CN101154824A - Charger circuit with output voltage compensation - Google Patents

Abstract

A charger circuit with output voltage compensation includes an AC-DC converter, an output interface, a charging control circuit and a compensation circuit, wherein the AC-DC converter converts an AC power source into a DC power source, the DC power source is boosted by the transformer and then charges a battery through the output interface, and the charging control circuit is used to increase the voltage of the output interface to accelerate the charging of the battery, and the compensation circuit is used to further compensate for the voltage lost by the line, so that the energy loss caused by the internal resistance of the line can be overcome, thereby maintaining the charging effect of the charger.

Description

Charger circuit with output voltage compensation

technical field

The invention relates to a charger circuit with output voltage compensation.

Background technique

At present, most chargers have the function of two-stage charging, that is, users can choose to charge at a normal speed or fast charging; the so-called fast charging refers to directly inputting a large power supply to the battery connected to the charger To charge the battery, while the so-called normal speed charging is to charge the battery with a smaller power source.

Please refer to Fig. 3, the general charger mainly converts an AC power supply 20 into a DC power supply by an AC-to-DC circuit 10, then sends it to a transformer 30 to boost the voltage to output a boosted power supply, and the boosted power supply is then passed through After rectification, a battery 50 is charged through an output interface 40, and a detection circuit 80 is connected to the output interface 40. The detection circuit 80 detects whether the battery 50 is connected to the output interface 40, and if connected, a feedback circuit 90 is used. Make a control circuit 91 increase the boosted power output from the transformer 30 to charge the battery 50 with a larger power.

However, in actual conditions, any line will have its internal resistance. When the boost power output by the transformer 30 is sent to the output interface 40 through the line, part of the energy will be consumed by the internal resistance of the line, causing the output interface 40 to actually output to the output interface 40. The power of the battery 50 is less than the boosted power output by the transformer 30, thereby affecting the charging effect of the charger. Although the boosted power output from the transformer 30 can be further increased by the control circuit 91 to compensate for the energy consumed by the line to maintain normal charging of the battery 50, the energy loss caused by the internal resistance of the line is related to the size of the power supply for charging the battery 50, so it is fixed The step-up power outputted by the step-up transformer 30 cannot properly compensate the energy lost by the line, so the existing charger still has the aforementioned disadvantages to be overcome.

Contents of the invention

The main technical problem to be solved by the present invention is to provide a charger circuit with output voltage compensation in order to overcome the shortcoming that the circuit internal resistance causes the output power of the charger to drop. resulting pressure drop.

The technical solution adopted by the present invention to solve its technical problems is:

A charger circuit with output voltage compensation, characterized in that it includes: an AC-to-DC circuit, which is connected to an AC power source, and converts the AC power source into a DC power source; a transformer, which has a primary coil and a secondary coil, and the primary The coil is connected to the aforementioned AC to DC circuit to receive the aforementioned DC power supply, and the secondary coil senses the DC power supply to output a boosted power supply; an output interface is connected to the aforementioned secondary coil of the transformer for connecting with a battery to output the boosted voltage The power supply charges the battery; a charging control circuit, one end is connected to the primary coil of the aforementioned transformer, and the other end is connected to the secondary coil of the transformer and the output interface, when the battery is connected to the output interface, the boosted power supply can be increased to speed up charging the battery; One end of the compensation circuit is connected to the secondary coil of the transformer, and the other end is connected to the aforementioned charging control circuit. When the battery is connected to the output interface, the charging control circuit cooperates with the boosted power supply to compensate for the energy lost by the line.

The aforementioned charger circuit with output voltage compensation, wherein the charging control circuit includes: a pulse width modulation circuit, which is connected to the aforementioned AC to DC circuit and the primary coil of the transformer to control the size of the DC power sent to the primary coil of the transformer; A circuit is connected to the secondary coil of the aforementioned transformer to detect the output voltage of the output interface; an isolated controller is connected to the aforementioned pulse width modulation circuit with a receiving end, and connected to the sensing circuit with a transmitting end; The switch is connected to the transmitting end of the sensing circuit and the isolated controller. The output voltage detected by the sensing circuit controls whether the switch is turned on or not, and then cooperates with the isolated controller to make the pulse wave The width modulation circuit controls the magnitude of the DC power input to the primary coil of the transformer.

In the aforementioned charger circuit with output voltage compensation, the pulse width modulation circuit mainly includes a control IC, and the control IC is connected to the aforementioned AC-to-DC circuit, the primary coil of the transformer, and the receiving end of the isolated controller.

The aforementioned charger circuit with output voltage compensation, wherein the isolated controller is an optocoupler, the equivalent light-emitting diode in the optocoupler is connected to the emitting end of the sensing circuit, and the equivalent phototransistor in the optocoupler Connect the receiving end of the pulse width modulation circuit.

The aforementioned charger circuit with output voltage compensation, wherein the compensation circuit includes: a diode, the negative end of which is connected to the secondary coil of the aforementioned transformer; a capacitor is connected between the positive end of the aforementioned diode and a grounding end; a fifth The resistor is connected between the diode and the capacitor; a sixth resistor is connected with the sensing circuit and the switch.

The aforementioned charger circuit with output voltage compensation, wherein the sensing circuit mainly includes first, second, third and fourth resistors, and these resistors are connected in series in sequence, wherein the other end of the first resistor is connected to the transformer secondary The stage coil is interfaced with the output, the fourth resistor is grounded, and the series node of the second and third resistors is connected to the sixth resistor of the compensation circuit.

The aforementioned charger circuit with output voltage compensation, wherein the switch is an IC with a model number of TL431, its anode is grounded and its cathode is connected to the emitter of the aforementioned isolated controller, and the reference electrode is connected to the second and third resistors Concatenate nodes.

In the aforementioned charger circuit with output voltage compensation, the AC-to-DC circuit is a full-wave rectification circuit.

Using the above-mentioned technical means, when the battery is connected to the output interface, in addition to being detected by the charging control circuit and increasing the boost power output of the secondary coil of the transformer, the compensation circuit can cooperate with the charging control circuit to further increase the secondary voltage of the transformer. The boost power output by the coil compensates the energy lost by the line, and maintains the charging effect of the charger.

The beneficial effect of the invention is that a compensation voltage can be provided to compensate the voltage drop caused by the internal resistance of the circuit.

Description of drawings

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

FIG. 1 is a functional block diagram of a preferred embodiment of the present invention.

Fig. 2 is a circuit diagram of a preferred embodiment of the present invention.

Fig. 3 is a functional block diagram of an existing charger.

Explanation of symbols in the figure:

10 AC to DC circuit 20 AC power supply

30 Transformers

31 primary coil 32 secondary coil

40 output interface

50 battery 60 charging control circuit

61 pulse width modulation circuit 62 sensing circuit

63 isolated controller

631 Receiver 632 Transmitter

64 switch 70 compensation circuit

80 detection circuit 90 feedback circuit

91 control circuit

Detailed ways

First please refer to FIG. 1, a preferred embodiment of the charger circuit with output voltage compensation of the present invention includes:

An AC to DC circuit 10 is connected to an AC power supply 20 to convert the AC power supply to a DC power supply;

A transformer 30 has a primary coil and a secondary coil, wherein the primary coil is connected to the aforementioned AC-to-DC circuit 10, and the secondary coil induces the DC power supply to output a boosted power supply;

An output interface 40 is connected to the secondary coil of the aforementioned transformer 30 for connecting with the battery 50 to output the boosted power supply to charge the battery 50;

A charging control circuit 60, one end is connected to the primary coil of the aforementioned transformer 30, and the other end is connected to the secondary coil of the transformer 30 and the output interface 40. When the battery 50 is connected to the output interface 40, the charging control circuit 60 can increase the boost voltage. power supply to accelerate charging of the battery 50;

A compensation circuit 70, one end is connected to the secondary coil of the aforementioned transformer 30, and the other end is connected to the aforementioned charging control circuit 60. When the battery 50 is connected to the output interface 40, the compensation circuit 70 cooperates with the charging control circuit 60 to further increase the boost voltage. Power supply, thereby compensating the energy consumed by the internal resistance of the line.

The following is a further introduction to the detailed circuit of the above-mentioned embodiment. Please refer to FIG. 1 and FIG. 2 . The AC-to-DC circuit 10 is mainly composed of a full-wave rectifier D1-D4.

The charging control circuit 60 includes a pulse width modulation PWM circuit 61, a sensing circuit 62, an isolated controller 63 and a switch 64, wherein:

The pulse width modulation PWM circuit 61 is to connect the aforementioned AC to DC circuit 10 and the primary coil 31 of the transformer 30 to control the size of the DC power sent into the primary coil 31 of the transformer 30. The boost power outputted by the secondary coil 32 is larger. In this embodiment, the pulse width modulation circuit 61 mainly includes a control ICU1, and the control IC is connected to the aforementioned AC-to-DC circuit 10 and the primary coil 31 of the transformer 30;

The sensing circuit 62 is connected to the secondary coil 32 of the aforementioned transformer 30 to detect the output voltage of the output interface 40. In this embodiment, the sensing circuit 62 mainly includes first, second, third and fourth resistors R17 , R14, R18, R15, these resistors R17, R14, R18, R15 are serially connected in sequence, wherein the other end of the first resistor R17 is connected to the secondary coil 32 of the transformer 30 and the output interface 40, and the fourth resistor R15 The other end is grounded;

The isolated controller 63 is connected to the pulse width modulation circuit 61 with a receiving end 631, and the sensing circuit 62 is connected with a transmitting end 632. In this embodiment, the isolated controller 63 is an optical coupling The equivalent light-emitting diode PH1A in the optocoupler is connected to the transmitting end 632 of the sensing circuit 62, and the equivalent phototransistor PH1B in the optocoupler is connected to the receiving terminal 61 of the pulse width modulation circuit 61. terminal 631;

The switch 64 is connected to the transmitter 632 of the aforementioned sensing circuit 62 and the isolated controller 63. In this embodiment, the switch 64 is an IC of a type (TL431) U11, the anode A of which is grounded and the cathode K is connected to the aforementioned light The equivalent light-emitting diode negative terminal in the coupler, and the other reference electrode R is connected to the series node K of the second and third resistors R14 and R18.

The compensation circuit 70 includes a diode D12, a capacitor C15, and fifth and sixth resistors R21, R20 in this embodiment, wherein the negative terminal of the diode D12 is connected to the secondary coil 32 of the aforementioned transformer 30, and the capacitor C15 is Connected between the positive terminal of the diode D12 and the ground terminal, and the fifth resistor R21 is connected between the diode D12 and the capacitor C15, and the sixth resistor R20 is connected to the reference electrode R of the capacitor C15, (TL431) U11 and the second Series node K with third resistors R14, R18.

When the battery 50 is not connected to the output interface 40, the sensing circuit 62 will obtain the high voltage output from the secondary coil 32 of the transformer 30, so the voltage at the node K connected in series between the second and third resistors R14 and R18 is also Micro Motion position, so the switch 64 is turned on. When the switch 64 is turned on, the equivalent light-emitting diode PH1A in the optocoupler is turned on and lights up, and then the equivalent phototransistor PH1B in the optocoupler is turned on. When the pulse When the pulse width modulation circuit 61 detects that the equivalent phototransistor PH1B in the optocoupler is on, the pulse width modulation circuit 61 will not adjust the DC power input to the primary coil 31 of the transformer 30 .

When a battery 50 to be charged is connected to the output interface 40, the voltage of the output interface 40 will be reduced due to insufficient power of the battery 50, and the voltage of the series node K will be reduced to a low level, thereby turning off the switch 64. , once the switch 64 is turned off, the equivalent light-emitting diode PH1A in the optocoupler is also turned off and does not light up so that the equivalent phototransistor PH1B in the optocoupler is turned off. At this time, the pulse width modulation circuit 61 detects that the optocoupler The equivalent phototransistor PH1B in the device is in a cut-off state, so the size of the DC power sent to the primary coil 31 of the transformer 30 is increased until the voltage of the output interface 40 is increased to make the voltage of the series node K enough to allow the switch 64 to turn to turn on, and then make the equivalent light-emitting diode PH1A in the optocoupler conduct and light up and drive the equivalent phototransistor PH1B in the optocoupler to conduct, and at this time, the pulse width modulation circuit 61 detects that the optocoupler The equivalent phototransistor PH1B inside is in the conduction state, so the pulse width modulation circuit 61 reduces the DC power sent to the primary coil 31 of the transformer 30 .

But because the actual line has line impedance, so when the output voltage of transformer 30 secondary coil 32 is transmitted to output interface 40, this line impedance will consume part of the output voltage, so the charging voltage of battery 50 is slightly lower than that of transformer 30 secondary. The output voltage of the coil 32; and the present invention connects the secondary coil 32 of the transformer 30 with the diode D12 of the compensation circuit 70 with the negative end, and can generate a negative voltage source equivalently at the positive end of the diode D12, and the negative voltage source is The output voltage of the secondary coil 32 of the corresponding transformer 30 changes. Therefore, when the battery to be charged 50 is connected to the output interface 40 and causes the voltage of the series node K to drop, the negative voltage source will further reduce the voltage of the series node K. The control ICU1 must be controlled to send higher DC power to the primary coil 31 of the transformer 30, and further increase the output voltage of the secondary coil of the transformer 30, thereby compensating for the electric energy lost by the actual line internal resistance, and a larger voltage can be obtained. The battery 50 is charged.

It can be known from the above that the present invention not only can increase the voltage for charging the battery when the battery is installed, but also can compensate the electric energy lost by the circuit through the compensation circuit and the charging control circuit to maintain a better charging effect.

The above are only preferred embodiments of the present invention, and are not intended to limit the present invention in any form. Any simple modifications, equivalent changes and modifications made to the above embodiments according to the technical essence of the present invention still belong to within the scope of the technical solutions of the present invention.

In summary, the present invention fully meets the needs of industrial development in terms of structural design, practicability and cost-effectiveness, and the disclosed structure also has an unprecedented innovative structure, novelty, creativity and practicability, and meets the requirements of relevant According to the requirements of the invention patent requirements, the application is filed according to law.

Claims (8)

1. the charger circuit of a tool output voltage compensation is characterized in that, comprising:

One exchanges the commentaries on classics DC circuit, is to connect an AC power, and AC power is converted to a direct current power supply;

One transformer has primary coil and secondary coil, and primary coil is to connect aforementioned interchange to change DC circuit to receive aforementioned DC power supply, and secondary coil is then responded to this DC power supply and exported a booster power;

One output interface is to connect aforementioned transformer secondary output coil, for being connected to export this booster power to battery charge with a battery;

One charging control circuit is that an end connects aforementioned transformer, and end connects this transformer secondary output coil and output interface in addition, can improve this booster power to quicken battery charge when battery connects this output interface;

One compensating circuit is that an end connects aforementioned transformer secondary output coil, and end connects aforementioned charging control circuit in addition, cooperates this charging control circuit to improve this booster power again when battery is connected in output interface.

2. according to the charger circuit of the described tool output voltage compensation of claim 1, it is characterized in that described charging control circuit comprises:

One pulse width modulation circuit is aforementioned interchange commentaries on classics DC circuit of connection and transformer are sent into transformer with control a DC power supply size;

One sensing circuit is to connect the output voltage size of aforementioned transformer secondary output coil with the detecting output interface;

One isolated controller connects aforementioned pulse width modulation circuit with a receiving terminal, and connects this sensing circuit with a transmitting terminal;

One switch, it is the transmitting terminal that connects aforementioned sensing circuit and isolated controller, by this switch conduction of output voltage that this sensing circuit detected size control whether, and then cooperate this isolated controller and allow the DC power supply size of this pulse width modulation circuit control input transformer primary coil.

3. according to the charger circuit of the described tool output voltage compensation of claim 2, it is characterized in that described pulse width modulation circuit mainly comprises a control IC, this control IC connects aforementioned interchange changes DC circuit, the primary coil of transformer and the receiving terminal of this isolated controller.

4. according to the charger circuit of the described tool output voltage compensation of claim 2, it is characterized in that described isolated controller is an optical coupler, the light effect LED that waits in this optical coupler connects the transmitting terminal of this sensing circuit, and the equivalent phototransistor in the optical coupler connects the receiving terminal of this pulse width modulation circuit in addition.

5. according to the charger circuit of each described tool output voltage compensation in the claim 2 to 4, it is characterized in that described compensating circuit comprises:

One diode, its negative terminal are the secondary coils that connects aforementioned transformer;

One electric capacity is to be connected between the anode and an earth terminal of aforementioned diodes;

One the 5th resistance is to be connected between aforementioned diodes and the electric capacity;

One the 6th resistance is to connect this sensing circuit and switch.

6. according to the charger circuit of the described tool output voltage compensation of claim 5, it is characterized in that described sensing circuit mainly is to comprise the first, second, third and the 4th resistance, this constant resistance is to connect in regular turn, wherein the end in addition of this first resistance is to connect transformer secondary output coil and output interface, the 4th resistance is ground connection, and second is the 6th resistance that is connected this compensating circuit with the series connection node of the 3rd resistance.

7. according to the charger circuit of the described tool output voltage compensation of claim 6, it is characterized in that described switch is that a model is the IC of TL431, its plus earth and negative electrode are the transmitting terminals that connects aforementioned isolated controller, in addition, then connect the series connection node of this second and the 3rd resistance with reference to the utmost point.

8. according to the charger circuit of the described tool output voltage compensation of claim 1, it is characterized in that it is a full-wave rectifying circuit that DC circuit is changeed in described interchange.

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