Self-protection switch tube control circuit, drive circuit and life electric appliance

Abstract

The utility model discloses a self-protection switch tube control circuit, a drive circuit and a life electric appliance, which relate to the technical field of life electric appliance drive circuits and comprise a switch tube Q1, a signal source T1, a capacitor C1 and a capacitor C2. The signal source T1, the capacitor C1 and the capacitor C2 are connected in sequence; the capacitor C2 is also connected with the control electrode of the switch tube Q1, so that the capacitor C2 can provide starting voltage for the control electrode of the switch tube Q1 after being charged; when the signal source T1 outputs a square wave signal to the capacitor C1, the capacitor C1 can charge the capacitor C2, so that the capacitor C2 can provide starting voltage for the control electrode of the switching tube Q1; when the signal source T1 outputs a level signal to the capacitor C1, the capacitor C1 can cut off the level signal. The utility model mainly solves the problem of how to provide a drive circuit with a self-protection function based on a field effect transistor. According to the utility model, a self-protection function is provided for the control circuit and the drive circuit, the switch tube can be effectively prevented from being driven by a wrong signal source, and the safety of life electric appliances in use is improved.

Description

Technical Field

[0001] The utility model relates to the technical field of driving circuits for household appliances, in particular to a self-protection switch tube control circuit, a driving circuit and a household appliance. Background Art

[0002] Field effect transistor (Metal-Oxide-Semiconductor Field-Effect Transistor, MOSFET) is a basic electronic component with a wide variety of uses. One important use is as a switching device and power control device for DC electrical appliances (such as heating elements, motors and lighting devices). Specifically, a field effect transistor is set in a DC circuit, and the on-off and duty cycle of the field effect transistor are controlled by signals, thereby controlling the switching and power of the DC electrical appliances.

[0003] Essential oil combs, aroma diffusers, aromatherapy machines, hair dryers, curling irons, electric thermos cups, electric thermal sleeves, heating fans and hand warmers are all commonly used household appliances, and are all equipped with heating elements (some essential oil combs, aroma diffusers and aromatherapy machines use heating elements to achieve the atomization of essential oils), thereby achieving the effects of atomization, evaporation, hairdressing, heating and insulation.

[0004] However, when the signal source of the field effect tube fails, the signal source may continue to output a certain level signal (that is, continue to output a high level signal or a low level signal). At this time, the field effect tube may remain in the on state, and the DC electrical appliances in the same DC circuit as the field effect tube will continue to run. If the DC electrical appliances are heating elements, it will cause a series of problems such as overheating, damage, and even fire in the household appliances.

[0005] In summary, how to provide a driving circuit with a self-protection function based on a field effect transistor has become one of the problems to be solved urgently. Utility Model Content

[0006] The purpose of the utility model is to provide a self-protection switch tube control circuit, a drive circuit and a household appliance, which have a self-protection function and can effectively prevent the switch tube from being driven by an erroneous signal source.

[0007] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a self-protection switch tube control circuit, comprising a switch tube Q1, a signal source T1, a capacitor C1 and a capacitor C2; the signal source T1, the capacitor C1 and the capacitor C2 are connected in sequence; the capacitor C2 is also connected to the control electrode of the switch tube Q1, so that the capacitor C2 can provide a turn-on voltage for the control electrode of the switch tube Q1 after being charged; when the signal source T1 outputs a square wave signal to the capacitor C1, the capacitor C1 can charge the capacitor C2, so that the capacitor C2 can provide a turn-on voltage for the control electrode of the switch tube Q1; when the signal source T1 outputs a level signal to the capacitor C1, the capacitor C1 can cut off the level signal.

[0008] In the above technical scheme, the self-protection switch tube control circuit of the utility model also includes a matching resistor R1 and a matching resistor R2; the matching resistor R1 is connected in series with the matching resistor R2 and then connected in parallel with the capacitor C2, and one end of the matching resistor R2 and one end of the capacitor C2 are both connected to the GND end, and the control electrode of the switch tube Q1 is connected to the middle node between the matching resistor R1 and the matching resistor R2.

[0009] In the above technical solution, the self-protection switch tube control circuit of the utility model further includes a diode D1; the anode of the diode D1 is connected to the capacitor C1, and the cathode of the diode D1 is connected to the capacitor C2.

[0010] In the above technical solution, the self-protection switch tube control circuit of the utility model further includes a diode D2; the anode of the diode D2 is connected to the GND terminal, and the cathode of the diode D2 is connected to the capacitor C1.

[0011] A driving circuit comprises the above-mentioned self-protection switch tube control circuit.

[0012] In the above technical solution, the driving circuit of the utility model further includes an electrical appliance; the VCC terminal, the electrical appliance, the first electrode of the switch tube Q1, the second electrode of the switch tube Q1 and the GND terminal are connected in sequence.

[0013] In the above technical solution, the driving circuit of the utility model further includes a fuse F1; the fuse F1 is connected between the VCC terminal and the electrical appliance.

[0014] In the above technical solution, the electrical appliance is one of a heating element, a motor and a lighting device.

[0015] In the above technical solution, the switch tube Q1 is a field effect tube, the first electrode of the switch tube Q1 is a drain, the second electrode of the switch tube Q1 is a source, and the control electrode of the switch tube Q1 is a gate.

[0016] A household appliance comprises the above-mentioned driving circuit.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: in the self-protection switch tube control circuit, drive circuit and household appliance of the present invention, when the signal source T1 outputs a square wave signal to the capacitor C1, the capacitor C1 can charge the capacitor C2, so that the capacitor C2 can provide a turn-on voltage for the control electrode of the switch tube Q1; when the signal source T1 outputs a level signal to the capacitor C1, the capacitor C1 can cut off the level signal; in this way, a self-protection function is provided for the control circuit and the drive circuit, which can effectively prevent the switch tube from being driven by an erroneous signal source, thereby improving the safety of the household appliance during use. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a circuit schematic diagram of the utility model. DETAILED DESCRIPTION

[0019] 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.

[0020] This embodiment provides a self-protection switch tube control circuit, which can at least be applied in a drive circuit based on a switch tube and can at least control the on and off of the switch tube.

[0021] See also Figure 1 The self-protection switch tube control circuit of this embodiment includes a switch tube Q1, a signal source T1, a capacitor C1 and a capacitor C2.

[0022] Among them, the signal source T1 can come from MCU such as a single-chip microcomputer, a digital processing chip (DSP) and an embedded chip, or from special equipment such as a programmable controller (PLC) and an industrial computer, or from a signal generating circuit based on a digital chip; in this embodiment, the signal source T1 comes from a single-chip microcomputer.

[0023] The signal source T1, the capacitor C1 and the capacitor C2 are connected in sequence, and the capacitor C2 is also connected to the control electrode of the switch tube Q1, so that the capacitor C2 can provide a turn-on voltage for the control electrode of the switch tube Q1 after being charged; when the signal source T1 outputs a square wave signal to the capacitor C1, the capacitor C1 can charge the capacitor C2, so that the capacitor C2 can provide a turn-on voltage for the control electrode of the switch tube Q1; when the signal source T1 outputs a level signal to the capacitor C1, the capacitor C1 can cut off the level signal.

[0024] Specifically, the self-protection switch tube control circuit of this embodiment also includes a matching resistor R1 and a matching resistor R2; the matching resistor R1 is connected in series with the matching resistor R2 and then connected in parallel with the capacitor C2, and one end of the matching resistor R2 and one end of the capacitor C2 are both connected to the GND end, and the control electrode of the switch tube Q1 is connected to the middle node between the matching resistor R1 and the matching resistor R2; in this way, a suitable turn-on voltage can be provided for the control electrode of the switch tube Q1.

[0025] More specifically, the self-protection switch tube control circuit of this embodiment also includes a diode D1; the anode of the diode D1 is connected to the capacitor C1, and the cathode of the diode D1 is connected to the capacitor C2; through the diode D1, the capacitor C2 can be prevented from outputting reverse current to the capacitor C1.

[0026] More specifically, the self-protection switch tube control circuit of this embodiment also includes a diode D2; the anode of the diode D2 is connected to the GND terminal, and the cathode of the diode D2 is connected to the capacitor C1; through the diode D2, the capacitor C1 can be prevented from outputting reverse current to the capacitor C2 and / or the GND terminal.

[0027] This embodiment also provides a driving circuit, which includes the above-mentioned self-protection switch tube control circuit.

[0028] See also Figure 1 The driving circuit of this embodiment also includes an electrical appliance; the VCC terminal, the electrical appliance, the first electrode of the switch tube Q1, the second electrode of the switch tube Q1 and the GND terminal are connected in sequence.

[0029] It should be noted that, in this embodiment, the VCC terminal and the GND terminal are provided by a lithium battery; in other embodiments, the VCC terminal and the GND terminal may be provided by a power adapter.

[0030] Furthermore, the drive circuit of this embodiment also includes a fuse F1, which is connected between the VCC terminal and the electrical appliance; the fuse F1 is configured to be blown when the electrical appliance is over-current, over-voltage or over-temperature to protect the switch tube Q1 and the entire drive circuit.

[0031] Specifically, the electrical appliance is one of a heating element, a motor and a lighting device. In this embodiment, the electrical appliance is a heating element Heat1, which is specifically a DC heating element.

[0032] Specifically, the switch tube Q1 is a field effect tube, the first electrode of the switch tube Q1 is a drain, the second electrode of the switch tube Q1 is a source, and the control electrode of the switch tube Q1 is a gate.

[0033] When the driving circuit of this embodiment is in normal operation, the signal source T1 outputs a square wave signal to the capacitor C1. Since the square wave signal is time-varying, the capacitor C1 can couple the electric energy to the capacitor C2. After the capacitor C2 is charged, it can provide a turn-on voltage between the control electrode and the GND terminal of the switch tube Q1. The turn-on voltage should be greater than the threshold voltage (Gate-sourcethreshold voltage, VGS) of the switch tube Q1, so that the switch tube Q1 enters the on state. The VCC terminal, the fuse F1, the electrical appliance, the first electrode of the switch tube Q1, the second electrode of the switch tube Q1 and the GND terminal form a loop, and the electrical appliance (the heating element Heat1 in this embodiment) can operate normally to provide heat for household appliances such as essential oil combs, aromatherapy diffusers, aromatherapy machines, hair dryers, curling irons, electric thermos cups, electric thermos sleeves, heating fans and hand warmers.

[0034] When the signal source T1 outputs a level signal (either a high level signal or a low level signal) to the capacitor C1 due to a fault (such as MCU abnormality, program error, pin damage, etc.), the capacitor C1 can cut off the level signal because the level signal does not have a time-varying property; at this time, the voltage across the capacitor C2 is very small and is not enough to turn on the switch tube Q1, and the electrical appliance will not operate, thereby effectively protecting the entire drive circuit.

[0035] This embodiment also provides a household appliance, which includes the above-mentioned driving circuit.

[0036] In the self-protection switch tube control circuit, drive circuit and household appliance of this embodiment, when the signal source T1 outputs a square wave signal to the capacitor C1, the capacitor C1 can charge the capacitor C2, so that the capacitor C2 can provide a turn-on voltage for the control electrode of the switch tube Q1; when the signal source T1 outputs a level signal to the capacitor C1, the capacitor C1 can cut off the level signal; in this way, a self-protection function is provided for the control circuit and the drive circuit, which can effectively prevent the switch tube from being driven by an erroneous signal source, thereby improving the safety of the household appliance during use.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A self-protection switch tube control circuit, characterized in that: It includes a switch tube Q1, a signal source T1, a capacitor C1 and a capacitor C2; The signal source T1, the capacitor C1 and the capacitor C2 are connected in sequence; The capacitor C2 is also connected to the control electrode of the switch tube Q1, so that the capacitor C2 can provide a turn-on voltage for the control electrode of the switch tube Q1 after being charged; When the signal source T1 outputs a square wave signal to the capacitor C1, the capacitor C1 can charge the capacitor C2, so that the capacitor C2 can provide a turn-on voltage for the control electrode of the switch tube Q1; When the signal source T1 outputs a level signal to the capacitor C1, the capacitor C1 can cut off the level signal.

2. The self-protection switch tube control circuit according to claim 1, characterized in that: Also includes a matching resistor R1 and a matching resistor R2; The matching resistor R1 is connected in series with the matching resistor R2 and then connected in parallel with the capacitor C2, and one end of the matching resistor R2 and one end of the capacitor C2 are both connected to the GND end, and the control electrode of the switch tube Q1 is connected to the middle node between the matching resistor R1 and the matching resistor R2.

3. The self-protection switch tube control circuit according to claim 2, characterized in that: Also includes a diode D1; An anode of the diode D1 is connected to the capacitor C1 , and a cathode of the diode D1 is connected to the capacitor C2 .

4. The self-protection switch tube control circuit according to claim 2 or 3, characterized in that: Also includes a diode D2; The anode of the diode D2 is connected to the GND terminal, and the cathode of the diode D2 is connected to the capacitor C1.

5. A driving circuit, characterized in that: It comprises the self-protection switch tube control circuit as described in any one of claims 1-4.

6. The driving circuit according to claim 5, characterized in that: It also includes electrical appliances; The VCC terminal, the electrical appliance, the first electrode of the switch tube Q1, the second electrode of the switch tube Q1 and the GND terminal are connected in sequence.

7. The driving circuit according to claim 6, characterized in that: Also includes fuse F1; The fuse F1 is connected between the VCC terminal and the electrical appliance.

8. The driving circuit according to claim 6, characterized in that: The electrical appliance is one of a heating element, a motor and a lighting device.

9. The driving circuit according to claim 5 or 6, characterized in that: The switch tube Q1 is a field effect tube, the first electrode of the switch tube Q1 is a drain, the second electrode of the switch tube Q1 is a source, and the control electrode of the switch tube Q1 is a gate.

10. A household appliance, characterized in that: The driving circuit comprises any one of claims 5-9.

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