CN211209330U

CN211209330U - Battery charging device

Info

Publication number: CN211209330U
Application number: CN201922080969.5U
Authority: CN
Inventors: 吴居谚; 许朝庆
Original assignee: Chicony Power Technology Co Ltd
Current assignee: Chicony Power Technology Co Ltd
Priority date: 2019-11-20
Filing date: 2019-11-27
Publication date: 2020-08-07
Anticipated expiration: 2029-11-27
Also published as: TWM592188U

Abstract

The utility model discloses a battery charging device, include: the charging device comprises a conversion unit, a first control unit, a main switch, a trickle charging unit, a second control unit and a mode control unit. The primary side of the conversion unit is coupled with an input power supply, and the first control unit is coupled with the conversion unit; the main switch is coupled with the conversion unit and the battery, and the trickle charging unit is connected with the main switch in parallel; the second control unit is coupled with the main switch and the trickle charge unit, and the mode control unit is coupled with the first control unit, the secondary side of the conversion unit and the second control unit. The utility model discloses can make battery charging device can have zero voltage start-up function.

Description

Battery charging device

Technical Field

The utility model relates to a battery charging device indicates a battery charging device who possesses zero voltage start function especially.

Background

Since the existing electronic products usually include a battery therein, and the battery must be charged when the battery is dead to avoid the electronic products from being out of service due to insufficient power, battery charging devices are increasingly widely used. When the voltage of the battery to be charged is lower than the working voltage of the control unit in the battery charging device, the control unit may receive insufficient voltage required by operation due to too low battery voltage, and the battery charging device may not charge the battery due to insufficient operating voltage of the control unit.

In order to solve the above problems, in the conventional battery charging device technology, a set of auxiliary conversion circuit is usually additionally provided to additionally provide a voltage required by the operation of the control unit, thereby avoiding the influence of the abnormal operation of the control unit caused by the too low battery voltage. However, the design of adding an additional set of auxiliary conversion circuit results in the cost of the circuit of the battery charging device being too high, the size of the battery charging device being too large, and the circuit design being too complex.

Therefore, how to design a battery charging device, which can have a zero voltage starting function by controlling the charging path, is an important subject to be studied by the present invention.

SUMMERY OF THE UTILITY MODEL

In order to solve the above problem, the present invention provides a battery charging device to overcome the problems of the prior art.

Therefore, the utility model discloses battery charging device includes: and the primary side of the conversion unit is coupled with an input power supply. The first control unit is coupled to the conversion unit and used for controlling the conversion unit to convert the input power into the output power. The main switch is coupled to the converting unit and the battery, and is used for providing a first charging path for the output power supply to charge the battery. And the trickle charging unit is connected with the main switch in parallel and is used for providing a second charging path for charging the battery by trickle current. The second control unit is coupled with the main switch and the trickle charging unit and used for conducting the second charging path according to the condition that the battery voltage of the battery is lower than a threshold value and conducting the first charging path according to the condition that the battery voltage is higher than the threshold value. The mode control unit is coupled to the first control unit, the secondary side of the conversion unit and the second control unit, and is used for controlling the first control unit and the second control unit according to the output power.

In one embodiment, the trickle charge unit includes: and the transistor is coupled with the output power supply and the battery. The control switch is coupled to the output power source, the second control unit and the transistor, and is used for establishing a channel of the transistor when the control switch is turned on so that the trickle charge unit provides a second charge path. The trickle control unit is coupled with the control switch, the transistor and the battery and used for generating trickle current in the second charging path when a channel is arranged.

In one embodiment, the trickle charge unit further includes: the current limiting resistor is coupled to the output power source, the transistor and the control switch, and is used for limiting the control current of the control end of the transistor.

In one embodiment, the trickle control unit includes: the voltage division unit is coupled with the transistor and the battery. The amplifying unit comprises a first input end, a second input end and an output end, wherein the output end is coupled with the transistor and the control switch, the first input end is coupled with the transistor and the voltage dividing unit, and the second input end is coupled with the reference voltage; the amplifying unit is used for generating trickle current according to the reference voltage and the voltage dividing unit when the amplifying unit has a channel.

In one embodiment, the trickle control unit includes: the voltage stabilizing unit is coupled with the transistor, the control switch and the battery and is used for generating a reference power supply. The resistor is coupled with the transistor, the voltage stabilizing unit and the battery and used for generating a reference current corresponding to the trickle current according to the reference power source when a channel is arranged.

In one embodiment, the voltage stabilizing unit is coupled to the battery through a resistor, so that the reference current is provided to the battery through the resistor as a trickle current.

In one embodiment, the trickle control unit further includes: the current comparing unit comprises a primary side and a secondary side, wherein the primary side is coupled with the voltage stabilizing unit and the resistor, and the secondary side is coupled with the battery; the current ratio unit is used for coupling the reference current from the primary side to the secondary side through the turn ratio, so that the secondary side provides trickle current to the battery.

In one embodiment, the trickle control unit further includes: the current mirror circuit is coupled to the voltage stabilizing unit, the resistor and the battery, and is used for adjusting the multiplying power of the reference current into a trickle current and providing the trickle current to the battery.

In one embodiment, the trickle current is between 100 milliamps and 200 milliamps.

In an embodiment, when the battery is not coupled to the battery charging device, the second control unit controls the first charging path and the second charging path to be open-circuited.

To further clarify the technology, means, and functions of the present invention, a further understanding of the invention, as embodied and broadly described herein, may be had by reference to the following detailed description and accompanying drawings, which are incorporated in and constitute a part of this invention.

Drawings

Fig. 1 is a block diagram of a battery charging apparatus according to the present invention;

FIG. 2 is a block diagram of the trickle charge unit of the present invention;

FIG. 3A is a circuit diagram of a trickle control unit according to a first embodiment of the present invention;

FIG. 3B is a circuit diagram of a trickle control unit according to a second embodiment of the present invention;

FIG. 3C is a circuit diagram of a trickle control unit according to a third embodiment of the present invention; and

fig. 3D is a circuit diagram of a trickle control unit according to a fourth embodiment of the present invention.

Wherein, the reference numbers:

100 … battery charging device

12 … conversion unit

12-1 … isolation transformer

12-2 … Primary side

12-3 … Secondary side

14 … first control unit

16 … second control unit

18 … mode control unit

20-1 … main switch

20-2 … trickle charging unit

22 … transistor

22-1, 262-1 … input terminal

22-2, 262-2 … output terminal

22-3, 262-3 … control terminal

24 … control switch

Rc … current limiting resistor

26. 26-1, 26-2, 26-3, 26-4 … trickle control unit

262 … voltage regulation unit

264 … resistor

266 … specific flow cell

266-1 … primary side

266-2 … secondary side

268 … current mirror circuit

272 … voltage dividing cell

R1 … first resistor

274 … amplification unit

274-1 … first input terminal

274-2 … second input terminal

274-3 … output terminal

200 … battery

Pc1 … first charging path

Pc2 … second charging path

Vin … input power

Vo … output power supply

Vb … Battery Voltage

Vref … reference Voltage

It … trickle current

Ib … reference current

Detailed Description

The technical content and the detailed description of the present invention are described below with reference to the drawings:

fig. 1 is a block diagram of a battery charging device according to the present invention. The battery charging apparatus 100 receives an input power Vin and converts the input power Vin into an output power Vo. When the battery 200 is coupled to the battery charging apparatus 100, the battery charging apparatus 100 charges the battery 200. The battery charging device 100 includes a conversion unit 12, a first control unit 14, a second control unit 16, and a mode control unit 18, and includes a main switch 20-1 providing a first charging path Pc1 and a trickle charging unit 20-2 providing a second charging path Pc 2. The converting unit 12 is an isolated switching converter (such as, but not limited to, a forward converter, a flyback converter, etc.) having an isolation transformer 12-1, the isolation transformer 12-1 divides the converting unit 12 into a primary side 12-2 and a secondary side 12-3, and the primary side 12-2 of the converting unit 12 is coupled to an input power Vin. The first control unit 14 is coupled to the converting unit 12, and the first control unit 14 controls the converting unit 12 to convert the input power Vin into the output power Vo. The main switch 20-1 is coupled to the output terminal of the switching unit 12, the trickle charging unit 20-2 is connected in parallel with the main switch 20-1, and the main switch 20-1 and the trickle charging unit 20-2 respectively provide a first charging path Pc1 and a second charging path Pc2 for charging the battery 200.

The second control unit 16 is coupled to the main switch 20-1, the trickle charge unit 20-2 and the battery 200, and determines to turn on the first charge path Pc1 or the second charge path Pc2 according to a battery voltage Vb of the battery 200. When the battery 200 is coupled to the battery charging apparatus 100 and the second control unit 16 detects that the battery voltage Vb is lower than the threshold value, the second control unit 16 controls the trickle charging unit 20-2 to provide the second charging path Pc2, so that the trickle charging unit 20-2 provides the trickle current It to charge the battery 200. When the second control unit 16 detects that the battery voltage Vb is higher than the threshold, the second control unit 16 controls to turn on the main switch 20-1 to provide the first charging path Pc1, so that the battery charging apparatus 100 provides the output power Vo to charge the battery 200. The second control unit 16 can be coupled to a path of the output terminal of the battery charging apparatus 100 or directly coupled to the battery 200 to detect the battery voltage Vb (fig. 1 is an example of a path in which the second control unit 16 is coupled to the output terminal of the battery charging apparatus 100). The mode control unit 18 is coupled to the first control unit 14, the output terminal of the converting unit 12 (i.e., the secondary side 12-3 of the converting unit 12) and the second control unit 16, and the mode control unit 18 drives and controls the first control unit 14 and the second control unit 16 according to the output power Vo and the state of the battery 200 (provided by the second control unit 16).

Specifically, when the converting unit 12 can convert the input power Vin into the output power Vo, the mode control unit 18 receives the output power Vo, and the power required by the first control unit 14 and the second control unit 16 is obtained by coupling an auxiliary winding (not shown) to the isolation transformer 12-1. When the battery 200 is not coupled to the battery charging apparatus 100, the second control unit 16 detects that the battery 200 is not coupled. At this time, the second control unit 16 controls the main switch 20-1 not to be conducted and not to provide the first charging path Pc1, and also controls the trickle charging unit 20-2 not to provide the second charging path Pc2, so as to avoid the non-battery 200 coupled with the battery charging apparatus 100 and increase the risk of unexpected failure of the battery charging apparatus 100.

When the battery 200 is coupled to the battery charging apparatus 100 and the second control unit 16 detects that the battery voltage Vb is lower than the threshold value, the second control unit 16 controls the trickle charging unit 20-2 to provide the second charging path Pc2 and notifies the mode control unit 18, so that the mode control unit 18 notifies the first control unit 14 to control the converting unit 12 to provide the output power Vo in the constant voltage mode. At this time, the trickle charging unit 20-2 charges the battery 200 by supplying the trickle current It according to the output power Vo. When the second control unit 16 detects that the battery voltage Vb is higher than the threshold, the second control unit 16 controls to turn on the main switch 20-1 to provide the first charging path Pc1 and notify the mode control unit 18, so that the mode control unit 18 notifies the first control unit 14 to perform the constant current charging mode or the constant voltage charging mode (determined according to whether the battery 200 is fully charged).

Further, since the battery 200 is coupled to the battery charging apparatus 100 and the battery voltage Vb is lower than the threshold (i.e., the battery is completely discharged to 0 volt or the battery voltage Vb is very low), if the main switch 20-1 is turned on, the output power Vo is pulled down to approximately 0 volt (i.e., the voltage of the secondary side 12-3 of the converting unit 12 is pulled down to approximately 0 volt) due to the turning on of the main switch 20-1. At this time, the voltage converted by the auxiliary winding is close to 0 v and cannot drive the first control unit 14 and the second control unit 16, so that the battery charging apparatus 100 is disabled momentarily. Therefore, the main objective of the present invention is to control the trickle charging unit 20-2 to provide the trickle current It to charge the battery 200 without turning on the main switch 20-1 in the state that the battery voltage Vb is lower than the threshold (at this time, the output power Vo is not pulled down to be close to 0 volt, so that the first control unit 14 and the second control unit 16 can still be stably driven), so as to avoid the instant failure of the battery charging device 100 caused by the failure of the first control unit 14 and the second control unit 16, and achieve the effect of still starting the battery charging device 100 when the battery 200 is at zero voltage.

Fig. 2 is a block diagram of a trickle charge unit according to the present invention, and fig. 1 is also included. The trickle charging unit 20-2 includes a transistor 22, a control switch 24, and a trickle control unit 26, and the transistor 22 includes an input terminal 22-1, an output terminal 22-2, and a control terminal 22-3. The input terminal 22-1 is coupled to the output power Vo, and the output terminal 22-2 is coupled to the battery 200 (coupled to the battery 200 via the trickle control unit 26). The control switch 24 is coupled to the output power Vo, the second control unit 16 and the control terminal 22-3 of the transistor 22, and the second control unit 16 controls the control switch 24 to be turned on or off. When the control switch 24 is turned on, the transistor 22 is turned on (operating in the Ohm region or the saturation region) to establish a channel, so that the trickle charge unit 20-2 provides the second charge path Pc 2. When the control switch 24 is turned off, the transistor 22 is turned off and cannot establish a channel, so that the trickle charge unit 20-2 cannot provide the second charge path Pc 2. The trickle control unit 26 is coupled to the control switch 24, the transistor 22 and the battery 200, and generates a trickle current It in the second charging path Pc2 when the transistor 22 establishes a channel to provide the second charging path Pc 2. It should be noted that in one embodiment of the present invention, the transistor 22 is a Bipolar Junction Transistor (BJT). Since the transistor 22 only provides a channel through which current flows to generate the second charging path Pc2, a semiconductor device that can be turned on to generate the channel is suitable. For example, but not limited to, semiconductor devices such as Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), Insulated Gate Bipolar Transistors (IGBTs), etc. may be substituted.

The trickle charging unit 20-2 further includes a current limiting resistor Rc having one end coupled to the output power Vo and the input terminal 22-1 of the transistor 22 and the other end coupled to the control switch 24. When the control switch 24 is turned on, the current limiting resistor Rc limits the control current flowing to the control terminal 22-3 of the transistor 22 to prevent the transistor 22 from being damaged due to the excessive control current. It should be noted that, in an embodiment of the present invention, since the battery 200 needs to be awakened by a low-current pre-charging method when the battery 200 is completely discharged, the trickle current It should not be too large or too small. Therefore, in an embodiment of the present invention, the trickle current It is set to a current value of 100 to 200 ma to achieve the effect of optimizing the pre-charge.

Fig. 3A is a circuit diagram of a trickle control unit according to a first embodiment of the present invention, and fig. 1 to 2 are combined. The trickle control unit 26-1 includes a voltage regulator unit 262 and a resistor 264, and the voltage regulator unit 262 includes an input terminal 262-1, an output terminal 262-2, and a control terminal 262-3. The input 262-1 is coupled to the control terminal 22-3 of the transistor 22 and the control switch 24, and the output 262-2 is coupled to the battery 200. One end of the resistor 264 is coupled to the control terminal 262-3 of the voltage regulator unit 262 and the output terminal 22-2 of the transistor 22, and the other end of the resistor 264 is coupled to the output terminal 262-2 of the voltage regulator unit 262 and the battery 200. The voltage regulator 262 generates a reference voltage Vref with a constant value at a node of the control terminal 262-3 when the channel of the transistor 22 is established. A reference voltage Vref of a fixed value generates a reference current Ib similar to a constant current source through resistor 264. In the present embodiment, under the condition that the battery 200 is directly coupled to the resistor 264, the reference current Ib is the trickle current It, so that the trickle current It with a fixed current value continuously charges the battery 200. It should be noted that, in an embodiment of the present invention, since the trickle charge unit 20-2 can be implemented by using only the circuit composed of the transistor 22, the control switch 24, the voltage stabilizing unit 262 and the resistor 264, the effect of starting the battery charging apparatus 100 when the battery 200 is at zero voltage can still be achieved. Therefore, the trickle charge unit 20-2 has the advantages of few necessary components, simple structure, low circuit cost and easy control.

Fig. 3B is a circuit diagram of a trickle control unit according to a second embodiment of the present invention, and fig. 1 to 3A are combined. The trickle control unit 26-2 of this embodiment is different from the trickle control unit 26-1 of the first embodiment of fig. 3A in that the trickle control unit 26-2 further includes a specific flow unit 266. The ratio flow unit 266 includes a primary side 266-1 and a secondary side 266-2. The primary side 266-1 of the current comparing unit 266 is coupled to the voltage stabilizing unit 262 and the resistor 264, and the secondary side 266-2 of the current comparing unit 266 is coupled to the battery 200. With reference current Ib, the ratio unit 266 couples the reference current Ib from the turns ratio of the primary side 266-1 to the secondary side 266-2, causing the secondary side 266-2 to provide the trickle current It to the battery 200. Since the current comparing unit 266 has a primary side 266-1 and a secondary side 266-2, and couples the reference current Ib to the secondary side 266-2 by electromagnetic coupling, the current comparing unit 266 can achieve the effect of electrical isolation. It should be noted that, in an embodiment of the present invention, since the current comparing unit 266 does not affect the generation of the reference current Ib, it can be coupled before the resistor 264 or after the resistor 264. In addition, the circuit coupling and control methods of the elements not mentioned in this embodiment are the same as those in fig. 3A, and are not described herein again.

Fig. 3C is a circuit diagram of a trickle control unit according to a third embodiment of the present invention, and fig. 1 to 3B are combined. The trickle control unit 26-3 of this embodiment is different from the trickle control unit 26-1 of the first embodiment of fig. 3A in that the trickle control unit 26-3 further includes a current mirror circuit 268. The current mirror circuit 268 is coupled to the voltage regulator 262, the resistor 264 and the battery 200, and when the reference current Ib exists, the current mirror circuit 268 adjusts the multiplying factor of the reference current Ib to the trickle current It so as to provide the trickle current It to the battery 200. Wherein the adjusted multiplying power can be more than or less than 1. Since the current mirror circuit 268 has the function of amplifying or reducing the current and the trickle current It provided is hardly affected by the variation of the battery voltage Vb at the output terminal, the effect of easily adjusting the required current value according to the actual requirement can be achieved. It should be noted that, in an embodiment of the present invention, the current mirror circuit 268 may be coupled before the resistor 264 or after the resistor 264 because it does not affect the generation of the reference current Ib. The current mirror circuit 268 is not limited to be implemented by the circuit structure shown in fig. 3C, and any circuit structure that can achieve the current mirror effect should be included in the scope of the present embodiment. In addition, the circuit coupling and control methods of the elements not mentioned in this embodiment are the same as those in fig. 3A, and are not described herein again.

Fig. 3D is a circuit diagram of a trickle control unit according to a fourth embodiment of the present invention, and fig. 1 to 3C are combined. The trickle control unit 26-4 of this embodiment is different from the trickle control unit 26-1 of the first embodiment of fig. 3A in that the trickle control unit 26-4 includes a voltage dividing unit 272 and an amplifying unit 274. The voltage divider 272 couples the transistor 22 and the battery 200, and includes a first resistor R1 coupled between the output terminal 22-2 of the transistor 22 and the battery 200. The amplifying unit 274 includes a first input terminal 274-1, a second input terminal 274-2 and an output terminal 274-3, the output terminal 274-3 is coupled to the control terminal 22-3 of the transistor 22 and the control switch 24, the first input terminal 274-1 is coupled to the output terminal 22-2 of the transistor 22 and the voltage dividing unit 272, and the second input terminal 274-2 is coupled to the reference voltage Vref. When the control switch 24 is turned on, the trickle control unit 26-4 forms an amplifying circuit such that the first input terminal 274-1 and the second input terminal 274-2 have the effect of a virtual ground. Thus, the reference voltage Vref is generated at the node between the first resistor R1 and the output terminal 22-2 of the transistor 22. The reference voltage Vref generates a trickle current It through the first resistor R1 so that the trickle current It can continuously charge the battery 200. It should be noted that, in an embodiment of the present invention, the trickle control unit 26-4 shown in fig. 3D may also apply the specific current unit 266 and the current mirror circuit 268 shown in fig. 3B to 3C, and the connection structure and the control method thereof are similar to those shown in fig. 3B to 3C and are not repeated herein. In addition, the circuit coupling and control methods of the elements not mentioned in this embodiment are the same as those in fig. 3A, and are not described herein again.

However, the above description is only for the detailed description and drawings of the preferred embodiments of the present invention, and the features of the present invention are not limited thereto, and the present invention is not limited thereto, and all the scope of the present invention should be defined by the claims, and all the embodiments that combine the spirit of the claims of the present invention and similar changes should be included in the scope of the present invention, and any person skilled in the art in the field of the present invention can easily think of the changes or modifications can be covered by the claims of the present invention. Furthermore, the features mentioned in the claims and in the description may be implemented separately or in any combination.

Of course, the present invention can have other embodiments, and those skilled in the art can make various corresponding changes and modifications according to the present invention without departing from the spirit and the essence of the present invention, and these corresponding changes and modifications should fall within the protection scope of the claims of the present invention.

Claims

1. A battery charging apparatus, comprising:

a conversion unit, a primary side of which is coupled with an input power supply;

the first control unit is coupled with the conversion unit and controls the conversion unit to convert the input power supply into an output power supply;

a main switch coupled to the conversion unit and a battery and providing a first charging path for the output power supply to charge the battery;

a trickle charging unit, connected in parallel with the main switch, and providing a second charging path for charging the battery with a trickle current;

a second control unit coupled to the main switch and the trickle charge unit, and conducting the second charge path according to a battery voltage of the battery being lower than a threshold value, and conducting the first charge path according to the battery voltage being higher than the threshold value; and

and the mode control unit is coupled with the first control unit, the secondary side of the conversion unit and the second control unit and controls the first control unit and the second control unit according to the output power supply.

2. The battery charging apparatus as set forth in claim 1, wherein the trickle charge unit comprises:

a transistor coupled to the output power source and the battery;

a control switch coupled to the output power source, the second control unit and the transistor, and establishing a channel of the transistor when the control switch is turned on so that the trickle charge unit provides the second charge path; and

and the trickle control unit is coupled with the control switch, the transistor and the battery and generates the trickle current in the second charging path when the channel is provided.

3. The battery charging apparatus as claimed in claim 2, wherein the trickle charge unit further comprises:

and the current limiting resistor is coupled with the output power supply, the transistor and the control switch and limits a control current of a control end of the transistor.

4. The battery charging apparatus as claimed in claim 2, wherein the trickle control unit comprises:

a voltage division unit coupled to the transistor and the battery; and

an amplifying unit including a first input terminal, a second input terminal and an output terminal, wherein the output terminal is coupled to the transistor and the control switch, the first input terminal is coupled to the transistor and the voltage dividing unit, and the second input terminal is coupled to a reference voltage; the amplifying unit generates the trickle current according to the reference voltage and the voltage dividing unit when the amplifying unit has the channel.

5. The battery charging apparatus as claimed in claim 2, wherein the trickle control unit comprises:

a voltage stabilizing unit coupled to the transistor, the control switch and the battery and generating a reference power; and

and a resistor coupled to the transistor, the voltage stabilizing unit and the battery, and generating a reference current corresponding to the trickle current according to the reference power source when the resistor has the channel.

6. The battery charging apparatus as claimed in claim 5, wherein the voltage-stabilizing unit and the resistor are coupled to the battery such that the reference current is provided as the trickle current to the battery through the resistor.

7. The battery charging apparatus as claimed in claim 5, wherein the trickle control unit further comprises:

a current-comparing unit, which includes a primary side and a secondary side, the primary side is coupled with the voltage-stabilizing unit and the resistor, and the secondary side is coupled with the battery; the current-comparing unit couples the reference current from the primary side to the secondary side through a turn ratio, so that the secondary side provides the trickle current to the battery.

8. The battery charging apparatus as claimed in claim 5, wherein the trickle control unit further comprises:

a current mirror circuit coupled to the voltage stabilizing unit, the resistor and the battery, and adjusting the reference current to the trickle current by a multiplying factor, and providing the trickle current to the battery.

9. The battery charging apparatus of claim 1, wherein the trickle current is between 100 milliamps and 200 milliamps.

10. The battery charging apparatus of claim 1, wherein the second control unit controls the first charging path and the second charging path to be open when the battery is not coupled to the battery charging apparatus.