CN113054723A - Electric screwdriver and charging circuit thereof - Google Patents

Electric screwdriver and charging circuit thereof Download PDF

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Publication number
CN113054723A
CN113054723A CN202110482428.4A CN202110482428A CN113054723A CN 113054723 A CN113054723 A CN 113054723A CN 202110482428 A CN202110482428 A CN 202110482428A CN 113054723 A CN113054723 A CN 113054723A
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CN
China
Prior art keywords
resistor
mosfet
electric screwdriver
capacitor
circuit
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CN202110482428.4A
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Chinese (zh)
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CN113054723B (en
Inventor
刘力丹
雷飞
刘晓东
刘海春
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Shanghai Qiwai Culture Technology Co ltd
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Shanghai Qiwai Culture Technology Co ltd
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H02J7/00308—Overvoltage protection
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25B—TOOLS OR BENCH DEVICES NOT OTHERWISE PROVIDED FOR, FOR FASTENING, CONNECTING, DISENGAGING OR HOLDING
    • B25B21/00—Portable power-driven screw or nut setting or loosening tools; Attachments for drilling apparatus serving the same purpose
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
    • H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
    • H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
    • H02H9/045—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage adapted to a particular application and not provided for elsewhere
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/0047—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with monitoring or indicating devices or circuits

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Emergency Protection Circuit Devices (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

The application provides an electric screwdriver and a charging circuit thereof, wherein the charging circuit comprises an overvoltage protection sub-circuit; the overvoltage protection sub-circuit comprises a first MOSFET, a triode, a voltage stabilizing diode, a third capacitor, a first resistor, a fifth resistor, a sixth resistor and a ninth resistor; the source electrode of the first MOSFET is connected to the first end of the fifth resistor; the base electrode of the triode is connected to the first end of the ninth resistor, the collector electrode of the triode is connected between the grid electrode of the first MOSFET and the sixth resistor, and the emitter electrode of the triode is connected between the source electrode of the first MOSFET and the fifth resistor; the negative electrode of the voltage stabilizing diode is connected between the second end of the fifth resistor and the second end of the ninth resistor; the first end of the third capacitor is connected to the source electrode of the first MOSFET; the first end of the first resistor is connected to the source of the first MOSFET. In summary, overvoltage protection can be achieved with an overvoltage protection sub-circuit.

Description

Electric screwdriver and charging circuit thereof
Technical Field
The application relates to the technical field of electric screwdrivers, in particular to an electric screwdriver and a charging circuit thereof.
Background
The screwdriver is a tool for screwing a screw to force the screw to be in place, and generally comprises a thin wedge-shaped head which can be inserted into a slot or a notch of a screw head and then is rotated to fix the screw at a specified position.
When the existing electric screwdriver is charged, the safety is low, and when the voltage of an internal charging circuit is abnormal, no overvoltage protection function exists, so that electronic components can be damaged.
Disclosure of Invention
The application aims to provide an electric screwdriver and a charging circuit thereof, which can utilize an overvoltage protection sub-circuit to realize overvoltage protection and avoid the damage of electronic components of the charging circuit.
The purpose of the application is realized by adopting the following technical scheme:
in a first aspect, the present application provides a charging circuit for an electric screwdriver, the charging circuit comprising an overvoltage protection sub-circuit; the overvoltage protection sub-circuit comprises a first MOSFET, a triode, a voltage stabilizing diode, a third capacitor, a first resistor, a fifth resistor, a sixth resistor and a ninth resistor; the grid electrode of the first MOSFET is connected to the common ground terminal through the sixth resistor, the source electrode of the first MOSFET is connected to the first end of the fifth resistor, and the drain electrode of the first MOSFET is connected to a power supply voltage; the base electrode of the triode is connected to the first end of the ninth resistor, the collector electrode of the triode is connected between the grid electrode of the first MOSFET and the sixth resistor, and the emitter electrode of the triode is connected between the source electrode of the first MOSFET and the fifth resistor; the anode of the voltage-stabilizing diode is connected to the common ground terminal, and the cathode of the voltage-stabilizing diode is connected between the second end of the fifth resistor and the second end of the ninth resistor; a first end of the third capacitor is connected to the source electrode of the first MOSFET, and a second end of the third capacitor is connected to the grid electrode of the first MOSFET; the first end of the first resistor is connected to the source of the first MOSFET, and the second end of the first resistor is connected to the gate of the first MOSFET. The technical scheme has the beneficial effects that through the arrangement of the third capacitor and the first resistor, two ends of the third capacitor and two ends of the first resistor can be respectively connected to the source electrode and the grid electrode of the first MOSFET, the third capacitor can absorb the peak voltage instantaneously generated by the switching of the first MOSFET, so that the overvoltage borne by the MOSFET is reduced, the MOSFET is prevented from being damaged, and the first resistor has the function of consuming certain overvoltage energy; by arranging the triode, the fifth resistor, the sixth resistor and the ninth resistor, the base electrode of the triode can be connected with the ninth resistor in series, so that the current at the base electrode of the triode is reduced, the triode is prevented from being burnt out, the collector electrode of the triode can be connected with the sixth resistor in series, the collector electrode of the triode has a current amplification effect, the amplified current can be converted into voltage output by arranging the sixth resistor, the emitter electrode of the triode can be connected with the fifth resistor in series, and the influence of temperature factors on static bias voltage can be reduced by arranging the fifth resistor, so that the current amplification factor is stabilized; the voltage stabilizing diode is arranged, so that the voltage stabilizing effect can be achieved, and high-precision electronic components in the overvoltage protection sub-circuit can be protected; in sum, the overvoltage protection subcircuit can be used for realizing overvoltage protection, and electronic components of the charging circuit are prevented from being damaged.
In some optional embodiments, the charging circuit further comprises a charge protection sub-circuit comprising a fourth MOSFET, a tenth resistor, and a thirteenth resistor; the grid electrode of the fourth MOSFET is connected to the charging protection signal output end of the MCU of the electric screwdriver through the tenth resistor, the source electrode of the fourth MOSFET is connected to the common grounding end, and the drain electrode of the fourth MOSFET is connected between the fifth resistor and the voltage stabilizing diode; a first end of the thirteenth resistor is connected between the tenth resistor and the gate of the fourth MOSFET, and a second end of the thirteenth resistor is connected to the common ground. The technical scheme has the advantages that by the tenth resistor and the thirteenth resistor, breakdown of surrounding components caused by over-high switching speed of the fourth MOSFET in a high-voltage state can be avoided due to the tenth resistor; the thirteenth resistor can be used as a discharge resistor to discharge a small amount of static electricity of the fourth MOSFET, so that the fourth MOSFET is prevented from misoperation, and the function of protecting the fourth MOSFET is achieved.
In some optional embodiments, the charging circuit further comprises a charging feedback sub-circuit comprising a charger and a second resistor; the charging state indicating end of the charger is connected to a charging state signal receiving end of the MCU of the electric screwdriver, the charging state indicating end of the charger outputs a charging state signal, the grounding end of the charger is connected to a public grounding end, a charging current output end of the charger is connected to the anode of the battery, a power voltage end of the charger is connected to a power supply voltage, and a drain open-circuit state indicating end of the charger is connected to the public grounding end through the second resistor. The technical scheme has the beneficial effects that on one hand, the charging state indicating end of the charger can be connected to the charging state signal receiving end of the MCU of the electric screwdriver, and the charging state indicating end of the charger is utilized to output a charging state signal; on the other hand, the open-drain state indicating end of the charger can be connected to the common grounding end through the second resistor, the charging current can be set based on the second resistor by setting the second resistor, the charging current monitoring effect is achieved, the open-drain state indicating end of the charger can also serve as a shutdown pin to shut down the charger, the second resistor can be disconnected with the common grounding end, the internal current pulls the open-drain state indicating end of the charger to a high level, when the voltage of the open-drain state indicating end of the charger reaches a shutdown threshold voltage, the charger enters a shutdown mode, the charging is stopped, the input power supply current is reduced, and the open-drain state indicating end of the charger is connected with the common grounding end again to enable the charger to recover to a normal operation state.
In some optional embodiments, the charging circuit further comprises a fourth capacitor and a fifth capacitor; a first end of the fourth capacitor is connected to the positive electrode of the battery, and a second end of the fourth capacitor is connected to the common ground end; the first end of the fifth capacitor is connected to the positive electrode of the battery, and the second end of the fifth capacitor is connected to the common ground terminal. The beneficial effect of this technical scheme lies in, through setting up fourth electric capacity and fifth electric capacity, can prevent that spike voltage and burr voltage from arousing the charger to damage.
In some optional embodiments, the charging circuit further comprises a first LED control sub-circuit comprising a second MOSFET, a first bi-directional zener diode, a third resistor, a seventh resistor, and an eleventh resistor; the grid electrode of the second MOSFET is connected to the first LED control signal output end of the MCU of the electric screwdriver through the seventh resistor, the source electrode of the second MOSFET is connected to the common grounding end, and the drain electrode of the second MOSFET is connected to the cathode of the first LED of the electric screwdriver through the third resistor; a first end of the first bidirectional voltage stabilizing diode is connected between the grid electrode of the second MOSFET and the seventh resistor, and a second end of the first bidirectional voltage stabilizing diode is connected to the common grounding end; a first end of the eleventh resistor is connected between the gate of the second MOSFET and the seventh resistor, and a second end of the eleventh resistor is connected to the common ground. The technical scheme has the advantages that the first bidirectional voltage stabilizing diode is arranged and can be connected between the grid electrode and the source electrode of the second MOSFET in parallel, and the forward direction and the reverse direction of the first bidirectional voltage stabilizing diode can play a voltage stabilizing role to prevent the second MOSFET from being broken down by high voltage; by arranging the seventh resistor and the eleventh resistor, the seventh resistor can prevent surrounding components from being broken down due to the fact that the switching speed of the second MOSFET is too high in a high-voltage state; the eleventh resistor can be used as a discharge leakage resistor to discharge a small amount of static electricity of the second MOSFET, so that the second MOSFET is prevented from misoperation, and the function of protecting the second MOSFET is achieved; by arranging the third resistor, the drain electrode of the second MOSFET can be ensured to be in a high level state, and misoperation is avoided.
In some optional embodiments, the charging circuit further comprises a second LED control sub-circuit comprising a third MOSFET, a second bidirectional zener diode, a fourth resistor, an eighth resistor, and a twelfth resistor; the grid electrode of the third MOSFET is connected to a second LED control signal output end of the MCU of the electric screwdriver through the eighth resistor, the source electrode of the third MOSFET is connected to the common grounding end, and the drain electrode of the third MOSFET is connected to the cathode of a second LED of the electric screwdriver through the fourth resistor; a first end of the second bidirectional voltage stabilizing diode is connected between the grid of the third MOSFET and the eighth resistor, and a second end of the second bidirectional voltage stabilizing diode is connected to the common ground terminal; a first end of the twelfth resistor is connected between the gate of the third MOSFET and the eighth resistor, and a second end of the twelfth resistor is connected to the common ground. The technical scheme has the advantages that the second bidirectional voltage stabilizing diode is arranged and can be connected between the grid electrode and the source electrode of the third MOSFET in parallel, the positive direction and the negative direction of the second bidirectional voltage stabilizing diode can play a voltage stabilizing role, and the third MOSFET is prevented from being broken down by high voltage; by arranging the eighth resistor and the twelfth resistor, the eighth resistor can prevent surrounding components from being broken down due to the fact that the switching speed of the third MOSFET is too high in a high-voltage state; the twelfth resistor can be used as a discharge leakage resistor to discharge a small amount of static electricity of the third MOSFET, so that the third MOSFET is prevented from misoperation, and the effect of protecting the third MOSFET is achieved; by arranging the fourth resistor, the drain electrode of the third MOSFET can be ensured to be in a high level state, and misoperation is avoided.
In some optional embodiments, the charging circuit further comprises an LED power supply electronic circuit, the LED power supply electronic circuit comprising a second magnetic bead, a third magnetic bead, and a third bidirectional zener diode; a first end of the second magnetic bead is connected to an internal working voltage, and a second end of the second magnetic bead is connected to the anode of the LED of the electric screwdriver; the first end of the third magnetic bead is connected to the grounding end of the Type-C connector of the electric screwdriver, and the second end of the third magnetic bead is connected to the common grounding end; the first end of the third bidirectional voltage stabilizing diode is connected to the second end of the second magnetic bead, and the second end of the third bidirectional voltage stabilizing diode is connected to the common ground end. The technical scheme has the beneficial effects that the second magnetic beads have better high-frequency filtering characteristics, so that the mutual interference between the anode of the LED of the electric screwdriver and the internal working voltage can be avoided; high-frequency noise and spike interference can be suppressed by arranging the third magnetic beads; through setting up the third two-way zener diode, the positive and negative two directions of third two-way zener diode all can play the steady voltage effect.
In some optional embodiments, the charging circuit further comprises an electrostatic protection sub-circuit comprising a first magnetic bead; the first end of the first magnetic bead is connected to the source electrode of the first MOSFET, and the second end of the first magnetic bead is connected between the first voltage end and the second voltage end of the Type-C connector of the electric screwdriver. The technical scheme has the beneficial effects that when the second end of the first magnetic bead is at a high level, the first MOSFET is cut off, the external power supply stops supplying power to the Type-C connector, the energy stored by the first magnetic bead can be utilized to supply power to the Type-C connector, along with the continuous consumption of the energy of the first magnetic bead, the second end of the first magnetic bead gradually becomes a low level, the first MOSFET is conducted, the external power supply starts supplying power to the Type-C connector, and in sum, the level at the second end of the first magnetic bead can be in a stable state by arranging the first magnetic bead and the first MOSFET, so that the voltage stabilizing effect is achieved; in addition, the first magnetic beads are connected in series to limit the electrostatic discharge current, so that the purpose of static electricity prevention can be achieved.
In some optional embodiments, the charging circuit further comprises a first capacitor and a second capacitor; a first end of the first capacitor is connected to a power supply voltage, and a second end of the first capacitor is connected to the common ground terminal; and the first end of the second capacitor is connected with a power supply voltage, and the second end of the second capacitor is connected to the common ground terminal. This technical scheme's beneficial effect lies in, through setting up first electric capacity and second electric capacity, can filter high frequency clutter, improves charging circuit's stability can.
In a second aspect, the present application provides an electric screwdriver comprising the charging circuit of any one of the electric screwdrivers described above. The technical scheme has the beneficial effects that the charging circuit of the electric screwdriver can be applied to the electric screwdriver, so that the intelligent level of the electric screwdriver is improved.
Drawings
The present application is further described below with reference to the drawings and examples.
Fig. 1 is a schematic structural diagram of a charging circuit of an electric screwdriver according to an embodiment of the present disclosure;
fig. 2 is a schematic structural diagram of an electric screwdriver provided in an embodiment of the present application.
In the figure: 10. a charger; 11. a charging state indicating terminal of the charger; 12. a ground terminal of the charger; 13. a charging current output terminal of the charger; 14. a supply voltage terminal of the charger; 15. a drain open state indicating terminal of the charger; m1, a first MOSFET; q2, second MOSFET; q3, third MOSFET; q4, fourth MOSFET; z1, zener diodes; q1, triode; d1, a first bidirectional voltage stabilizing diode; d2, a second bidirectional zener diode; d3, a third zener diode; FB1, first magnetic bead; FB2, second magnetic bead; FB3, third magnetic bead; r1, a first resistor; r2, a second resistor; r3, third resistor; r4, fourth resistor; r5, fifth resistor; r6, sixth resistor; r7, seventh resistor; r8, eighth resistor; r9, ninth resistor; r10, tenth resistor; r11, eleventh resistor; r12, twelfth resistor; r13, thirteenth resistor; c1, a first capacitance; c2, a second capacitor; c3, a third capacitance; c4, a fourth capacitance; c5, a fifth capacitance.
Detailed Description
The present application is further described with reference to the accompanying drawings and the detailed description, and it should be noted that, in the present application, the embodiments or technical features described below may be arbitrarily combined to form a new embodiment without conflict.
Referring to fig. 1, an embodiment of the present application provides a charging circuit of an electric screwdriver, where the charging circuit includes an overvoltage protection sub-circuit; the overvoltage protection sub-circuit comprises a first MOSFET M1, a triode Q1, a zener diode Z1, a third capacitor C3, a first resistor R1, a fifth resistor R5, a sixth resistor R6 and a ninth resistor R9; the gate of the first MOSFET M1 is connected to the common ground terminal through the sixth resistor R6, the source of the first MOSFET M1 is connected to the first end of the fifth resistor R5, and the drain of the first MOSFET M1 is connected to a supply voltage; the base of the transistor Q1 is connected to the first end of the ninth resistor R9, the collector of the transistor Q1 is connected between the gate of the first MOSFET M1 and the sixth resistor R6, and the emitter of the transistor Q1 is connected between the source of the first MOSFET M1 and the fifth resistor R5; the anode of the zener diode Z1 is connected to the common ground, and the cathode of the zener diode Z1 is connected between the second end of the fifth resistor R5 and the second end of the ninth resistor R9; a first end of the third capacitor C3 is connected to the source of the first MOSFET M1, and a second end of the third capacitor C3 is connected to the gate of the first MOSFET M1; the first end of the first resistor R1 is connected to the source of the first MOSFET M1, and the second end of the first resistor R1 is connected to the gate of the first MOSFET M1.
A Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET), which is a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET).
The network reference for the supply voltage is for example VCC and the network reference for the common ground is for example GND.
The network label (net label) is an electrical connection point, generally composed of letters, symbols, numbers, etc., the electrical connection lines, pins and networks with the same network label are connected together, and the network labels are not connected.
In the embodiment of the present application, the selection of the first MOSFET M1, the transistor Q1, and the zener diode Z1 is not limited, the model of the first MOSFET M1 is, for example, LT1525SI, the model of the transistor Q1 is, for example, MMBT5401, and the model of the zener diode Z1 is, for example, BZT52C6V 2.
The capacity of the third capacitor C3 is not limited in the embodiments of the present application, and the capacity of the third capacitor C3 is, for example, 0.08 μ F, 0.1 μ F, or 0.12 μ F.
In the embodiment of the present application, the resistance values of the first resistor R1, the fifth resistor R5, the sixth resistor R6, and the ninth resistor R9 are not limited, and the resistance value of the first resistor R1 is, for example, 0.8M Ω, 1M Ω, or 1.2M Ω; the resistance of the fifth resistor R5 is, for example, 8K Ω, 10K Ω or 12K Ω; the resistance of the sixth resistor R6 is 350K Ω, 390K Ω or 420K Ω, for example; the ninth resistor R9 has a resistance of, for example, 8K Ω, 10K Ω or 12K Ω.
Therefore, by arranging the third capacitor C3 and the first resistor R1, two ends of the third capacitor C3 and two ends of the first resistor R1 can be respectively connected to the source and the gate of the first MOSFET M1, the third capacitor C3 can absorb the spike voltage generated instantly when the first MOSFET M1 is switched, so that the overvoltage borne by the MOSFET is reduced, the MOSFET is prevented from being damaged, and the first resistor R1 has the function of consuming certain overvoltage energy; by arranging the triode Q1, the fifth resistor R5, the sixth resistor R6 and the ninth resistor R9, the base electrode of the triode Q1 can be connected with the ninth resistor R9 in series, so that the current at the base electrode of the triode Q1 is reduced, the burning of the triode Q1 is avoided, the collector electrode of the triode Q1 can be connected with the sixth resistor R6 in series, the collector electrode of the triode Q1 has a current amplification effect, the amplified current can be converted into voltage output by arranging the sixth resistor R6, the emitter electrode of the triode Q1 can be connected with the fifth resistor R5 in series, and the influence of temperature factors on static bias voltage can be reduced by arranging the fifth resistor R5, so that the current amplification factor is stabilized; the voltage stabilizing diode Z1 is arranged, so that the voltage stabilizing effect can be achieved, and high-precision electronic components in the overvoltage protection sub-circuit can be protected; in sum, the overvoltage protection subcircuit can be used for realizing overvoltage protection, and electronic components of the charging circuit are prevented from being damaged.
In some embodiments, the charging circuit may further include a charge protection sub-circuit, which may include a fourth MOSFET Q4, a tenth resistor R10, and a thirteenth resistor R13; the gate of the fourth MOSFET Q4 may be connected to the charge protection signal output terminal of the MCU of the electric screwdriver through the tenth resistor R10, the source of the fourth MOSFET Q4 may be connected to the common ground, and the drain of the fourth MOSFET Q4 may be connected between the fifth resistor R5 and the zener diode Z1; a first terminal of the thirteenth resistor R13 may be connected between the tenth resistor R10 and the gate of the fourth MOSFET Q4, and a second terminal of the thirteenth resistor R13 may be connected to the common ground. Wherein, the network label of the charging protection signal output terminal of the MCU is, for example, OV CHG.
In the embodiment of the present application, the selection of the MCU and the fourth MOSFET Q4 is not limited, the model of the MCU is, for example, CMS8S6990, and the model of the fourth MOSFET Q4 is, for example, 2N 7002.
In the embodiment of the present application, the resistance values of the tenth resistor R10 and the thirteenth resistor R13 are not limited, the resistance value of the tenth resistor R10 is, for example, 8K Ω, 10K Ω or 12K Ω, and the resistance value of the thirteenth resistor R13 is, for example, 0.8M Ω, 1M Ω or 1.2M Ω.
Therefore, by arranging the tenth resistor R10 and the thirteenth resistor R13, the tenth resistor R10 can prevent the breakdown of surrounding components due to the over-high switching speed of the fourth MOSFET Q4 in a high-voltage state; the thirteenth resistor R13 can discharge a small amount of static electricity of the fourth MOSFET Q4 as a leakage resistor, thereby preventing malfunction of the fourth MOSFET Q4 and protecting the fourth MOSFET Q4.
In some embodiments, the charging circuit may further include a charging feedback sub-circuit, which may include the charger 10 and a second resistor R2; the charging state indicating terminal 11 of the charger may be connected to a charging state signal receiving terminal of the MCU of the electric screwdriver, the charging state indicating terminal 11 of the charger may output a charging state signal, the ground terminal 12 of the charger may be connected to a common ground terminal, the charging current output terminal 13 of the charger may be connected to a positive electrode of a battery, the power voltage terminal 14 of the charger may be connected to a power supply voltage, and the drain open state indicating terminal 15 of the charger may be connected to the common ground terminal through the second resistor R2. Wherein, the network label of the battery anode is, for example, B +.
The embodiment of the present application is not limited to the selection of the charger 10, the model of the charger 10 is, for example, TP4065, and the charger 10 may include 5 pins.
The 1 st pin of the charger 10 is a charging state indicating terminal 11 of the charger, and a network number of the charging state indicating terminal 11 of the charger is, for example, CHG; the 2 nd pin of the charger 10 is the ground terminal 12 of the charger, and the network label of the ground terminal 12 of the charger is, for example, GND; the 3 rd pin of the charger 10 is a charging current output end 13 of the charger; the 4 th pin of the charger 10 is the power supply voltage terminal 14 of the charger, and the network number of the power supply voltage terminal 14 of the charger is VCC, for example; the 5 th pin of the charger 10 is the open drain status indicator terminal 15 of the charger.
The resistance of the second resistor R2 is not limited in the embodiment of the present application, and the resistance of the second resistor R2 is, for example, 4.8K Ω, 5.1K Ω, or 5.4K Ω.
Therefore, on one hand, the charging state indicating terminal 11 of the charger can be connected to the charging state signal receiving terminal of the MC U of the electric screwdriver, and the charging state indicating terminal 11 of the charger is used for outputting a charging state signal; on the other hand, the open drain state indicator 15 of the charger may be connected to the common ground through the second resistor R2, and by providing the second resistor R2, the charging current may be set based on the second resistor R2, so as to achieve the function of monitoring the charging current, the open drain state indicator 15 of the charger may also serve as a shutdown pin to turn off the charger 10, the second resistor R2 may be disconnected from the common ground, the internal current pulls the open drain state indicator 15 of the charger to a high level, when the voltage of the open drain state indicator 15 of the charger reaches a shutdown threshold voltage, the charger 10 enters a shutdown mode, the charging stops and the input power current decreases, and the open drain state indicator 15 of the charger is connected to the common ground again, so as to enable the charger 10 to recover to a normal operation state.
In some embodiments, the charging circuit may further include a fourth capacitor C4 and a fifth capacitor C5; a first terminal of the fourth capacitor C4 may be connected to the battery positive terminal, and a second terminal of the fourth capacitor C4 may be connected to the common ground terminal; a first terminal of the fifth capacitor C5 may be connected to the battery anode, and a second terminal of the fifth capacitor C5 may be connected to the common ground.
The capacity of the fourth capacitor C4 and the capacity of the fifth capacitor C5 are not limited in the embodiments of the present application, the capacity of the fourth capacitor C4 is, for example, 8 μ F, 10 μ F or 12 μ F, and the capacity of the fifth capacitor C5 is, for example, 0.08 μ F, 0.1 μ F or 0.12 μ F.
Thus, by providing the fourth capacitor C4 and the fifth capacitor C5, it is possible to prevent the spike voltage and the glitch voltage from causing damage to the charger 10.
In some embodiments, the charging circuit may further include a first LED control sub-circuit, which may include a second MOSFET Q2, a first bi-directional zener diode D1, a third resistor R3, a seventh resistor R7, and an eleventh resistor R11; the gate of the second MOSFET Q2 may be connected to the first LED control signal output terminal of the MCU of the electric screwdriver through the seventh resistor R7, the source of the second MOSFET Q2 may be connected to the common ground, and the drain of the second MOSFET Q2 may be connected to the cathode of the first LED of the electric screwdriver through the third resistor R3; a first terminal of the first bidirectional zener diode D1 may be connected between the gate of the second MOSFET Q2 and the seventh resistor R7, and a second terminal of the first bidirectional zener diode D1 may be connected to the common ground; a first terminal of the eleventh resistor R11 may be connected between the gate of the second MOSFET Q2 and the seventh resistor R7, and a second terminal of the eleventh resistor R11 may be connected to the common ground. The network label of the first LED control signal output end of the MCU is, for example, RED _ EN, and the network label of the cathode of the first LED is, for example, RED.
The second MOSFET Q2 is not limited in the embodiments of the present application, and the model of the second MOSFET Q2 is, for example, 2N 7002K.
In the embodiment of the present application, the resistance values of the third resistor R3, the seventh resistor R7, and the eleventh resistor R11 are not limited, and the resistance value of the third resistor R3 is, for example, 1.5K Ω, 2K Ω, or 2.5K Ω; the resistance of the seventh resistor R7 is, for example, 8K Ω, 10K Ω or 12K Ω; the eleventh resistor R11 has a resistance of, for example, 0.8M Ω, 1M Ω, or 1.2M Ω.
Therefore, by arranging the first bidirectional voltage stabilizing diode D1, the first bidirectional voltage stabilizing diode D1 can be connected between the grid electrode and the source electrode of the second MOSFET Q2 in parallel, the positive and negative directions of the first bidirectional voltage stabilizing diode D1 can play a role in voltage stabilization, and the high voltage breakdown of the second MOSFET Q2 is prevented; by arranging the seventh resistor R7 and the eleventh resistor R11, the seventh resistor R7 can prevent the breakdown of surrounding components due to the over-high switching speed of the second MOSFET Q2 in a high-voltage state; the eleventh resistor R11 can be used as a discharge leakage resistor to discharge a small amount of static electricity of the second MOSFET Q2, prevent the second MOSFET Q2 from misoperation and play a role in protecting the second MOSFET Q2; by arranging the third resistor R3, the drain electrode of the second MOSFET Q2 can be ensured to be in a high level state, and misoperation is avoided.
In some embodiments, the charging circuit may further include a second LED control sub-circuit, which may include a third MOSFET Q3, a second bidirectional zener diode D2, a fourth resistor R4, an eighth resistor R8, and a twelfth resistor R12; the gate of the third MOSFET Q3 may be connected to the second LED control signal output terminal of the MCU of the electric screwdriver through the eighth resistor R8, the source of the third MOSFET Q3 may be connected to the common ground, and the drain of the third MOSFET Q3 may be connected to the cathode of the second LED of the electric screwdriver through the fourth resistor R4; a first terminal of the second bidirectional zener diode D2 may be connected between the gate of the third MOSFET Q3 and the eighth resistor R8, and a second terminal of the second bidirectional zener diode D2 may be connected to the common ground; a first end of the twelfth resistor R12 may be connected between the gate of the third MOSFET Q3 and the eighth resistor R8, and a second end of the twelfth resistor R12 may be connected to the common ground. The network label of the second LED control signal output end of the MCU is, for example, WH _ EN, and the network label of the cathode of the second LED is, for example, WH.
In the embodiment of the present application, the selection of the third MOSFET Q3 is not limited, and the model of the third MOSFET Q3 is, for example, 2N 7002K.
In the embodiment of the present application, the resistance values of the fourth resistor R4, the eighth resistor R8, and the twelfth resistor R12 are not limited, and the resistance value of the fourth resistor R4 is, for example, 1.5K Ω, 2K Ω, or 2.5K Ω; the resistance of the eighth resistor R8 is, for example, 8K Ω, 10K Ω or 12K Ω; the resistance of the twelfth resistor R12 is, for example, 0.8M Ω, 1M Ω or 1.2M Ω.
Therefore, by arranging the second bidirectional voltage stabilizing diode D2, the second bidirectional voltage stabilizing diode D2 can be connected between the grid and the source of the third MOSFET Q3 in parallel, the positive and negative directions of the second bidirectional voltage stabilizing diode D2 can play a role in voltage stabilization, and the high voltage is prevented from breaking through the third MOSFET Q3; by arranging the eighth resistor R8 and the twelfth resistor R12, the eighth resistor R8 can prevent the breakdown of surrounding components due to the over-high switching speed of the third MOSFET Q3 in a high-voltage state; the twelfth resistor R12 can be used as a discharge leakage resistor to discharge a small amount of static electricity of the third MOSFET Q3, prevent the third MOSFET Q3 from misoperation and play a role in protecting the third MOSFET Q3; by arranging the fourth resistor R4, the drain of the third MOSFET Q3 can be ensured to be in a high level state, and malfunction is avoided.
In some embodiments, the charging circuit may further include an LED power supply sub-circuit, which may include a second magnetic bead FB2, a third magnetic bead FB3, and a third bidirectional zener diode D3; a first end of the second magnetic bead FB2 can be connected with an internal working voltage, and a second end of the second magnetic bead FB2 can be connected to the anode of the LED of the electric screwdriver; a first end of the third magnetic bead FB3 may be connected to a ground terminal of a Type-C connector of the electric screwdriver, and a second end of the third magnetic bead FB3 may be connected to the common ground terminal; a first terminal of the third zener diode D3 may be connected to the second terminal of the second bead FB2, and a second terminal of the third zener diode D3 may be connected to the common ground terminal. The network label of the internal operating voltage is VDD, for example, the network label of the ground terminal of the Type-C connector is GND1, and the network label of the anode of the LED of the electric screwdriver is VDD1, for example.
In a specific application, the first LED and the second LED may be packaged together, that is, the LED of the electric screwdriver, the network label of the cathode of the first LED is, for example, RED, the network label of the cathode of the second LED is, for example, WH, and the network label of the anode of the LED of the electric screwdriver is, for example, VDD 1.
The magnetic beads have very high resistivity and permeability, which are equivalent to a resistor and an inductor connected in series, but the resistance value and the inductance value change along with the frequency.
In the embodiment of the present application, the inductance values of the second magnetic bead FB2 and the third magnetic bead FB3 are not limited, and the inductance value of the second magnetic bead FB2 is, for example, 1K/100M, that is, the inductance value is 1000H at 100 MHz; the inductance value of the third magnetic bead FB3 is, for example, 1K/100M, i.e., 1000H at 100 MHz.
Therefore, the second magnetic bead FB2 is arranged, the second magnetic bead FB2 has good high-frequency filtering characteristics, and mutual interference between the anode of the LED of the electric screwdriver and the internal working voltage can be avoided; by arranging the third magnetic bead FB3, high-frequency noise and spike interference can be suppressed; by providing the third zener diode D3, the voltage of the third zener diode D3 can be stabilized in both the forward and reverse directions.
In some embodiments, the charging circuit may further include an electrostatic protection sub-circuit, which may include a first magnetic bead FB 1; a first end of the first magnetic bead FB1 may be connected to the source of the first MOSFET M1, and a second end of the first magnetic bead FB1 may be connected between a first voltage terminal and a second voltage terminal of a Type-C connector of the electric screwdriver. Wherein, the network label between the first voltage terminal and the second voltage terminal of the Type-C connector of the electric screwdriver is V1N1, for example.
The embodiment of the present application does not limit the choice of the first MOSFET M1, and the model of the first MOSFET M1 is, for example, LT1525 SI.
In the embodiment of the present application, the inductance value of the first bead FB1 is not limited, and the inductance value of the first bead FB1 is, for example, 1K/100M, that is, the inductance value is 1000H at 100 MHz.
Therefore, by arranging the first magnetic bead FB1, when the second end of the first magnetic bead FB1 is at a high level, the first MOSFET M1 is turned off, the external power supply stops supplying power to the Type-C connector, the Type-C connector can be supplied with power by using the energy stored in the first magnetic bead FB1, as the energy of the first magnetic bead FB1 is continuously consumed, the second end of the first magnetic bead FB1 gradually becomes a low level, the first MOSFET M1 is turned on, and the external power supply starts supplying power to the Type-C connector, so that in summary, by arranging the first FB1 and the first MOSFET M1, the level at the second end of the first magnetic bead FB1 can be in a stable state to achieve a voltage stabilizing effect; in addition, the first magnetic beads FB1 are connected in series to limit the electrostatic discharge current, so that the purpose of electrostatic prevention can be achieved.
In some embodiments, the charging circuit may further include a first capacitor C1 and a second capacitor C2; a first end of the first capacitor C1 may be connected to a supply voltage, and a second end of the first capacitor C1 may be connected to the common ground; a first terminal of the second capacitor C2 may be connected to a supply voltage, and a second terminal of the second capacitor C2 may be connected to the common ground.
The embodiments of the present application do not limit the capacitance of the first capacitor C1 and the second capacitor C2, the capacitance of the first capacitor C1 is, for example, 8 μ F, 10 μ F or 12 μ F, and the capacitance of the second capacitor C2 is, for example, 0.08 μ F, 0.1 μ F or 0.12 μ F.
Therefore, the first capacitor C1 and the second capacitor C2 are arranged, high-frequency noise can be filtered, and the stability of the charging circuit is improved.
Referring to fig. 2, the present application further provides an electric screwdriver, which includes a charging circuit of any one of the electric screwdrivers.
Therefore, the charging circuit of the electric screwdriver can be applied to the electric screwdriver, and the intelligent level of the electric screwdriver is improved.
While the present application is described in terms of various aspects, including exemplary embodiments, the principles of the invention should not be limited to the disclosed embodiments, but are also intended to cover various modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims.

Claims (10)

1. The charging circuit of the electric screwdriver is characterized by comprising an overvoltage protection sub-circuit;
the overvoltage protection sub-circuit comprises a first MOSFET, a triode, a voltage stabilizing diode, a third capacitor, a first resistor, a fifth resistor, a sixth resistor and a ninth resistor;
the grid electrode of the first MOSFET is connected to the common ground terminal through the sixth resistor, the source electrode of the first MOSFET is connected to the first end of the fifth resistor, and the drain electrode of the first MOSFET is connected to a power supply voltage;
the base electrode of the triode is connected to the first end of the ninth resistor, the collector electrode of the triode is connected between the grid electrode of the first MOSFET and the sixth resistor, and the emitter electrode of the triode is connected between the source electrode of the first MOSFET and the fifth resistor;
the anode of the voltage-stabilizing diode is connected to the common ground terminal, and the cathode of the voltage-stabilizing diode is connected between the second end of the fifth resistor and the second end of the ninth resistor;
a first end of the third capacitor is connected to the source electrode of the first MOSFET, and a second end of the third capacitor is connected to the grid electrode of the first MOSFET;
the first end of the first resistor is connected to the source of the first MOSFET, and the second end of the first resistor is connected to the gate of the first MOSFET.
2. The charging circuit of the electric screwdriver according to claim 1, further comprising a charge protection sub-circuit comprising a fourth MOSFET, a tenth resistor and a thirteenth resistor;
the grid electrode of the fourth MOSFET is connected to the charging protection signal output end of the MC U of the electric screwdriver through the tenth resistor, the source electrode of the fourth MOSFET is connected to the common grounding end, and the drain electrode of the fourth MOSFET is connected between the fifth resistor and the voltage stabilizing diode;
a first end of the thirteenth resistor is connected between the tenth resistor and the gate of the fourth MOSFET, and a second end of the thirteenth resistor is connected to the common ground.
3. The charging circuit of the electric screwdriver according to claim 1, further comprising a charging feedback sub-circuit, the charging feedback sub-circuit comprising a charger and a second resistor;
the charging state indicating end of the charger is connected to a charging state signal receiving end of the MCU of the electric screwdriver, the charging state indicating end of the charger outputs a charging state signal, the grounding end of the charger is connected to a public grounding end, a charging current output end of the charger is connected to the anode of the battery, a power voltage end of the charger is connected to a power supply voltage, and a drain open-circuit state indicating end of the charger is connected to the public grounding end through the second resistor.
4. The charging circuit of the electric screwdriver according to claim 3, further comprising a fourth capacitor and a fifth capacitor;
a first end of the fourth capacitor is connected to the positive electrode of the battery, and a second end of the fourth capacitor is connected to the common ground end;
the first end of the fifth capacitor is connected to the positive electrode of the battery, and the second end of the fifth capacitor is connected to the common ground terminal.
5. The charging circuit of the electric screwdriver according to claim 1, further comprising a first LED control sub-circuit comprising a second mosfet T, a first bi-directional zener diode, a third resistor, a seventh resistor, and an eleventh resistor;
the grid electrode of the second MOSFET is connected to the first LED control signal output end of the MC U of the electric screwdriver through the seventh resistor, the source electrode of the second MOSFET is connected to the common ground terminal, and the drain electrode of the second MOSFET is connected to the negative electrode of the first LED of the electric screwdriver through the third resistor;
a first end of the first bidirectional voltage stabilizing diode is connected between the grid electrode of the second MOSFET and the seventh resistor, and a second end of the first bidirectional voltage stabilizing diode is connected to the common grounding end;
a first end of the eleventh resistor is connected between the gate of the second MOSFET and the seventh resistor, and a second end of the eleventh resistor is connected to the common ground.
6. The charging circuit of the electric screwdriver according to claim 1, further comprising a second LED control sub-circuit comprising a third mosfet T, a second bi-directional zener diode, a fourth resistor, an eighth resistor, and a twelfth resistor;
the grid electrode of the third MOSFET is connected to the second LED control signal output end of the MC U of the electric screwdriver through the eighth resistor, the source electrode of the third MOSFET is connected to the common ground terminal, and the drain electrode of the third MOSFET is connected to the negative electrode of the second LED of the electric screwdriver through the fourth resistor;
a first end of the second bidirectional voltage stabilizing diode is connected between the grid of the third MOSFET and the eighth resistor, and a second end of the second bidirectional voltage stabilizing diode is connected to the common ground terminal;
a first end of the twelfth resistor is connected between the gate of the third MOSFET and the eighth resistor, and a second end of the twelfth resistor is connected to the common ground.
7. The charging circuit of the electric screwdriver according to claim 1, further comprising an LED power supply electronic circuit, wherein the LED power supply electronic circuit comprises a second magnetic bead, a third magnetic bead and a third bidirectional voltage regulator diode;
a first end of the second magnetic bead is connected to an internal working voltage, and a second end of the second magnetic bead is connected to the anode of the LED of the electric screwdriver;
the first end of the third magnetic bead is connected to the grounding end of the Type-C connector of the electric screwdriver, and the second end of the third magnetic bead is connected to the common grounding end;
the first end of the third bidirectional voltage stabilizing diode is connected to the second end of the second magnetic bead, and the second end of the third bidirectional voltage stabilizing diode is connected to the common ground end.
8. The charging circuit of the electric screwdriver according to claim 1, further comprising an electrostatic protection sub-circuit, the electrostatic protection sub-circuit comprising a first magnetic bead;
the first end of the first magnetic bead is connected to the source electrode of the first MOSFET, and the second end of the first magnetic bead is connected between the first voltage end and the second voltage end of the Type-C connector of the electric screwdriver.
9. The charging circuit of the electric screwdriver according to claim 1, further comprising a first capacitor and a second capacitor;
a first end of the first capacitor is connected to a power supply voltage, and a second end of the first capacitor is connected to the common ground terminal;
and the first end of the second capacitor is connected with a power supply voltage, and the second end of the second capacitor is connected to the common ground terminal.
10. An electric screwdriver, characterized in that it comprises a charging circuit of an electric screwdriver according to any one of claims 1 to 9.
CN202110482428.4A 2021-04-30 2021-04-30 Electric screwdriver and charging circuit thereof Active CN113054723B (en)

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Application Number Priority Date Filing Date Title
CN202110482428.4A CN113054723B (en) 2021-04-30 2021-04-30 Electric screwdriver and charging circuit thereof

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Application Number Priority Date Filing Date Title
CN202110482428.4A CN113054723B (en) 2021-04-30 2021-04-30 Electric screwdriver and charging circuit thereof

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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201886052U (en) * 2010-12-10 2011-06-29 威胜集团有限公司 Split-type single-phase electric energy meter
CN202042887U (en) * 2011-05-03 2011-11-16 深圳Tcl新技术有限公司 Charging input overvoltage protecting circuit
CN103167663A (en) * 2011-12-09 2013-06-19 鸿富锦精密工业（深圳）有限公司 Light-emitting diode (LED) control circuit
CN103390883A (en) * 2013-06-28 2013-11-13 惠州市蓝微电子有限公司 Lithium battery charging protection circuit
CN207910527U (en) * 2018-02-28 2018-09-25 深圳市安特信技术有限公司 A kind of charging circuit and charging unit
CN208589916U (en) * 2018-08-30 2019-03-08 宇能电气有限公司 It is a kind of with overvoltage protection and it is anti-sparking function dc power interface circuit
JP3227594U (en) * 2020-06-03 2020-09-03 東莞市福洋電子有限公司 Charger output protection device
CN212726525U (en) * 2020-08-12 2021-03-16 北京一雄信息科技有限公司 Automobile diagnostic instrument with charging function

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN201886052U (en) * 2010-12-10 2011-06-29 威胜集团有限公司 Split-type single-phase electric energy meter
CN202042887U (en) * 2011-05-03 2011-11-16 深圳Tcl新技术有限公司 Charging input overvoltage protecting circuit
CN103167663A (en) * 2011-12-09 2013-06-19 鸿富锦精密工业（深圳）有限公司 Light-emitting diode (LED) control circuit
CN103390883A (en) * 2013-06-28 2013-11-13 惠州市蓝微电子有限公司 Lithium battery charging protection circuit
CN207910527U (en) * 2018-02-28 2018-09-25 深圳市安特信技术有限公司 A kind of charging circuit and charging unit
CN208589916U (en) * 2018-08-30 2019-03-08 宇能电气有限公司 It is a kind of with overvoltage protection and it is anti-sparking function dc power interface circuit
JP3227594U (en) * 2020-06-03 2020-09-03 東莞市福洋電子有限公司 Charger output protection device
CN212726525U (en) * 2020-08-12 2021-03-16 北京一雄信息科技有限公司 Automobile diagnostic instrument with charging function

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