Driving circuit and handheld household appliance

Abstract

The utility model relates to the technical field of power supply circuits, in particular to a driving circuit and a handheld household appliance, which can provide effective driving voltage for a semiconductor refrigeration element through a simple circuit structure. According to the technical scheme, the driving circuit comprises a driving chip, a voltage dividing unit and a voltage drop unit. Two ends of an external power supply are respectively connected with the input end and the grounding end of the driving chip, and two ends of an external load are connected with the output end and the grounding end of the driving chip; one end of the voltage drop unit is connected with the output end of the driving chip and an external load, and the other end is connected with the input end of the driving chip.

Description

Technical Field

[0001] The utility model relates to the technical field of power supply circuits, and in particular provides a driving circuit and a handheld household electrical appliance having the driving circuit. Background Art

[0002] When hair dryers, hair combs and other household appliances are drying hair, the water ion generators in them need to drive semiconductor refrigeration elements for cooling. The driving voltage of semiconductor refrigeration elements is very low, and the driving voltage needs to be adjusted according to the temperature. The driving voltage range is between 0.05-2V. In the prior art, AC-DC switching power supply circuits or DC-DC voltage conversion chips are usually used to provide output voltage for semiconductor refrigeration elements.

[0003] However, in the above-mentioned prior art, a special transformer needs to be set in the AC-DC switching power supply circuit. The transformer is large in size and high in cost, which is not conducive to the miniaturization and low-cost design of the refrigeration circuit and the household appliances having the refrigeration circuit. Due to its own characteristics, the voltage value of the voltage feedback terminal of the DC-DC voltage conversion chip is clamped to the feedback reference voltage value (0.6V) and cannot be reduced. In other words, the output voltage of the DC-DC voltage conversion chip cannot be lower than 0.6V. When the ambient temperature is low, the corresponding driving voltage cannot be lower than 0.6V, and the semiconductor refrigeration element may freeze and fail to work normally. Utility Model Content

[0004] In view of the above problems, the utility model provides a driving circuit and a handheld household appliance having the driving circuit, which can provide an effective driving voltage for a semiconductor refrigeration element through a simple circuit structure.

[0005] In the technical solution of the utility model, a driving circuit is provided, including a driving chip, a voltage dividing unit and a voltage drop unit. The two ends of the external power supply are respectively connected to the input end and the ground end of the driving chip, and the two ends of the external load are connected to the output end and the ground end of the driving chip; one end of the voltage dividing unit is connected to the voltage feedback end of the driving chip, and the other end is connected to the input end of the driving chip; one end of the voltage drop unit is respectively connected to the output end of the driving chip and the external load, and the other end is connected to the input end of the driving chip.

[0006] According to the technical solution of the utility model, the voltage drop unit and the external load are connected in series between the input terminal and the ground terminal of the driving chip, and the sum of the voltages of the voltage drop unit and the external load is the input voltage value of the driving chip; and the voltage value of one end of the voltage divider unit is the input voltage value of the driving chip, and the voltage value of the other end is the feedback reference voltage value of the driving chip, which can be obtained by: voltage across the voltage drop unit + feedback reference voltage value = voltage across the voltage drop unit + voltage across the external load. Furthermore, the voltage across the voltage drop unit is clamped by the voltage drop unit to the voltage drop voltage value, so that the output voltage of the driving circuit, i.e., the voltage across the external load = voltage across the voltage drop unit + (feedback reference voltage value - voltage drop voltage value), wherein the feedback reference voltage value and the voltage drop voltage value are fixed values. The smaller the voltage across the voltage drop unit, the smaller the output voltage of the driving circuit; when the voltage across the voltage drop unit approaches 0, the minimum value of the output voltage of the driving circuit approaches the difference between the feedback reference voltage value and the voltage drop voltage value. In the above driving circuit, the feedback reference voltage value is compensated by setting the voltage drop voltage value of the voltage drop unit, so that the minimum value of the output voltage of the driving circuit can be lower than the feedback reference voltage value of the driving chip, so that the output voltage range of the driving circuit is not limited by the characteristics of the driving chip itself, which greatly expands the output voltage range of the driving circuit and can better provide an effective driving voltage for the semiconductor refrigeration element. In addition, while ensuring high output control efficiency, the above driving circuit itself has a simple structure and low cost.

[0007] Preferably, in the technical solution of the utility model, the driving circuit further comprises a thermal sensing unit having one end connected to the voltage feedback end of the driving chip and the other end connected to the ground end of the driving chip.

[0008] According to the technical solution of the utility model, the resistance of the thermistor unit changes with the change of temperature, and the voltage across the thermistor unit is clamped to the feedback reference voltage value, so the current value flowing through the thermistor unit changes with the change of the resistance of the thermistor unit. Further, the thermistor unit is connected in series with the voltage divider unit, and the resistance of the voltage divider unit is unchanged, so the voltage across the voltage divider unit changes with the change of the resistance of the thermistor unit, and the output voltage of the driving circuit = the voltage across the voltage divider unit + (feedback reference voltage value - voltage drop voltage value), so that the output voltage of the driving circuit can change with the change of temperature.

[0009] Preferably, in the technical solution of the present utility model, the voltage drop value of the voltage drop unit in the driving circuit is equal to the feedback reference voltage value of the driving chip.

[0010] According to the technical solution of the utility model, the feedback reference voltage value and the voltage drop voltage value are equal to zero, so that the output voltage of the drive circuit, that is, the voltage across the external load, is equal to the voltage across the voltage divider unit. When the voltage across the voltage divider unit approaches 0, the output voltage of the drive circuit can approach 0. Furthermore, the value range of the output voltage of the drive circuit is expanded, so that the output voltage of the drive circuit can be flexibly adjusted, thereby better providing an effective drive voltage for the semiconductor refrigeration element.

[0011] Preferably, in the technical solution of the present invention, the voltage drop unit is a diode, the anode of the diode is connected to the input end of the driver chip, and the cathode is respectively connected to the output end of the driver chip and the external load. The voltage drop of the diode when it is forward-conducted is used to achieve a stable voltage drop function, which is low-cost and easy to control.

[0012] In the technical solution of the utility model, the driving circuit further comprises a first current limiting unit, one end of which is connected to the input end of the driving chip, and the other end of which is respectively connected to the voltage dividing unit and the voltage drop unit.

[0013] According to the technical solution of the utility model, the first current limiting unit is connected in series between the input terminal and the ground terminal of the driving chip to limit the current flowing into the voltage dividing unit and the voltage drop unit, thereby controlling the voltage drop voltage value of the voltage drop unit.

[0014] Preferably, in the technical solution of the present utility model, the first current limiting unit is a resistor unit with adjustable resistance.

[0015] In the technical solution of the utility model, the driving circuit also includes an input capacitor, a bootstrap capacitor and an output capacitor. The input capacitor is connected between the input end and the ground end of the driving chip; the bootstrap capacitor is connected between the output end and the bootstrap boost end of the driving chip; and the output capacitor is connected between the output end and the ground end of the driving chip.

[0016] According to the technical solution of the utility model, the input capacitor and the output capacitor filter the input and output voltages of the driver chip; the bootstrap capacitor is used to raise the voltage value of the bootstrap boost terminal.

[0017] Preferably, in the technical solution of the present utility model, the driving circuit further comprises a second current limiting unit, one end of which is connected to the input end of the driving chip, and the other end of which is connected to the enable end of the driving chip.

[0018] According to the technical solution of the utility model, the input current flows into the enable terminal through the second current limiting unit, so that the driver chip remains in a working state, and the current flowing into the enable terminal is limited to avoid damage to the driver chip caused by overcurrent input.

[0019] In the technical solution of the utility model, a handheld household appliance is also provided, and the power supply circuit of the handheld household appliance includes the above-mentioned drive circuit. The above-mentioned drive circuit has a simple structure and low cost, which is conducive to the low-cost miniaturization design of the handheld household appliance.

[0020] Preferably, in the technical solution of the utility model, the handheld household electrical appliance includes a semiconductor refrigeration element, and the driving circuit supplies power to the semiconductor refrigeration element.

[0021] According to the technical solution of the utility model, in the above-mentioned driving circuit, the feedback reference voltage value is compensated by setting the voltage drop voltage value of the voltage drop unit, so that the minimum value of the output voltage of the driving circuit can be lower than the feedback reference voltage value of the driving chip, so that the output voltage range of the driving circuit is not limited by the characteristics of the driving chip itself, which greatly expands the output voltage range of the driving circuit and can better provide an effective driving voltage for the semiconductor refrigeration element. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of a driving circuit provided in the prior art.

[0023] Figure 2 It is a schematic diagram of a driving circuit provided in an embodiment of the utility model.

[0024] Figure 3 It is a schematic diagram of the UI characteristic curve of the diode provided in the embodiment of the present utility model.

[0025] Description of reference numerals: driver chip U0, voltage divider resistor R 01 , voltage divider resistor R 02 , 1-driving circuit, 2-driving chip, 3-thermistor, 4-voltage dividing unit, 5-voltage drop unit, 6-first current limiting unit, 7-second current limiting unit, input terminal VIN, output terminal SW, ground terminal GND, bootstrap voltage terminal VBST, enable terminal EN, voltage feedback terminal VFB, thermistor R TH , diode D, voltage divider resistor R1, current limiting resistor R2, current limiting resistor R3, input capacitor C1, input capacitor C2, bootstrap capacitor C3, output capacitor C4, output capacitor C5, output inductor L. DETAILED DESCRIPTION

[0026] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0027] Figure 1 It is a schematic diagram of a driving circuit provided in the prior art.

[0028] like Figure 1 As shown, the driving circuit in the prior art includes a driving chip U0, and the input voltage V IN is 30V, the maximum output current I OUT The feedback reference voltage is 3A. FB is 0.6V. Output voltage V OUT The series voltage divider resistor R 01 The voltage across the two ends and the voltage divider resistor R 02 The voltage between the two ends. And the voltage feedback terminal VFB of the driver chip U0 is connected to the series voltage divider resistor R 01 And the voltage divider resistor R 02 Between, the voltage divider resistor R 01 The voltage across the two ends is always equal to the feedback reference voltage value V of the driver chip U0. FB From the above, we can get V OUT / (R 01 +R 02 )=V FB / R 01 In other words, the output voltage V OUT =V FB +(R 02 / R 01 )V FB =0.6+0.6(R 02 / R 01 ). Among them, the output voltage V OUT With R 02 / R 01 Positively correlated and always greater than 0.6V.

[0029] In the above prior art, the output voltage V of the driver chip U0 is OUT The minimum value of the feedback reference voltage value V of the driven chip U0 FB Due to the limitation, the driver chip U0 cannot be lower than the feedback reference voltage value V FB Ultra low voltage output.

[0030] Figure 2 It is a schematic diagram of a driving circuit provided in an embodiment of the utility model.

[0031] like Figure 2As shown, in an embodiment of the present utility model, a driving circuit 1 is provided, comprising a driving chip 2, a thermistor unit 3, a voltage dividing unit 4 and a voltage drop unit 5. The driving circuit 1 is respectively connected to an external power supply (not shown) and an external load (not shown), and the external power supply supplies power to the external load through the driving circuit 1, and the driving circuit 1 is used to perform output voltage control.

[0032] In this embodiment, the driver chip 2 is a DC-DC BUCK chip for performing DC step-down chopping control. The driver chip 2 includes an input terminal VIN, an output terminal SW, a ground terminal GND, a bootstrap voltage terminal VBST, an enable terminal EN and a voltage feedback terminal VFB.

[0033] The two ends of the external power supply are connected to the input terminal VIN and the ground terminal GND of the driver chip 2 respectively. The voltage value of the input terminal VIN is the input voltage V IN The two ends of the external load are connected to the output terminal SW of the driver chip 2 and the ground terminal GND respectively. The voltage value of the output terminal SW of the driver chip 2 is the output voltage V provided by the driver chip 2 to the external load. OUT .

[0034] One end of the thermistor 3 is connected to the voltage feedback terminal VFB of the driver chip 2, and the other end is connected to the ground terminal GND of the driver chip 2. The thermistor 3 can be a combination of one or more components or circuits whose resistance value changes with temperature. In this embodiment, the thermistor 3 is configured as a thermistor R TH , thermistor R TH The resistance value of thermistor decreases as the temperature increases. TH The voltage across the two ends is V RTH The voltage of the voltage feedback terminal VFB of the driver chip 2 is equal to the feedback reference voltage value V FB , feedback reference voltage value V FB is 0.6V.

[0035] One end of the voltage divider unit 4 is connected to the voltage feedback terminal VFB of the driver chip 2, and the other end is connected to the input terminal VIN of the driver chip 2. The voltage divider unit 4 and the thermistor unit 3 are connected in series between the input terminal VIN and the ground terminal GND of the driver chip 2. In this embodiment, the voltage divider unit 4 is configured as a voltage divider resistor R1, and the voltage divider resistor R1 and the thermistor R are connected in series between the node A and the ground terminal GND. TH , voltage at point A V A =Thermistor R TH The voltage across the two ends is V RTH +Voltage across the voltage divider resistor R1 V R1 .

[0036] One end of the voltage drop unit 5 is connected to the output terminal SW of the driver chip 2 and the external load, respectively, and the other end is connected to the input terminal VIN of the driver chip 2. The voltage drop unit 5 refers to a combination of one or more components or circuits that can provide a stable voltage drop. In other words, the voltage difference across the voltage drop unit 5 can be maintained at a constant value.

[0037] Preferably, in this embodiment, the voltage drop unit 5 is configured as a diode D, the anode of the diode D is connected to the input terminal VIN of the driver chip 2, and the cathode is connected to the output terminal SW of the driver chip 2 and the external load respectively. According to the forward conduction characteristic of the diode D, the voltage V RD is the conduction voltage drop value of diode D. A diode D and an external load are connected in series between node A and the ground terminal GND. The voltage V A =Voltage V across diode D RD +Output voltage V OUT .

[0038] In summary, in this embodiment, the voltage V A =Thermistor R TH The voltage across the two ends is V RTH +Voltage across the voltage divider resistor R1 R1 =Voltage V across diode D RD +Output voltage V OUT , and V RTH =V FB =0.6V. The output voltage V OUT =V RTH +V R1 -V RD =V R1 +(0.6VV RD ), where V RD is a constant value, that is, the conduction voltage drop value of diode D.

[0039] According to the above formula, the output voltage V OUT With V R1 V R1 When it approaches 0, the output voltage V OUT The minimum value is approximately equal to (0.6VV RD ). RD The value range can be (0, 0.6V], so that the output voltage V OUT The minimum value can be much lower than 0.6V.

[0040] Compared to Figure 1 In the driving circuit of the prior art shown in the figure, in this embodiment, by setting the voltage drop value (V RD ) to compensate the feedback reference voltage value V of the driver chip 2 FB, so that the output voltage V of the driving circuit 1 OUT The minimum value can be lower than the feedback reference voltage value V of the driver chip 2 FB , so that the output voltage V of the driving circuit 1 can be OUT The range is not limited by the characteristics of the driver chip itself, which greatly expands the output voltage V of the driver circuit 1 OUT Within the range of , the driving circuit 1 ensures high output control efficiency while the circuit itself has a simple structure and low cost.

[0041] Preferably, in the embodiment of the present utility model, the voltage drop value of the voltage drop unit 5 in the driving circuit 1 is the conduction voltage drop value V of the diode D. RD Equal to the feedback reference voltage value V of driver chip 2 FB =0.6V, and V RTH =0.6V. The output voltage V OUT =V RTH +V R1 -V RD =V R1 , the output voltage V of the driving circuit 1 OUT The voltage value V of thermistor R1 R1 equal, its minimum value can approach 0, further expanding the output voltage V of the driving circuit 1 OUT range, the driving circuit 1 can achieve ultra-low voltage output.

[0042] Further, in the embodiment of the present utility model, according to the voltage divider resistor R1 and the thermistor R TH The series relationship can be obtained (V RTH +V R1 ) / (R TH +R1)=V R1 / R1 is V RTH +V R1 =V R1 *R TH / R1+V R , and V RTH =0.6V, and then we can get V R1 =0.6R1 / R TH .

[0043] In summary, in this embodiment, the output voltage V OUT =V R1 =0.6R1 / R TH , where the resistance value of the voltage divider resistor R1 is a constant value. TH The resistance value of the thermistor changes with temperature. TH The larger the resistance value, the higher the output voltage V OUT Specifically, the output voltage VOUT And thermistor R TH The resistance value changes with temperature as shown in Table 1.

[0044] Temperature(℃) 5 10 15 20 25 30 35 40 45 <![CDATA[R TH (KΩ)]]> 297.4 223.9 169.8 129.8 100 77.57 60.58 47.63 37.69 <![CDATA[V OUT (V)]]> 0.15 0.20 0.27 0.35 0.45 0.58 0.74 0.94 1.19

[0045] Table 1

[0046] As shown in Table 1, the output voltage V of the driving circuit 1 OUT The minimum value can reach 0.15V, which is much smaller than the feedback reference voltage value V of the driver chip 2. FB The above-mentioned driving circuit 1 can realize the output voltage V OUT While adjusting the function according to temperature changes, it also widens the output voltage V of the drive circuit 1 OUT The value range can meet the driving requirements of different loads, thereby improving the applicability of the driving circuit 1.

[0047] Furthermore, in an embodiment of the present utility model, the driving circuit 1 also includes a first current limiting unit 6, which is configured as a current limiting resistor R2, one end of the current limiting resistor R2 is connected to the input terminal VIN of the driving chip 2, and the other end is respectively connected to the voltage divider unit 4 and the voltage drop unit 5.

[0048] In this embodiment, a voltage divider resistor R1 and a thermistor R are connected in series between the node A and the ground terminal GND. TH , and a diode D and an external load are connected in series between node A and the ground terminal GND; in other words, the voltage divider resistor R1 and the thermistor R TH The series body formed by the diode D and the external load is connected in parallel; then the parallel structure is connected in series with the first current limiting unit 6. The first current limiting unit 6 can control the current flowing through the voltage dividing resistor R1 and the thermistor R TH , diode D and external load current is limited.

[0049] In the embodiment of the present utility model, the input voltage V of the driving circuit 1 is set IN is 15V, the output voltage V of the driving circuit 1 OUT The target range is 0.2 to 1 V. The resistance value of the voltage divider resistor R1 is 75 kΩ, and the thermistor R TH The resistance value of is 100kΩ, and the resistance value of the current limiting resistor R2 is 13kΩ.

[0050] In the series circuit composed of current limiting resistor R2, diode D and external load, the current I flowing through diode D D That is the current value flowing through the current limiting resistor R2, we can get

[0051] I D =I R2 ≈(VIN -V D -V OUT ) / R2

[0052] ≈(15V-0.6VV OUT ) / 13kΩ

[0053] ≈1±0.1mA

[0054] The current limiting resistor R2, the voltage dividing resistor R1 and the thermistor R TH In the series circuit composed of

[0055] I R1 ≈V IN / (R2+R1+R TH )

[0056] ≈15V / (13kΩ+75kΩ+100kΩ)

[0057] ≈0.009mA<<(1±0.1mA)

[0058] In summary, the current value I in the series circuit composed of the current limiting resistor R2, the diode D and the external load is D Much larger than the current limiting resistor R2, the voltage divider resistor R1 and the thermistor R TH The current value I in the series circuit R1 Therefore, most of the current flowing through the current limiting resistor R2 flows to the diode D and the external load side.

[0059] Figure 3 It is a schematic diagram of the UI characteristic curve of the diode provided in the embodiment of the present utility model.

[0060] like Figure 3 As shown in the figure, the horizontal axis is the voltage drop value U of the diode, in V; the vertical axis is the current value I flowing through the diode, in mA; the three curves from left to right are the UI characteristic curves of the diode when the ambient temperature is 85℃, 25℃ and -30℃ respectively. Figure 3 , when the ambient temperature is 25℃, the current flowing through the diode is about 1mA and the voltage drop across the diode is about 0.6V.

[0061] Preferably, in the implementation manner of the present utility model, the first current limiting unit 6 is a resistor unit with adjustable resistance to adapt to different current requirements.

[0062] Preferably, in the embodiment of the present utility model, the driving circuit 1 further includes an input capacitor C1 and an input capacitor C2 connected between the input terminal VIN and the ground terminal GND of the driving chip 2, and the input voltage V INThe bootstrap capacitor C3 is connected between the output terminal SW of the driver chip 2 and the bootstrap boost terminal VBST, so that the voltage of the bootstrap capacitor C3 itself is superimposed on the voltage of the output terminal SW of the driver chip 2, and the bootstrap boost terminal VBST provides a higher voltage; the output capacitor C4 and the output capacitor C5 are connected between the output terminal SW of the driver chip 2 and the ground terminal GND, and the output voltage V OUT In addition, the output terminal SW of the driver chip 2 is also connected in series with an output inductor L, which is also used to stabilize the output voltage V of the driver chip 2. OUT .

[0063] Preferably, in an embodiment of the present utility model, the driving circuit 1 also includes a second current limiting unit 7, which is configured as a current limiting resistor R3, one end of the current limiting resistor R3 is connected to the input terminal VIN of the driving chip 2, and the other end is connected to the enable terminal EN of the driving chip 2, and the input current of the driving chip 2 flows into the enable terminal EN through the second current limiting unit 7.

[0064] The enable terminal EN is used to keep the driver chip 2 in an activated state. When the enable terminal EN is at a high level, the driver chip 2 can be kept in an activated state. However, the input current of the driver chip 2 is relatively large, and the input current directly input into the enable terminal EN may damage the driver chip 2 due to overcurrent. The current flowing into the enable terminal EN is limited by the second current limiting unit 7 to prevent the driver chip 2 from being damaged by overcurrent input.

[0065] In an embodiment of the present utility model, a handheld household appliance is also provided, and the power supply circuit of the handheld household appliance includes the above-mentioned drive circuit 1. The above-mentioned drive circuit 1 has a simple structure and low cost, which is conducive to the low-cost miniaturization design of the handheld household appliance.

[0066] In this embodiment, the handheld household appliance can be a hair dryer, a hair comb or other hair drying and hair care device. The water ion generator in the handheld household appliance needs to condense water through a semiconductor refrigeration element. In this embodiment, the semiconductor refrigeration element in the handheld household appliance is powered by the above-mentioned driving circuit 1.

[0067] In the embodiment of the present utility model, by setting the voltage drop value (V RD ) to compensate the feedback reference voltage value V of the driver chip 2 FB , so that the output voltage V of the driving circuit 1 OUT The minimum value can be lower than the feedback reference voltage value V of the driver chip 2 FB , so that the output voltage V of the driving circuit 1 can be OUT The range is not limited by the characteristics of the driver chip 2 itself, which greatly expands the output voltage V of the driver circuit 1. OUTrange, and better provide effective driving voltage for semiconductor refrigeration elements through ultra-low voltage output.

[0068] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A driving circuit, characterized in that: include: A driving chip, two ends of an external power supply are respectively connected to an input end and a ground end of the driving chip, and two ends of an external load are connected to an output end and a ground end of the driving chip; A voltage dividing unit, one end of which is connected to the voltage feedback end of the driving chip, and the other end of which is connected to the input end of the driving chip; A voltage drop unit has one end connected to the output end of the driving chip and an external load respectively, and the other end connected to the input end of the driving chip.

2. The driving circuit according to claim 1, characterized in that: It also includes a thermal sensing unit, one end of which is connected to the voltage feedback end of the driving chip, and the other end of which is connected to the ground end of the driving chip.

3. The driving circuit according to claim 2, characterized in that: The voltage drop value of the voltage drop unit is equal to the feedback reference voltage value of the driving chip.

4. The driving circuit according to claim 3, characterized in that: The voltage drop unit is a diode, an anode of the diode is connected to the input end of the driving chip, and a cathode of the diode is connected to the output end of the driving chip and an external load respectively.

5. The driving circuit according to claim 4, characterized in that: It also includes a first current limiting unit, one end of which is connected to the input end of the driving chip, and the other end of which is respectively connected to the voltage dividing unit and the voltage drop unit.

6. The driving circuit according to claim 5, characterized in that: The first current limiting unit is a resistor unit with adjustable resistance.

7. The driving circuit according to claim 6, characterized in that: Also includes: An input capacitor connected between the input terminal of the driver chip and a ground terminal; A bootstrap capacitor connected between the output terminal of the driving chip and the bootstrap boost terminal; The output capacitor is connected between the output terminal of the driving chip and the ground terminal.

8. The driving circuit according to claim 7, characterized in that: It also includes a second current limiting unit, one end of which is connected to the input end of the driving chip, and the other end of which is connected to the enable end of the driving chip.

9. A handheld household appliance, characterized in that: The power supply circuit of the handheld household appliance comprises the driving circuit as described in any one of claims 1-8.

10. The handheld household appliance according to claim 9, characterized in that: The handheld household electrical appliance comprises a semiconductor refrigeration element, and the driving circuit supplies power to the semiconductor refrigeration element.

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