A high-side driving circuit of a switching tube, a solid-state power controller and an electronic device

Abstract

The disclosure provides a high-side driving circuit of a switching tube, a solid-state power controller and an electronic device. The circuit comprises an isolation switching power supply, a pull-down resistor and a switching tube. The output end of the isolation switching power supply is connected with the gate of the switching tube. The first pole of the switching tube is connected with a first working voltage. The second pole of the switching tube is connected with the output end reference ground of the isolation switching power supply and one end of a load. The other end of the load is grounded. The pull-down resistor is connected with the load in parallel. The input end of the isolation switching power supply inputs a second working voltage. The disclosure utilizes the variable characteristics of the output end reference ground of the isolation switching power supply, so that the driving voltage output by the isolation switching power supply always meets the switching-on condition of the switching tube, and the 100% duty cycle output of the switching tube is realized. Based on the isolation characteristics of the isolation switching power supply, the isolation of the control signal and the power signal is realized, the circuit reliability is improved, the overall circuit structure is simple, the occupied space of the driving circuit is effectively reduced, and the use requirements of complex electromagnetic environment and limited accommodation space are met.

Description

Technical Field

[0001] This disclosure relates to the field of drive control technology, and in particular to a high-side drive circuit for a switching transistor, a solid-state power controller, and electronic equipment. Background Technology

[0002] As drone electrical equipment becomes increasingly complex and powerful, the power and distribution capacity cannot be increased indefinitely due to limitations in takeoff weight and size. Therefore, adopting intelligent power distribution methods—distributing power supply and distribution according to different payloads based on the drone's flight profile to improve power utilization—has become an inevitable choice. Currently, solid-state power controllers (SSPCs) have become the main implementation method for intelligent power distribution due to their small size and high switching speed. In the design and implementation of SSPCs, the high-side drive method of metal-oxide-semiconductor transistors (MOSFETs) has become a core element.

[0003] The essence of high-side driving of a MOSFET is the process of charging the gate input capacitor to make the gate-source voltage greater than the threshold voltage for activation. Existing driving technologies mostly use bootstrap driving or transformer driving. The former requires the addition of external isolation circuits, while the latter, although it has isolation capabilities, has a complex design, large size, and poor electromagnetic compatibility, making it unsuitable for the complex electromagnetic environment and limited space of UAVs. Summary of the Invention

[0004] The purpose of this disclosure is to provide a high-side drive circuit for a switching transistor, a solid-state power controller, and an electronic device to solve the problems existing in the prior art.

[0005] The embodiments of this disclosure adopt the following technical solution: a high-side driving circuit for a switching transistor, comprising: an isolated switching power supply, a pull-down resistor, and a switching transistor to be driven; wherein, the output terminal of the isolated switching power supply is connected to the gate of the switching transistor, the first terminal of the switching transistor is connected to a first operating voltage, the second terminal of the switching transistor is connected to the output terminal reference ground of the isolated switching power supply and one end of a load, the other end of the load is grounded, the pull-down resistor is connected in parallel with the load, and the input terminal of the isolated switching power supply receives a second operating voltage.

[0006] In some embodiments, the drive voltage output by the isolated switching power supply is greater than or equal to the threshold voltage of the switching transistor.

[0007] In some embodiments, the system further includes: a Zener diode, wherein the anode of the Zener diode is connected to a reference ground at the output terminal of the isolated switching power supply, and the cathode of the Zener diode is connected to the output terminal of the isolated switching power supply.

[0008] In some embodiments, the device further includes a bleed diode and a protection resistor, wherein the protection resistor is connected in series between the output terminal of the isolation switching power supply and the gate of the switching transistor, the anode of the bleed diode is connected to the gate of the switching transistor, and the cathode of the bleed diode is connected to the output terminal of the isolation switching power supply.

[0009] In some embodiments, the system further includes a filter capacitor, wherein a first plate of the filter capacitor is connected to the output terminal of the isolation switching power supply, and a second plate of the filter capacitor is connected to the reference ground of the output terminal of the isolation switching power supply.

[0010] In some embodiments, the system further includes: an energy storage capacitor, wherein a first plate of the energy storage capacitor is connected to the input terminal of the isolation switching power supply reference ground, and a second plate of the energy storage capacitor is connected to the input terminal of the isolation switching power supply.

[0011] In some embodiments, the output terminal of the isolation switching power supply outputs a drive voltage when an enable control signal is input to the control terminal of the isolation switching power supply.

[0012] In some embodiments, the voltage at the output reference ground of the isolated switching power supply varies with the size of the load.

[0013] This disclosure also provides a solid-state power controller, which includes at least the high-side drive circuit of the switching transistor as described above.

[0014] This disclosure also provides an electronic device that includes at least the solid-state power controller described above.

[0015] The beneficial effects of the embodiments disclosed herein are as follows: by utilizing the variable reference ground characteristic of the output terminal of the isolated switching power supply, the driving voltage output by its output terminal always meets the conduction condition of the switching transistor, thereby achieving 100% duty cycle output of the switching transistor; at the same time, based on the isolation characteristics of the isolated switching power supply, the isolation of control signals and power signals is achieved, improving the reliability of the circuit; the overall circuit structure is simple, effectively reducing the space occupied by the driving circuit, and meeting the usage requirements of complex electromagnetic environments and limited space. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in one or more embodiments of this specification or in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this specification. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a circuit diagram of the high-side drive circuit of the switching transistor according to the first embodiment of this disclosure;

[0018] Figure 2 This is another circuit diagram of the high-side drive circuit of the switching transistor according to the first embodiment of this disclosure. Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solutions in one or more embodiments of this specification, the technical solutions in one or more embodiments of this specification will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this specification, and not all of the embodiments. Based on one or more embodiments of this specification, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this document.

[0020] As drone electrical equipment becomes increasingly complex and powerful, the power and distribution capacity cannot be increased indefinitely due to limitations in takeoff weight and size. Therefore, adopting intelligent power distribution methods—distributing power supply and distribution according to different payloads based on the drone's flight profile to improve power utilization—has become an inevitable choice. Currently, solid-state power controllers (SSPCs) have become the main implementation method for intelligent power distribution due to their small size and high switching speed. In the design and implementation of SSPCs, the high-side drive method of metal-oxide-semiconductor transistors (MOSFETs) has become a core element. Currently, the traditional high-side drive methods for MOSFETs include the following:

[0021] (1) IC driving method. This method has high integration, but the cost is high. Most IC chips do not have isolation function and require external isolation circuits. Moreover, most IC chips do not support 100% duty cycle output.

[0022] (2) Bootstrap circuit drive. This method does not require an external isolation circuit, but it does not support 100% duty cycle output and the drive current is relatively small.

[0023] (3) Pulse transformer drive, which is complex to design, large in size and high in cost;

[0024] (4) Optocoupler isolation drive. This method requires a separate isolation power supply, and the optocoupler is prone to aging, has weak driving capability, and is easily affected by temperature.

[0025] (5) Charge pump drive: This method has low driving current and low efficiency, which limits the turn-on speed of the switching transistor.

[0026] The essence of high-side driving of a MOSFET is the process of charging the gate input capacitor to make the gate-source voltage greater than the turn-on threshold voltage. Existing driving technologies cannot meet the requirements of the complex electromagnetic environment and limited space of drones.

[0027] To address the aforementioned issues, the first embodiment of this disclosure provides a high-side drive circuit for a switching transistor. High-side drive refers to the switching transistor being positioned between the power supply and the load. In this case, if the switching transistor needs to remain in a conducting state, its gate voltage must change in accordance with the load when the load size changes. Figure 1 A circuit diagram of the high-side drive circuit of this embodiment is shown, as follows: Figure 1 As shown, in this embodiment, the isolated switching power supply U1 is used as the driver for the switching transistor M to be driven, so as to realize the switching control of the switching transistor M.

[0028] Specifically, the output terminal +Vo (i.e., pin 4) of the isolation switching power supply U1 is connected to the gate of the switching transistor M to control the conduction state of the switching transistor M. The first terminal of the switching transistor M is connected to the first operating voltage VCC, and the second terminal is connected to one end of the load RLoad. The other end of the load RLoad is grounded to enable power supply to the load RLoad when the switching transistor M is conducting. When the switching transistor M is an N-type transistor, its first terminal is usually the drain and its second terminal is usually the source. The drive voltage output by the output terminal of the isolation switching power supply U1 should be greater than or equal to the threshold voltage of the switching transistor M to ensure that the switching transistor M is normally turned on. Meanwhile, the output reference ground of the isolated switching power supply U1 (i.e., pin 5) is also connected to the second terminal of the switching transistor M, so that the actual voltage value of the output reference ground of the isolated switching power supply U1 is the voltage across the load RLoad. When the magnitude of the load RLoad changes, the voltage of the output reference ground of the isolated switching power supply U1 will also change accordingly. Based on the characteristics of the isolated switching power supply, the voltage value output by its output terminal is generated with the voltage of the output reference ground as a reference, and the voltage difference between the two is fixed. Therefore, the driving voltage value output by the output terminal will also change with the magnitude of the load, thereby ensuring that the voltage difference between the gate voltage and the source voltage of the switching transistor M is always greater than its inherent threshold voltage, thus ensuring the continuous conduction state of the switching transistor M and realizing the 100% duty cycle output of the effective driving voltage.

[0029] In this embodiment, a pull-down resistor Rp is also connected in parallel across the load RLoad. When the load RLoad is infinite or there is no load, it provides a stable reference point for the isolation power supply U1, preventing output failure of the isolation power supply. Figure 1The pull-down resistor Rp is 100KΩ, but its actual resistance can be determined based on the rated parameters of other components in the circuit, such as the first operating voltage and the drive voltage output by U1. This embodiment does not impose specific limitations. Additionally, the input terminal Vin (pin 3) of the isolating power supply U1 receives a second operating voltage, such as +5V. Its input reference ground GND (pin 2) is different from its output reference ground, and a potential difference between them is permissible. In actual use, the output terminal of the isolating power supply U1 outputs a drive voltage when the enable control signal Ctr is input at the control terminal Ctrl (pin 1). The enable control signal Ctr can be generated based on other drive circuits or the drive body to power on the load RLoad.

[0030] The isolated switching power supply U1 is typically a device that drives a high-voltage output from a low-voltage source. The specific input and output voltage requirements can be selected based on the driving requirements of other devices in the circuit; this embodiment does not impose any limitations. For example, in this embodiment, the isolated switching power supply U1 is a 5V to 12V isolated switching power supply, meaning it inputs 5V and outputs 12V. Normally, a 12V output voltage can meet the conduction requirements of the switching transistor. However, excessively high gate voltage may cause the device to break down, affecting the driving function.

[0031] Figure 2 Another circuit diagram of the high-side drive circuit in this embodiment is shown. For example... Figure 2 As shown, the circuit also includes a Zener diode Z. The anode of Zener diode Z is connected to the reference ground at the output terminal of the isolated power supply U1, and its cathode is also connected to the output terminal of the isolated power supply U1. Its regulated voltage is the same as the drive voltage output by U1. In actual use, the load RLoad changes dynamically, causing a change in the reference ground potential at the output terminal of the isolated power supply U1. Zener diode Z can maintain the potential difference between the output terminal of the isolated power supply U1 and its reference ground. To prevent large switching losses caused by dynamic changes in the gate-source voltage of the switching transistor M, among other things, This refers to the drive voltage value output from the output terminal of the isolation switching power supply U1. This is the potential of the output terminal of the isolation switching power supply U1, which is reference ground.

[0032] In some embodiments, such as Figure 2As shown, the circuit also includes a bleed diode D1 and a protection resistor Rs. The protection resistor Rs is connected in series between the output terminal of the isolation switching power supply U1 and the gate of the switching transistor M. It is used to provide a certain degree of voltage division protection for the drive voltage output by U1 during the conduction of the switching transistor M. The bleed diode D1 is connected in parallel across the protection resistor Rs. Its positive terminal is connected to the gate of the switching transistor M, and its negative terminal is connected to the output terminal of the isolation switching power supply U1. When the switching transistor M is turned off, the parasitic capacitance charge on its gate can be quickly discharged through the bleed diode D1, thereby improving the turn-off speed of the switching transistor.

[0033] In some embodiments, such as Figure 2 As shown, the circuit also includes a filter capacitor Co and an energy storage capacitor Cin. The first plate of the filter capacitor Co is connected to the output terminal of the isolation power supply U1, and the second plate of the filter capacitor Co is connected to the reference ground of the output terminal of the isolation power supply U1. That is, the filter capacitor Co is the output capacitor of the isolation power supply U1, and has the functions of filtering and voltage regulation. The first plate of the energy storage capacitor Cin is connected to the reference ground of the input terminal of the isolation power supply U1, and the second plate of the energy storage capacitor Cin is connected to the input terminal of the isolation power supply U1. That is, the energy storage capacitor Cin is the input capacitor of the isolation power supply U1, and while playing the role of energy storage, it can also absorb input voltage spikes to protect the subsequent circuits.

[0034] This embodiment utilizes the variable reference ground characteristic of the output terminal of the isolated switching power supply to ensure that the drive voltage output by the power supply always meets the conduction condition of the switching transistor, thereby achieving 100% duty cycle output of the switching transistor. At the same time, based on the isolation characteristics of the isolated switching power supply, the isolation of control signals and power signals is achieved, improving the reliability of the circuit. The overall circuit structure is simple, effectively reducing the space occupied by the drive circuit, and meeting the usage requirements of complex electromagnetic environments and limited space.

[0035] Based on the same inventive concept, the second embodiment of this disclosure provides a solid-state power controller, which includes at least the high-side drive circuit of the switching transistor as provided in the first embodiment of this disclosure. By utilizing the simple structure of the circuit and the variable characteristics of the output terminal reference ground, the 100% duty cycle output of the switching transistor can be achieved, while reducing the space occupied by the solid-state power controller, thus meeting the needs of use in complex electromagnetic environments and with limited space.

[0036] Based on the same inventive concept, the third embodiment of this disclosure provides an electronic device that includes at least the solid-state power controller provided in the second embodiment of this disclosure, and works in conjunction with other devices to achieve different functions. For example, the electronic device can be a drone, utilizing a small-sized, high-switching-speed solid-state power controller with isolation characteristics and 100% duty cycle output to achieve distributed power supply and distribution operations for different loads within the limited space of the drone.

[0037] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A high-side drive circuit for a switching transistor, characterized in that, Applied to drones, including: The isolated switching power supply, pull-down resistors, and the switching transistor to be driven; among them, The output terminal of the isolation switching power supply is connected to the gate of the switching transistor. The first terminal of the switching transistor is connected to a first operating voltage. The second terminal of the switching transistor is connected to the reference ground of the output terminal of the isolation switching power supply and one end of the load. The other end of the load is grounded. The pull-down resistor is connected in parallel with the load. The input terminal of the isolation switching power supply receives a second operating voltage. The voltage of the reference ground at the output terminal of the isolation switching power supply varies with the size of the load, so that the effective driving voltage is output with a 100% duty cycle.

2. The high-side driving circuit according to claim 1, characterized in that, The driving voltage output by the isolated switching power supply is greater than or equal to the threshold voltage of the switching transistor.

3. The high-side driving circuit according to claim 1, characterized in that, Also includes: A Zener diode, wherein the anode of the Zener diode is connected to the reference ground of the output terminal of the isolated switching power supply, and the cathode of the Zener diode is connected to the output terminal of the isolated switching power supply.

4. The high-side driving circuit according to claim 1, characterized in that, Also includes: A bleed diode and a protection resistor are provided, wherein the protection resistor is connected in series between the output terminal of the isolation switching power supply and the gate of the switching transistor, the anode of the bleed diode is connected to the gate of the switching transistor, and the cathode of the bleed diode is connected to the output terminal of the isolation switching power supply.

5. The high-side driving circuit according to claim 1, characterized in that, It also includes: a filter capacitor, the first plate of which is connected to the output terminal of the isolation switching power supply, and the second plate of which is connected to the reference ground of the output terminal of the isolation switching power supply.

6. The high-side driving circuit according to claim 1, characterized in that, Also includes: An energy storage capacitor, wherein the first plate of the energy storage capacitor is connected to the input terminal of the isolation switching power supply as a reference ground, and the second plate of the energy storage capacitor is connected to the input terminal of the isolation switching power supply.

7. The high-side driving circuit according to claim 1, characterized in that, The output terminal of the isolation switching power supply outputs a drive voltage when an enable control signal is input to the control terminal of the isolation switching power supply.

8. A solid-state power controller, characterized in that, It includes at least the high-side drive circuit of the switching transistor as described in any one of claims 1 to 7.

9. An electronic device, characterized in that, It includes at least the solid-state power controller as described in claim 8.

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