Dual-output type quick charger circuit

Abstract

The utility model relates to the technical field of chargers, in particular to a dual-output type quick charger circuit, which comprises a power supply circuit, a charging circuit and a control circuit, and is characterized in that the power supply circuit comprises a power supply switch S, a power supply transformer T, a bridge rectifier UR and a three-terminal integrated voltage stabilizing integrated circuit IC1; the charging circuit comprises a diode VD, a three-terminal adjustable voltage-stabilizing integrated circuit IC3, a potentiometer RP2 and a control contact of a relay K1; the control circuit comprises a time base integrated circuit IC2, a potentiometer RP1, a transistor V1, a transistor V2, a relay K2, a light emitting diode VL1 and a light emitting diode VL2. The constant-current charging / constant-voltage charging automatic conversion circuit has a constant-current charging / constant-voltage charging automatic conversion function, a constant-current charging mode is adopted when the voltage of the battery end is lower than 4.2 V, and the constant-voltage charging mode is automatically converted into a constant-voltage small-current 60mA charging mode when the voltage of the battery end is charged to 4.2 V, so that the battery is not overcharged, and the safety of the battery GB is greatly improved.

Description

Technical Field

[0001] The utility model relates to a charger circuit, in particular to a dual-output fast charger circuit, belonging to the technical field of chargers. Background Art

[0002] As people have more and more portable electronic devices, in order to solve the problem of charging multiple electronic devices simultaneously, there is an urgent need to solve a charger with at least two charging interfaces to realize simultaneous external power supply for the two charging interfaces.

[0003] For a storage battery such as a mobile phone, a fast charging circuit is a high-performance charger that can quickly charge the battery. However, when the battery is full, it cannot quickly disconnect the charging. Especially when there are two charging interfaces, the initial charging current is limited to 2A. As the battery current and voltage increase, when the current increases to 150 mA, the charger cannot adjust the voltage and current, which easily leads to overcharging, causing irreversible damage to the battery and even causing the battery to bulge and catch fire. Summary of the Utility Model

[0004] Aiming at the deficiencies of the prior art, the utility model provides a dual-output fast charger circuit with an automatic conversion function of constant current charging / constant voltage charging, which can prevent battery overcharging and greatly improve the safety of battery GB.

[0005] The technical solution adopted by the utility model to solve the above technical problems is as follows:

[0006] A dual-output fast charger circuit includes a power supply circuit, a charging circuit and a control circuit. It is characterized in that the power supply circuit includes a power switch S, a power transformer T, a rectifier bridge UR, a filter capacitor C1, a filter capacitor C2 and a three-terminal integrated voltage regulator integrated circuit IC1. The power switch S, the power transformer T and the rectifier bridge UR are connected in series. The output end of the rectifier bridge UR is electrically connected to the pin 1 of the three-terminal integrated voltage regulator integrated circuit IC1. The filter capacitor C1 is arranged between the rectifier bridge UR and the three-terminal integrated voltage regulator integrated circuit IC1. The filter capacitor C2 is electrically connected to the pin 3 of the three-terminal integrated voltage regulator integrated circuit IC1 and is electrically connected to the charging circuit through a diode VD.

[0007] The charging circuit includes a diode VD, a three-terminal adjustable voltage regulator integrated circuit IC3, a resistor R2, a resistor R3, a resistor R4, a potentiometer RP2, and a control contact of a relay K1. The diode VD is electrically connected to pin 3 of the three-terminal adjustable voltage regulator integrated circuit IC3. One end of the resistors R3 and R4 in parallel is connected to pin 1 of the three-terminal adjustable voltage regulator integrated circuit IC3, and the other end is connected to pin 2 and is in parallel with the control contact of the relay K1. The voltage output at the other end is 1-12V and is electrically connected to a battery GB.

[0008] The control circuit includes a time-base integrated circuit IC2, a potentiometer RP1, a resistor R1, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C3, a capacitor C4, transistors V1 and V2, a relay K2, and light-emitting diodes VL1 and VL2. Pin 4 and pin 8 of the time-base integrated circuit IC2 are electrically connected to pin 3 of the rectifier bridge UR through the potentiometer RP1.

[0009] Pin 6 of the time-base integrated circuit IC2 is electrically connected to the charging circuit through a resistor R2, and then electrically connected to pin 3 of the rectifier bridge UR through the diode VD. Pin 2 of the time-base integrated circuit IC2 is connected to a resistor R1 through a capacitor C3. The end of the resistor R1 away from the time-base integrated circuit IC2 is electrically connected to pin 3 of the rectifier bridge UR.

[0010] Further, in a dual-output fast charger circuit, it is characterized in that: pin 3 of the time-base integrated circuit IC2 is electrically connected to the transistors V1 and V2. The ends of the relay K2, the transistors V1 and V2 away from the time-base integrated circuit IC2 are electrically connected to pin 1 of the three-terminal integrated voltage regulator integrated circuit IC1.

[0011] One side of the relay K2 is provided with a series connection of a resistor R7 and a resistor R8 in parallel. The resistor R7 is in series with the light-emitting diode VL1, and the resistor R8 is in series with the light-emitting diode VL2.

[0012] Further, in a dual-output fast charger circuit, it is characterized in that: the rectifier bridge UR is electrically connected to the battery GB through a capacitor U5, and an ammeter is provided between the capacitor U5 and the battery GB.

[0013] Compared with the prior art, the beneficial effects of the present utility model are:

[0014] 1. This application has the function of automatic conversion between constant current charging and constant voltage charging. When the battery terminal voltage is lower than 4.2V, the constant current charging method is adopted. When the battery terminal voltage is charged to 4.2V, it will automatically switch to the constant voltage and small current 60mA charging method, preventing overcharging of the battery and greatly improving the safety of battery GB.

[0015] 2. When the battery voltage is charged to 4.2V, the voltage at pin 6 of the time base integrated circuit IC2 reaches the 2VCc / 3 threshold level. The flip-flop inside the time base integrated circuit IC2 is reset, and the voltage at pin 3 changes from high level to low level, turning off the transistor V1 and saturating and conducting the transistor V2. The relay K2 is attracted, its normally closed contact is disconnected, and its normally open contact is connected. The charging circuit changes from the constant current charging method to the constant voltage charging method to perform constant voltage charging on GB.

[0016] 3. When the battery is nearly fully charged, the charger automatically switches to the voltage-limited floating charge state. The voltage-limited floating charge voltage is set to 13.8V. For a 6V storage battery, the floating charge voltage should be set to 6.9V. At this time, the charging current gradually decreases from the fast charging state. After the battery is fully charged, the charging current is only 10 - 30mA, which is used to supplement the power lost by the battery due to self-discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of the present utility model;

[0018] Figure 2 is a circuit diagram of the present utility model.

[0019] In the figure, 1. Power supply circuit; 2. Charging circuit; 3. Control circuit. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The following will combine the drawings and specific embodiments to detail the implementation manner of this application, so as to fully understand the implementation process of how this application uses technical means to solve technical problems and achieve technical effects and implement accordingly.

[0021] As Figure 1-2 shown, the dual-output fast charger circuit provided in this embodiment includes a power supply circuit 1, a charging circuit 2, and a control circuit 3. The power supply circuit 1 includes a power switch S, a power transformer T, a rectifier bridge UR, a filter capacitor C1, a filter capacitor C2, and a three-terminal integrated voltage regulator integrated circuit IC1. The time base integrated circuit IC2 in the control circuit 3 includes the chip IC555. The lithium-ion battery charger made by using the time base integrated circuit with the chip IC555 has the function of automatic conversion between constant current charging and constant voltage charging. When the battery terminal voltage is lower than 4.2V, the constant current charging method is adopted. When the battery terminal voltage is charged to 4.2V, it will automatically switch to the constant voltage and small current 60mA charging method, preventing overcharging of the battery and greatly improving the safety of battery GB.

[0022] The power switch S, the power transformer T, and the rectifier bridge UR are connected in series. The output terminal of the rectifier bridge UR is electrically connected to pin 1 of the three-terminal integrated voltage regulator IC1. The filter capacitor C1 is arranged between the rectifier bridge UR and the three-terminal integrated voltage regulator IC1. After the power is turned on, the AC 220V voltage is stepped down by the power transformer T, rectified by the rectifier bridge UR, filtered by the filter capacitor C1, and regulated by the three-terminal integrated voltage regulator IC1. Then, the diode VD is electrically connected to pin 3 of the three-terminal adjustable voltage regulator IC3. The resistors R3, R4, and the relay K are connected in parallel and one end is connected to pins 1 and 2 of the three-terminal adjustable voltage regulator IC3, and the other end outputs a voltage of 1 - 12V and is electrically connected to the battery GB. The control contact of the relay K is connected to the battery GB or the potentiometer RP2, generating a 12V DC voltage at both ends of the charging circuit 2, and the output current is stable, improving the safety factor of the battery GB.

[0023] The charging circuit 2 includes the diode VD, the three-terminal adjustable voltage regulator IC3, the resistors R2, R3, R4, the potentiometer RP2, and the control contact of the relay K1. Pin 4 and pin 8 of the time-base integrated circuit IC2 are electrically connected to pin 3 of the rectifier bridge UR through the potentiometer RP1. Pin 6 of the time-base integrated circuit IC2 is electrically connected to the charging circuit 2 through the resistor R2 and then electrically connected to pin 3 of the rectifier bridge UR through the diode VD.

[0024] Pin 2 of the time-base integrated circuit IC2 is connected to the resistor R1 through the capacitor C3, and the end of the resistor R1 far from the time-base integrated circuit IC2 is electrically connected to pin 3 of the rectifier bridge UR.

[0025] Pin 3 of the time-base integrated circuit IC2 is electrically connected to the transistors V1 and V2. The ends of the relay K2, the transistors V1, and V2 far from the time-base integrated circuit IC2 are electrically connected to pin 1 of the three-terminal integrated voltage regulator IC1.

[0026] The filter capacitor C2 is electrically connected to pin 3 of the three-terminal integrated voltage regulator IC1 and is electrically connected to the charging circuit 2 through the diode VD.

[0027] This voltage is divided into three paths:

[0028] One path is stepped down and adjusted by the potentiometer RP1 to provide the operating voltage VCC for the time-base integrated circuit IC2;

[0029] One path is added to the voltage input terminal pin 3 of the three-terminal adjustable voltage regulator IC33 through the diode as the input voltage of the charging circuit;

[0030] Another path charges the capacitor C3 through a resistor. The operating power supplies of the transistor V1, the transistor V2, and the relay K2 are taken from the DC voltage rectified by UR.

[0031] The control circuit 3 includes a time-base integrated circuit IC2, a potentiometer RP1, resistors R1, R5, R6, R7, R8, capacitors C3, C4, transistors V1, V2, a relay K2, and light-emitting diodes VL1, VL2. One side of the relay K2 is connected in parallel with a series connection of a resistor R7 and a resistor R8. The resistor R7 is connected in series with the light-emitting diode VL1, and the resistor R8 is connected in series with the light-emitting diode VL2. When the power is just turned on, since the voltage across the capacitor C3 cannot change suddenly, the voltage at pin 2 of the time-base integrated circuit IC2 is lower than Vcc / 3. The flip-flop inside the time-base integrated circuit IC2 is set, and pin 3 outputs a high level. The transistor V1 is saturated and conducting, and the transistor V2 is cut off. The relay K2 cannot be attracted, and its normally closed contact is closed, shorting the resistor R4. The charging circuit 2 charges the battery GB with a constant current. At this time, the light-emitting diode VL2 lights up, indicating that the charger is in the constant-current charging state.

[0032] When the battery voltage is charged to 4.2V, the voltage at pin 6 of the time-base integrated circuit IC2 reaches the 2VCc / 3 threshold level. The flip-flop inside the time-base integrated circuit IC2 is reset, and pin 3 changes from a high level to a low level, causing the transistor V1 to cut off and the transistor V2 to be saturated and conducting. The relay K2 is attracted, its normally closed contact is opened, and its normally open contact is closed. The charging circuit 2 changes from the constant-current charging mode to the constant-voltage charging mode and performs constant-voltage charging on GB.

[0033] The charging current is about 60mA and gradually decreases as the charging progresses. When the charging current drops to about 20mA, the charging ends.

[0034] When the battery is nearly fully charged, the charger automatically switches to the constant-voltage floating-charging state. The constant-voltage floating-charging voltage is set to 13.8V. For a 6V storage battery, the floating-charging voltage should be set to 6.9V. At this time, the charging current will gradually decrease from the fast-charging state. After the battery is fully charged, the charging current is only 10 - 30mA, which is used to supplement the power lost by the battery due to self-discharge.

[0035] Further, as Figure 2 shown, the rectifier bridge UR is electrically connected to the battery GB through a capacitor U5. An ammeter is provided between the capacitor U5 and the battery GB, which facilitates the intuitive observation of the current magnitude, improves the convenience of use, and ensures the safety factor of charging.

[0036] The above description shows and describes the preferred embodiments of the present utility model. It should be understood that the present utility model is not limited to the forms disclosed herein. Any modifications and variations made by those skilled in the art without departing from the spirit and scope of the present utility model shall fall within the protection scope of the appended claims of the present utility model.

Claims

1. A dual-output fast charger circuit, comprising a power supply circuit (1), a charging circuit (2) and a control circuit (3), characterized in that, The power supply circuit (1) includes a power switch S, a power transformer T, a rectifier bridge UR, a filter capacitor C1, a filter capacitor C2, and a three-terminal integrated voltage regulator integrated circuit IC1. The power switch S, the power transformer T, and the rectifier bridge UR are connected in series. The output terminal of the rectifier bridge UR is electrically connected to pin 1 of the three-terminal integrated voltage regulator integrated circuit IC1. The filter capacitor C1 is arranged between the rectifier bridge UR and the three-terminal integrated voltage regulator integrated circuit IC1. The filter capacitor C2 is electrically connected to pin 3 of the three-terminal integrated voltage regulator integrated circuit IC1 and is electrically connected to the charging circuit (2) through a diode VD. The charging circuit (2) includes a diode VD, a three-terminal adjustable voltage regulator integrated circuit IC3, a resistor R2, a resistor R3, a resistor R4, a potentiometer RP2, and the control contact of a relay K1. The diode VD is electrically connected to pin 3 of the three-terminal adjustable voltage regulator integrated circuit IC3. One end of the resistor R3 and the resistor R4 after being connected in parallel is connected to pin 1 of the three-terminal adjustable voltage regulator integrated circuit IC3, and the other end is connected to pin 2 and is connected in parallel with the control contact of the relay K1. The voltage output from the other end is 1 to 12V and is electrically connected to a battery GB. The control circuit (3) includes a time base integrated circuit IC2, a potentiometer RP1, a resistor R1, a resistor R5, a resistor R6, a resistor R7, a resistor R8, a capacitor C3, a capacitor C4, transistors V1, V2, a relay K2, and light-emitting diodes VL1, VL2. Pin 4 and pin 8 of the time base integrated circuit IC2 are electrically connected to pin 3 of the rectifier bridge UR through the potentiometer RP1. Pin 6 of the time base integrated circuit IC2 is electrically connected to the charging circuit (2) through a resistor R2 and then electrically connected to pin 3 of the rectifier bridge UR through the diode VD. A resistor R1 is connected to pin 2 of the time base integrated circuit IC2 through a capacitor C3. The end of the resistor R1 far from the time base integrated circuit IC2 is electrically connected to pin 3 of the rectifier bridge UR.

2. The dual-output fast charger circuit according to claim 1, wherein: Pin 3 of the time base integrated circuit IC2 is electrically connected to the transistors V1 and V2. The ends of the relay K2, the transistors V1, and V2 far from the time base integrated circuit IC2 are electrically connected to pin 1 of the three-terminal integrated voltage regulator integrated circuit IC1. One side of the relay K2 is provided with a series connection of a resistor R7 and a resistor R8 in parallel. The resistor R7 is connected in series with the light-emitting diode VL1, and the resistor R8 is connected in series with the light-emitting diode VL2.

3. The dual-output fast charger circuit according to claim 1, characterized in that: The rectifier bridge UR is electrically connected to the battery GB through a capacitor U5. An ammeter is arranged between the capacitor U5 and the battery GB.

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