Super capacitor charging and discharging control circuit

Abstract

The utility model discloses a super capacitor charging and discharging control circuit, which comprises a power supply, a super capacitor, a relay, a diode, a charging current limiting device and a relay control circuit, and is used for reducing current impact of initial charging of the super capacitor and completely accessing input end voltage to work when the voltage of the super capacitor is nearly fully charged. When the power supply is powered off or cut off, the loop of the super capacitor and the input end power supply is cut off to store the stored power of the super capacitor, the power-off and power-off states of the main power supply are not affected, and the stored power of the super capacitor can be used for corresponding occasions according to needs.

Description

Technical Field

[0001] This application relates to supercapacitor applications and power supply technology for electronic and electrical products. Background Art

[0002] At present, supercapacitors, also known as farad capacitors, have the characteristics of fast charging speed, high energy storage density, and extremely large current discharge compared to batteries or rectifier power supplies. The number of charge and discharge cycles is almost unlimited, which is much longer than the battery life.

[0003] However, when a supercapacitor is used for the first time or has not been used for a long time, there is basically no voltage, and the supercapacitor has an extremely low internal resistance. At this time, directly connecting it to the power supply will form a large impact current, which may cause the power supply system to be overloaded and damaged or enter the overcurrent protection state.

[0004] In addition, when the power is cut off, the stored electricity of the supercapacitor will not disappear immediately, which will affect the process of shutting down the circuit immediately and cutting off the power. Summary of the invention

[0005] The present application provides a supercapacitor charge and discharge control circuit, which prevents the supercapacitor from large voltage fluctuations at the initial stage of circuit connection. When the supercapacitor voltage is close to being fully charged, it can be fully connected to the power supply end without impedance, and when the power is cut off, the supercapacitor can cut off or continue to supply power as needed.

[0006] The scheme is as follows: a supercapacitor charge and discharge control circuit, characterized in that it includes: a power supply, a supercapacitor, a relay, a diode, a charging current limiting device, a relay control circuit, a diode and a charging current limiting device connected in series between the power supply input terminal and the supercapacitor, the polarity of the diode is set according to the direction of the charging current, and the power supply input terminal and the supercapacitor are also connected by the normally open contact of the relay, and the switch closure of the relay contact is determined by the relay control circuit. When the power supply input terminal is connected to the power supply, the current passes through the diode and the charging buffer device to charge the supercapacitor to a voltage close to the input terminal voltage, and the relay control circuit outputs to the relay to close the normally open contact of the relay, so that the supercapacitor can be fully connected to the input terminal and participate in the direct charging and discharging of the power supply. When the power supply needs to be powered off or cut off, the relay control circuit supplies power synchronously with the main power supply, and the normally open contact of the relay is released and disconnected to keep the stored electricity of the supercapacitor from discharging to other circuits or electrical devices, or the relay and the control circuit use the stored electricity of the supercapacitor for occasions where discharge is required.

[0007] When the power supply starts to supply power, it first passes through the diode and then the charging current limiting device to charge the supercapacitor to offset the charging current impact caused by the low internal resistance of the supercapacitor. When the supercapacitor charging voltage rises to a level close to the input voltage and does not affect the circuit, the relay control circuit outputs to the relay to close the normally open contact of the relay. The normally open contact of the relay connects the power supply end and the supercapacitor. After the contact is closed, the supercapacitor is fully connected to the circuit to work, achieving impedance-free full access to the power supply end. When the power supply is cut off and the circuit needs to stop supplying power, the relay control circuit power supply can be cut off synchronously to disconnect the normally open contact of the relay. At this time, the stored electricity of the supercapacitor will not be able to feed the circuit through the unidirectional conducting diode, so that the stored electricity of the supercapacitor can be stored for a long time, which can reduce the charging current of the next startup. This usage scenario is suitable for occasions such as high-power amplifier power supplies that require transient large current discharge and need to maintain a stable power supply. In addition, the stored electricity of the supercapacitor can also be called according to the triggering conditions of the relay control circuit according to the use needs. For example, this circuit can be used in the automobile circuit. When the car starts, the stored electricity of the supercapacitor is called as the starting power supply. This usage scenario is suitable for occasions that also require instantaneous high current applications. This circuit is not limited to a single group. Multiple groups can be added, or the current control polarity of the diode and the charging current limiting device and the +- polarity of the supercapacitor can be changed to make a supercapacitor charging and discharging control circuit with +- power supply two inputs. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram of a supercapacitor charging and discharging control circuit;

[0009] Figure 2 It is a schematic diagram of a supercapacitor charging and discharging control circuit with two inputs of + and - power supply;

[0010] Markings in the figure: 1 super capacitor, 2 relay, 3 diode, 4 charging current limiting device, 5 relay control circuit, +vcc represents the positive power input terminal positive pole +, GND is the power loop ground, -vcc represents the negative power input terminal negative pole -, DETAILED DESCRIPTION

[0011] In order to make the objectives, technical solutions and advantages of the present application more clear, the implementation methods of the present application are further described in detail below with reference to the accompanying drawings.

[0012] Figure 1 Schematic diagram of the circuit structure of the embodiment of the present application. Figure 1 As shown, the circuit includes: 1 super capacitor, 2 relay, 3 diode, 4 charging current limiting device, 5 relay control circuit.

[0013] In this embodiment, the unidirectionally conducting diode 3 serves to prevent the stored electricity of the supercapacitor from being supplied to the circuit by the charging buffer device 4 when the machine is shut down or the power is cut off. The complete access between the supercapacitor and the main power supply is controlled by the relay 2, and the timing of the access is determined by the relay control circuit 5. The charging current limiting device 4 can be a current limiting circuit composed of a resistor, a tungsten filament bulb, a constant current IC, a transistor and corresponding external components. Regardless of the form used, the purpose is to prevent the initial charging current of the supercapacitor from being too large to affect the main power supply. The specific current limiting value of the charging current limiting device is determined by the safe and suitable charging current that can be provided by the input power supply.

[0014] When the voltage of the supercapacitor is charged to a voltage close to the input main power supply voltage, the relay control circuit 5 outputs it to the relay 2 to close the normally open contact of the relay, thus achieving full access without impedance between the supercapacitor and the input power supply.

[0015] The relay control circuit 5 can be time controlled according to the charging time of the supercapacitor from 0 to full charge, or a comparison circuit can be used to first measure the voltage between the input terminal and the supercapacitor terminal for comparison, and then determine the closing timing of the output to the relay 2 according to the set target voltage.

[0016] The purpose of using a relay is that when the main power is cut off or disconnected, the relay control circuit is also disconnected to restore the relay to the normally open state, forming a supercapacitor to store electricity, which also cuts off the power supply to the main power supply, achieving immediate shutdown and power off, and also allows the charging voltage to quickly reach the full charge value of the supercapacitor when it is turned on again without a very long interval (this time depends on the capacity of the supercapacitor and its self-discharge performance), without having to charge from 0 voltage, so that the supercapacitor can be quickly fully connected to the circuit next time it is used. The relay can be a mechanical type with an electromagnetic coil controlling the mechanical contact, or it can be a semiconductor solid-state relay. The transistor that performs on-off in the solid-state relay is equivalent to the normally open contact of the mechanical relay.

[0017] In addition, the relay control circuit can control the use of supercapacitor power storage according to the required working scenario, taking advantage of the supercapacitor's ability to discharge large currents, such as as a vehicle starting power source.

[0018] Figure 2 It is an implementation method of +- dual power supply input. The added diodes are set according to the current direction, and the components are increased accordingly. It can be used in occasions requiring +- power supply, such as high-power amplifier circuits.

Claims

1. A supercapacitor charge and discharge control circuit, characterized in that: include: A power supply, a supercapacitor, a relay, a diode, a charging current limiting device, a relay control circuit, a diode and a charging current limiting device are connected in series between the power input terminal and the supercapacitor, the polarity of the diode is set according to the direction of the charging current, and the power input terminal and the supercapacitor are also connected by the normally open contact of the relay. The switch closure of the relay contact is determined by the relay control circuit. When the power input terminal is connected to the power supply, the current passes through the diode and the charging buffer device to charge the supercapacitor to a voltage close to the input terminal. The relay control circuit outputs to the relay to close the normally open contact of the relay, so that the supercapacitor can be fully connected to the input terminal and participate in the direct charging and discharging of the power supply. When the power supply needs to be powered off or cut off, the relay control circuit supplies power synchronously with the main power supply, and the normally open contact of the relay is released and disconnected to keep the stored electricity of the supercapacitor from discharging to other circuits or electrical devices, or the relay and control circuit use the stored electricity of the supercapacitor in situations where discharge is required.

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