CN206250786U - A kind of aptitude chargeable circuit to lithium cell charging - Google Patents

Abstract

The utility model relates to the technical field of an intelligent charging circuit, in particular to an intelligent charging circuit for charging a lithium battery, comprising an EMC circuit sequentially connected from an input end to an output end, a primary side rectification filter circuit, an energy storage circuit, an absorption circuit, The switch conversion circuit and the secondary side rectification and filtering circuit also include the constant current control circuit, the feedback branch and the single-chip microcomputer U4 of the model HT46R01N, making full use of the output characteristics of the NMOS interface of the single-chip microcomputer U4, directly using the NMOS of the single-chip microcomputer U4 to modulate the operation Put the reference voltage, thus saving a switch tube, thus simplifying the circuit structure and reducing the cost.

Description

An intelligent charging circuit for charging lithium batteries

technical field

The utility model relates to the technical field of an intelligent charging circuit, in particular to an intelligent charging circuit for charging a lithium battery.

Background technique

At present, in order to output a constant current to charge the lithium battery, the general intelligent charging circuit will have a constant current control circuit, and the constant current control circuit modulates the current output through the PWM current modulation method. The traditional PWM current modulation method is shown in Figure 1. As shown, the single-chip microcomputer modulates the reference voltage of the operational amplifier by controlling a switch tube Q5, so as to achieve the purpose of modulating the charging current. However, adding a switch tube Q5 will undoubtedly increase the complexity and cost of the circuit.

Contents of the invention

The purpose of the utility model is to provide an intelligent charging circuit for charging lithium batteries with simple circuit and low cost.

The utility model provides an intelligent charging circuit for charging a lithium battery, comprising an EMC circuit sequentially connected from an input end to an output end, a primary side rectification filter circuit, an energy storage circuit, an absorption circuit, a switch conversion circuit and a secondary side rectification filter The circuit also includes a constant current control circuit, a feedback branch, and a single-chip microcomputer U4 whose model is HT46R01N with an NMOS interface. The constant current control circuit includes a comparator U3A, a diode D10, resistors R32, R33, R34, R38, R43, and R44 , Capacitors C21, C27, a resistor R38 and a capacitor C21 are connected in series between the inverting input terminal and the output terminal of the comparator U3A, the inverting input terminal of the comparator U3A is connected to the negative electrode of the charging output terminal via the resistor R34 on the one hand, and on the other hand The capacitor C21 is grounded, and the non-inverting input terminal of the comparator U3A is connected to one end of the resistors R33, R43, and R44, and the other ends of R33, R43, and R44 are respectively connected to the ground, the reference voltage terminal, and the microcontroller U4, and the output terminal of the comparator U3A is connected to The cathode of the diode D10 and the anode of the diode D10 are connected to the input end of the feedback branch, and the output end of the feedback branch is connected to the switching conversion circuit.

Wherein, the intelligent charging circuit also includes an output voltage sampling circuit, which includes resistors R39, R40, R41 and a capacitor C25. The resistors R39 and R40 are connected in series and connected between the positive pole of the charging output terminal and the ground, and one end of the capacitor R41 is connected to the resistor R39 And the node of R40, its other end is connected to single-chip microcomputer U4 on the one hand, on the other hand is grounded through electric capacity C25.

Wherein, the intelligent charging circuit also includes a battery temperature control circuit, which includes a comparator U3B, a thermistor RT2, resistors R25, R26, R27, R28, R29, R30, R31, R35, R36, R37, a capacitor C22, a switching tube Q4, Zener diode ZD and diode D11, the cathode of Zener diode ZD is connected to the anode of diode D10, the anode of Zener diode ZD is connected to the collector of switching tube Q4, the emitter of switching tube Q4 is grounded, and the gate of switching tube Q4 Connect the resistors R26, R25 and the capacitor C22, the other end of the resistor R26 and the capacitor C22 share the ground, the other end of the resistor R25 is connected to the output terminal of the comparator U3B on the one hand, and connected to the +5V power supply via 29, R30, R31 on the other hand. The non-inverting input terminal of U3B is connected to one end of resistor R28, the other end is connected to one end of resistor R36 and thermistor RT2, the other end of resistor R36 and thermistor RT2 is connected to +5V power supply through R35, and the inverting phase of comparator U3B The input end is connected to one end of the resistor R27, the other end of the resistor R27 is connected to one end of the resistor R37, and the other end of the resistor R37 is respectively connected to the anode of the diode D11 and the single chip microcomputer U4.

Wherein, the intelligent charging circuit also includes LED1 and LED2, both of which are connected to the single-chip microcomputer U4.

Beneficial effects: the utility model is an intelligent charging circuit for charging lithium batteries, which utilizes the single-chip microcomputer U4 of the model HT46R01N, fully utilizes the output characteristics of the NMOS interface of the single-chip microcomputer U4, and directly uses the NMOS of the single-chip microcomputer U4 to modulate the benchmark of the operational amplifier Voltage, thus saving a switch tube, thus simplifying the circuit structure and reducing the cost.

Description of drawings

Utilize accompanying drawing to further illustrate the utility model, but the embodiment in the accompanying drawing does not constitute any restriction to the utility model, for those of ordinary skill in the art, under the premise of not paying creative work, also can obtain according to following accompanying drawing Additional drawings.

FIG. 1 is a circuit schematic diagram of a constant current control circuit of an existing intelligent charging circuit.

Fig. 2 is a schematic circuit diagram of an intelligent charging circuit for charging lithium batteries of the present invention.

Fig. 3 is a schematic circuit diagram of a constant current control circuit in an intelligent charging circuit for charging a lithium battery of the present invention.

Fig. 4 is a schematic circuit diagram of an output voltage sampling circuit in an intelligent charging circuit for charging a lithium battery of the present invention.

Fig. 5 is a schematic circuit diagram of a battery temperature control circuit in an intelligent charging circuit for charging a lithium battery of the present invention.

Fig. 6 is a schematic circuit diagram of the single-chip microcomputer U4 in an intelligent charging circuit for charging lithium batteries of the present invention.

In Figure 2 to Figure 6, it includes: 1—EMC circuit, 2—primary side rectification and filtering circuit, 3—energy storage circuit, 4—absorbing circuit, 5—switching conversion circuit, 6—secondary side Rectification filter circuit, 7—feedback branch, 8—constant current control circuit, 9—output voltage sampling circuit, 10—battery temperature control circuit.

detailed description

The utility model is further described in conjunction with the following examples.

A schematic circuit diagram of an intelligent charging circuit of the utility model for charging a lithium battery is shown in Figure 2. The intelligent charging circuit includes an EMC circuit 1 connected sequentially from the input end to the output end, a primary side rectification filter circuit 2, and an energy storage The circuit 3, the absorption circuit 4, the switching conversion circuit 5 and the secondary side rectification and filtering circuit 6 also include a constant current control circuit 8, a feedback branch 7 and a single-chip microcomputer U4 whose model is HT46R01N with an NMOS interface. As shown in Figure 3, the constant current control circuit includes comparator U3A, diode D10, resistors R32, R33, R34, R38, R43, R44, capacitors C21, C27, the inverting input terminal and output terminal of comparator U3A A resistor R38 and a capacitor C21 are connected in series. The inverting input terminal of the comparator U3A is connected to the negative electrode of the charging output terminal through the resistor R34 on the one hand, and grounded through the capacitor C21 on the other hand. The positive phase input terminal of the comparator U3A is connected to the resistor R33, One end of R43, R44, the other end of R33, R43, R44 are respectively connected to the ground, the reference voltage end and the single chip microcomputer U4, the output end of the comparator U3A is connected to the cathode of the diode D10, and the anode of the diode D10 is connected to the input end of the feedback branch 7, The output end of the feedback branch 7 is connected to the switching conversion circuit 5 . Using the single-chip microcomputer U4 of the model HT46R01N, making full use of the output characteristics of the NMOS interface of the single-chip microcomputer U4, directly using the NMOS of the single-chip microcomputer U4 to modulate the reference voltage of the op amp, thus saving a switch tube, thereby simplifying the circuit structure and reducing the cost. cost.

As shown in Figure 4, the output voltage sampling circuit includes resistors R39, R40, R41 and capacitor C25. The resistors R39 and R40 are connected in series and connected between the positive pole of the charging output terminal and the ground. One end of the capacitor R41 is connected to the node of the resistors R39 and R40. , the other end of which is connected to the single-chip microcomputer U4 on the one hand, and grounded through the capacitor C25 on the other hand.

As shown in Figure 5, the battery temperature control circuit includes comparator U3B, thermistor RT2, resistors R25, R26, R27, R28, R29, R30, R31, R35, R36, R37, capacitor C22, switch tube Q4, regulator Diode ZD and diode D11, the cathode of Zener diode ZD is connected to the anode of diode D10, the anode of Zener diode ZD is connected to the collector of switching tube Q4, the emitter of switching tube Q4 is grounded, the gate of switching tube Q4 is connected to resistor R26, R25 and capacitor C22, the other end of resistor R26 and capacitor C22 share the ground, the other end of resistor R25 is connected to the output terminal of comparator U3B on the one hand, and connected to +5V power supply through 29, R30, R31 on the other hand, the positive of comparator U3B The phase input end is connected to one end of resistor R28, the other end is connected to one end of resistor R36 and thermistor RT2, the other end of resistor R36 and thermistor RT2 is connected to +5V power supply through R35, and the inverting input end of comparator U3B is connected to resistor One end of R27 and the other end of the resistor R27 are connected to one end of the resistor R37, and the other end of the resistor R37 is respectively connected to the anode of the diode D11 and the microcontroller U4. Use the thermistor RT2 to detect the temperature of the lithium battery. When the temperature of the lithium battery is higher than the set value, the battery temperature control circuit will send a signal to the microcontroller U4, and the microcontroller U4 will suspend charging until the temperature of the lithium battery is lower than the set value. After setting the value, charge again.

As shown in Figure 6, both LED1 and LED2 are connected to single-chip microcomputer U4, and LED1 and LED2 can display the charging status. When the smart charging circuit is plugged into the power supply, both LED1 and LED2 are lit, indicating that the smart charging circuit has been powered on; when the lithium battery is connected to the smart During the charging circuit, LED1 is on, indicating that the lithium battery is being charged; when the lithium battery is fully charged, LED2 is on, indicating that the lithium battery is fully charged; when both LED1 and LED2 are flashing, it indicates that the charging is abnormal.

Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present utility model, rather than limiting the protection scope of the present utility model. Personnel should understand that the technical solution of the utility model can be modified or equivalently replaced without departing from the essence and scope of the technical solution of the utility model.

Claims (4)

1. a kind of aptitude chargeable circuit to lithium cell charging, it is characterised in that be sequentially connected including from input to output end EMC circuits, primary side current rectifying and wave filtering circuit, energy storage circuit, absorbing circuit, switch transformed circuit and secondary side rectification filter Wave circuit, the single-chip microcomputer U4 also including constant-current control circuit, feedback branch and model with the HT46R01N of NMOS interfaces, institute State constant-current control circuit including comparator U3A, diode D10, resistance R32, R33, R34, R38, R43, R44, electric capacity C21, Resistance R38 and electric capacity C21 is serially connected between the inverting input and output end of C27, comparator U3A, comparator U3A's is anti-phase defeated Enter the negative pole that on the one hand end connects charging output end through resistance R34, be on the other hand grounded through electric capacity C21, the positive of comparator U3A Input is all connected with one end of resistance R33, R43, R44, the other end of R33, R43, R44 connect respectively ground, reference voltage terminal and The negative electrode of the output end connection diode D10 of single-chip microcomputer U4, comparator U3A, the anode of diode D10 connects the feedback branch Input, the output end of the feedback branch connects the switch transformed circuit.

2. a kind of aptitude chargeable circuit to lithium cell charging according to claim 1, it is characterised in that also including output Voltage sampling circuit, it includes that resistance R39, R40, R41 and electric capacity C25, resistance R39 and R40 are connected to charging after being connected in series Between the positive pole and ground of output end, one end of electric capacity R41 connects the node of resistance R39 and R40, and on the one hand its other end connects single Piece machine U4, is on the other hand grounded through electric capacity C25.

3. a kind of aptitude chargeable circuit to lithium cell charging according to claim 2, it is characterised in that also including battery Temperature-control circuit, it include comparator U3B, thermistor RT2, resistance R25, R26, R27, R28, R29, R30, R31, R35, R36, R37, electric capacity C22, switching tube Q4, voltage-regulator diode ZD and diode D11, the negative electrode connection diode of voltage-regulator diode ZD The anode of D10, the colelctor electrode of the anode connecting valve pipe Q4 of voltage-regulator diode ZD, the grounded emitter of switching tube Q4, switching tube Q4 grid connection resistance R26, R25 and electric capacity C22, the other end of resistance R26 and electric capacity C22 altogether, the other end of resistance R25 On the one hand the output end of connection comparator U3B, on the other hand connects+5V power supplys, the positive input of comparator U3B through 29, R30, R31 End connects one end of resistance R28, and its other end connects one end of resistance R36 and thermistor RT2, resistance R36 and thermistor The other end of RT2 connects+5V power supplys through R35, and the inverting input of comparator U3B connects one end of resistance R27, and resistance R27's is another One end connects one end of resistance R37, and the other end of resistance R37 connects the anode and single-chip microcomputer U4 of diode D11 respectively.

4. a kind of aptitude chargeable circuit to lithium cell charging according to claim 1, it is characterised in that also including LED1 And LED2, LED1 and LED2 are all connected with single-chip microcomputer U4.