CN221728155U - Switch driving circuit, power converter and charger - Google Patents
Switch driving circuit, power converter and charger Download PDFInfo
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- CN221728155U CN221728155U CN202323445176.1U CN202323445176U CN221728155U CN 221728155 U CN221728155 U CN 221728155U CN 202323445176 U CN202323445176 U CN 202323445176U CN 221728155 U CN221728155 U CN 221728155U
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- 230000001133 acceleration Effects 0.000 claims abstract description 44
- 239000003990 capacitor Substances 0.000 claims abstract description 22
- 229910002601 GaN Inorganic materials 0.000 claims description 14
- JMASRVWKEDWRBT-UHFFFAOYSA-N Gallium nitride Chemical compound [Ga]#N JMASRVWKEDWRBT-UHFFFAOYSA-N 0.000 claims description 14
- 230000009286 beneficial effect Effects 0.000 abstract description 5
- 239000012084 conversion product Substances 0.000 description 10
- 238000010586 diagram Methods 0.000 description 10
- 238000004146 energy storage Methods 0.000 description 5
- 238000006243 chemical reaction Methods 0.000 description 3
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- 230000005611 electricity Effects 0.000 description 2
- 230000005669 field effect Effects 0.000 description 2
- 230000000630 rising effect Effects 0.000 description 2
- 238000005070 sampling Methods 0.000 description 2
- 230000003068 static effect Effects 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 230000000740 bleeding effect Effects 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000003071 parasitic effect Effects 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 description 1
- 229910010271 silicon carbide Inorganic materials 0.000 description 1
- 230000001960 triggered effect Effects 0.000 description 1
- 238000004804 winding Methods 0.000 description 1
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Abstract
The application provides a switch driving circuit, a power converter and a charger, and belongs to the technical field of power electronics. The switch driving circuit comprises a control signal input end, a driving output end, a current limiting resistor and an accelerating unit, wherein the current limiting resistor and the accelerating unit are connected in parallel between the control signal input end and the driving output end, the driving output end is connected with a grid end of the power switch, the accelerating unit comprises an accelerating on resistor and an accelerating capacitor which are connected in series, and the resistance value of the accelerating on resistor is smaller than that of the current limiting resistor. The switch driving circuit realizes quick conduction based on the acceleration unit, is beneficial to improving the switching frequency of the power switch and reducing the switching loss. When the switch driving circuit is applied to the power converter, the size of a transformer in the power converter is reduced, the miniaturization development requirement of the charger containing the power converter is met, and the portability of the charger is improved.
Description
Technical Field
The application relates to the technical field of power electronics, in particular to a switch driving circuit, a switch power supply and a charger.
Background
With the increasing demands of pen books and mobile phones for charging, more young people pursue small-volume chargers in view of portability. The power transformer volume is reduced by increasing the switching frequency of the power switch in the power converter, and the power transformer is a realization way for miniaturization of the charger.
However, in order to solve the EMC (Electro Magnetic Compatibility ) problem, the current limiting resistor connected to the control signal input terminal and the gate terminal of the power switch is generally set to be very large, and the current limiting resistor with a larger resistance value can reduce the switching frequency of the power switch, increase the switching loss, and is not beneficial to the realization of the miniaturization development of power conversion products such as chargers.
Disclosure of utility model
In order to solve the existing technical problems, the application provides a switch driving circuit capable of effectively improving the switching frequency and reducing the switching loss, a power converter comprising the switch driving circuit and a charger comprising the power converter.
According to a first aspect of the present embodiment, there is provided a switch driving circuit, including a control signal input terminal, a driving output terminal, and a current limiting resistor and an accelerating unit connected in parallel between the control signal input terminal and the driving output terminal, the driving output terminal being connected to a gate terminal of a power switch;
The accelerating unit comprises an accelerating on-resistance and an accelerating capacitor which are connected in series, and the resistance value of the accelerating on-resistance is smaller than that of the current-limiting resistor.
In some embodiments, the acceleration unit further comprises an acceleration off diode connected between the control signal input and the drive output, the current flowing from the gate terminal flowing to the control signal input via the acceleration off diode.
In some embodiments, the accelerating on-resistance is connected between the control signal input terminal and a first terminal of the accelerating capacitor, and a second terminal of the accelerating capacitor is connected to the drive output terminal.
In some embodiments, an anode terminal of the turn-off accelerating diode is connected to the first terminal of the accelerating capacitor, a cathode terminal of the turn-off accelerating diode is connected to the control signal input terminal, or an anode terminal of the turn-off accelerating diode is connected to the driving output terminal, and a cathode terminal is connected to the control signal input terminal.
In some embodiments, the acceleration unit further comprises an acceleration off resistance connected in series with the acceleration off diode between the control signal input and the drive output.
In some embodiments, the resistance of the turbo-off resistor is less than the resistance of the turbo-on resistor.
In some embodiments, the switch drive circuit further comprises a bleeder resistor connected between the drive output and the source terminal of the power switch.
According to a second aspect of an embodiment of the present application, there is provided a power converter comprising a power switch, a switch driving circuit as described in any one of the above, and a switch control circuit;
the control signal input end of the switch driving circuit is connected with the control signal output end of the switch control circuit, and the driving output end of the switch driving circuit is connected with the power switch.
In some embodiments, the power switch is a gallium nitride switch.
According to a second aspect of embodiments of the present application, there is provided a charger comprising the power converter.
As can be seen from the above, the switch driving circuit provided by the embodiment of the application includes the accelerating unit formed by the accelerating on-resistance and the accelerating capacitor, when the gate-source voltage of the power switch is rapidly pulled up to the state of making the power switch fully conducted by the accelerating unit, the miller platform time of the power switch is effectively reduced, the conducting speed of the power switch is accelerated, so that the switching frequency of the power switch is high, and the switching loss is low. When the power switch driven by the switch driving circuit provided by the embodiment of the application is applied to a power conversion product, the size of a transformer in the power conversion product is reduced, and therefore, the development of miniaturization of the power conversion product is facilitated.
Drawings
FIG. 1 is a schematic diagram of a gate-source voltage variation of a conventional power switch during driving;
Fig. 2 is a schematic circuit diagram of a switch driving circuit capable of driving a power switch to be turned on rapidly according to some embodiments of the present application;
fig. 3 is a schematic circuit diagram of a switch driving circuit capable of driving a power switch to be turned on rapidly according to other embodiments of the present application;
FIG. 4 is a schematic diagram illustrating a gate-source voltage conversion of a power switch driven by a switch driving circuit according to some embodiments of the present application;
Fig. 5 is a schematic circuit diagram of a power converter according to some embodiments of the application.
Detailed Description
The technical scheme of the application is further elaborated below by referring to the drawings in the specification and the specific embodiments.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the implementations of the application. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items. In the description of the present application, unless otherwise indicated, the meaning of "a plurality" is two or more.
In the description of the present application, it should be noted that, unless explicitly stated and limited otherwise, the terms "connected" and "connected" should be interpreted broadly, and for example, they may be directly connected, or they may be indirectly connected through an intermediate medium, or they may be in communication with each other between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
Fig. 1 is a schematic diagram showing a change of a gate-source voltage during driving of a conventional power switch. Where Vgs represents the gate-source voltage between the gate and source terminals of the power switch, vsp represents the gate-source voltage of the power switch at Mi Leping, and Vth represents the on-threshold voltage. When the switch control signal received by the switch driving circuit is switched to a high level, the gate-source voltage Vgs of the power switch starts to rise, and when the gate-source voltage Vgs rises to the ta time when the conduction threshold voltage Vth is reached, the power switch starts to conduct until the tb time when the miller platform is finished, and the power switch is completely conducted. Therefore, in order to increase the switching frequency of the power switch, it is necessary to reduce the miller stage time as much as possible to speed up the turning-on of the power switch, even if the period of time from the start of the conduction to the complete conduction of the power switch is as short as possible.
In order to reduce the time for the power switch to reach the miller stage, the rising edge of the gate-source voltage of the power switch needs to be steeper, that is, when the switch control signal starts to switch to a high level, the gate-source voltage of the power switch needs to rise to a voltage when the power switch is fully turned on as soon as possible. For this reason, please refer to fig. 2, which is a schematic circuit diagram of a switch driving circuit 100 capable of driving a power switch Q1 to be turned on rapidly according to some embodiments of the present application. Among them, the power switch Q1 may be formed based on a gallium nitride switch, a silicon carbide switch, a conventional silicon-based switch, and the like. Based on the type of structure of the power switch Q1, it may be a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor, metal Oxide field effect transistor). The switch driving circuit 100 includes a control signal input terminal a, a driving output terminal B, a current limiting resistor R1, and an acceleration unit 101. The current limiting resistor R1 and the acceleration unit 101 are connected in parallel between the control signal input terminal a and the drive output terminal B. The control signal input terminal a is configured to be connected to a switch control circuit of the power switch Q1, so as to receive a switch control signal output by the switch control circuit 200, where the switch control signal is configured to control the power switch Q1 to switch between on and off. The driving output terminal B is configured to be connected to the gate terminal g of the power switch Q1, and configured to provide the driving voltage Vg to the gate g of the power switch Q1, so that the gate-source voltage Vgs of the power switch Q1 reaches the corresponding on condition and off condition. Specifically, when the power switch Q1 is turned on, the switching current flows from the drain terminal d of the power switch Q1 to the source terminal s of the power switch Q1. The current limiting resistor R1 is used for limiting the gate current during the on period of the power switch Q1 so as to improve the electromagnetic compatibility of the power switch Q1. The acceleration unit 101 includes an acceleration on-resistance R2 and an acceleration capacitance C1 connected in series between the control signal input terminal a and the driving output terminal B, wherein the resistance value of the acceleration on-resistance R2 is smaller than the resistance value of the current limiting resistance R1.
According to the switch driving circuit 100 provided by the embodiment of the application, the accelerating unit 101 formed by the accelerating on-resistance R2 with the resistance smaller than the current-limiting resistance R1 and the accelerating capacitor connected in series is connected in parallel to the two ends of the current-limiting resistance R1, so that after the PWM (Pulse Width Modulation, pulse width modulation signal) switch control signal input by the control signal input end a starts to switch to the first state, the accelerating capacitor C1 can be charged through the accelerating on-resistance R2 quickly, and the gate-source voltage Vgs of the power switch Q1 can be quickly pulled up to the state of completely conducting the power switch Q1. The first state of the PWM switch control signal refers to a state, such as a high state, in which the power switch Q1 is controllable to be turned on. After the PWM switching control signal is completely switched to the first state, the PWM switching control signal stops charging the accelerating capacitor C1 via the accelerating on-resistance R2. During the period when the PWM switch control signal is maintained in the first state, the PWM switch control signal is converted into a corresponding gate current through the current limiting resistor R1 and is input to the gate terminal g of the power switch Q1. The gate current of the power switch Q1 is limited in a certain range by selecting a current limiting resistor R1 with a proper resistance value, so that the damage of the power switch Q1 caused by large gate current is avoided.
Therefore, the switch driving circuit 100 provided in some embodiments of the present application reduces the miller stage time of the power switch Q1, accelerates the conduction speed of the power switch Q1, and makes the switching frequency of the power switch Q1 high and the switching loss low. The power switch Q1 driven by the switch driving circuit 100 according to some embodiments of the present application is beneficial to reduce the volume of a transformer in a power conversion product when applied to the power conversion product, and is beneficial to the development of miniaturization of the power conversion product.
In some embodiments, the switch driving circuit 100 further includes an accelerated turn-off diode connected between the control signal input terminal a and the driving output terminal B, and the current flowing from the gate terminal g flows to the control signal input terminal via the accelerated turn-off diode to quickly drain the charge at the gate terminal g, so that the gate voltage of the power switch Q1 is quickly reduced to meet the condition that the power switch Q1 is completely turned off, and quick turn-off of the power switch Q1 is achieved. Specifically, when the PWM switching control signal starts to switch to the second state, the current at the gate terminal g of the power switch Q1 flows to the control signal input terminal a through the fast turn-off diode. The second state of the PWM switch control signal refers to a state, such as a low state, in which the controllable power switch Q1 is turned off. Therefore, in some embodiments, after the PWM switch control signal starts to switch to the first state capable of controlling the turn-on of the power switch Q1, the accelerating unit 100 in the switch driving circuit 100 according to other embodiments of the present application can quickly charge and pull up the voltage at the gate terminal g of the power switch Q1 to accelerate the turn-on speed of the power switch Q1, and after the PWM switch control signal starts to switch to the second state capable of controlling the turn-off of the power switch Q1, the voltage at the gate terminal g of the power switch Q1 can be quickly pulled down to accelerate the turn-off speed of the power switch Q1. Therefore, the power switch Q1 driven by the switch driving circuit 100 according to other embodiments of the present application has a fast on-speed and a fast off-speed, so as to further increase the switching frequency.
Fig. 3 is a schematic circuit diagram of a switch driving circuit 100 according to other embodiments of the application. In other embodiments, the accelerating on-resistance R2 is connected between the control signal input a and the first terminal of the accelerating capacitor C1, and the second terminal of the accelerating capacitor C1 is connected to the driving output B. The above-mentioned turn-off accelerating diode is a diode D1 in the present embodiment. The anode terminal of the diode D1 is connected to the first terminal of the accelerating capacitor C1, and the cathode terminal of the diode D1 is connected to the control signal input terminal a. In other embodiments, the diode D1 is connected in parallel to two ends of the accelerating on-resistance R2, so that after the PWM switching control signal starts to switch to the second state, the current flowing from the gate terminal g of the power switch Q1 is rapidly discharged through the fast discharging path formed by the accelerating capacitor C1 and the accelerating off-diode D1, so as to rapidly pull the voltage of the gate terminal g of the power switch Q1 down to a negative voltage, thereby enabling the power switch Q1 to be rapidly turned off. In addition, the voltage of the grid end g of the power switch Q1 is pulled down to negative pressure, so that the anti-interference performance of the driving circuit is effectively improved. Therefore, the switch driving circuit 100 according to other embodiments of the present application can further reduce the volume of the transformer in the power conversion product using the power switch Q1 as the main power tube while increasing the switching frequency of the power switch Q1, thereby further meeting the development requirement of miniaturization of the power conversion product.
With continued reference to fig. 3, in other embodiments, the acceleration unit 101 in the switch driving circuit 100 further includes an acceleration off resistor R3. The acceleration off resistance R3 is connected in series with the diode D1 between the control signal input terminal a and the first terminal of the acceleration capacitor C1. The rapid turn-off resistor R3 is added in the discharging path of the current output by the grid electrode terminal g, so that the turn-off time of the power switch Q1 can be flexibly adjusted. Specifically, the resistance of the acceleration off resistor R3 may be set smaller than the resistance of the acceleration on resistor R2, so as to facilitate the bleeding of the current at the gate terminal g.
In other embodiments, the anode terminal of the above-mentioned turn-off accelerating diode is connected to the driving output terminal B, and the cathode terminal is connected to the control signal input terminal a. The acceleration turn-off diode is connected in parallel to two ends of the current limiting resistor R1 to serve as an acceleration turn-off unit in the acceleration unit 101, and the acceleration on resistor R2 and the acceleration capacitor C1 in the acceleration unit 101 form an acceleration on unit. The acceleration conduction unit and the acceleration turn-off unit are connected in parallel, the acceleration capacitor C1 does not need to take the current of the grid electrode terminal g into consideration, optimization of circuit parameters is facilitated, and the on time and the off time of the power switch Q1 are respectively accelerated as soon as possible. Specifically, in the embodiment in which the accelerating turn-off diode is connected in parallel to two ends of the current limiting resistor R1, an accelerating turn-off resistor connected in series with the accelerating turn-off diode may be added, that is, the accelerating turn-off resistor and the accelerating turn-off diode are connected in series and then connected in parallel with the current limiting resistor R1, so as to be beneficial to adjusting the turn-off time of the power switch Q1 through the accelerating turn-off resistor.
With continued reference to fig. 3, the switch driving circuit 100 further includes a bleeder resistor R4 connected between the driving output terminal B and the source terminal s of the power switch Q1. The discharging resistor R4 is connected between the grid sources of the power switch Q1, so that static electricity between the grid sources is released, false triggering operation of the power switch Q1 is avoided, and the grid end g and the source end s of the power switch Q1 are protected from being damaged by static electricity.
Fig. 4 is a schematic diagram showing the conversion of the gate-source voltage Vgs of the power switch Q1 driven by the switch driving circuit 100 according to some embodiments of the present application. Vdd is the dc supply voltage at the drain terminal d of the power switch Q1, VF is the value of the gate-source voltage Vgs of the power switch Q1 during the full on period, VN is the value corresponding to the gate-source voltage Vgs of the power switch Q1 immediately after the power switch Q1 enters the full off state, and VNf is the value of the gate-source voltage Vgs of the power switch Q1 when the PWM switch control signal starts to switch from the second state to the first state. Obviously, the rising edge and the falling edge of the gate-source voltage Vgs of the power switch Q1 provided by the embodiment of the application are very steep, and the on time and the off time of the power switch Q1 are relatively fast. In addition, during the off period of the power switch Q1, the gate-source voltage Vgs thereof is in a negative voltage (-VN to-VNf) state, so that the power switch Q1 is not easily disturbed, and is triggered by mistake. Obviously, the driving switch circuit provided by some embodiments of the application can not bring EMC problems while increasing the switching speed, and is particularly suitable for driving a gallium nitride switch with smaller driving voltage.
In some embodiments, the power switch Q1 is a MOSFET, such as a gallium nitride MOSFET. The driving performance of the switch driving circuit provided by the implementation of the application is described in an auxiliary manner based on the working principle of the MOSFET and related parameters. Taking the power switch Q1 as an example of a gallium nitride MOSFET, the parameters of the gallium nitride MOSFET are as follows: vth=1.2v; vsp=1.8v; rds_on=0.19Ω; q g＝3.2nC;Cgs = 157pf; vf=3.5v; vdd=10v. Further, assume that driving parameters corresponding to driving the power switch Q1 by the switch driving circuit according to the embodiment of the present application are: rss=1.5 kΩ; roff=47 Ω; c c =3.3 nF. According to the switching driving circuit provided by the embodiment of the application, the following calculation formula can be obtained by combining the working principle of the MOSFET:
Cgs-off＝Cc+Cgs＝3.457×10-9(F)；
Qgs-off＝Cc*(Vdd-VF)-Qg＝1.825×10-8(C)；
Ip2＝Imosrms＝1.783(A)；
Poff＝εsw*fswmin＝0.132(W)；
In the above formula, vth is a gate voltage power supply required by the power switch Q1 to form a channel, that is, a turn-on threshold voltage; vsp is the gate voltage of the power switch Q1 when in the Miller platform; rds_on is the on-resistance of the power switch Q1, and Q g is the total amount of charge on the gate of the power switch Q1; c gs is the parasitic gate-source junction capacitance of the power switch Q1; VF is the gate-source voltage when the power switch Q1 is fully conducted, namely the forward direct current gate-source voltage; vdd is the drain dc supply voltage of the power switch Q1; rss is the resistance of the limiting resistor R1; roff is the resistance of the acceleration off resistor R3; rtr is the resistance of the acceleration on-state resistor R2; c gs_off is the total gate-source capacitance when the power switch Q1 is turned off; q gs_off is the total gate-source charge when the power switch Q1 is off; VN is the gate-source voltage value when the power switch Q1 is completely turned off; i gs_off is the driving current of the gate terminal when the power switch Q1 is completely turned off; toff is the total time of the crossover period when the power switch is completely closed, and the drive current (i gs_off) and the drive voltage (Vgs) of the power switch cross; IP2 and Imos rms are currents flowing from the drain terminal to the source terminal when the power switch Q1 is turned on, i.e., on currents; ioff (t) is the drain-source current (the current flowing from the drain terminal to the source terminal) of the power switch Q1 at time t in the crossover period; t is any time in the crossover time period; vds_off (t) is the drain-source voltage at time t in the crossover period; epsilon sw is the energy loss when the power switch Q1 is completely turned off; poff is the power consumption when the power switch Q1 is completely turned off; vds1 is an actual measurement value of the drain-source voltage when the power switch Q1 is completely turned off; fsw min is the minimum switching frequency of the power switch Q1.
Based on the above embodiments, it can be seen that the switch driving circuit 100 provided by the present application can drive the power switch Q1 to be turned on and off rapidly, so as to effectively improve the switching frequency of the power switch Q1 and reduce the switching power consumption. Meanwhile, the power switch Q1 is turned off rapidly with lower negative pressure and maintained as negative pressure in the turn-off period, so that EMC performance of the power switch Q1 in the switching process is improved.
Fig. 5 is a schematic circuit diagram of a power converter according to some embodiments of the application. The power converter according to some embodiments of the present application includes a power switch Q1, a switch driving circuit 100 and a switch control circuit 200 according to any of the embodiments of the present application. The control signal input terminal a of the switch driving circuit 100 is connected to the control signal output terminal of the switch control circuit 200, and the driving output terminal B of the switch driving circuit 100 is connected to the power switch Q1. The control signal output end of the switch control circuit 200 outputs a PWM switch control signal for controlling the power switch Q1 to be turned on and off. The PWM switching control signal output by the switching control circuit 200 controls the power switch Q1 to perform corresponding switching and switching-off actions via the switching drive circuit 100 to convert energy input to the input of the power converter into corresponding energy output. The power converter can be an isolated converter or a non-isolated converter, and can be a conventional switching power supply or a switching power supply of a PFC circuit. The power switch Q1 is the main power switch for power conversion in the power stage circuit of the power converter. The power converter comprises, but is not limited to, a PFC circuit, an AHB (ASYMMETRICAL HALF-Bridge) topological structure switching power supply circuit, a forward switching power supply circuit and the like. The main power switches in the PFC circuit, the AHB topology switching power supply circuit, and the forward switching power supply circuit may be driven by the switch driving circuit 100 according to the embodiment of the present application. The power converter provided according to the embodiment of the present application has the same technical effects as those of the switch driving circuit provided by the embodiment of the present application, and will not be described in detail herein.
In some embodiments, the power switch Q1 is a gallium nitride switch, specifically a gallium nitride MOSFET. The switch driving circuit 100 rapidly pulls up the gate-source voltage of the gallium nitride MOSFET to a voltage that makes the gallium nitride MOSFET fully turned on through the acceleration on-resistance R2 and the acceleration capacitance C1, and rapidly pulls down the gate-source voltage of the gallium nitride MOSFET to a negative pressure through the acceleration capacitance C1, the acceleration off-diode D1 and the acceleration off-resistance R3, so as to rapidly turn off the gallium nitride MOSFET under the negative pressure, thereby effectively improving the switching frequency and EMC performance of the gallium nitride MOSFET.
Specifically, referring to fig. 5, in some embodiments, the power converter provided by the present application is a PFC power converter, and further includes a current sampling resistor R5 connected between the source terminal s of the power switch Q1 and the reference ground terminal. The switch control circuit 200 outputs a corresponding PWM switch control signal according to the on current of the power switch Q1 sampled by the sampling resistor R5. Specifically, the power converter further includes an energy storage inductor L1, a freewheeling diode D2 and an output capacitor C2, where a first end of the energy storage inductor L1 is connected to the drain end D of the power switch Q1, and a second end receives the input voltage Vin of the PFC power converter. The first end of the energy storage inductor L1 is also connected with the anode end of the freewheel diode D2, the cathode end of the freewheel diode D2 is connected with the output end of the power converter, the output capacitor C2 is connected between the output end of the power converter and the grounding end, and the output end of the power converter is used for outputting the voltage VOUT. Further, the power converter further includes a transformer (not shown in fig. 5) connected to the energy storage inductor L1, and the ac mains is rectified and filtered, and then input to the transformer, and energy is transmitted to the energy storage inductor L1 through the transformer. In other embodiments, the drain terminal d of the power switch Q1 may also be directly connected to the primary winding of the transformer. Because the power switch Q1 has higher switching frequency, the volume of the transformer in the power converter can be made smaller, so that the power converter has smaller volume, and the requirement of people on miniaturization of power conversion products is met.
In some embodiments, the present application also provides a charger comprising a power converter according to any of the embodiments of the present application. The charger provided by the embodiment of the application can be used for charging portable electronic products such as mobile phones, notebooks and the like, and the transformer volume in the charger can be effectively reduced due to the fact that the switching frequency of a power switch in the charger is high, the power loss is low, the EMC performance is good. Therefore, the charger provided by the embodiment of the application has smaller volume and is convenient to carry.
The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily appreciate variations or alternatives within the scope of the present application. Therefore, the protection scope of the application is subject to the protection scope of the claims.
Claims (10)
1. The switch driving circuit is characterized by comprising a control signal input end, a driving output end, a current limiting resistor and an accelerating unit, wherein the current limiting resistor and the accelerating unit are connected between the control signal input end and the driving output end in parallel, and the driving output end is connected with a grid end of a power switch;
The accelerating unit comprises an accelerating on-resistance and an accelerating capacitor which are connected in series, and the resistance value of the accelerating on-resistance is smaller than that of the current-limiting resistor.
2. The switch drive circuit of claim 1 wherein the boost on-resistance is connected between the control signal input and a first terminal of the boost capacitor, a second terminal of the boost capacitor being connected to the drive output.
3. The switch drive circuit of claim 1 wherein the acceleration unit further comprises an acceleration off diode connected between the control signal input and the drive output, the current flowing from the gate terminal flowing through the acceleration off diode to the control signal input.
4. A switch driving circuit according to claim 3, wherein an anode terminal of the turn-off accelerating diode is connected to the first terminal of the accelerating capacitor, a cathode terminal of the turn-off accelerating diode is connected to the control signal input terminal, or an anode terminal of the turn-off accelerating diode is connected to the driving output terminal, and a cathode terminal is connected to the control signal input terminal.
5. The switch drive circuit according to any one of claims 3 to 4, wherein the acceleration unit further comprises an acceleration off resistance connected in series with the acceleration off diode between the control signal input terminal and the drive output terminal.
6. The switch driving circuit according to claim 5, wherein a resistance value of the acceleration off-resistance is smaller than a resistance value of the acceleration on-resistance.
7. The switch drive circuit of claim 1 further comprising a bleeder resistor connected between the drive output and the source terminal of the power switch.
8. A power converter comprising a power switch, a switch drive circuit according to any one of claims 1 to 7, and a switch control circuit;
the control signal input end of the switch driving circuit is connected with the control signal output end of the switch control circuit, and the driving output end of the switch driving circuit is connected with the power switch.
9. The power converter of claim 8, wherein the power switch is a gallium nitride switch.
10. A charger comprising a power converter as claimed in claim 8 or 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202323445176.1U CN221728155U (en) | 2023-12-15 | 2023-12-15 | Switch driving circuit, power converter and charger |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202323445176.1U CN221728155U (en) | 2023-12-15 | 2023-12-15 | Switch driving circuit, power converter and charger |
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| CN221728155U true CN221728155U (en) | 2024-09-17 |
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| CN202323445176.1U Active CN221728155U (en) | 2023-12-15 | 2023-12-15 | Switch driving circuit, power converter and charger |
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| CN (1) | CN221728155U (en) |
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2023
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