CN2794011Y

CN2794011Y - Charging circuit

Info

Publication number: CN2794011Y
Application number: CN 200520041457
Authority: CN
Inventors: 杨景翔
Original assignee: Shanghai Huanda Computer Technology Co Ltd; Mitac International Corp
Current assignee: Shanghai Huanda Computer Technology Co Ltd; Mitac International Corp
Priority date: 2005-05-12
Filing date: 2005-05-12
Publication date: 2006-07-05
Anticipated expiration: 2015-05-12

Abstract

The utility model relates to a charging circuit which is a circuit capable of changing the charging current intensity of a device to be charged according to the voltage drop intensity of an alternating current adapter, and the circuit comprises an automatic detecting circuit, wherein the automatic detecting circuit switches over the circuit by detecting the voltage drop intensity of an alternating current adapter. The automatic detecting circuit is coupled with a resistor circuit which is additionally coupled with a control circuit, the input end of the control circuit is coupled with the resistor circuit, the charging end of the control circuit is connected with a device to be charged, and the energy delivering end of the control circuit is used for controlling the control circuit to operate or not to operate. When in charging, the total resistance values of the resistor circuit connected with the input end of the control circuit are different by following the voltage drop change of the automatic detecting circuit so as to make the control circuit change the intensity of electric current delivered to the device to be charged by following the change of the resistance values. Thereby, the utility model enhances the availability ratio of the alternating current adapter, and effectively finishes charging for the device to be charged in a short time.

Description

Charging circuit

Technical field

The utility model is about a kind of charging circuit, especially the control circuit about regulating the charging current size.

Background technology

The seat formula charger of electronic product such as mobile phone or PDA(Personal Digital Assistant) generally can be given the charging of main frame and rechargeable battery simultaneously, as shown in Figure 1, alternating current (AC) offers charger 2 by exchanging adapter 1, thereby give main frame 3 and rechargeable battery 4 chargings, and the charging current that offers main frame 3 and rechargeable battery 4 is relevant with interchange adapter 1 capacity, and it is big more that the big more charging current summation that can provide of adapter 1 capacity is provided.

In the prior art, under the situation that exchanges adapter 1 finite capacity, make the charging current that offers rechargeable battery 4 remain on a less preset value usually, thereby offer main frame 3 one big charging currents, to guarantee main frame 3 effectively charging fast.In such cases, because it is less to offer the charging current of rechargeable battery 4, it is longer to cause it to be full of the required time of electricity.

Another kind of situation is the capacity that increases adapter 1, makes the charging current that offers main frame 3 and rechargeable battery 4 all bigger, reduces the charging interval, but can increase adapter 1 manufacturing cost.

And under above-mentioned two kinds of situations, do not insert charger 2 charging when main frame 3 is in, insert charger 2 chargings when not starting shooting, inserting charger 2 chargings and starting shooting three kinds of different conditions, although it is different that charger 2 offers the charging current of main frame 3, but it is constant that the charging current size that offers rechargeable battery 4 remains at a preset value, so, then can not adjust the charging current size that offers rechargeable battery 4 according to different situations in good time, the utilance that the old friend flows adapter 1 is not high.

Summary of the invention

The utility model main purpose provides a kind of charging circuit, and this charging circuit can be adjusted the charging current size that it is exported automatically according to the difference that exchanges the adapter voltage drop.

The technical scheme that the utility model adopted is as follows for achieving the above object: this charging circuit is according to the voltage drop size that exchanges adapter, and the charging current size of device to be charged is supplied with in change, wherein this charging circuit comprises: an Auto-Sensing circuit, and it switches by detecing top-cross stream adapter voltage drop carrying out circuit; One resistance circuit, it couples mutually with this Auto-Sensing circuit; One control circuit, it comprises input, activation end and charging end, and this input links to each other with the output of this resistance circuit, and this charging end is connected to described device to be charged, and whether this activation end couples an activation device, be used to control this control circuit and operate.

During this charging circuit running, detecting exchanges the adapter voltage drop, this Auto-Sensing circuit carries out circuit according to this voltage drop size and switches, and causes the resistance change that is connected to the control circuit input, thereby the charging current that causes offering this device to be charged changes.

After adopting technical solutions of the utility model, can regulate the charging current size that offers device to be charged, treat the charging device charging, effectively improve interchange adapter utilance in the shortest time, effectively to finish according to exchanging adapter voltage drop difference.

Description of drawings

Below in conjunction with most preferred embodiment and accompanying drawing the utility model is described in further detail.

Fig. 1 is a prior art charging principle rough schematic.

Fig. 2 is the utility model charging circuit schematic diagram.

Fig. 3 is the utility model first embodiment circuit diagram.

Fig. 4 is the utility model second embodiment circuit diagram.

Embodiment

The charging circuit of the utility model can offer device charging current size to be charged and change according to the voltage drop size that exchanges adapter, and this device to be charged is a rechargeable battery in the present embodiment.

As shown in Figure 2, this charging circuit comprises: an Auto-Sensing circuit 10, and it is used for detecting and exchanges the adapter voltage drop; One resistance circuit 20 that couples mutually with this Auto-Sensing circuit 10; One control circuit 30 that couples mutually with this resistance circuit 20, exchanging adapter 1 provides part voltage (V) in this control circuit 30, in order to giving device to be charged (rechargeable battery) 304 chargings, and this control circuit 30 to offer the charging current size of device to be charged (rechargeable battery) 304 relevant with the total resistance value size of resistance circuit 20.Along with the change that exchanges adapter 1 voltage drop, Auto-Sensing circuit 10 carries out circuit and switches, the resistance value of resistance circuit 20 outputs is varied in size, cause the resistance value difference that is connected to control circuit 30, thereby the charging current that causes offering device to be charged (rechargeable battery) 304 varies in size.

Below describe index map 3 physical circuit of the utility model first specific embodiment in detail.

In this embodiment, when exchanging adapter 1 voltage and equal 5 volts of rated voltages, the charging current summation that main frame and device to be charged (rechargeable battery) 304 are described is less than exchanging adapter 1 capacity, it is lower to exchange adapter 1 utilance, when exchanging adapter 1 voltage drop less than 4.7 volts of rated voltages, the charging current summation that main frame and device to be charged (rechargeable battery) 304 are described exchanges adapter 1 and utilizes height near exchanging adapter 1 capacity, and state has almost reached capacity.

Be provided with comparator 101 in the described Auto-Sensing circuit 10, electric capacity 102 and field effect transistor 103, these comparator 101 1 inputs (in the present embodiment promptly anodal) with exchange adapter 1 and couple, exchange adapter 1 voltage drop with detecting, another input (being negative pole in the present embodiment) is connected to 4.7 volts voltage, comparator 101 outputs are coupled with resistance R 3, in the present embodiment, the characteristic of this comparator 101 is: when anodal input voltage is come in and gone out voltage greater than negative pole, its output is equivalent to unsettled, anodal input voltage is during less than the negative pole input voltage, and its output is equivalent to ground connection.These electric capacity 102 1 end ground connection, the other end also connects a lifting resistance R 4 and comparator 101 output resistance R 3, promote resistance R 4 booster tensions in the present embodiment and reduce to 1 voltage drop of interchange adapter, and should promote the resistance value of the resistance value of resistance R 4, so that electric capacity 102 can slowly charge, repid discharge much larger than resistance R 3.These field effect transistor 103 grids (G) couple with electric capacity 102 unearthed ends, source electrode (S) ground connection, this field effect transistor 103 is an insulation lock field effect transistor in the present embodiment, the characteristic of this insulation lock field effect transistor is: grid (G) and source electrode (S) are when voltage difference reaches certain value, conducting between drain electrode (D) and the source electrode (S), and along with grid (G) and source electrode (S) voltage difference increase, resistance value reduces gradually between drain electrode (D) and the source electrode (S), until approaching zero.

This resistance circuit 20 is drawn together first resistance R 1 and second resistance R 2, wherein field effect transistor 103 drain electrodes (D) couple in first resistance R, 1 one ends and the Auto-Sensing circuit 10, the other end and second resistance R, 2 one ends also connect the output 201 that the back forms resistance circuit, these second resistance R, 2 other end ground connection.

This control circuit 30 comprises input 301, activation end 302 and charging end 303, and wherein input 301 links to each other with resistance circuit 20 outputs 201, and charging end 303 is connected to described device to be charged (rechargeable battery) 304, and this activation end 302 couples a power supply 40.The characteristic of this control circuit 30 is: it can operate when activation end 302 was high potential, and, this moment, its charging current size that can offer device to be charged (rechargeable battery) 304 was relevant with 301 connecting resistance values of its input, also promptly relevant in the present embodiment with the total resistance value of resistance circuit 20, this total resistance value is big more, charging current is more little, otherwise charging current is big more.

When charger carried out work, control circuit 30 activation ends 302 coupled a power supply, are high potentials, and this control circuit 30 can operate, and promptly can give device to be charged (rechargeable battery) 304 chargings.

At this moment, comparator 101 detectings exchange adapter 1 voltage drop, when voltage drop reaches 5 volts, resistance R 3 is equivalent to vacant state, exchanging adapter 1 voltage drop slowly charges for electric capacity 102, field effect transistor 103 grid voltages increase gradually, after a period of time, field effect transistor 103 conductings, conducting between its drain electrode and the source electrode, and resistance reduces gradually between drain electrode and source electrode, and this moment control circuit 30 inputs 301 connecting resistances be field effect transistor 103 drain electrodes with source electrode between resistance with after first resistance R 1 is connected again with second resistance R, 2 sums in parallel, so 301 connecting resistance values of control circuit 30 inputs reduce gradually, according to the characteristic of control circuit 30, the charging current that then can offer rechargeable battery 304 increases gradually.

Along with the charging current that offers device to be charged (rechargeable battery) 304 increases gradually, it is more and more higher to exchange adapter 1 utilance, it is then more and more lower to exchange adapter 1 voltage drop, when 1 voltage drop of comparator 101 detecting interchange adapters drops to 4.7 volts, resistance R 3 is equivalent to ground connection, electric capacity 102 repid discharges, field effect transistor 103 grid voltages descend fast, field effect transistor 103 not conductings, then control circuit 30 inputs institute connecting resistance value is second resistance R, 2 resistance value sizes, promptly 301 connecting resistance values of control circuit 30 inputs this moment increase, and charging current that control circuit provides reduces.

Figure 4 shows that another specific embodiment circuit diagram of the utility model, this charging circuit also comprises Auto-Sensing circuit 10, resistance circuit 20, control circuit 30, and in the resistance circuit 20, control circuit 30 institute to comprise assembly, inter-module annexation and performance etc. all as above routine described, do not giving unnecessary details at this, different is is to change the field effect transistor in the Auto-Sensing circuit 10 103 into transistor 103 ' in the present embodiment, and the unearthed end of this transistor 103 ' base stage and electric capacity 102 couples, collector electrode links to each other grounded emitter with first resistance R 1.In the present embodiment, used transistor is a NPN transistor, and this kind transistor turns characteristic and field effect transistor on state characteristic are basic identical, are not described in detail the operation principle of circuit shown in Figure 4 at this.

After adopting technical solutions of the utility model, can not increase under interchange adapter 1 capacity situation, automatically adjust the charging current that offers device to be charged (rechargeable battery) 304 according to exchanging adapter 1 present state of living in, make interchange adapter 1 utilance keep almost saturated state all the time, in the shortest time, effectively to finish charging.

The above person only is the utility model preferred embodiment wherein, is not to be used for limiting practical range of the present utility model; Be that all equalizations of doing according to the utility model change and modification, be all the utility model scope of patent protection and contain.

Claims

1, a kind of charging circuit mainly is according to the voltage drop size that exchanges adapter, and changes the size of current of supplying with device to be charged, it is characterized in that this circuit comprises:

One Auto-Sensing circuit, it switches by detecing top-cross stream adapter voltage drop carrying out circuit;

One resistance circuit, it couples mutually with this Auto-Sensing circuit;

One control circuit, it comprises input, activation end and charging end, and this input links to each other with the output of this resistance circuit, and this charging end is connected to described device to be charged, and whether this activation end couples an activation device, be used to control this control circuit and operate;

Detecting exchanges the adapter voltage drop, and this Auto-Sensing circuit carries out circuit according to this voltage drop size and switches, and causes the resistance change that is connected to the control circuit input, thereby the charging current that causes offering this device to be charged changes.

2, charging circuit according to claim 1, it is characterized in that: described Auto-Sensing circuit comprises comparator, electric capacity and field effect transistor, wherein this comparator one input with exchange adapter and couple, exchange the voltage drop of adapter with detecting, another input couples a size and exchanges the voltage drop equal voltage of adapter utilance when the highest, this comparator output terminal is connected to resistance (R3), this electric capacity one end ground connection, the other end also connects a lifting resistance (R4) and a resistance (R3), the unearthed end of this fet gate and electric capacity couples, its source ground.

3, as charging circuit as described in the claim 2, it is characterized in that: described resistance circuit comprises first resistance (R1) and second resistance (R2), the field effect transistor drain electrode couples mutually in this first resistance (R1) end and the Auto-Sensing circuit, its other end and second resistance (R2) end couple the output that the back forms resistance circuit, this second resistance (R2) other end ground connection.

4, as charging circuit as described in the claim 2, it is characterized in that: described Auto-Sensing circuit comprises comparator, electric capacity and transistor, wherein this comparator one input with exchange adapter and couple, exchange the adapter voltage drop with detecting, another input couples a size and exchanges the voltage drop equal voltage of adapter utilance when the highest, comparator output terminal is connected to resistance (R3), this electric capacity one end ground connection, the other end also connects a lifting resistance (R4) and a resistance (R3), this transistor base couples its grounded emitter mutually with the unearthed end of electric capacity.

5, as charging circuit as described in the claim 4, it is characterized in that: described resistance circuit comprises first resistance (R1) and second resistance (R2), transistor collector couples in this first resistance (R1) end and the Auto-Sensing circuit, its other end and second resistance (R2) end couple the output that the back forms resistance circuit, this second resistance (R2) other end ground connection.

6, as charging circuit as described in the claim 2,3,4 or 5, it is characterized in that: the booster tension of described lifting resistance (R4) is reduced to and is exchanged the adapter voltage drop.

7, as charging circuit as described in the claim 2,3,4 or 5, it is characterized in that: described lifting resistance (R4) resistance value is much larger than the resistance value of resistance (R3).

8, as charging circuit as described in the claim 1,2,3,4 or 5, it is characterized in that: the activation end of described control circuit couples a power supply.