CN100574042C - Charge and discharge control device - Google Patents

Abstract

A charge and discharge control device has a selector, a charging circuit and at least two battery pack circuits. The selector has a controller, when the voltage output to the controller is greater than the predetermined voltage, the controller makes the charge and discharge control signal at a first level, and when the voltage output to the controller is not greater than the predetermined voltage, the controller makes the charge and discharge control signal at a second level and a discharge switch is turned on. Each battery pack circuit is provided with a first switch and a second switch which are connected in series, a battery and a switch controller. When the switch controller receives the charge-discharge control signal of the first level, the first switch is conducted and the second switch becomes an ideal diode, and at the moment, the charging circuit charges the battery. When the switch controller receives the charge-discharge control signal of the second level, the first switch becomes an ideal diode and the second switch is conducted, and at the moment, the battery supplies power to the load system.

Description

Charge and discharge control device

technical field

The invention relates to a charging and discharging control device which can be used to control charging and discharging of a battery pack circuit. More particularly, the present invention relates to a charge and discharge control device capable of reducing cost and improving charge and discharge efficiency.

Background technique

The application of portable devices has become one of the trends of electronic products. For example, a portable device may be a digital camera, notebook computer, personal digital assistant (PDA), or mobile phone. The battery pack has also become an important power supply component of these portable devices. In order to prolong the service time, two battery packs are usually used in parallel, so a device that can control the charging and discharging of the two battery packs is needed.

FIG. 1 is a functional block diagram illustrating a conventional charging and discharging control device, which can control charging and discharging of a battery pack circuit. In FIG. 1, the AC/DC converter 100 is coupled to the selector 150 via the charging circuit 101, so as to select to charge and discharge the first battery pack circuit 120 or the second battery pack circuit 130, and the first battery pack circuit 120 and the second battery pack circuit 130 can also supply power to the load system 199 via the DC/DC converter 135 through the selector 150 . And the selector 150 has eight transistors 160 , 165 , 170 , 175 , 180 , 185 , 190 and 195 . Usually, two transistors are connected in series with opposite directions to form a switch to achieve a completely off state, which can effectively isolate the interference between different charging and discharging paths. Wherein, the transistor 160 and the transistor 165 form a first switch, which is controlled by the control signal C11. The transistor 170 and the transistor 175 form a second switch, which is controlled by the control signal C12. The transistor 180 and the transistor 185 form a third switch, which is controlled by the control signal C13. The transistor 190 and the transistor 195 form a fourth switch, which is controlled by the control signal C14. Therefore, the charging and discharging paths of the first battery pack circuit 120 are respectively controlled by the first switch and the third switch, while the charging and discharging paths of the second battery pack circuit 130 are respectively controlled by the second switch and the fourth switch.

The control signals C11 , C12 , C13 and C14 can be controlled by the control module 155 in the selector 150 . For example, when the first battery pack circuit 120 is to be charged, the control signal C11 turns on the first switch to charge the first battery pack circuit 120 . When the second battery pack circuit 130 is to be discharged, the control signal C14 turns on the fourth switch, so that the second battery pack circuit 130 is discharged.

FIG. 2 is a functional block diagram illustrating a conventional battery pack circuit. In the first battery pack circuit 120 , the battery connector 260 is coupled to the selector 150 , and the switch 271 is coupled to the battery connector 260 in series with the switch 272 , and the switch 272 is coupled to the battery 290 . The switch 271 and the switch 272 are respectively coupled to the protection controller 280, and the switch 271 is turned on or off by the first protection controller signal 266, and the switch 272 is turned on or off by the second protection controller signal 268. . The conduction or disconnection of the switch 271 and the switch 272 will control the charging and discharging of the battery 290 .

FIG. 3 is a functional block diagram illustrating another conventional charging and discharging control device. This figure is roughly the same as the existing charge and discharge control device of FIG. 1 (please also refer to FIG. 1), the difference is that the selector 350 uses six transistors 360, 365, 370, 375, 380 and 390, and six independent The control signals C31 , C32 , C33 , C34 , C35 and C36 form four switches to control the charging and discharging paths of the first battery pack circuit 120 and the second battery pack circuit 130 respectively. Wherein, the transistor 360 and the transistor 365 are switches constituting the charging path of the first battery pack circuit 120, and are respectively controlled by the control signal C31 and the control signal C35. The transistor 370 and the transistor 375 are switches constituting the charging path of the second battery pack circuit 130 , and are controlled by a control signal C32 and a control signal C36 respectively. The transistor 380 and the transistor 365 are switches constituting the discharge path of the first battery pack circuit 120 and are controlled by the control signal C33 and the control signal C35 respectively. The transistor 390 and the transistor 375 are switches constituting the discharge path of the second battery pack circuit 130 , and are controlled by the control signal C34 and the control signal C36 respectively.

The control signals C31 , C32 , C33 , C34 , C35 and C36 can be controlled by the control module 355 in the selector 350 . It is worth noting that, as can be seen from the comparison between FIG. 3 and FIG. 1, transistor 165 and transistor 185 in FIG. 1 are simplified to transistor 365 in FIG. 3, and transistor 175 and transistor 195 in FIG. of transistor 375 .

To sum up, the current selector circuit includes too many transistors, which will lead to high cost and affect the efficiency of charging and discharging. Moreover, in the current design of battery pack circuits, when two sets of battery pack circuits with different potentials are coupled to the same selector to charge and discharge at the same time, the efficiency of charging and discharging will decrease because the two sets of battery pack circuits with different potentials cannot be effectively isolated. However, if the two sets of battery pack circuits with different potentials are effectively isolated during charging and discharging, the low potential battery pack circuits are charged first when charging, and then the two sets of battery pack circuit potentials are charged simultaneously when the potentials of the two sets of battery pack circuits are the same. And when discharging, the high-potential battery circuit is discharged first, and when the potentials of the two battery circuits are the same, the two battery circuits are discharged at the same time, so that the efficiency of charging and discharging can be improved. Therefore, there is an urgent need for a selector circuit with fewer transistors and a design that can effectively isolate two sets of battery pack circuits with different potentials during charging and discharging, so as to reduce costs and improve charging and discharging efficiency.

Contents of the invention

Therefore, the object of the present invention is to propose a charging and discharging control device with fewer transistors.

Another object of the present invention is to provide a charging and discharging control device capable of effectively isolating two sets of battery pack circuits with different voltages during charging and discharging.

Another object of the present invention is to provide a charging and discharging control device for portable devices, so as to reduce costs and improve charging and discharging efficiency.

According to the above purpose, the present invention proposes a charging and discharging control device, including a selector, a charging circuit, and at least two battery pack circuits. Wherein, the selector includes a controller. When the voltage output to the controller is greater than a predetermined voltage, the controller will make the charge and discharge control signal at the first level, and when the voltage output to the controller is not greater than the predetermined voltage, the controller will The charge and discharge control signal is at the second level; and the discharge switch is turned on when the voltage output to the controller is not greater than a predetermined voltage. And each battery pack circuit includes a first switch and a second switch connected in series; a battery; and a switch controller. When the switch controller receives the charge and discharge control signal of the first level, it will turn on the first switch and make the second switch an ideal diode, and the charging circuit will charge the battery at this time; and when the switch controller receives the first level When the two-level charge and discharge control signal is used, the first switch becomes an ideal diode and the second switch is turned on. At this time, the battery discharges the load system through the discharge switch.

Description of drawings

In order to make the above and other objects, features, advantages and embodiments of the present invention more comprehensible, the detailed description of the accompanying drawings is as follows.

FIG. 1 is a functional block diagram illustrating a conventional charging and discharging control device;

FIG. 2 is a functional block diagram illustrating an existing battery pack circuit;

FIG. 3 is a functional block diagram illustrating another existing charging and discharging control device;

4 is a functional block diagram illustrating a charging and discharging control device according to a preferred embodiment of the present invention;

FIG. 5 is a detailed flowchart illustrating charging and discharging according to a preferred embodiment of the present invention;

6 is a functional block diagram illustrating the charging operation of the charging and discharging control device according to a preferred embodiment of the present invention;

7 is a functional block diagram illustrating the discharge operation of the charge and discharge control device according to a preferred embodiment of the present invention; and

FIG. 8 is a detailed circuit diagram of a switch controller according to a preferred embodiment of the present invention.

Description of reference symbols

C11, C12, C13, C14, C31, C32, C33, C34, C35, C36, C41, C42, C43: control signal

40: Charge and discharge control device

100: AC/DC Converter

101: charging circuit

120, 520: the first battery pack circuit

130, 530: the second battery pack circuit

135: DC/DC Converter

150, 350, 450, 550: selector

155, 355, 455: control module

160, 165, 170, 175, 180, 185, 190, 195, 360, 365, 370, 375, 380, 390, 460, 465, 470, 475, 480: field effect transistor

199: Loading System

260, 560, 760: battery connector

266: First protection controller signal

268: Second protection controller signal

271, 571, 771: switch

272, 572, 772: switch

290, 590, 790: battery

510: Controller

511: Transistor

515: discharge switch

505, 517, 518: endpoints

570: switch controller

595, 795: Protection controllers

1010, 1020: ideal diode

602-638: Steps

1040: First emitter follower

1045: Second emitter follower

1050: first logic circuit

1055: second logic circuit

1060: Inverting circuit

Detailed ways

Please refer to FIG. 4 , which is a functional block diagram of a charging and discharging control device 40 according to a preferred embodiment of the present invention. The charging and discharging control device 40 includes a selector 550 , a charging circuit 101 , a first battery pack circuit 520 , and a second battery pack circuit 530 . Wherein, the selector 550 includes a controller 510 and a discharge switch 515 , and the selector 550 is coupled to the AC/DC converter 100 and the DC/DC converter 135 . In addition, the DC/DC converter 135 is coupled to the load system 199 .

Next, how the charging and discharging control device 40 performs the charging and discharging operation will be described. FIG. 6 is a functional block diagram illustrating the charging operation of the charging and discharging control device 40 according to a preferred embodiment of the present invention. Please refer to FIG. 4 and FIG. 6 at the same time. The charging operation principle of the charging and discharging control device 40 is described as follows. When an external power source is connected, the external power source converts the AC power into a DC power through the AC/DC converter 100 to generate a voltage of VA at the terminal 505 . When the voltage of VA is greater than a predetermined voltage (for example, 17.2 volts), the transistor 511 in the controller 510 will be turned on, and a high level (High) charge and discharge control signal (CHG/DIS#=1) will be generated at the terminal 517 ). Then, the high-level charge-discharge control signal (CHG/DIS#=1) is sent to the first battery pack circuit 520 and the second battery pack circuit 530 . When the charging protection signal (CHG#) sent by the protection controllers 595 and 795 is low level (CHG#=0), if the voltage of the battery 790 is greater than the voltage of the battery 590, and the voltage of the terminal 518 is greater than or equal to the voltage of the battery 590 voltage, the charging circuit 101 will charge the battery 590 . Next, when the voltage of the battery 590 is charged to be the same as the voltage of the battery 790, if the voltage of the terminal 518 is greater than or equal to the voltage of the batteries 590 and 790, the charging circuit 101 will simultaneously charge the batteries 590 and 790; due to ideal Diode (the switch 572 in the first battery pack circuit 520 and the switch 772 in the second battery pack circuit 530 both become ideal diodes), so it can be charged in parallel without the battery pack circuit with higher voltage flowing to the battery pack circuit with lower voltage Low battery pack circuit problem. Afterwards, if the charging protection signal (CHG#) sent by the protection controllers 595 and 795 becomes a high level (CHG#=1) (for example, when the temperature of the battery is too high, or the voltage of the battery is too high, etc.), then Charging will end.

Since the structure of the first battery pack circuit 520 is identical to that of the second battery pack circuit 530 , the charging circuit 101 charges the first battery pack circuit 520 for illustration. When the first battery pack circuit 520 receives a high-level charge-discharge control signal (CHG/DIS#=1), the high-level charge-discharge control signal (CHG/DIS#=1) will pass through the battery connector 560 and sent to the switch controller 570 . Switch controller 570 turns on switch 571 and makes switch 572 an ideal diode, as shown in FIG. 6 . When the charging protection signal (CHG#) sent by the protection controller 595 is at a low level (CHG#=0), if the voltage of the terminal 518 is greater than or equal to the voltage of the battery 590, the charging circuit 101 will pass through the battery connector 560 and switch 572 to charge the battery 590 . When the charging protection signal generated by the protection controller 595 becomes high level (CHG#=1), the switch 571 becomes an ideal diode, while the switch 572 remains an ideal diode. Since the switches 571 and 572 form ideal diodes connected back to back, the charging circuit 101 will not charge the battery 590 any more. The truth table in the switch controller 570 for the above charging operation can be expressed as Table 1 below.

Table 1

Charge and discharge control signal (CHG/DIS#) Charging protection signal (CHG#) Discharge protection serial number (DIS#) switch 571 switch 572 1 0 x ON ideal diode The charging circuit 101 charges the battery 590 via the switch 572 1 1 x ideal diode ideal diode Do not allow charging of battery 590

FIG. 7 is a functional block diagram illustrating the discharge operation of the charge and discharge control device 40 according to a preferred embodiment of the present invention. Please refer to FIG. 4 and FIG. 7 at the same time, the operation principle of the discharge of the charge and discharge control device 40 is described as follows. When the voltage of VA is not greater than the predetermined voltage (for example, 17.2 volts) (such as no external power supply), the transistor 511 will be turned off and the discharge switch 515 will be turned on, so the charge and discharge control signal (CHG/DIS#) will be activated by the controller 510 The resistor R45 in the ground is at low level (CHG/DIS#=0). Then, the low-level charge-discharge control signal (CHG/DIS#=0) is sent to the first battery pack circuit 520 and the second battery pack circuit 530 . When the discharge protection signal (DIS#) sent by the protection controller 595 and 795 is low level (DIS#=0), if the voltage of the battery 590 is greater than the voltage of the battery 790, and the voltage of the terminal 518 is less than or equal to the voltage of the battery 590 voltage, the battery 590 will discharge the load system 199 through the battery connector 560 , the discharge switch 515 and the DC/DC converter 135 . Next, when the voltage of the battery 590 is equal to the voltage of the battery 790 due to discharge, if the voltage of the terminal 518 is less than or equal to the voltages of the batteries 590 and 790, the battery 590 and the battery 790 will simultaneously discharge the load system 199; Ideal diodes (the transistor 571 in the first battery pack circuit 520 and the transistor 771 in the second battery pack circuit 530 both become ideal diodes), so they can be discharged in parallel without the battery pack circuit with higher voltage flowing to the voltage A problem with the lower battery pack circuit. Afterwards, if the discharge protection signal (DIS#) sent by the protection controllers 595 and 795 becomes a high level (DIS#=1) (for example, the temperature of the battery is too high, or the voltage of the battery is too low, etc.), The discharge will end.

Since the structure of the first battery pack circuit 520 is identical to that of the second battery pack circuit 530 , the discharge of the load system 199 by the first battery pack circuit 520 is used for illustration. When the first battery pack circuit 520 receives a low-level charge-discharge control signal (CHG/DIS#=0), the low-level charge-discharge control signal (CHG/DIS#=0) will pass through the battery connector 560 and sent to the switch controller 570 . Switch controller 570 makes switch 571 an ideal diode and turns switch 572 on, as shown in FIG. 7 . When the discharge protection signal (DIS#) sent by the protection controller 595 is low level (DIS#=0), if the voltage of the terminal 518 is less than or equal to the voltage of the battery 590, the battery 590 will be connected via the switch 571 and the battery. The device 560, the discharge switch 515, and the DC/DC converter 135 discharge the load system 199. When the switch controller 570 generates a discharge protection signal (DIS#=1), the switch 572 becomes an ideal diode, while the switch 571 remains an ideal diode. Since the switches 571 and 572 form ideal diodes connected back to back, the battery 590 no longer discharges the load system 199 . The truth table in the switch controller 570 for the above discharge operation can be expressed as Table 2 below.

Table 2

Charge and discharge control signal (CHG/DIS#) Charging Protection Signal (CHG#) Discharge protection signal (DIS#) switch 571 switch 572 0 x 0 ideal diode ON The battery 590 discharges the load system 199 via the switch 571 0 x 1 ideal ideal two Do not allow battery 590 to discharge

diode pole tube electricity

As can be seen from the above, compared with the existing selector (please refer to FIG. 1 and FIG. 3 ), the selector 550 of the present invention uses fewer transistors than the existing selector, so the efficiency loss during charging and discharging can be reduced.

Furthermore, as can be seen from the above-mentioned Fig. 6 and Fig. 7, when the remaining battery potentials of the battery pack circuits are different, the charging and discharging control device 40 of the present invention can charge the battery pack circuit with a lower residual battery potential first until the two battery packs When the remaining battery potentials of the circuit are the same, they are charged together again. In this way, two sets of battery pack circuits with different potentials can be effectively isolated to improve charging efficiency. Similarly, the charging and discharging control device of the present invention can also discharge the battery pack circuit with higher residual battery potential first, and then discharge together when the remaining battery potentials of the two battery pack circuits are the same. In this way, two sets of battery pack circuits with different potentials can be effectively isolated to improve discharge efficiency.

Next, please refer to FIG. 5 (please refer to FIG. 6 and FIG. 7 at the same time), which is a detailed flowchart illustrating charging and discharging according to a preferred embodiment of the present invention.

In FIG. 5 , it is first determined whether the voltage at the terminal 505 is greater than a predetermined voltage (for example, 17.2V) (step 602 ). If the voltage at the terminal 505 is greater than the predetermined voltage, the charging and discharging control signal is at a high level (CHG/DIS#=1), and the charging mode operation will be performed at this time (step 604 ). Next, it is judged whether the charging protection signal (CHG#) of the first battery pack circuit 520 is low level (step 606), and whether the charging protection signal (CHG#) of the second battery pack circuit 530 is low level (step 608). Afterwards, if the charging protection signal (CHG#) of the first battery pack circuit 520 is low level (CHG#=0), it will be judged whether the voltage of the terminal 518 is greater than or equal to the voltage of the battery 590 (step 610); When the charging protection signal (CHG#) of the second battery pack circuit 530 is low level (CHG#=0), it is determined whether the voltage of the terminal 518 is greater than or equal to the voltage of the battery 790 (step 612 ). Then, if the voltage of terminal 518 is greater than or equal to the voltage of battery 590, then charging circuit 101 will charge battery 590 (step 614); and if the voltage of terminal 518 is greater than or equal to the voltage of battery 790, then charging circuit 101 will be charged to battery 790 charging (step 616). In addition, if the charging protection signal (CHG#) of the first battery pack circuit 520 is at a high level (CHG#=1), or if the voltage of the terminal 518 is lower than the voltage of the battery 590, the battery 590 will not be charged or discharged ( Step 618). And if the charging protection signal (CHG#) of the second battery pack circuit 530 is a high level (CHG#=1), or if the voltage of the terminal 518 is less than the voltage of the battery 790, then the battery 790 will not charge or discharge (step 620).

And if the voltage at the terminal 505 is not greater than the predetermined voltage (for example, 17.2V), the charge and discharge control signal is at low level (CHG/DIS#=0), and the operation of the discharge mode will be performed at this time (step 622 ). Next, it is judged whether the discharge protection signal (DIS#) of the first battery pack circuit 520 is low level (step 624), and whether the discharge protection signal (DIS#) of the second battery pack circuit 530 is low level (step 626). Afterwards, if the discharge protection signal (DIS#) of the first battery pack circuit 520 is low level (DIS#=0), it will be judged whether the voltage of the terminal 518 is less than or equal to the voltage of the battery 590 (step 628); When the discharge protection signal (DIS#) of the second battery pack circuit 530 is low (DIS#=0), it is determined whether the voltage of the terminal 518 is less than or equal to the voltage of the battery 790 (step 630). Then, if the voltage of the terminal 518 is less than or equal to the voltage of the battery 590, the battery 590 will discharge the load system 199 (step 632); 199 discharges (step 634). In addition, if the discharge protection signal (DIS#) of the first battery pack circuit 520 is high level (DIS#=1), or if the voltage of the terminal 518 is greater than the voltage of the battery 590, the battery 590 will not be charged or discharged ( Step 636). And if the discharge protection signal (DIS#) of the second battery pack circuit 530 is a high level (DIS#=1), or if the voltage of the terminal 518 is greater than the voltage of the battery 790, then the battery 790 will not charge or discharge (step 638).

FIG. 8 is a detailed circuit diagram of the switch controller 570 in FIG. 4 . It can be seen from FIG. 8 that the switch controller 570 includes an ideal diode circuit 1010, an ideal diode circuit 1020, a first emitter follower 1040, a second emitter follower 1045, a first logic circuit 1050, a second logic circuit 1055, and an inverter. phase circuit 1060. Wherein, the purpose of the first emitter follower 1040 is to increase the output current capability to speed up the turn-on and turn-off of the transistor 571 . Likewise, the purpose of the second emitter follower 1045 is to increase the output current capability to speed up the turn-on and turn-off of the transistor 572 . The inverting circuit 1060 is used to invert the charging and discharging control signal, that is, CHG/DIS# is inverted into CHG#/DIS.

According to the first logic circuit 1050 and Table 1, when the charge and discharge control signal is at a high level (CHG/DIS#=1) and the charging protection signal is at a low level (CHG#=0), the switch 571 is turned on, And the switch 572 will become an ideal diode, and it will perform charging operation at this time. And when the charging and discharging control signal is high level (CHG/DIS#=1) and the charging protection signal is high level (CHG#=1), both switch 571 and switch 572 will become ideal diodes, and charging will stop at this time operate.

According to the second logic circuit 1055 and Table 2, when the charge and discharge control signal is low level (CHG/DIS#=0) and the discharge protection signal is low level (DIS#=0), the switch 572 will be turned on, And the switch 571 will become an ideal diode, and will perform discharge operation at this time. And when the charge and discharge control signal is low level (CHG/DIS#=0) and the discharge protection signal is high level (DIS#=1), both the switch 571 and the switch 572 will become ideal diodes, and the discharge will stop at this time operate.

Although the present invention has been disclosed above with a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art can make various modifications and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be defined by the scope of the appended patent application.

Claims (11)

1. a charge-discharge controller comprises a selector, a charging circuit and at least two battery circuits, wherein:

This selector comprises

One controller, when the voltage that exports this controller to during greater than a predetermined voltage, this controller can make one to discharge and recharge control signal and be in one first level, and when the voltage that exports this controller to is not more than this predetermined voltage, and this controller can make this discharge and recharge control signal to be in one second level; And

One discharge switch, when the voltage that exports this controller to is not more than this predetermined voltage, this discharge switch meeting conducting;

This charging circuit is coupled to this selector; And

These at least two battery circuits be coupled to this controller and this charging circuit and receive that this controller produces this discharge and recharge control signal, wherein, each those battery circuit comprises:

One first switch and a second switch connect in the mode of connecting;

One battery is coupled to second switch; And

One on-off controller, be coupled to this first switch and this second switch and this battery, when this that receives this first level discharges and recharges control signal, can make this first switch conduction and make this second switch become ideal diode, this moment, this charging circuit can be to this battery charge, when this that receives this second level discharges and recharges control signal, can make this first switch become ideal diode and make this second switch conducting; This moment, this battery can discharge to a load system via this discharge switch.

2. charge-discharge controller as claimed in claim 1, wherein, when this that receives this first level discharges and recharges control signal, and the voltage of this battery separately in those battery circuits is not simultaneously, this battery charge that this charging circuit is can be to the voltage in those battery circuits minimum.

3. charge-discharge controller as claimed in claim 1, wherein, when this that receives this first level discharges and recharges control signal, and the voltage of this battery separately in those battery circuits is when identical, and this charging circuit can be simultaneously to each those battery charge in those battery circuits.

4. charge-discharge controller as claimed in claim 1, wherein, each those battery circuit more comprises:

One protection controller; be coupled to this on-off controller, when being in a particular case, can export a charge protection signal to this on-off controller; make this first switch and this second switch form the back-to-back ideal diode that is connected, and this charging circuit is stopped this battery charge.

5. charge-discharge controller as claimed in claim 4, wherein, this particular case comprises the overtension of too high or this battery of the temperature of this battery.

6. charge-discharge controller as claimed in claim 1, wherein, this first level is a high level.

7. charge-discharge controller as claimed in claim 1, wherein, when this that receives this second level discharged and recharged control signal, if the voltage of this battery separately in those battery circuits is not simultaneously, this battery that the voltage in those battery circuits is the highest can be to this load system discharge.

8. charge-discharge controller as claimed in claim 1, wherein, when this that receives this second level discharged and recharged control signal, if when the voltage of this battery separately in those battery circuits is identical, those batteries of each in those battery circuits can be simultaneously to this load system discharge.

9. charge-discharge controller as claimed in claim 1, wherein, each those battery circuit more comprises:

One protection controller; be coupled to this on-off controller, when being in a particular case, can export a discharge prevention signal to this on-off controller; make this first switch and this second switch form the back-to-back ideal diode that is connected, and this battery is stopped this load system discharge.

10. charge-discharge controller as claimed in claim 9, wherein, this particular case comprises the brownout of too high or this battery of the temperature of this battery.

11. charge-discharge controller as claimed in claim 1, wherein, this second level is a low level.

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