Battery power supply switching circuit

Abstract

The utility model relates to a battery power supply switching circuit comprising a base station power supply pin X2, an optocoupler U1, a Schottky diode U2, Zener diodes ZD1 and ZD2, diodes D1 and D2, a PNP triode Q1, an NPN triode Q2, resistors R1, R2, R3, R4, R5, R6, R7, R8 and R9, capacitors C1, C2 and C3, a relay K1 and a fuse F3. By arranging the backup energy storage battery, the backup power supply function can be achieved after the mains supply cannot supply power. According to the utility model, uninterrupted power supply can be realized after the mains supply is powered off due to external factors, and the continuity and effectiveness of power supply are ensured.

Description

Technical Field

[0001] The utility model is applied to the uninterrupted power supply of mobile communication base stations. The battery power supply switching circuit is connected between the AC-DC power supply and the backup energy storage battery to realize the switching power supply between the backup energy storage battery and the AC-DC communication power supply. Background Art

[0002] The communication base station needs to achieve long-term full-power uninterrupted power supply, and the power supply voltage adapted to the base station needs to be converted from the commercial power through the AC-DC power supply.

[0003] If the commercial power is cut off due to external factors, the backup energy storage battery needs to be switched to supply power to the mobile communication base station, and then switched back to the AC-DC communication power supply after the commercial power is restored, and the backup energy storage battery is charged.

[0004] Therefore, it is necessary to provide a battery power supply switching circuit that can achieve uninterrupted power supply after the commercial power is cut off due to external factors, and ensure the continuity and effectiveness of power supply. Summary of the Utility Model

[0005] In order to achieve the above object, the utility model provides a battery power supply switching circuit connected between the AC-DC power supply and the backup energy storage battery. The battery power supply switching circuit includes:

[0006] A base station power supply pin X2, an optocoupler U1, a Schottky diode U2, zener diodes ZD1 and ZD2, diodes D1 and D2, a PNP transistor Q1, an NPN transistor Q2, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, capacitors C1, C2, C3, a relay K1 and a fuse F3;

[0007] Among them, the AC commercial power is connected to the AC-DC power supply, and the DC power supply voltage is output and connected to the base station power supply pin X2;

[0008] The positive electrode BAT+ of the backup energy storage battery is connected to the positive electrode of the DC power supply voltage, and the negative electrode BAT- of the backup energy storage battery is connected in series to the negative electrode GND of the DC power supply voltage through the normally open contact pin of the relay K1 and the fuse F3;

[0009] The zener diodes ZD1, the optocoupler U1, the resistor R2, and the diode D2 are connected in series and then connected in parallel between the positive electrode BAT+ and the negative electrode BAT- of the backup energy storage battery;

[0010] One end of the winding of the relay K1 is connected to the positive pole of the DC power supply voltage, and the other end is connected to the E pole of the PNP triode Q1. The diode D1 is connected in parallel with the winding of the relay K1; the C pole of the PNP triode Q1 is connected to the negative pole GND of the DC power supply voltage, the B pole of the PNP triode Q1 is connected to the K pole of the Schottky diode U2, the A pole of the Schottky diode U2 is connected to the negative pole GND of the DC power supply voltage, the voltage stabilizing diode ZD2 is connected in parallel between the K pole of the Schottky diode U2 and the negative pole GND of the DC power supply voltage, one end of the resistor R3 is connected to the positive pole of the DC power supply voltage, and the other end is connected to the K pole of the Schottky diode U2;

[0011] The E pole of the optocoupler U1 is connected to the positive pole of the DC power supply voltage. The C pole of the optocoupler U1 is connected to the resistors R1 and R4 and is connected in series with the R pole of the Schottky diode U2. The resistors R7, R8, and the capacitor C2 are connected in parallel between the R pole of the Schottky diode U2 and the negative pole GND of the DC power supply voltage;

[0012] One end of the resistor R6 is connected to the R pole of the Schottky diode U2, the other end of the resistor R6 is connected to the E pole of the NPN triode Q2. The C pole of the NPN triode Q2 is connected to the negative pole GND of the current power supply voltage. The B pole of the NPN triode Q2 is connected to the E pole of the PNP triode Q1 through the resistor R5. A resistor R9 and a capacitor C3 are connected in parallel between the B pole of the NPN triode Q2 and the negative pole GND of the DC power supply voltage.

[0013] In a possible implementation, the DC power supply voltage is any one of 54V, 48V, or 24V.

[0014] In a possible implementation, the positive pole of the DC power supply voltage is connected to pin 2 of the base station power supply pin X2, and the negative pole GND of the DC power supply voltage is connected to pin 1 of the base station power supply pin X2.

[0015] In a possible implementation, when the backup energy storage battery is correctly connected, the battery voltage is stepped down by the voltage stabilizing diode ZD1, the resistor R2 limits the current, and then passes through the diode D2 for unidirectional conduction, generating a current between the A and K poles of the optocoupler U1. The E and C poles of the optocoupler U1 are turned on. The DC power supply voltage is divided by the resistors R1, R4 and the resistors R7, R8 connected in parallel between the R pole of the Schottky diode U2 and GND. When the voltage at the R pole is greater than the preset voltage, the K and A poles of the Schottky diode U2 are turned on, pulling down the voltage at the B pole of the PNP triode Q1. The E and C poles of the three poles of the PNP triode Q1 are turned on, the winding of the relay K1 is connected to the DC power supply voltage, and the normally open contact of K1 is closed. The backup energy storage battery BAT- is connected to the power supply negative pole through the contact and the fuse F3. In this way, the backup energy storage battery is connected in parallel between the positive and negative poles GND of the DC power supply voltage and is charged and stored through the AC-DC power supply.

[0016] In a possible implementation, when the mains input power fails, the AC-to-DC power supply has no output, and the backup energy storage battery is connected in parallel between the positive pole of the DC power supply voltage and the negative pole GND to supply power to the base station.

[0017] In a possible implementation, when the voltage of the backup energy storage battery drops due to power supply, it is divided by resistors R1, R4 and R7, R8 through the E and C poles of optocoupler U1, and the voltage of the R pole of U2 also drops in the same proportion. When the divided voltage is less than the set voltage, the K and A poles of U2 are disconnected, and the B pole voltage of the PNP triode Q1 is connected to the positive pole of the DC power supply voltage through R3. At this time, the B pole of Q1 is at a high level, the E and C poles of the three poles of Q1 are disconnected, the winding of relay K1 is also disconnected, and the contacts of K1 are disconnected, cutting off the loop between the negative pole of the battery and GND to prevent over-discharge of the backup energy storage battery.

[0018] The beneficial effects of the present utility model are as follows: Since the voltage stabilizing diode ZD1, optocoupler U1, resistor R2, and diode D2 are connected in series and then connected in parallel between BAT+ and BAT-, when the backup energy storage battery is reversely connected at the engineering site, due to the unidirectional conduction of diode D2, no current will be generated between the A and K poles of optocoupler U1, the E and C of U1 are not conducting, and the relay control circuit will not work, avoiding engineering damage caused by reverse connection of the energy storage battery. In addition, since the voltage, current, and power consumption of the optocoupler A and K devices are limited when connected in series, the series-connected voltage stabilizing diode ZD1 and R2 can also be adjusted according to the voltage of the actually connected backup energy storage battery to ensure the optimal voltage, current, and power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present utility model. For those skilled in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 FIG. 15 is a circuit structure diagram of an embodiment of a battery power supply switching circuit provided by the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0021] The following will specifically describe the preferred embodiments of the present utility model with reference to the drawings. The drawings form a part of the present utility model and are used together with the embodiments of the present utility model to explain the principle of the present utility model, rather than to limit the scope of the present utility model.

[0022] "Embodiments" provided in this document mean that specific features, structures, or characteristics described in conjunction with the embodiments can be included in at least one embodiment of the present utility model. The occurrence of this phrase at various positions in the specification does not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive with other embodiments. Those skilled in the art explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0023] Please refer to Figure 1 , the present utility model provides a battery power supply switching circuit connected between an AC-DC power supply and a backup energy storage battery. The battery power supply switching circuit includes:

[0024] A base station power supply pin X2, an optocoupler U1, a Schottky diode U2, zener diodes ZD1 and ZD2, diodes D1 and D2, a PNP transistor Q1, an NPN transistor Q2, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, capacitors C1, C2, C3, a relay K1, and a fuse F3;

[0025] Among them, the AC mains power is connected to the AC-DC power supply, and the output DC power supply voltage is connected to the base station power supply pin X2;

[0026] The positive electrode BAT+ of the backup energy storage battery is connected to the positive electrode of the DC power supply voltage, and the negative electrode BAT- of the backup energy storage battery is connected in series to the negative electrode GND of the DC power supply voltage through the normally open contact pin of the relay K1 and the fuse F3;

[0027] The zener diodes ZD1, the optocoupler U1, the resistor R2, and the diode D2 are connected in series and then connected in parallel between the positive electrode BAT+ and the negative electrode BAT- of the backup energy storage battery;

[0028] One end of the winding of the relay K1 is connected to the positive electrode of the DC power supply voltage, and the other end is connected to the E pole of the PNP transistor Q1. The diode D1 is connected in parallel to the winding of the relay K1; the C pole of the PNP transistor Q1 is connected to the negative electrode GND of the DC power supply voltage, the B pole of the PNP transistor Q1 is connected to the K pole of the Schottky diode U2, the A pole of the Schottky diode U2 is connected to the negative electrode GND of the DC power supply voltage, the zener diode ZD2 is connected in parallel between the K pole of the Schottky diode U2 and the negative electrode GND of the DC power supply voltage, and one end of the resistor R3 is connected to the positive electrode of the DC power supply voltage and the other end is connected to the K pole of the Schottky diode U2;

[0029] The E pole of the optocoupler U1 is connected to the positive electrode of the DC power supply voltage, the C pole of the optocoupler U1 is connected to the resistors R1 and R4 and is connected in series to the R pole of the Schottky diode U2, and the resistors R7, R8, and the capacitor C2 are connected in parallel between the R pole of the Schottky diode U2 and the negative electrode GND of the DC power supply voltage;

[0030] One end of resistor R6 is connected to the R pole of Schottky diode U2, and the other end of resistor R6 is connected to the E pole of NPN transistor Q2. The C pole of NPN transistor Q2 is connected to the negative pole GND of the DC power supply voltage. The B pole of NPN transistor Q2 is connected to the E pole of PNP transistor Q1 via resistor R5. A resistor R9 and a capacitor C3 are connected in parallel between the B pole of NPN transistor Q2 and the negative pole GND of the DC power supply voltage.

[0031] In a preferred embodiment, the DC power supply voltage is any one of 54V, 48V or 24V.

[0032] For the convenience of description, in the following description, the working principle of the present utility model is described based on the DC power supply voltage of 54V.

[0033] In a specific embodiment, the positive pole 54V of the DC power supply voltage is connected to pin 2 of the base station power supply pin X2, and the negative pole GND of the DC power supply voltage is connected to pin 1 of the base station power supply pin X2, that is: connected to X2 for the base station to work.

[0034] In a specific embodiment, since the voltage stabilizing diode ZD1, optocoupler U1, resistor R2, and diode D2 are connected in series and then connected in parallel between BAT+ and BAT-, when the backup energy storage battery is correctly connected, the battery voltage is stepped down by the voltage stabilizing diode ZD1, the current is limited by resistor R2, and then passes through the one-way conduction of diode D2 to generate a current between the A and K poles of the optocoupler U1. The E and C poles of the optocoupler U1 are turned on. The DC power supply voltage is divided by resistors R1, R4 and resistors R7, R8 connected in parallel between the R pole of Schottky diode U2 and GND. When the voltage at the R pole is greater than the preset voltage (which can be specifically 2.5V), the K and A poles of Schottky diode U2 are turned on, pulling down the voltage at the B pole of PNP transistor Q1. The E and C poles of the three poles of PNP transistor Q1 are turned on, and the relay K1 winding is connected to the DC power supply voltage of 54V. The normally open contact of K1 is attracted, and the backup energy storage battery BAT- is connected to the power supply negative pole through the contact and fuse F3. In this way, the backup energy storage battery is connected in parallel between the positive pole of the DC power supply voltage and the negative pole GND, and is charged and stored through the AC-DC power supply.

[0035] In a further embodiment, when the mains input power fails, the AC-DC power supply has no output, and the backup energy storage battery is connected in parallel between the positive pole 54V of the DC power supply voltage and the negative pole GND to supply power to the base station.

[0036] In a possible implementation, when the voltage of the backup energy storage battery drops after power supply, it is divided by resistors R1, R4 and R7, R8 through the E and C poles of optocoupler U1. The voltage of the R pole of U2 also drops in the same proportion. When the divided voltage is less than the set voltage of 2.5V, the K and A poles of U2 are disconnected. The B pole voltage of PNP transistor Q1 is connected to the positive pole of the DC power supply voltage of 54V through R3. At this time, the B pole of Q1 is at a high level, the E and C poles of the three poles of Q1 are disconnected, the winding of relay K1 is also disconnected, and the contacts of K1 are disconnected, cutting off the loop between the negative pole of the battery and GND to prevent over-discharge of the backup energy storage battery.

[0037] During the process of the above battery voltage dropping to the disconnection of the K1 contacts, due to the voltage fluctuation of the battery, the voltage of the R pole of U2 will also fluctuate. At the critical value of 2.5V, the K and A poles of U2 will have a repeated switching phenomenon, which will cause the K1 contacts to repeatedly open and close, and in severe cases, it will cause the backup energy storage battery to not be reliably switched off. Therefore, the BATC signal taken out from the C pole of Q1 is connected to R5, and after being divided by R5, R9, and filtered by C3, it is connected to the B pole of NPN transistor Q2. When PNP transistor Q1 conducts (when PNP transistor Q1 conducts, the C and E pole voltages are at a low level), the BATC signal is lower than 0.7V, and after being divided by R5, R9, and filtered by C3, it is set to be lower than 0.5V. The NPN transistor Q2 selected will not conduct when it is lower than 0.5V and will not affect the voltage of the R pole of U1. However, when the E and C poles of the three poles of Q1 are disconnected, the BATC signal is equivalent to being connected to 54V through the K1 winding, and the voltage will rise instantaneously, exceeding 0.7V. At this time, after being divided by R5, R9, and filtered by C3, the B pole voltage of Q2 rises, and Q2 conducts to connect R6 in parallel between the R pole of U2 and GND. The voltage of the R pole of U2 is pulled down below 2.5V, and the K and A poles of U2 are disconnected. From the above description, when the K and A poles of U2 are disconnected, the contacts of relay K1 are disconnected, cutting off the loop between the negative pole of the backup energy storage battery and GND. This part of the Q2 circuit is equivalent to adding a turn-off hysteresis function to the backup energy storage battery, and the K and A poles of U2 are disconnected at one time at the critical point of 2.5V.

[0038] The beneficial effects of the present utility model are as follows: Since the voltage stabilizing diode ZD1, optocoupler U1, resistor R2, and diode D2 are connected in series and then connected in parallel between BAT+ and BAT-, when the backup energy storage battery at the engineering site is reversely connected, due to the one-way conduction of diode D2, no current will be generated between the A and K poles of optocoupler U1, the E and C of U1 will not conduct, and the relay control circuit will not work, avoiding engineering damage caused by the reverse connection of the energy storage battery. In addition, since there are limitations on the voltage, current, and power consumption of the optocoupler A and K devices connected in series, the voltage stabilizing diode ZD1 and R2 connected in series can also be adjusted according to the actual voltage of the backup energy storage battery connected, ensuring the optimal voltage, current, and power consumption.

[0039] In addition, this part of the Q2 circuit is equivalent to adding a backup energy storage battery with a turn-off hysteresis function to ensure reliable disconnection of the backup energy storage battery at one time.

[0040] The circuit is provided with a voltage detection circuit. When the E and C poles of the optocoupler U1 are conducting, the 54V voltage is divided by the resistors R1, R4 and the parallel-connected R7, R8 between the R pole of U2 and GND. The resistance values of R1, R4 and R7, R8 can be adjusted to realize the on-off voltage. For example, if the backup energy storage battery is 48V and the battery over-discharge voltage is 43.2V, when the resistance values of R1, R4 and R7, R8 are adjusted so that the voltage at the R pole of U2 is 2.5V at 44V, over-discharge protection of the backup energy storage battery can be prevented, and the backup energy storage battery can be directly powered on again after AC power is applied to charge. When changing to a 24V power supply system, replace the corresponding AC-DC power supply and adjust the resistance values of R1, R4 and R7, R8 to realize the replacement of the base station power supply system. The circuit has high compatibility.

[0041] The capacitor connected in parallel to the R and K pins of U2 in the above circuit can prevent the switching oscillation of U2 when the voltage at the R pole of U2 is 2.5V critically; the pull-up R3 can provide a bias current for U2 to prevent Q1 from malfunctioning due to the working leakage current between the A and K of U2; the ZD2 connected in parallel between the K and A of U2 can limit the maximum voltage between the K and A of U2 to prevent the occurrence of a situation higher than the working voltage of U2.

[0042] The fuse connected in series between K1 and GND can prevent the backup energy storage battery pack from being reliably disconnected when an abnormally large current occurs at the base station power supply end in the battery power supply mode.

[0043] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention should be covered by the protection scope of the present invention.

Claims

1. A battery-powered switching circuit is connected between an AC-to-DC power supply and a backup energy storage battery, and is characterized in that, The battery-powered switching circuit includes: A base station power supply pin X2, an optocoupler U1, a Schottky diode U2, zener diodes ZD1, ZD2, diodes D1, D2, a PNP transistor Q1, an NPN transistor Q2, resistors R1, R2, R3, R4, R5, R6, R7, R8, R9, capacitors C1, C2, C3, a relay K1, and a fuse F3; Wherein, the AC mains power is connected to the AC-DC power supply, and a DC power supply voltage is output and connected to the base station power supply pin X2; the positive electrode BAT+ of the backup energy storage battery is connected to the positive electrode of the DC power supply voltage, and the negative electrode BAT- of the backup energy storage battery is connected in series to the negative electrode GND of the DC power supply voltage through the normally open contact pin of the relay K1 and the fuse F3; the zener diodes ZD1, the optocoupler U1, the resistor R2, and the diode D2 are connected in series and then connected in parallel between the positive electrode BAT+ and the negative electrode BAT- of the backup energy storage battery; One end of the relay K1 winding is connected to the positive electrode of the DC power supply voltage, and the other end is connected to the E pole of the PNP transistor Q1. The diode D1 is connected in parallel to the relay K1 winding; the C pole of the PNP transistor Q1 is connected to the negative electrode GND of the DC power supply voltage, the B pole of the PNP transistor Q1 is connected to the K pole of the Schottky diode U2, the A pole of the Schottky diode U2 is connected to the negative electrode GND of the DC power supply voltage, the zener diode ZD2 is connected in parallel between the K pole of the Schottky diode U2 and the negative electrode GND of the DC power supply voltage, one end of the resistor R3 is connected to the positive electrode of the DC power supply voltage, and the other end is connected to the K pole of the Schottky diode U2; the E pole of the optocoupler U1 is connected to the positive electrode of the DC power supply voltage, the C pole of the optocoupler U1 is connected to the resistors R1, R4 and connected in series to the R pole of the Schottky diode U2, and the resistors R7, R8, and the capacitor C2 are connected in parallel between the R pole of the Schottky diode U2 and the negative electrode GND of the DC power supply voltage; One end of the resistor R6 is connected to the R pole of the Schottky diode U2, the other end of the resistor R6 is connected to the E pole of the NPN transistor Q2, the C pole of the NPN transistor Q2 is connected to the negative electrode GND of the DC power supply voltage, the B pole of the NPN transistor Q2 is connected to the E pole of the PNP transistor Q1 through the resistor R5, and a resistor R9 and a capacitor C3 are connected in parallel between the B pole of the NPN transistor Q2 and the negative electrode GND of the DC power supply voltage.

2. The battery-powered switching circuit according to claim 1, wherein The DC power supply voltage is any one of 54V, 48V, or 24V.

3. The battery-powered switching circuit according to claim 2, wherein The positive electrode of the DC power supply voltage is connected to pin 2 of the base station power supply pin X2, and the negative electrode GND of the DC power supply voltage is connected to pin 1 of the base station power supply pin X2.

4. The battery-powered switching circuit according to claim 1, wherein When the backup energy storage battery is correctly connected, the battery voltage is stepped down by the voltage stabilizing diode ZD1, limited by the resistor R2, and then unidirectionally conducted through the diode D2, generating a current between the A and K poles of the optocoupler U1. The E and C poles of the optocoupler U1 are conducted. The DC power supply voltage is divided by the resistors R1, R4 and the resistors R7, R8 connected in parallel between the R pole of the Schottky diode U2 and GND. When the voltage of the R pole is greater than the preset voltage, the K and A poles of the Schottky diode U2 are conducted, pulling down the voltage of the B pole of the PNP triode Q1. The E and C poles of the three poles of the PNP triode Q1 are conducted, and the winding of the relay K1 is connected to the DC power supply voltage. The normally open contact of K1 is closed, and the backup energy storage battery BAT- is connected to the negative pole of the power supply through the contact and the fuse F3. In this way, the backup energy storage battery is connected in parallel between the positive pole of the DC power supply voltage and the negative pole GND, and the AC-to-DC power supply is used for charging and energy storage.

5. The battery-powered switching circuit according to claim 1, characterized in that, When the mains input power fails, the AC-to-DC power supply has no output, and the backup energy storage battery is connected in parallel between the positive pole of the DC power supply voltage and the negative pole GND to supply power to the base station.

6. The battery-powered switching circuit according to claim 5, wherein When the voltage of the backup energy storage battery drops after power supply, it is divided by the E and C poles of the optocoupler U1, the resistors R1, R4 and R7, R8. The voltage of the R pole of U2 also drops in the same proportion. When the divided voltage is less than the set voltage, the K and A poles of U2 are disconnected, and the voltage of the B pole of the PNP triode Q1 is connected to the positive pole of the DC power supply voltage through R3. At this time, the B pole of Q1 is at a high level, the E and C poles of the three poles of Q1 are disconnected, the winding of the relay K1 is also disconnected, and the contact of K1 is disconnected, cutting off the loop between the negative pole of the battery and GND to prevent over-discharge of the backup energy storage battery.

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