CN207339355U - It is a kind of that there is the phone charger for automatically powering off defencive function - Google Patents

Abstract

It is a kind of that there is the phone charger for automatically powering off defencive function; it includes input terminal; input terminal is connected with rectification circuit; rectification circuit is connected with high pressure absorbing circuit; the primary side winding of high pressure absorbing circuit and transformer connects; the secondary windings of transformer is connected with control circuit, and control circuit is connected with output terminal.It is a kind of device that high voltage is converted into low-voltage by transformer that the utility model, which can solve phone charger, do not pulled out for a long time if charger is placed on wiring board, even if charger does not connect mobile phone, but its internal circuit board leads to electricity, it is still within working status, meeting persistent fever, so as to accelerate the aging of device and material, like this easily cause short circuit or high-voltage breakdown, so as to trigger the technical problem of fire hazard.

Description

It is a kind of that there is the phone charger for automatically powering off defencive function

Technical field

Cable semi-conductive shield layer resistivity measurement experiment is the utility model is related to, more particularly to one kind has and automatically powers off The phone charger of defencive function.

Background technology

With the arrival of information age, people become increasingly dependent on mobile phone, will fill electric several times, desk, bed with daily Charger has been ready for charge on the socket of head, and usually mobile phone charges the habit that electricity does not all pull out charger to most people It is used.Phone charger is a kind of device that high voltage is converted into low-voltage by transformer, if charger is placed on wiring board Upper long-time is not pulled out, even if charger does not connect mobile phone, but its internal circuit board leads to electricity, it is still within work State, meeting persistent fever, so as to accelerate the aging of device and material, like this easily causes short circuit or high-voltage breakdown, from And trigger fire hazard, and in actual life, such accident is commonplace.For this problem, phone charger is added Defencive function is automatically powered off to be particularly important.

The content of the invention

In view of the above-mentioned problems, the utility model provides a kind of phone charger for having and automatically powering off defencive function, its energy It is a kind of device that high voltage is converted into low-voltage by transformer to solve phone charger, if charger is placed on wiring board Upper long-time is not pulled out, even if charger does not connect mobile phone, but its internal circuit board leads to electricity, it is still within work State, meeting persistent fever, so as to accelerate the aging of device and material, like this easily causes short circuit or high-voltage breakdown, from And trigger the technical problem of fire hazard.

To solve the above-mentioned problems, the technical solution of the utility model is：

A kind of to have the phone charger for automatically powering off defencive function, it includes input terminal, and input terminal connects with rectification circuit Connect, rectification circuit is connected with high pressure absorbing circuit, the primary side winding connection of high pressure absorbing circuit and transformer, the secondary of transformer Winding is connected with control circuit, and control circuit is connected with output terminal.

The primary side winding both ends of above-mentioned transformer are connected with sample circuit, positive-feedback circuit respectively.

Above-mentioned rectification circuit includes diode D1, resistance R1 and capacitance C1, and diode D1 is halfwave rectifier diode.

Above-mentioned high pressure absorbing circuit includes resistance R3, capacitance C2 and diode D2.

Above-mentioned sample circuit includes resistance R4, capacitance C3, triode Q2, diode D4 and diode D5, and resistance R4 is Sample resistance.

Above-mentioned positive-feedback circuit includes resistance R5 and diode D6.

The iron core of above-mentioned transformer is high frequency ferrite core.

Above-mentioned control circuit includes detection circuit, and detection circuit includes power supply, relay K2 and diode D6.

Above-mentioned control circuit includes photodiode DL, diode D8 and relay K1.

The beneficial effects of the utility model are：

1）The utility model can detect whether to have accessed mobile phone by detection circuit for access, pass through control circuit and control two Relay is cut-off, and makes charger in the case where not accessing mobile phone, electrically disconnected with city, is ensured safety；

2）By setting detection circuit for access and control circuit, cut-offfing for relay is controlled, charger is not being accessed hand It is electrically disconnected with city in the case of machine, ensure safety；

3）One 10 ohm of resistance is added in 220V incoming ends and is used for overcurrent protection, if the problems such as breaking down below is led Cause overcurrent, then this resistance will be blown, so as to avoid the failure for causing bigger；

4）By adding sample circuit, limitation prevents that electric current is excessive and burns by the electric current of switching tube Q1.

Brief description of the drawings

The utility model is described further below in conjunction with the accompanying drawings：

Fig. 1 is the circuit diagram of the utility model；

Fig. 2 is the circuit diagram of control circuit in the utility model.

Embodiment

As shown in Figure 1, a kind of have the phone charger for automatically powering off defencive function, D1, R1, C1 together constitute one D1 halfwave rectifier is passed through in rectification circuit, input terminal input 220V alternating currents, one end, and the other end is filtered after R1 by C1.Its In, small resistor R1（10 ohm）For overcurrent protection, if the problems such as breaking down below causes overcurrent, then this resistance will It is blown, so as to avoid the failure for causing bigger.R3, C2, the D2 on the right together constitute a high pressure absorbing circuit, work as switch When pipe Q1 is turned off, which is responsible for the induced voltage on absorbing coil, so as to prevent high pressure to be added on Q1 and cause it to hit Wear.The wherein pressure-resistant 400V of switching tube MJE13003, maximum collector currnt 1.5A, maximum collector power consumption is 14W, for controlling Switching between primary side winding and power supply, when primary side winding ceaselessly break-make, will form change in switch transformer Magnetic field, so as to produce induced voltage in secondary windings.The R2 of left end provides the base stage of startup to switching tube to start resistance Electric current.R4, C3, Q2, D3, D4, D5 below switching tube MJE13003 together constitute sample circuit, R4（10 ohm）For sampling Resistance, becomes voltage (its value is 10*I), this voltage adds to the base stage of triode Q2 after diode D3 after electric current is sampled On, when sampling voltage is approximately greater than 1.4V, i.e., switch tube current is more than 0.14A, Q2 is turned on, and drags down the base voltage of Q1, from And collector current reduces, the electric current of switch is so limited, prevents that electric current is excessive and burns.The sampling of transformer lower left The rectified diode D4 rectifications of induced voltage of winding, form sampling voltage after 22uF capacitor filterings, when output voltage is excessive, take Sample voltage make it that zener diode D5 is breakdown, drags down the base potential of Q1, so that cause Q1 to disconnect or postpone the conducting of switch, And then control energy input into transformer, that is, the rise of output voltage is controlled, realizes the function of voltage stabilizing output.Lower section C4, R5 together constitute positive-feedback circuit, the partial circuit from sampling winding in take out induced voltage, be added to the base of switching tube On extremely, to maintain to vibrate.D6, C5 on the right of winding together constitute secondary winding circuit, and induced voltage is through Schottky diode After D6 rectifications, C5 filtering, the voltage of 6V is exported.Wherein, because the working frequency of Switching Power Supply is higher, Schottky two is selected Pole pipe, and the consideration high equally based on frequency, transformer is it is necessary that with high frequency switch transformer, iron core is generally high-frequency iron oxygen Body magnetic core, has high resistivity, to reduce vortex, so select E6 high frequency magnetic cores.The common structure of 5V power supplys, K2, D6 on right side Into detection circuit for access, mobile phone access charger, partial circuit conducting, LED light is bright, which is arranged in control circuit Near photodiode DL.

As shown in Fig. 2, control circuit part is collectively formed by DL, D8 and two relays, wherein K1 is normally opened, and K2 is normal Close.When mobile phone is not attached to charger, K1 is disconnected, and K2 closures, even if charger is inserted on socket, its charging circuit part does not have yet Have access alternating current, so will not operational heat, make device aging.And when mobile phone is connected on charger, detection circuit for access is led Logical, LED light is bright, its light sent is received by photodiode, and control circuit conducting, is opened to close so that K1 relay status becomes, K2 relay status, which becomes, to be closed to open, and the charging circuit of charger is partially ON, and detection circuit for access disconnects, but LED light this moment Power without 5V power supplys, but powered by the output voltage of charger, so lamp is still bright, K1 is kept closed, and K2 is protected Hold off-state.And when mobile phone is unplugged, right side circuit disconnects, and LED light is extinguished because losing power supply, so that light in control circuit Quick diode is in high-impedance state, and K1 recovers off-state, and K2 recovers closure state, and charging circuit is electrically disconnected with city again.

Using the above structure, in use, the utility model can detect whether to have accessed mobile phone by detection circuit for access, lead to Cut-offfing for control circuit two relays of control is crossed, makes charger in the case where not accessing mobile phone, it is electrically disconnected with city, ensure peace Entirely.

Claims (9)

1. a kind of have the phone charger for automatically powering off defencive function, it is characterised in that：It includes input terminal, input terminal with it is whole Current circuit connects, and rectification circuit is connected with high pressure absorbing circuit, the primary side winding connection of high pressure absorbing circuit and transformer, transformation The secondary windings of device is connected with control circuit, and control circuit is connected with output terminal.

It is 2. according to claim 1 a kind of with the phone charger for automatically powering off defencive function, it is characterised in that：It is described The primary side winding both ends of transformer are connected with sample circuit, positive-feedback circuit respectively.

It is 3. according to claim 1 or 2 a kind of with the phone charger for automatically powering off defencive function, it is characterised in that： The rectification circuit includes diode D1, resistance R1 and capacitance C1, and diode D1 is halfwave rectifier diode.

It is 4. according to claim 1 or 2 a kind of with the phone charger for automatically powering off defencive function, it is characterised in that： The high pressure absorbing circuit includes resistance R3, capacitance C2 and diode D2.

It is 5. according to claim 2 a kind of with the phone charger for automatically powering off defencive function, it is characterised in that：It is described Sample circuit includes resistance R4, capacitance C3, triode Q2, diode D4 and diode D5, and resistance R4 is sample resistance.

It is 6. according to claim 2 a kind of with the phone charger for automatically powering off defencive function, it is characterised in that：It is described Positive-feedback circuit includes resistance R5 and diode D6.

It is 7. according to claim 1 a kind of with the phone charger for automatically powering off defencive function, it is characterised in that：It is described The iron core of transformer is high frequency ferrite core.

It is 8. according to claim 1 a kind of with the phone charger for automatically powering off defencive function, it is characterised in that：It is described Control circuit includes detection circuit, and detection circuit includes power supply, relay K2 and diode D6.

It is 9. according to claim 8 a kind of with the phone charger for automatically powering off defencive function, it is characterised in that：It is described Control circuit includes photodiode DL, diode D8 and relay K1.