A super capacitor charging and discharging control circuit

Abstract

The application 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, a relay control circuit, and is used for reducing the current impact of initial charging of the super capacitor, completely connecting the input terminal voltage to work when the voltage of the super capacitor approaches fullness, cutting off the loop of the super capacitor and the input terminal power supply to save the power storage of the super capacitor when the power supply is powered off or cut off, and realizing the state of not affecting the power-off and shutdown of the main power supply, and the power storage of the super capacitor can be used in corresponding occasions according to needs.

Description

Technical Field

[0002] This application relates to supercapacitor applications and power supply technologies for electronic and electrical products. Background Technology

[0004] Supercapacitors, also known as farad capacitors, offer advantages over batteries or rectified power supplies. They feature rapid charging, high energy density, and extremely high discharge current, with virtually unlimited charge-discharge cycles, significantly extending battery life. However, supercapacitors have virtually no voltage upon initial use or after prolonged periods of inactivity. Furthermore, their extremely low internal resistance means that directly connecting them to a power source can create a large inrush current, potentially overloading and damaging the power system or triggering overcurrent protection. Additionally, the stored energy in supercapacitors doesn't immediately dissipate when power is cut off, affecting the process of quickly shutting down circuits. Summary of the Invention

[0006] This application provides a supercapacitor charging and discharging control circuit, which avoids large voltage fluctuations in the supercapacitor during the initial connection to the circuit, allows the supercapacitor to operate with no impedance when the voltage is close to full, and allows the supercapacitor to be disconnected or continue to supply power as needed when the power is cut off.

[0007] The proposed solution is as follows: A supercapacitor charging and discharging 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, and 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. The power supply input terminal and the supercapacitor are also connected by a normally open contact of a relay. The relay control circuit determines the opening and closing of the relay contacts. 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 near the input terminal voltage. At this point, the relay control circuit outputs to the relay to close the normally open contact of the relay, allowing the supercapacitor to 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 disconnected 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 to prevent the supercapacitor's stored energy from discharging to other circuits or electrical devices. Alternatively, the relay and control circuit can use the supercapacitor's stored energy for situations requiring discharge. When the power supply starts, the supercapacitor is first charged by a diode and then by a current-limiting device to limit the current, thus offsetting the charging current surge caused by the supercapacitor's low internal resistance. When the supercapacitor's charging voltage rises to near the input voltage without affecting the circuit, the relay control circuit outputs to the relay to close its normally open contact. The relay's normally open contact connects the power supply terminal and the supercapacitor. After the contact closes, the supercapacitor is fully connected to the circuit, achieving impedance-free full-connection operation with the power supply terminal. When the power supply is cut off and the power supply to the circuit needs to be stopped, the power supply to the relay control circuit can be simultaneously cut off to open the relay's normally open contact. At this time, the supercapacitor's stored energy cannot be fed to the circuit through the unidirectional diode, allowing the supercapacitor's stored energy to be stored for a long time. This reduces the charging current during the next power-on. This application scenario is suitable for situations such as high-power amplifier power supplies that require transient high-current discharge and need to maintain a stable power supply. Furthermore, the energy stored in the supercapacitor can be activated by setting the trigger conditions of the relay control circuit according to usage needs. For example, this circuit can be used in automotive circuits, where the supercapacitor's stored energy is used as a starting power source when the car starts. This application scenario is suitable for situations requiring instantaneous high current. This circuit is not limited to a single set; multiple sets can be added, or the current control polarity of the diodes and charging current limiting devices can be changed, as well as the positive and negative polarities of the supercapacitor, to create a supercapacitor charging and discharging control circuit with both positive and negative power inputs. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of a supercapacitor charging and discharging control circuit.

[0010] Figure 2 This is a schematic diagram of a supercapacitor charging and discharging control circuit with both positive and negative power inputs. The markings in the diagram are: 1 Supercapacitor, 2 Relay, 3 Diode, 4 Charging current limiting device, 5 Relay control circuit, +VCC indicates the positive terminal of the power supply input, GND is the power supply ground, and -VCC indicates the negative terminal of the power supply input. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0013] Figure 1 This is a schematic diagram of the circuit structure of an embodiment of this application, as shown below. Figure 1 As shown, the circuit includes: 1 supercapacitor, 2 relay, 3 diode, 4 charging current limiting device, and 5 relay control circuit.

[0014] In this embodiment, the unidirectional diode 3 prevents the supercapacitor's stored energy from being supplied to the circuit by the charging buffer device 4 when the power is off or disconnected. The complete connection between the supercapacitor and the main power supply is controlled by the relay 2, and the timing of the connection 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, its purpose is to ensure that the initial charging current of the supercapacitor is not too large and affects 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 the input power supply can provide. When the voltage of the supercapacitor is charged to near the input main power supply voltage, the relay control circuit 5 outputs to the relay 2 to close the normally open contact of the relay, realizing the complete connection of the supercapacitor with the input power supply without impedance. The relay control circuit 5 can be time-controlled according to the charging time of the supercapacitor from 0 to full charge, or it can use a comparison circuit to first measure and compare the voltage at the input terminal and the supercapacitor terminal, and then determine the closing timing of the output to the relay 2 according to the set target voltage. The purpose of using a relay is to ensure that when the main power supply is cut off or disconnected, the relay control circuit also disconnects, returning the relay to its normally open state. This allows the supercapacitor to retain its stored energy, thus cutting off power supply to the main power supply and achieving immediate power-off. Simultaneously, it allows the supercapacitor to quickly reach its full charge value before the next power-on (this time depends on the supercapacitor's capacity and self-discharge performance), without having to start charging from 0 voltage. This ensures the supercapacitor can be quickly and fully connected to the circuit for the next use. The relay can be a mechanical type with an electromagnetic coil controlling mechanical contacts, or a semiconductor solid-state relay. In a solid-state relay, the transistor that performs the switching action is equivalent to the normally open contacts of a mechanical relay. Furthermore, the relay control circuit can control the use of the supercapacitor's stored energy according to the required operating scenario, leveraging the supercapacitor's ability to discharge high currents, such as when used as a vehicle starting power source.

[0015] Figure 2 This is an implementation of a +- dual power input, with added diodes arranged according to the current direction and correspondingly increased components. It can be used in applications requiring +- power supply, such as high-power amplifiers.

[0016] Circuit.

Claims

1. A supercapacitor charging and discharging control circuit, characterized in that, include: The circuit consists of a power supply, a supercapacitor, a relay, a diode, a charging current limiting device, and 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. A normally open contact of a relay is also connected between the power input terminal and the supercapacitor. The relay control circuit determines the opening and closing of the relay contacts. When the power input terminal is connected, current flows through the diode and charging buffer to charge the supercapacitor to near the input voltage. At this point, the relay control circuit outputs a signal to the relay, causing the normally open contact to close, allowing the supercapacitor to 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 disconnected, the relay control circuit synchronizes its power supply with the main power supply, and the normally open contact of the relay opens to prevent the supercapacitor's stored energy from discharging to other circuits or electrical devices. Alternatively, the relay and control circuit can use the supercapacitor's stored energy for situations requiring discharge.

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