Battery reverse connection protection control circuit and switching power supply

Abstract

The utility model discloses a battery anti-reverse connection protection control circuit and switching power supply, wherein the battery anti-reverse connection protection control circuit includes: relay, its control end is connected in the loop of battery and DC / DC series connection, switch circuit, its control end and first end all connect power supply voltage, and the second end is grounded through the control end of relay, control circuit, its control end connects battery negative pole wiring end, the control end of first end connection switch circuit, and the second end is grounded, when the positive pole of battery is connected to battery negative pole wiring end, control circuit will power supply voltage and pull down as low level, make power supply voltage unable through switch circuit and form current loop in the control end of relay, and relay does not attract and close, when the negative pole of battery connects the negative pole wiring end of battery, control circuit will not pull down power supply voltage as low level, and power supply voltage can form current loop in the control end of relay through switch circuit, and relay attracts and closes. The utility model can increase the stability of anti-reverse circuit.

Description

Technical Field

[0001] This utility model relates to the field of power supply protection technology, and in particular to a battery reverse connection protection control circuit and a switching power supply. Background Technology

[0002] As an energy storage device, batteries have been widely used in various fields such as transportation and photovoltaic energy storage. Therefore, the management and application of batteries have been the subject of relevant research.

[0003] When a user charges a large battery using a DC / DC converter, if the battery polarity is reversed, it is equivalent to the battery being connected in series with the rectifier circuit on the output side of the DC / DC converter. The battery will discharge to the rectifier circuit on the output side of the DC / DC converter, and the discharge current is very large. This can not only easily blow the fuse and damage the DC / DC converter itself, but the battery may also overheat and burn out or even explode, causing personal injury and other safety problems, or even serious fires and other unpredictable dangerous accidents.

[0004] To avoid the above problems, existing DC / DC designs have reverse connection protection diodes. When the capacitor is connected in reverse, the reverse connection protection diode can block the battery from discharging into the internal output rectifier circuit of the DC / DC. However, if the diode is reverse connected for a long time, unpredictable consequences may occur. Utility Model Content

[0005] In view of this, the technical problem to be solved by this utility model is to provide a battery reverse connection protection control circuit and a switching power supply, which at least to some extent solves one of the technical problems existing in the prior art.

[0006] As a first aspect of the present invention, the technical solution of the battery reverse connection protection control circuit embodiment is as follows:

[0007] A battery reverse connection protection control circuit is connected between a battery and a DC / DC converter, wherein the battery reverse connection protection control circuit includes:

[0008] A relay, the controlled terminal of which is connected in series with the battery and the DC / DC converter;

[0009] The switching circuit has its control terminal and first terminal connected to the power supply voltage, and its second terminal grounded via the control terminal of the relay.

[0010] The control circuit has a control terminal connected to the negative terminal of the battery, a first terminal connected to the control terminal of the switch circuit, and a second terminal grounded.

[0011] When the positive terminal of the battery is connected to the negative terminal of the battery, the control circuit pulls the supply voltage down to a low level, so that the supply voltage cannot form a current loop through the switching circuit at the control terminal of the relay, and the relay does not engage.

[0012] When the negative terminal of the battery is connected to the negative terminal of the battery, the control circuit will not pull the supply voltage down to a low level. The supply voltage can form a current loop at the control terminal of the relay through the switching circuit, and the relay will be energized.

[0013] Preferably, the control circuit includes an NPN transistor, the base of which is the control terminal of the control circuit, the collector of which is the first terminal of the control circuit, and the emitter of which is the second terminal of the control circuit.

[0014] Alternatively, the control circuit may include an optocoupler, wherein the anode of the primary-side photodiode of the optocoupler is the control terminal of the control circuit, the cathode of the primary-side photodiode of the optocoupler is grounded, the collector of the secondary-side phototransistor of the optocoupler is the first terminal of the control circuit, and the emitter of the secondary-side phototransistor of the optocoupler is the second terminal of the control circuit.

[0015] Alternatively, the control circuit may include an N MOSFET, the gate of which is the control terminal of the control circuit, the drain of which is the first terminal of the control circuit, and the source of which is the second terminal of the control circuit.

[0016] Furthermore, the control terminal of the control circuit is connected to the negative terminal of the battery through a resistor; or the control terminal of the control circuit is connected to the negative terminal of the battery through a two-terminal network composed of a resistor and a diode. This two-terminal network has unidirectional conductivity, allowing current to flow only from the negative terminal of the battery to the control terminal of the control circuit.

[0017] Preferably, the switching circuit includes an NPN transistor, the base of which is the control terminal of the switching circuit, the collector of which is the first terminal of the control circuit, and the emitter of which is the second terminal of the control circuit; or the switching circuit includes an N MOSFET, the gate of which is the control terminal of the switching circuit, the drain of which is the first terminal of the control circuit, and the source of which is the second terminal of the control circuit.

[0018] Furthermore, the switching circuit further includes a first resistor, and the control terminal of the switching circuit is connected to the power supply voltage through the first resistor; and / or the switching circuit further includes a second resistor, and the second terminal of the switching circuit is connected to the power supply voltage through the second resistor.

[0019] Furthermore, the battery reverse connection protection control circuit also includes a diode, the anode of which is grounded and the cathode is connected to the second terminal of the switching circuit.

[0020] As a second aspect of the present invention, the technical solution of the provided switching power supply embodiment is as follows:

[0021] A switching power supply, comprising a DC / DC converter and a battery reverse connection protection control circuit as described in any of the first aspects above.

[0022] The advantages of this utility model compared to the prior art are as follows:

[0023] (1) When the battery and DC / DC are connected in reverse, the battery reverse connection protection control circuit of this utility model pulls the supply voltage down to a low level through the control circuit, so that the supply voltage cannot form a current loop at the control terminal of the relay through the switching circuit. The controlled terminal (contact pin) of the relay is disconnected, thereby reliably blocking the large current input of the battery to the DC / DC. It can effectively avoid damage to the battery and the DC / DC. Compared with the prior art using diode reverse connection protection scheme, it can increase the stability of the circuit and the reverse connection protection effect.

[0024] (2) The battery reverse connection protection control circuit of this utility model embodiment has a simple structure, easy-to-select components, low price and small size. Attached Figure Description

[0025] Figure 1 A schematic diagram of a battery reverse connection protection control circuit provided by this utility model;

[0026] Figure 2 A schematic diagram of another battery reverse connection protection control circuit provided by this utility model. Detailed Implementation

[0027] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of this application.

[0028] It should be noted that the terms "comprising" and "having" and any variations thereof described in the specification and claims of this application are intended to cover non-exclusive inclusion. For example, including a series of components, unit circuits or control timings is not necessarily limited to those components, unit circuits or control timings that are explicitly listed, but may include components, unit circuits or control timings that are not explicitly listed or that are inherent to these circuits.

[0029] Furthermore, unless otherwise specified, the embodiments and features described in this application may be combined with each other.

[0030] It should be understood that, in the specification and claims, when an element is described as being "connected" to another element, that element may be "directly connected" to that other element or "connected" to that other element through a third element; when a step is described as being connected to another step, that step may be connected directly to that other step or connected to that other step through a third step.

[0031] Figure 1 Please refer to the structural schematic diagram of a battery reverse connection protection control circuit provided by this utility model. Figure 1 The battery reverse connection protection control circuit includes: a relay K1, whose controlled terminal is connected in the series circuit between the battery and the DC / DC converter; a switching circuit, whose control terminal and first terminal are both connected to the power supply voltage VCC, and whose second terminal is grounded through the control terminal of relay K1; and a control circuit, whose control terminal is connected to the negative terminal of the battery, whose first terminal is connected to the control terminal of the switching circuit, and whose second terminal is grounded. When the positive terminal of the battery is connected to the negative terminal of the battery, the control circuit pulls the power supply voltage down to a low level, so that the power supply voltage cannot form a current loop through the control terminal of the relay through the switching circuit, and the relay does not engage. When the negative terminal of the battery is connected to the negative terminal of the battery, the control circuit does not pull the power supply voltage down to a low level, and the power supply voltage can form a current loop through the control terminal of the relay through the switching circuit, and the relay engages.

[0032] It should be noted that, Figure 1 The controlled terminal of relay K1 is connected in the line between the negative terminal of the battery and the ground terminal of the DC / DC output. Those skilled in the art will know that the purpose of the invention can also be achieved by connecting the controlled terminal of relay K1 between the positive terminal of the battery and the positive terminal of the DC / DC output.

[0033] Please continue reading Figure 1The control circuit includes an NPN transistor Q1, whose base is the control terminal of the control circuit, whose collector is the first terminal of the control circuit, and whose emitter is the second terminal of the control circuit; the switching circuit includes an NPN transistor Q2, whose base is the control terminal of the switching circuit, whose collector is the first terminal of the control circuit, and whose emitter is the second terminal of the control circuit.

[0034] As an equivalent replacement, the above NPN transistors Q1 and Q2 can be replaced with NMOS transistors.

[0035] When the battery is reversed Figure 1 The circuit's working principle is analyzed as follows:

[0036] The base of transistor Q1 is connected to the positive terminal of the battery, so the base voltage of transistor Q1 is a high-level signal with a voltage amplitude much greater than 0.7V. The emitter of transistor Q1 is connected to GND, so the base voltage of transistor Q1 is 0.7V higher than the emitter voltage, thus transistor Q1 is saturated and conducting.

[0037] After transistor Q1 is saturated and turned on, its collector is pulled down to a low level signal. Since the base of transistor Q2 is connected to the collector of transistor Q1, the base of transistor Q2 is also a low level signal. However, since the turn-on condition for transistor Q2 is that its base voltage is 0.7V higher than its emitter voltage, when the base of transistor Q2 is a low level signal, it cannot reach the turn-on condition of 0.7V higher than its emitter voltage. Therefore, transistor Q2 does not turn on.

[0038] Transistor Q2 is not conducting, so the constant voltage source VCC cannot supply power to the control terminal of relay K1. The control terminal of relay K1 does not form a current loop, the controlled terminal of relay K1 does not engage, and the battery terminal and the DC / DC terminal device do not form a charging and discharging loop, effectively protecting the battery and the DC / DC terminal device.

[0039] When the battery is connected correctly Figure 1 The circuit's working principle is analyzed as follows:

[0040] The base of transistor Q1 is connected to the negative terminal of the battery, so the base of transistor Q1 is a low-level signal. The emitter of transistor Q1 is connected to GND. Since the conduction condition of transistor Q1 is that the base voltage is 0.7V higher than the emitter voltage, transistor Q1 is not conducting.

[0041] Since transistor Q1 is not conducting, its collector voltage will not be pulled down, so the collector of transistor Q1 is a high-level signal with an amplitude equal to the constant voltage source VCC. Since the base of transistor Q2 is connected to the collector of transistor Q1, the base of transistor Q2 is also a high-level signal. Since the conduction condition of transistor Q2 is that the base voltage is 0.7V higher than the emitter voltage, transistor Q2 is conducting.

[0042] When transistor Q2 is turned on, the constant voltage source VCC will supply power to the control terminal of relay K1. The control terminal of relay K1 forms a current loop. The current returns to GND through the relay KI winding (connected between the first coil pin 3 and the second coil pin 4 of the relay). Relay K1 is energized by the control terminal, and the battery terminal and the DC / DC terminal device form a charging and discharging loop. The DC / DC terminal device normally charges and discharges the battery terminal.

[0043] Please continue reading Figure 1 The control terminal of the control circuit is connected to the negative terminal of the battery through a two-terminal network consisting of resistor R3 and diode D1. This two-terminal network has unidirectional conductivity, allowing current to flow only from the negative terminal of the battery to the control terminal of the control circuit. Resistor R3 serves for impedance matching and current limiting, while diode D1 provides unidirectional conduction. It should be noted that the positions of resistor R3 and diode D1 in this two-terminal network can be interchanged.

[0044] Please continue reading Figure 1 The switching circuit also includes a resistor R1, the control terminal of which is connected to the power supply voltage VCC through the resistor R1. The function of the resistor R1 is impedance matching and current limiting; and / or the switching circuit also includes a resistor R2, the second terminal of which is connected to the power supply voltage VCC through the resistor R2. The function of the resistor R2 is also impedance matching and current limiting.

[0045] Please continue reading Figure 1 The battery reverse connection protection control circuit also includes diode D2. The anode of the diode is grounded and the cathode is connected to the second terminal of the switching circuit. The function of diode D2 is to protect the components in the circuit from damage. When the control signal is suddenly disconnected, a reverse electromotive force voltage spike will be generated on the coil of the controlled terminal 3 and 4 of the relay. The parallel diode provides a low-impedance discharge path.

[0046] Figure 2 For a schematic diagram of another battery reverse connection protection control circuit provided by this utility model, please refer to [link / reference]. Figure 2 ,and Figure 1The difference lies in the following: the control circuit includes an optocoupler U1, where the anode of the primary-side photodiode of the optocoupler U1 is the control terminal of the control circuit, the cathode of the primary-side photodiode is grounded, the collector of the secondary-side phototransistor of the optocoupler is the first terminal of the control circuit, and the emitter of the secondary-side phototransistor is the second terminal of the control circuit. Figure 2 Working principle and Figure 1 The same applies, so I won't go into details here.

[0047] This utility model also provides a switching power supply, including a DC / DC converter and any of the above-mentioned battery reverse connection protection control circuits. Since the switching power supply includes any of the above-mentioned battery reverse connection protection control circuits, it can effectively prevent the battery from being connected in reverse, thereby improving the reliability of the switching power supply.

[0048] The above description is only a preferred embodiment of the present utility model and does not limit the patent scope of the present utility model. All equivalent structural transformations made under the inventive concept of the present utility model using the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A battery reverse connection protection control circuit, connected between the battery and a DC / DC converter, characterized in that, The battery reverse connection protection control circuit includes: A relay, the controlled terminal of which is connected in series with the battery and the DC / DC converter; The switching circuit has its control terminal and first terminal connected to the power supply voltage, and its second terminal grounded via the control terminal of the relay. The control circuit has a control terminal connected to the negative terminal of the battery, a first terminal connected to the control terminal of the switch circuit, and a second terminal grounded. When the positive terminal of the battery is connected to the negative terminal of the battery, the control circuit pulls the supply voltage down to a low level, so that the supply voltage cannot form a current loop through the switching circuit at the control terminal of the relay, and the relay does not engage. When the negative terminal of the battery is connected to the negative terminal of the battery, the control circuit will not pull the supply voltage down to a low level. The supply voltage can form a current loop at the control terminal of the relay through the switching circuit, and the relay will be energized.

2. The battery reverse connection protection control circuit according to claim 1, characterized in that: The control circuit includes an NPN transistor, the base of which is the control terminal of the control circuit, the collector of which is the first terminal of the control circuit, and the emitter of which is the second terminal of the control circuit. Alternatively, the control circuit may include an optocoupler, wherein the anode of the primary-side photodiode of the optocoupler is the control terminal of the control circuit, the cathode of the primary-side photodiode of the optocoupler is grounded, the collector of the secondary-side phototransistor of the optocoupler is the first terminal of the control circuit, and the emitter of the secondary-side phototransistor of the optocoupler is the second terminal of the control circuit. Alternatively, the control circuit may include an N MOSFET, wherein the gate of the N MOSFET is the control terminal of the control circuit, the drain of the N MOSFET is the first terminal of the control circuit, and the source of the N MOSFET is the second terminal of the control circuit.

3. The battery reverse connection protection control circuit according to claim 2, characterized in that: The control terminal of the control circuit is connected to the negative terminal of the battery through a resistor; or the control terminal of the control circuit is connected to the negative terminal of the battery through a two-terminal network consisting of a resistor and a diode. This two-terminal network has unidirectional conductivity, allowing current to flow only from the negative terminal of the battery to the control terminal of the control circuit.

4. The battery reverse connection protection control circuit according to claim 1, characterized in that: The switching circuit includes an NPN transistor, the base of which is the control terminal of the switching circuit, the collector of which is the first terminal of the control circuit, and the emitter of which is the second terminal of the control circuit; or the switching circuit includes an N MOSFET, the gate of which is the control terminal of the switching circuit, the drain of which is the first terminal of the control circuit, and the source of which is the second terminal of the control circuit.

5. The battery reverse connection protection control circuit according to claim 1, characterized in that: The switching circuit further includes a first resistor, and the control terminal of the switching circuit is connected to the power supply voltage through the first resistor; and / or the switching circuit further includes a second resistor, and the second terminal of the switching circuit is connected to the power supply voltage through the second resistor.

6. The battery reverse connection protection control circuit according to any one of claims 1 to 5, characterized in that: The battery reverse connection protection control circuit also includes a diode, the anode of which is grounded and the cathode is connected to the second terminal of the switching circuit.

7. A switching power supply, comprising a DC / DC converter and a battery reverse connection protection control circuit as described in any one of claims 1 to 6.

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