COMPRISING THE SAME

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to and benefits of Chinese Patent Application

No. 201020122605.5, filed with the State Intellectual Property Office of the People's Republic of China (SIPO) on February 27, 2010, the entire content of which is hereby incorporated by reference. FIELD

The disclosure relates to a power supply, more particularly to a reverse connection protecting device and a backup power supply comprising the same.

BACKGROUND

Continuous power supplying is very important for many electronic equipments such as communication systems, internet servers, etc. When a power supply interruption occurs, a backup power supply has to be activated for protecting the circuit of the equipments. Therefore, the power supplying for protecting the circuit is especially important. Conventionally, a high-voltage reverse connection protecting diode, a transient voltage suppressor (TVS) or a fuse is used for protecting the circuit when the power supply is reversely connected. However, if the fuse is broken, it must be replaced. Therefore, the maintenance is inconvenient.

SUMMARY

According to an embodiment of the present disclosure, a reverse connection protecting device for a backup power supply is provided, comprising: a charging and discharging interface defining first and second lead-in ends, and first and second lead-out ends corresponding to the first and second lead-in ends respectively, in which the second lead-in end is adapted to couple to a negative electrode of a secondary battery of the backup power supply, and the second lead-out end is adapted to couple to a negative electrode of a load and a negative electrode of an external power supply; a battery control module coupled to the first lead-in end of the charging and discharging interface and adapted to couple to a positive electrode of the secondary battery for controlling the charging or discharging of the secondary battery; a switch unit adapted to be coupled between the first lead-out end and a positive electrode of the load as well as a positive electrode of the external power supply; a switch control module coupled to the switch unit for controlling the switch unit according to voltages of the first and second lead-out ends of the charging and discharging interface; and an activation module adapted to couple to the battery control module, the load and the external power supply respectively for activating the battery control module after the external power supply is powered on and disconnected when any one of the load, the secondary battery and the external power supply is reversely connected.

According to another embodiment of the present disclosure, a backup power supply is provided, comprising: a secondary battery and a reverse connection protecting device. The reverse connection protecting device comprises: a charging and discharging interface defining first and second lead-in ends, and first and second lead-out ends corresponding to the first and second lead-in ends respectively, in which the second lead-in end is adapted to couple to a negative electrode of a secondary battery, and the second lead-out end is adapted to couple to a negative electrode of a load and a negative electrode of an external power supply; a battery control module coupled to the first lead-in end of the charging and discharging interface and adapted to couple to a positive electrode of the secondary battery for controlling the charging or discharging of the secondary battery; a switch unit adapted to be coupled between the first lead-out end and a positive electrode of the load as well as a positive electrode of the external power supply; a switch control module coupled to the switch unit for controlling the switch unit according to voltages of the first and second lead-out ends of the charging and discharging interface; and an activation module adapted to couple to the battery control module, the load and the external power supply respectively for activating the battery control module after the external power supply is powered on and disconnected when any one of the load, the secondary battery and the external power supply is reversely connected.

With the embodiments of the present disclosure, the secondary battery, the battery control module, the charging and discharging interface, the external power supply and the load constitute a main charging and discharging circuit. The battery control module may be activated by the activation module independent of the main charging and discharging circuit, and whether the main charging and discharging circuit is inversely connected is determined by the switch control module according to the voltage output from the charging and discharging interface, so as to control the turning on and turning off of the main circuit of the backup power supply by the switch unit, thus controlling turning on and turning off of the secondary battery and the main charging and discharging circuit. When the main charging and discharging circuit is inversely connected, the main charging and discharging circuit is turned off, thus preventing the inverse connection of the main charging and discharging circuit (that is, at least one of the secondary battery, the external power supply and the load is inversely connected). The reverse connection protecting device and the backup power supply having the same according to embodiments of the present disclosure are simple in structure and low in cost.

Additional aspects and advantages of the embodiments of the present disclosure will be given in part in the following descriptions, become apparent in part from the following descriptions, or be learned from the practice of the embodiments of the present disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects and advantages of the disclosure will become apparent and more readily appreciated from the following descriptions taken in conjunction with the drawings in which:

Fig. 1 is a structural diagram of a backup power supply according to an embodiment of the present disclosure;

Fig. 2 is a structural diagram of a backup power supply according to another embodiment of the present disclosure; and

Fig. 3 is a detailed circuit diagram of the battery control module shown in Fig. 2.

DETAILED DESCRIPTION

Reference will be made in detail to embodiments of the present disclosure. The embodiments described herein with reference to the accompany drawings are explanatory and illustrative, which are used to generally understand the present disclosure. The embodiments shall not be construed to limit the present disclosure. The same or similar elements and the elements having same or similar functions are denoted by like reference numerals throughout the descriptions.

Referring to Figs. 1 -3, Fig. 1 is a structural diagram of a backup power supply according to an embodiment of the present disclosure; Fig. 2 is a structural diagram of a backup power supply according to another embodiment of the present disclosure; and Fig. 3 is a detailed circuit diagram of the activation module shown in Fig. 2.

As shown in Figs.1 to 3, in some embodiments, a reverse connection protecting device may be used in electronic devices having a backup power supply. The electronic equipments may be powered by the external power supply or the backup power supply.

In one embodiment, a reverse connection protecting device comprises a charging and discharging interface 2 for the charging or discharging of the secondary battery 1 , a battery control module 7 for controlling the charging or discharging of the secondary battery 1 , an activation module 8 for activating the battery control module 7, a switch unit 5, and a switch control module 6 coupled to the switch unit 5. The charging and discharging interface 2 comprises first and second lead-in ends, and first and second lead-out ends corresponding to the first and second lead-in ends respectively, in which the second lead-in end is coupled to a negative electrode (B-) of the secondary battery 1 , and the second lead-out end is coupled to a negative electrode of a load 4 and a negative electrode of an external power supply 3. The battery control module 7 is coupled to the first lead-in end of the charging and discharging interface 2 and a positive electrode (B+) of the secondary battery 1 for controlling the charging or discharging of the secondary battery 1. The switch unit 5 is coupled between the first lead-out end of the charging and discharging interface 2 and a positive electrode of the load 4 as well as a positive electrode of the external power supply 3. The switch control module 6 is coupled to the switch unit 5 for controlling the switch unit 5 according to voltages of the first and second lead-out ends of the charging and discharging interface 2. The switch control module 6 determines whether to switch on the switch unit 5 according to voltages of the first and second lead-out ends of the charging and discharging interface 2. The activation module 8 is coupled to the battery control module 7, the load 4 and the external power supply 3 respectively for activating the battery control module 7 after the external power supply 3 is powered on and for turning off the activation module 8 when any one of the load 4, the secondary battery 1 and the external power supply 3 is reversely connected.

In embodiments of the present disclosure, the secondary battery 1 , the battery control module 7, the charging and discharging interface 2, the external power supply 3 and the load 4 constitute the main charging and discharging circuit.

As shown in Figs. 2-3, the power interface 2 may be a four-terminal interface defining two lead-in ends and two lead-out ends. The switch unit 5 may be a normally open switch.

As shown in Fig. 2, the activation module 8 comprises an activation terminal 83, a lightning protection circuit 82, a voltage stabilizing and reverse connection protecting circuit 81 and an optical coupler U. The activation terminal 83 is adapted to couple to the load 4 and the external power supply 3 respectively. The lightning protection circuit 82 is coupled to the activation terminal 83. The voltage stabilizing and reverse connection protecting circuit 81 is coupled to the lightning protection circuit 82 and disconnected when any one of the load 4, the secondary battery 1 and the external power supply 3 is reversely connected. First and second input ends of the optical coupler U are coupled to the voltage stabilizing and reverse connection protecting circuit 81 respectively, and an output end of the optical coupler U is coupled to the battery control module 7.

In one embodiment, the activation terminal 83 is an anti-mistake activation terminal. In one embodiment, the lightning protection circuit 82 comprises a first capacitor C1 , a second capacitor C2, a first current-limiting resistor R1 , a second current-limiting resistor R2, a first magnetic bead L1 and a second magnetic bead L2. One end of the first capacitor C1 is coupled to one end of the activation terminal 83. The second capacitor C2 is connected to the first capacitor C1 in series, one end of the second capacitor C2 is coupled to the other end of the activation terminal 83, and a connection point between the first capacitor C1 and the second capacitor C2 is grounded. One end of the first current-limiting resistor R1 is coupled to the one end of the activation terminal 83, and one end of the second current-limiting resistor R2 is coupled to the other end of the activation terminal 83. The first magnetic bead L1 is coupled to the other end of the first current-limiting resistor R1 , and the second magnetic bead L2 is coupled to the other end of the second current-limiting resistor R2. In one embodiment, the lightning protection circuit 82 further comprises a third capacitor C3 connected to the series connected first and second capacitors C1 , C2 in parallel.

In one embodiment, the voltage stabilizing and reverse connection protecting circuit 81 comprises a first diode D having a cathode coupled to the first magnetic bead L1 of the lightning protection circuit 82 and an anode coupled to the first input end of the optical coupler U.

In one embodiment, the voltage stabilizing and reverse connection protecting circuit 81 further comprises a zener diode ZD having an anode coupled to the second input end of the optical coupler U and a cathode coupled to the second magnetic bead L2 of the lightning protection circuit 82.

The battery control module comprises a first field effect transistor (FET) Q1 , a second field effect transistor Q2, series connected third resistor R3 and fourth resistor R4, series connected fifth resistor R5 and sixth resistor R6, a third field effect transistor Q3, a fourth field effect transistor Q4 and a single chip microcomputer U1 . A source of the first field effect transistor Q1 is coupled to the first lead-in end. A drain of the second field effect transistor Q2 is coupled to a drain of the first field effect transistor Q1 , and a source of the second field effect transistor Q2 is adapted to couple to the positive electrode of the secondary battery 1 . A non-common terminal of the third resistor R3 is coupled to the first lead-in end, and a common terminal of the third resistor R3 and the fourth resistor R4 is coupled to a gate of the first field effect transistor Q1 . A non-common terminal of the fifth resistor R5 is adapted to couple to the positive electrode of the secondary battery 1 , and a common terminal of the fifth resistor R5 and the sixth resistor R6 is coupled to a gate of the second field effect transistor Q2. A source of the third field effect transistor Q3 is coupled to a non-common terminal of the fourth resistor R4, and a drain of the third field effect transistor Q3 is grounded. A source of the fourth field effect transistor Q4 is coupled to a non-common terminal of the sixth resistor R6, and a drain of the fourth field effect transistor Q4 is grounded. An input terminal of the single chip microcomputer U1 is coupled to the activation module 8, and an output terminal of the single chip microcomputer U1 is coupled to gates of the third field effect transistor Q3 and the fourth field effect transistor Q4 respectively. In one embodiment, the battery control module 7 further comprises: a seventh resistor R7 coupled between the drain and the gate of the third field effect transistor Q3; and an eighth resistor R8 coupled between the drain and the gate of the fourth field effect transistor Q4.

In one embodiment, the battery control module 7 further comprises third to sixth diodes in inverse parallel connection to the first field effect transistor Q1 , the second field effect transistor Q2, the third field effect transistor Q3 and the fourth field effect transistor Q4 respectively.

In one embodiment, the first field effect transistor Q1 and the second field effect transistor Q2 are P-type, and the third field effect transistor Q3 and the fourth field effect transistor Q4 are N-type.

A backup power supply according to an embodiment of the present disclosure comprises the secondary battery 1 and the reverse connection protecting device described above.

The following provides detailed principle of the reverse connection protecting device in conjunction with the above embodiment of the present disclosure.

In practice, for various reasons, the load may be inversely connected, the external power supply may be inversely connected, or the charging and discharging interface may be inversely connected, which may cause the main charging and discharging circuit to be inversely connected, thus destroying the whole circuit. The backup power supply 1 such as the secondary battery does not supply power at normal conditions, so that it needs to be activated for being charged or discharged when it is connected into the circuit. After the activation module 8 is powered on by the external power supply 3, an electric signal may be transmitted from the activation terminal 83, the lightning protection circuit 82, the voltage stabilizing and reverse connection protecting circuit 81 in turn to the optical coupler U and then may be output from the optical coupler U so as to drive the battery control module 7. The single chip microcomputer U1 in the battery control module 7 may control the battery and the main charging and discharging circuit to turn on or turn off. For example, when the electric quantity of the secondary battery 1 is insufficient because the secondary battery 1 is overcharged or over-discharged, the FETs in the battery control module 7 may be open such that the connection of the secondary battery 1 and the charging and discharging interface 2 may be broken. When the single chip microcomputer U1 is turned on, the four FETs are switched on in turn to turn the main charging and discharging circuit on so as to charge or discharge the secondary battery 1 .

The switch control module 6 comprises a sampling circuit configured to sample a voltage signal, and a control chip configured to test the voltage signal from the sampling circuit and provide a control signal to the switch unit 5. When the detected voltage meets the requirement, the control chip controls the switch unit 5 to switch on so as to switch the main charging and discharging circuit on. When the main charging and discharging circuit is not inversely connected, the detected voltage is positive, and the switch control module 6 controls the switch unit 5 to switch on; whereas when the main charging and discharging circuit is inversely connected, the detected voltage is negative, the switch control module 6 controls the switch unit 5 to switch off, and the secondary battery 1 is not connected to a subsequent circuit, thus avoiding the danger.

In one embodiment, the first magnetic bead L1 and the second magnetic bead L2 may prevent the static electricity of the terminal. The first current-limiting resistor R1 and the second current-limiting resistor R2 may limit the current of the activation circuit and the current impact during a lightning stroke. The first capacitor C1 and the second capacitor C2 may release the static electricity and the common-mode lightning current. The third capacitor C3 may release the static electricity and the differential-mode lightning current. If the activation terminal 83 is inversely connected, the first diode D in the voltage stabilizing and reverse connection protecting circuit 81 will not be turned on, and thus the first diode D in the voltage stabilizing and reverse connection protecting circuit 81 may prevent the damage to the inner circuit resulted from the inverse connection of the positive electrode and the negative electrode of the activation terminal 83. The zener diode ZD in the voltage stabilizing and reverse connection protecting circuit 81 may avoid the repetitive starting of the activation module 8 when the voltage of the external power supply 3 is low or instable. When the voltage of the external power supply 3 does not reach a voltage stabilizing value of the zener diode ZD, the activation circuit is not turned on, and the battery control module 7 is not activated, and thus the secondary battery 1 may not be turned on.

The optical coupler U not only may be used as a switch between the activation module 8 and the secondary battery 1 , but also may separate the secondary battery 1 from the external power supply 3 to avoid the negative effect on the interior control system caused by the different electrical level. Particularly, the activation terminal 83 may be an anti-mistake activation terminal. The secondary battery 1 is a nickel-hydrogen battery, a nickel-cadmium battery, or a lithium-ion battery.

With the reverse connection protecting device for a backup power supply according to an embodiment of the present disclosure, the battery control module may be activated by the activation module separate from the main charging and discharging circuit, and it is determined whether the main charging and discharging circuit is inversely connected by the switch control module on the main charging and discharging circuit according to the voltage output from the charging and discharging interface, to control the turn-on and turn-off states of the whole main circuit by the switch unit, thus controlling the turning on and turning off of the secondary battery and the main charging and discharging circuit. Moreover, when the main charging and discharging circuit is inversely connected, the secondary battery and the main charging and discharging circuit are turned off to avoid the danger, thus effectively preventing the inverse connection of the secondary battery and the main charging and discharging circuit. The reverse connection protecting device according to an embodiment of the present disclosure is simple in structure and low in cost.

Although explanatory embodiments have been shown and described, it would be appreciated by those skilled in the art that changes, alternatives, and modifications all falling into the scope of the claims and their equivalents may be made in the embodiments without departing from spirit and principles of the disclosure.