other end of the capacitor Co and the other end of the resistor RL are connected to the center tap of the secondary coil of the transformer Tr.

[0079] certainly Figures 1 to 4The figure is only an example of the structure of the DC-DC converter 104 , and the present application does not limit the circuit structure of the DC-DC converter 104 .

[0080] Figure 5 is a flow chart of a control method for a half-bridge DC-DC conversion circuit provided by some embodiments of the present disclosure. The method is applied to Figures 1 to 4 Any half-bridge DC-DC converter circuit shown in Figure 1, see Figure 5 , the method comprising:

[0081] 201: When the half-bridge DC-DC conversion circuit is working, control the MOSFET to be turned on through the EN signal provided by the EN signal providing terminal.

[0082] 202: In a first timing cycle, control the first HEMT to be turned on and the second HEMT to be turned off by using the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end respectively.

[0083] 203: In a second timing cycle, control the first HEMT to be turned off and the second HEMT to be turned on by using the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end respectively.

[0084] The first timing cycle and the second timing cycle are alternately arranged. The frequency range of the alternation of the first timing cycle and the second timing cycle is 100 KHz to 1 MHz.

[0085] The half-bridge DC-DC conversion circuit provided by the embodiment of the present disclosure is adopted. When the half-bridge DC-DC conversion circuit is working, the MOSFET is controlled to be turned on by the EN signal provided by the EN signal providing end. Then, in the first timing cycle, the first HEMT is controlled to be turned on and the second HEMT is controlled to be turned off by the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end respectively; in the second timing cycle, the first HEMT is controlled to be turned off and the second HEMT is controlled to be turned on by the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end respectively. The operation of the half-bridge DC-DC conversion circuit is realized by alternating the control of the above two timing cycles. In the above working process, the MOSFET is continuously turned on, so the operating frequency of the half-bridge DC-DC conversion circuit will not be subject to the switching characteristics of the MOSFET, thereby increasing the frequency of the half-bridge DC-DC conversion circuit.

[0086] Figure 6 is a flow chart of another control method of a half-bridge DC-DC conversion circuit provided in some embodiments of the present disclosure. The method is applied to Figures 1 to 4Any half-bridge DC-DC converter circuit shown in Figure 1, see Figure 6 , the method comprising:

[0087] 301: When the half-bridge DC-DC conversion circuit is working, provide a high-level EN signal through the EN signal providing terminal to control the MOSFET to be turned on.

[0088] 302: In a first timing cycle, provide a high level PWM signal through the first PWM signal providing end to control the first HEMT to be turned on; and provide a low level PWM signal through the second PWM signal providing end to control the second HEMT to be turned off.

[0089] In the embodiment of the present disclosure, the frequencies of the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end are the same.

[0090] Exemplarily, when the two HEMTs are of the same type, for example, both adopt a HEMT that is turned on by a high level and turned off by a low level, the high and low levels of the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end are set oppositely, that is, the high level of the PWM signal provided by the first PWM signal providing end corresponds to the low level of the PWM signal provided by the second PWM signal providing end, and the low level of the PWM signal provided by the first PWM signal providing end corresponds to the high level of the PWM signal provided by the second PWM signal providing end, thereby achieving an effect of turning one on and the other off.

[0091] In an example, the high level and the low level of the PWM signal provided by the first PWM signal providing end and the second PWM signal providing end may be respectively the same.

[0092] In another example, at least one of a high level and a low level of the PWM signal provided by the first PWM signal providing end and the second PWM signal providing end may be different.

[0093] Exemplarily, the voltage range of the PWM signals provided by the first PWM signal providing terminal and the second PWM signal providing terminal is -18 to 0V.

[0094] For example, the low level is -18V and the high level is 0V.

[0095] 303: In a second timing cycle, provide a low level PWM signal through the first PWM signal providing end to control the first HEMT to be turned off; and provide a high level PWM signal through the second PWM signal providing end to control the second HEMT to be turned on.

[0096] The first timing cycle and the second timing cycle are alternately arranged. The frequency range of the alternation of the first timing cycle and the second timing cycle is 100 KHz to 1 MHz.

[0097] 304: When the half-bridge DC-DC conversion circuit stops working, provide a low-level EN signal through the EN signal providing terminal to control the MOSFET to turn off.

[0098] In the embodiment of the present disclosure, the high and low level waveforms of the EN signal provided by the EN signal providing end are designed according to needs.

[0099] The EN signal provided by the EN signal providing end is EN in the figure.

[0100] Exemplarily, the EN signal uses a MOSFET that is turned on when at a high level and turned off when at a low level.

[0101] Exemplarily, the voltage range of the EN signal provided by the EN signal providing terminal is 0 to 12V.

[0102] For example, a low level is 0V and a high level is 12V.

[0103] Compared with the half-bridge DC-DC conversion circuit of the related technology, this solution is not only no longer limited by the frequency of MOSFET, but also takes advantage of the operating frequency of gallium nitride power switching devices (HEMT) to improve the volume power density of power products; it also saves a MOSFET and reduces the cost of the half-bridge DC-DC conversion circuit.

[0104] At least one embodiment of the present disclosure provides an electronic device, the electronic device comprising: Figures 1 to 4 Any of the half-bridge DC-DC converter circuits shown.

[0105] The above description is only an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A half-bridge DC-DC conversion circuit, characterized in that: The half-bridge DC-DC conversion circuit comprises: a first HEMT (101), a second HEMT (102), a MOSFET (103) and a DC-DC converter (104); The first end of the first HEMT (101) is connected to a voltage supply end (VBUS), and the control end of the first HEMT (101) is connected to a first PWM signal supply end; the first end of the second HEMT (102) is connected to a first input end of the DC-DC converter (104), and the control end of the second HEMT (102) is connected to a second PWM signal supply end; the control end of the MOSFET (103) is connected to an EN signal supply end; and the second input end of the DC-DC converter (104) is grounded; The second end of the first HEMT (101) is connected to the first end of the second HEMT (102); the second end of the second HEMT (102) is connected to the first end of the MOSFET (103); the second end of the MOSFET (103) is grounded; or the second end of the first HEMT (101) is connected to the first end of the MOSFET (103); the second end of the second HEMT (102) is grounded; and the second end of the MOSFET (103) is connected to the first end of the second HEMT (102).

2. The half-bridge DC-DC conversion circuit according to claim 1, characterized in that: The first HEMT (101), the second HEMT (102) and the MOSFET (103) are three discrete components.

3. The half-bridge DC-DC conversion circuit according to claim 1, characterized in that: The first HEMT (101) is a discrete element, and the second HEMT (102) and the MOSFET (103) form a discrete element.

4. The half-bridge DC-DC conversion circuit according to claim 1, characterized in that: The second HEMT (102) is a discrete element, and the first HEMT (101) and the MOSFET (103) form a discrete element.

5. The half-bridge DC-DC conversion circuit according to any one of claims 1 to 4, characterized in that: The first HEMT (101) and the second HEMT (102) are normally-off gallium nitride HEMTs.

6. The half-bridge DC-DC conversion circuit according to any one of claims 1 to 4, characterized in that: The MOSFET (103) is an enhancement type MOSFET.

7. The half-bridge DC-DC conversion circuit according to any one of claims 1 to 4, characterized in that: The frequency range of the PWM signals provided by the first PWM signal providing end and the second PWM signal providing end is 100 KHz to 1 MHz.

8. The half-bridge DC-DC conversion circuit according to any one of claims 1 to 4, characterized in that: The voltage range of the PWM signals provided by the first PWM signal providing terminal and the second PWM signal providing terminal is -18 to 0V.

9. The half-bridge DC-DC conversion circuit according to any one of claims 1 to 4, characterized in that: The voltage range of the EN signal provided by the EN signal providing terminal is 0 to 12V.

10. An electronic device, characterized in that: The electronic device comprises the half-bridge DC-DC conversion circuit according to any one of claims 1 to 9.

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