WO2013113236A1

WO2013113236A1 - Secondary battery charging device

Info

Publication number: WO2013113236A1
Application number: PCT/CN2012/086825
Authority: WO
Inventors: 樊晓微; 周湘鲁
Original assignee: 无锡华润上华半导体有限公司
Priority date: 2012-02-03
Filing date: 2012-12-18
Publication date: 2013-08-08
Also published as: CN103248074B; CN103248074A

Abstract

A secondary battery charging device (70) includes a thermostatic charging module (330) and/or a constant current charging module. While charging, the thermostatic charging module regulates the charging current to substantially maintain the charging device at a predetermined temperature value when the temperature of the charging device exceeds a predetermined temperature value; and the constant current charging module regulates the charging current to substantially maintain at a predetermined current value when the charging current exceeds a predetermined current value. The charging device has a high charging efficiency, long life, and small impact on the life of the secondary battery charged. The charging device and the secondary battery have high safety and reliability in the normal charging process.

Description

Secondary battery charging device

[Technical Field]

The invention belongs to the technical field of secondary battery charging, and relates to a charging device for a secondary battery, and more particularly to a charging device with a constant temperature charging module and/or a constant current charging module.

【Background technique】

Secondary batteries are widely used in various portable electronic devices (for example, notebook computers, mobile phones, digital music players, etc.), for example, various rechargeable nickel-cadmium (Ni-Cd) batteries, nickel-hydrogen (Ni- H) Battery, lithium-ion battery, nickel metal hydride (Nickel Metal-Hydride, Ni-H) batteries, etc., therefore, generally, corresponding secondary batteries are provided with corresponding charging devices.

The control drive portion of the charging device is typically implemented by an integrated circuit (IC) chip that is used to control the charging process. When designing the integrated circuit chip, it is usually necessary to consider the influence of the charging process on the battery performance and the chip itself, and at the same time, the charging efficiency must be taken into consideration. Currently, the industry is constantly pursuing improvements in charging efficiency, reducing the impact of the charging process on the life of secondary batteries and charging devices, and improving the safety and reliability of charging devices and secondary batteries.

[Summary of the Invention]

In order to solve the deficiencies in the charging device of the secondary battery in the prior art, one of the objects of the present invention is to substantially achieve constant temperature charging control of the secondary battery to improve the service life of the secondary battery and the charging device, and to improve the charging efficiency.

Still another object of the present invention is to improve the safety and reliability of a charging device and a secondary battery.

To achieve the above object or other objects, the present invention provides a charging device for a secondary battery, comprising a main module of a charging control circuit and a main module of a logic control circuit, characterized in that it further comprises: a constant temperature charging module and/or a constant current charging module. ;

The thermostatic charging module is coupled to the main control module of the charging control circuit, and after the temperature of the charging device exceeds a predetermined temperature value during charging, the thermostatic charging module is configured to adjust and control the charging current to enable The charging device is substantially maintained at a predetermined temperature value;

The constant current charging module is coupled to the charging control circuit main module, and after the charging current exceeds a predetermined current value during charging, the constant current charging module is configured to adjust a control charging current to make it basic The ground is maintained at a predetermined current value.

According to a charging apparatus of an embodiment of the present invention, the secondary battery is a secondary battery used in a mobile phone, and the charging device is a universal charger adapted to charge a secondary battery used in a plurality of mobile phones.

A charging device according to still another embodiment of the present invention, wherein the charging device includes a charging circuit of the secondary battery, and a driving MOS transistor for controlling a charging current of the secondary battery is disposed in the charging circuit;

The constant temperature charging module includes:

a triode for sampling a feedback temperature signal;

a first operational amplifier for performing a comparison operation;

A first strobe transistor is controlled by an output of the first operational amplifier to selectively output a temperature feedback signal to a gate of the drive MOS transistor.

In the charging device of any of the foregoing embodiments, preferably, the triode is a PNP type triode, and an emitter of the triode is connected to a constant current source, and a base and a collector of the triode are grounded and have a negative The emitter base voltage of the transistor of temperature coefficient is input to the first input of the first operational amplifier.

In the charging device of any of the foregoing embodiments, preferably, the second input terminal of the first operational amplifier is connected to the first reference voltage, and the size of the first reference voltage is set to determine the The predetermined temperature value.

In the charging device of any of the foregoing embodiments, preferably, the first strobe is a PMOS/NMOS transistor, and a gate and a drain of the PMOS/NMOS transistor are coupled to the first operational amplifier. The output of the PMOS/NMOS transistor is coupled to the gate of the driving MOS transistor.

The constant current charging module includes:

a sampling MOS transistor for sampling a charging current in the charging circuit;

a resistor connected in series with the sampling MOS transistor;

a second operational amplifier for performing a comparison operation;

A second strobe transistor is controlled by an output of the second operational amplifier to selectively output a charging current feedback signal to a gate of the driving MOS transistor and the sampling MOS transistor.

In the charging device of any of the foregoing embodiments, preferably, the constant current charging module further includes:

Third operational amplifier, and

a third MOS transistor;

Wherein the drain of the driving MOS transistor is connected to the first input end of the third operational amplifier, and the drain of the sampling MOS transistor is simultaneously connected to the second input end of the third operational amplifier and the third MOS a source of the transistor, an output of the third operational amplifier being coupled to a gate of the third MOS transistor.

In the charging device of any of the foregoing embodiments, preferably, the sampling MOS transistor is a MOS transistor that is scaled down relative to the driving MOS transistor.

In the charging device of any of the foregoing embodiments, preferably, the sampling MOS transistor and the driving MOS transistor are both PMOS transistors.

In the charging device of any of the foregoing embodiments, preferably, the voltage signal across the resistor is fed back to the two inputs of the second operational amplifier, and the first input of the second operational amplifier is A second reference voltage is input, and the predetermined current value is determined by setting a magnitude of the second reference voltage.

In the charging device of any of the foregoing embodiments, preferably, the second strobe is a PMOS/NMOS transistor, and a gate and a drain of the PMOS/NMOS transistor are coupled to the second operational amplifier. The output of the PMOS/NMOS transistor is coupled to the gates of the driving MOS transistor and the sampling MOS transistor.

A charging device according to still another embodiment of the present invention, wherein the charging device further comprises:

Reference current and reference voltage module,

Battery polarity detection module,

Power-on detection module,

Trickle charge detection module,

Charging saturation detection module,

Short circuit protection module, and / or

Internal oscillator.

In the charging device of any of the foregoing embodiments, preferably, the predetermined temperature value is about 120 °C.

In the charging device of any of the foregoing embodiments, preferably, the predetermined current value is about 500 mA.

The technical effect of the present invention is that, when the temperature of the charging device is too high, the charging current can be reduced in real time through the feedback loop in the thermostatic charging module, so that the charging device does not have repeated over-temperature phenomenon when the temperature is high, and The charging process is not interrupted, so that the subsequent charging process can be maintained at a predetermined temperature value for charging. Therefore, the charging efficiency is high, the life of the charged secondary battery is small, and the life of the charging device is long. In addition, after the charging current is greater than the predetermined current value, the "high current" constant current charging can be realized by the constant current charging module, so that the charging current is controlled at a safer predetermined current value in the subsequent charging process, thereby greatly improving the charging device and The safety and reliability of the secondary battery.

[Description of the Drawings]

The above and other objects and advantages of the present invention will be more fully understood from the aspects of the appended claims.

1 is a schematic structural diagram of a functional module of an embodiment of a charging device of the prior art.

2 is a block diagram showing the structure of a charging device in accordance with an embodiment of the present invention.

3 is a schematic view showing a circuit configuration of a constant temperature charging module and a constant current charging module used in the charging device shown in FIG. 2.

4 is a block diagram showing the structure of a charging device according to still another embodiment of the present invention.

FIG. 5 is a schematic diagram showing a circuit configuration of a constant temperature charging module used in the charging device shown in FIG. 4. FIG.

Figure 6 is a block diagram showing the structure of a charging device in accordance with still another embodiment of the present invention.

Fig. 7 is a view showing a circuit configuration of a constant current charging module used in the charging device shown in Fig. 6.

【detailed description】

The following is a description of some of the various possible embodiments of the invention, which are intended to provide a basic understanding of the invention and are not intended to identify key or critical elements of the invention or the scope of the invention. It is to be understood that, in accordance with the technical aspects of the present invention, those skilled in the art can suggest other alternatives that are interchangeable without departing from the spirit of the invention. Therefore, the following detailed description and the accompanying drawings are merely illustrative of the embodiments of the invention, and are not intended to

As used herein, the terms "substantially", "about" or "left and right" are used to provide industry-accepted tolerances for their respective modified terms.

FIG. 1 is a schematic structural diagram of a functional module of a prior art charging device embodiment. In this embodiment, the charging device 10 is used to charge a secondary battery, and the secondary battery may specifically be a lithium battery used in a mobile phone terminal. As shown in FIG. 1, the drive control portion of the charging device 10 includes a plurality of functional module implementations, which can generally be implemented by an integrated circuit (IC). Specifically, the functional modules of the charging device 10 include a charging control circuit main module 110 and a logic control circuit main module 120. The charging control circuit main module 110 is generally realized in the form of an analog circuit, and the output end thereof can be externally connected to the positive and negative electrodes of the secondary battery. In different states of the secondary battery, the charging control circuit main module 110 can realize the control of charging and stopping charging of the secondary battery, including battery positive charging, reverse charging, trickle charging when the battery voltage is too low, and output short circuit. The control of the function such as charging is stopped; the logic control circuit main module 120 is generally implemented in the form of a digital circuit for displaying various charging and protection states through the LED for the user to judge the state of charge of the battery.

Continuing to refer to FIG. 1, the charging device 10 further includes the following functional modules:

(1) A reference current and reference voltage module 111 for supplying a reference voltage and a reference current to the circuit.

(2) a battery polarity detecting module 112, which is connected to the charging control circuit main module 110, through which the polarity of the charged secondary battery can be automatically recognized, and further controlled so that the secondary battery is in Whether the polarity is positive or reverse can enter the charging state.

(3) The power-on power-on detection module 114 detects whether the power supply is correctly powered up to the secondary battery. When (V _DD -V _BAT ) is greater than a predetermined value (for example, 40 mV), it is considered that the power is correctly turned on, and there is a corresponding Indicator lights (such as LEDs) indicate.

(4) trickle charge detection module 117; when the power source is connected and the secondary battery is connected, if the secondary battery voltage is less than the precharge threshold voltage V _{MIN of the} trickle charge (for example, about 2.5 V), for the secondary battery A small precharge current I _PCHA (about 25 mA) is precharged (or called a trickle charge phase), and normal charging starts when the voltage of the secondary battery reaches V _MIN ; therefore, the trickle charge detection module 117 uses It is detected whether the voltage of the secondary battery is less than the pre-charge threshold voltage, and outputs a control signal to the logic control circuit main module 120 to further control the pre-charging process.

(5) The charging saturation detecting module 116; when the power source is connected and the secondary battery is not full and the battery voltage is greater than V _MIN , the power supply starts to normally charge the battery through the control of the chip, and the voltage across the secondary battery will gradually decrease. Raise, when the battery voltage rises to a voltage V _S (about 4.20V) indicating that the battery is full, enters the constant voltage charging phase, the charging current gradually decreases, and when the charging current is less than the saturation off current I _FULL , the battery is considered to be saturated and charged. End; therefore, the charge saturation detection module 116 is configured to detect whether the charging current is less than the saturation off current I _FULL after the normal charging process (relative to the pre-charging process definition), and output a control signal to the logic control circuit main module 120 to further terminate Charging process.

(6) The short circuit protection module 118, if a secondary battery short circuit occurs after the power source is connected, the charging device and the secondary battery may be burnt out; the short circuit protection module 118 is configured to detect whether the secondary battery is short-circuited, and The signal is output to the logic control circuit main module 120 to automatically reduce the charging current while giving a short circuit status indication.

(7) An internal oscillator 115, which is coupled to the logic control circuit main module 120 for providing timing signals.

(8) The over temperature protection module 113, if the temperature of the charging device (for example, the junction temperature of a certain junction in the chip) exceeds the over temperature protection threshold T _O (for example, about 140 ° C), the over temperature protection module 113 outputs a control signal. The normal charging state is resumed by automatically cutting off the charging current until the junction temperature drops to the over-temperature recovery threshold T _R (eg, about 120 ° C).

The specific meanings of the above parameters are listed in Table 1 below.

Table I

parameter name	Parameter symbol
Input voltage	V _DD
Saturation voltage	V _S
No-load voltage	V _O
Secondary battery voltage	V _BAT
recharging current	I _CHARGE
Saturation off current	I _FULL
Precharge threshold voltage	V _MIN
Precharge current	I _PCHA
Short circuit detection voltage	V _SHORT
Over temperature protection threshold	T _O
Over temperature recovery threshold	T _R

In the charging device of the embodiment shown in FIG. 1, when the over-temperature protection is performed, there is a possibility that the charging device enters a "open-close-on-off-off" cycle operation mode, that is, the normal state of the secondary battery. The charging process is continuously suspended, thus affecting the efficiency of charging and reducing the service life of the charging device and the secondary battery.

In addition, when the charging device of the embodiment shown in FIG. 1 charges the secondary battery during the normal charging process, the charging current is not limited until the secondary battery voltage reaches V _s , and therefore, the large current of the charging process cannot be obtained. Effective current limiting, if an abnormality occurs during charging, it may cause excessive current, which affects the life and safety of the charging device and the secondary battery.

The charging process of the secondary battery can be generally divided into a pre-charging process and a normal charging process, and enters a normal charging process after the pre-charging process ends; in the pre-charging process, generally a smaller pre-charging current is used for charging; During the charging process, if the voltage difference between the power-on voltage (such as V _DD shown in Figure 3) and the secondary battery is too large, or if an abnormality occurs, the charging current may be very large.

FIG. 2 is a block diagram showing the structure of a charging device according to an embodiment of the invention. The charging device 70 is for charging a secondary battery (for example, a lithium battery) used in a mobile phone. In practical applications, the structural parameters of the secondary battery are also different due to differences in various types of mobile phones; in order to achieve compatibility with charging of secondary batteries of various mobile phone models, the charging device 70 may preferably be a universal charger.

As shown in FIG. 2, the charging device 70 also includes a charging control circuit main module 110 and a logic control circuit main module 120 of the embodiment shown in FIG. 1. To prevent over-temperature charging, the charging device 70 is provided with a constant temperature charging module 330. The constant temperature charging module 330 can output a signal to the charging control circuit main module 110, which is different from the working principle of the over-temperature protection module 113 shown in FIG. 1 , when the ambient temperature of the charging device 70 is too high or the charging current is too large. When the temperature of the charging device (for example, the junction temperature of the device in which it is used) is too high, for example, greater than a predetermined temperature value (for example, 120 ° C), the constant temperature charging module 330 can thereafter feedback the temperature signal and reduce the charging current in real time, thereby The temperature of the charging device 70 can be made substantially constant at the predetermined temperature value (e.g., 120 ° C), thereby achieving a constant temperature charging process thereafter, and does not frequently occur beyond the predetermined temperature value. Therefore, the constant temperature charging module 330 does not interrupt the charging process because the temperature is too high during the charging process, but adjusts the charging current according to the temperature feedback in real time, and then the temperature of the charging process is substantially constant at the safe predetermined temperature value. When charging is performed, the lifespan of the charging device and the secondary battery are not interrupted, the life is long, and the charging efficiency is high.

2, the charging device 70 is further provided with a constant current charging module 540, and the constant current charging module 540 can also output a signal to the charging control circuit main module 110; during the normal charging process, if the power is turned on (for example, as shown in FIG. 3) The voltage difference between the V _DD ) and the secondary battery is too large, or if an abnormality occurs, the charging current may be very large; by the constant current charging module 540, a predetermined current value that makes the charging device and the secondary battery relatively safe may be set. The predetermined current value is generally relative to the current greater than the normal charging process and is therefore also referred to as "high current." After the charging current exceeds the predetermined current value, the constant current charging module 540 starts operating to reduce the charging current and substantially maintain the constant current charging, that is, "high current" constant current charging. In this embodiment, the magnitude of "high current" (i.e., predetermined current value) is in the order of magnitude of 100 mA to 1000 mA, for example, "high current" is substantially set to 500 mA. It should be understood by those skilled in the art that the magnitude of the predetermined current value may be set according to a specific situation. At least, when the predetermined current value is charged, the charging device and the charged secondary battery should be relatively safe; The "flow" is also a relative concept, and the error range of the current magnitude is well known to those skilled in the art, and may continue to narrow the error range as the charging technology develops.

3 is a schematic view showing an embodiment of a circuit configuration of a constant temperature charging module and a constant current charging module used in the charging device shown in FIG. 2. As shown in FIG. 3, the constant current charging module 330 is provided with a constant current source _Ib , and the current of the constant current source _Ib is input to the emitter (E) of the series connected transistor Q1, and the base and the emitter of the transistor Q1 are simultaneously grounded. In this example, the transistor Q1 is a PNP type transistor, and the emitter base voltage _{Vbe of the} transistor Q1 has a negative temperature coefficient. Therefore, it can be used to sample the temperature signal of the chip where the feedback transistor Q1 is located, that is, the sampling charging device. Temperature signal. As the chip temperature changes, _Vbe changes with temperature. Further, V _be (ie, point B voltage) is input to the negative ("-") input terminal of the operational amplifier OA1 of the constant temperature charging module 330, and the positive ("+") input terminal of the operational amplifier OA1 is connected to the reference voltage V _ref1 . Therefore, when V _ref1 of the input terminal of the operational amplifier OA1 is greater than V _be , OA1 outputs a positive voltage; otherwise, OA1 outputs a negative voltage. The output of the operational amplifier OA1 is used to control the on and off of the MOS transistor M3 to selectively output a temperature feedback signal. In this example, the MOS transistor M3 is an NMOS transistor whose drain (D) and gate (G) are simultaneously connected to the output terminal of the operational amplifier OA1, and therefore, the MOS transistor M3 is connected in the form of a diode. The source of the MOS transistor M3 is further connected to the gate of the driving MOS transistor M1 (in this example, M1 is a PMOS transistor) of the charging circuit of the charging device, so that the charging current I ₁ in the charging circuit can be controlled.

The basic working principle of the constant temperature charging module 330 is as follows:

For example, when the charging current I _{1 of} the charging circuit is too large, relatively large heat is generated to cause the temperature of the entire chip to rise (that is, the temperature of the charging device is increased), and the junction temperature of the transistor Q1 is increased synchronously, V. _Be decreases; when V _be decreases to less than the reference voltage V _ref1 , OA1 outputs a positive voltage, the MOS transistor M3 connected in the form of a diode is turned on, and the on current of the driving MOS transistor M1 is decreased, that is, the charging current is reduced. ₁ , so that the negative feedback loop formed by the thermostatic charging module 330 can work normally. Reducing the charging current I ₁ will decrease the temperature of the entire chip, in the subsequent charging process for charging may be maintained at the predetermined temperature value, the chip temperature at the predetermined temperature substantially fixed value. It should be noted that the specific predetermined temperature value may be set by the value of the V _ref1 value. For example, preferably, the predetermined temperature value may be selected to be about 120 ° C.

On the contrary, when the whole chip temperature does not exceed the predetermined temperature value, V _be will be greater than the reference voltage V _ref1 , OA1 outputs a negative voltage, the diode-connected MOS transistor M3 is turned off, and the constant temperature charging module 330 cannot achieve the negative feedback loop operation. The charging current I ₁ continues to remain constant or continues to rise. At this time, the constant temperature charging module 330 does not operate, and the charging device can perform normal charging at a temperature below the predetermined temperature value.

It should be understood that the control principle process of the circuit shown in FIG. 3 can be implemented by other conversion forms of the circuit. For example, the MOS transistor M3 is replaced by a diode, and other devices having the function of sampling the temperature signal can also be used instead of the triode; The skilled person can make various modifications and equivalent replacements according to the principle of the circuit structure of the constant temperature charging module 330 shown in FIG. 2 above.

Referring to FIG. 3, the constant current charging module 540 is provided with a sampling MOS transistor M2, which is the same type of transistor as the driving MOS transistor M1. In this example, both are PMOS transistors; and, the sampling MOS transistor M2 is structurally a MOS transistor scaled down relative to the driving MOS transistor M1. The source (S) is connected to the voltage V _dd , and the gate (G) is connected to the same potential (that is, the voltage at point B). Therefore, the sampling MOS The drain (D) of transistor M2 outputs current I ₂ to enable sampling of charging current I ₁ . The constant current charging module 540 is further provided with an operational amplifier OA3 and a MOS transistor M4; the positive ("+") input terminal of the operational amplifier OA3 is connected to the drain of the driving MOS transistor M1, and the negative ("-") input terminal of the operational amplifier OA3 is connected. The drain of the sampling MOS transistor M2 is connected; at the same time, the drain of the sampling MOS transistor M2 is connected to the source of the MOS transistor M4, and the gate of the MOS transistor M4 is controlled by the output terminal of the operational amplifier OA3. Therefore, the operational amplifier OA3 and the MOS transistor M4 can together form a negative feedback regulator circuit, the drain of the sampling MOS transistor M2 is exactly equal to the driving voltage of the drain of the MOS transistor M1 charging circuit of the charging device, the charging current I ₂ is implemented the current I ₁ accurate sampling . Therefore, I ₂ can be calculated by the following relation (1):

I ₂ = I ₁ /N (1)

Where N is the current sampling scale factor.

Further, the drain of the MOS transistor M4 is connected in series with the resistor R, and the point C is located between the resistor R and the MOS transistor M4, so the voltage V _c at the point C is calculated by the following relation (2):

V _c = R × I ₂ = R × I ₁ /N (2)

The voltage V _c at point _{C is} further input to the positive ("+") input terminal of the operational amplifier OA2, and the negative ("-") input terminal of the operational amplifier OA2 is input with the reference voltage V _ref2 ; therefore, when the input terminal of the operational amplifier OA2 is V _{When c is} greater than V _ref ₂ , the operational amplifier OA2 outputs a positive voltage; otherwise, the operational amplifier OA2 outputs a negative voltage.

The output of the operational amplifier OA2 is used to control the turn-on and turn-off of the MOS transistor M5. In this example, the MOS transistor M5 is an NMOS transistor, and the drain (D) and the gate (G) are simultaneously connected to the output of the operational amplifier OA2. Therefore, the MOS transistor M5 is connected in the form of a diode. The source of the MOS transistor M5 outputs a feedback signal based on the charging current to the gates of the driving MOS transistor M1 and the sampling MOS transistor M2, that is, point B.

When the constant current charging module 540 operates, if the charging current I _{1 of the} charging circuit is greater than "high current" (ie, a predetermined current value), for example, greater than 500 mA, I ₂ will also increase, and the voltage at V _c rises. High, further causing V _c of the input terminal of the operational amplifier OA2 to be greater than V _ref2 , OA2 outputting a positive voltage, MOS transistor M5 is turned on, and voltage at point B is increased, further modulating the driving MOS transistor M1, reducing the charging current I ₁ , and finally reaching equilibrium That is, V _c = V _ref2 = (R × I ₁ /N). Therefore, when the charging current I _{1 is} too large, the negative feedback loop (composed of OA2, M2, M5, and R) in the constant current charging module 540 operates to maintain the charging current substantially at a predetermined current value during the subsequent charging process. on.

In the constant current charging module 540 of the embodiment shown in FIG. 3, the predetermined current value is determined by the input voltage V _{ref2 of the} input terminal of the negative ("-") input terminal of the operational amplifier OA2, and the predetermined current can be set by setting V _{ref2 .} Value (for example, 500 mA).

In the circuit configuration of the embodiment shown in FIG. 3, the reference voltages V _ref1 , V _ref2 and the constant current source I _b may be specifically provided by the reference voltage and reference current module 111 shown in FIG. 2. Point B is also connected to the charging control circuit main module 110.

With continued reference to FIG. 2, the charging device 70 further includes the following functional modules:

(4) trickle charge detection module 117; when the power source is connected and the secondary battery is connected, if the secondary battery voltage is less than the precharge threshold voltage V _{MIN of the} trickle charge (for example, about 2.5 V), for the secondary battery A small current precharge current I _PCHA (about 25 mA) is precharged (or called a trickle charge phase), and normal charging begins when the voltage of the secondary battery reaches V _MIN . Therefore, the trickle charge detection module 117 is configured to detect whether the voltage of the secondary battery is less than the precharge threshold voltage, and output a control signal to the logic control circuit main module 120 to further control the precharge process.

(5) The charging saturation detecting module 116; when the power source is connected and the secondary battery is not full and the battery voltage is greater than V _MIN , the power supply starts to normally charge the battery through the control of the chip, and the voltage across the secondary battery will gradually decrease. Raise, when the battery voltage rises to a voltage V _S (about 4.20V) indicating that the battery is full, enters the constant voltage charging phase, the charging current gradually decreases, and when the charging current is less than the saturation off current I _FULL , the battery is considered to be saturated and charged. End. Therefore, the charge saturation detection module 116 is configured to detect whether the charging current is less than the saturation off current I _FULL after the normal charging process (relative to the precharge process definition), and output a control signal to the logic control circuit main module 120 to further terminate the charging process. .

It should be understood that a person skilled in the art can selectively set the reference current and reference voltage module 111, the battery polarity detecting module 112, the power-on power detecting module 114, and the trickle charge detection on the charging device according to specific charging performance requirements. Module 117, charge saturation detection module 116, short circuit protection module 118 or internal oscillator 115.

4 is a block diagram showing the structure of a charging device according to still another embodiment of the present invention; and FIG. 5 is a schematic view showing a circuit configuration of a constant temperature charging module used in the charging device shown in FIG. 4. 4 and 2, the charging device 30 is opposite to the charging device 70, in which the constant current charging module 540 is not provided, and therefore, the charging device 30 does not have a "high current" constant current charging function. However, the charging device 30 has a constant temperature charging function compared to the charging device 10 of the embodiment shown in FIG. 1, avoiding the phenomenon of repeated over-temperature during charging, and can adjust the charging current according to the temperature in real time, the charging device and The service life of the secondary battery is not interrupted, the life is long, and the charging efficiency is high.

Compared with the embodiment shown in FIG. 2, the functions of the constant temperature charging module 330 are basically the same. Similarly, the circuit structure of the constant temperature charging module shown in FIG. 5 is basically the same as that of the constant temperature charging module shown in FIG. 3, and the working principle is basically the same. I will not repeat them here.

6 is a block diagram showing a structure of a charging device according to still another embodiment of the present invention; and FIG. 7 is a schematic view showing a circuit configuration of a constant current charging module used in the charging device shown in FIG. 6. 6 and FIG. 2, the charging device 50 is opposite to the charging device 70, wherein the thermostatic charging module 330 is not provided, and therefore, the charging device 50 does not have a constant temperature charging function. However, compared with the charging device 10 of the embodiment shown in FIG. 1, the charging device 50 is provided with a constant current charging module 540, which can perform "high current" constant current charging during normal charging, and the charging current is set at A safe predetermined value improves the safety and reliability of the secondary battery and its charging device.

Compared with the embodiment shown in FIG. 2, the functions of the constant current charging module 540 are basically the same. Similarly, the circuit structure of the constant current charging module shown in FIG. 7 is basically the same as the circuit structure of the constant current charging module shown in FIG. They are basically the same, and will not be repeated here.

In the charging apparatus of the embodiment shown in Figs. 2, 4 and 6, the respective functional modules included therein can be implemented on one IC chip.

It should be noted that the “connection” mentioned in the above embodiments may refer to a direct connection between the two, but those skilled in the art should understand that, without affecting the basic functions of the circuit, “ Elements or components that are "connected" may also be inserted between other components or components (the components or components that are inserted into the connection do not alter the signal transmission between the "connected" components or components). Therefore, "coupled" herein may refer to either a direct connection or an indirect coupling connection.

The above examples mainly illustrate the charging device of the secondary battery of the present invention. Although only a few of the embodiments of the present invention have been described, it will be understood by those skilled in the art that the present invention can be implemented in many other forms without departing from the spirit and scope thereof, for example, the NMOS transistor is replaced with a PMOS. The transistor and the PMOS transistor are replaced by NMOS transistors, and the signals at the input terminals of the operational amplifiers are exchanged accordingly. Accordingly, the present invention is to be construed as illustrative and not restrictive, and the invention may cover various modifications without departing from the spirit and scope of the invention as defined by the appended claims With replacement.

Claims

A charging device for a secondary battery, comprising a charging control circuit main module (110) and a logic control circuit main module (120), characterized by further comprising: a constant temperature charging module (330) and/or a constant current charging module (540) );

The thermostatic charging module (330) is coupled to the charging control circuit main module (110), and after the charging device exceeds a predetermined temperature value during charging, the thermostatic charging module (330) Means for adjusting the control charging current to maintain the charging device substantially at a predetermined temperature value;

The constant current charging module (540) is coupled to the charging control circuit main module (110), and after the charging current exceeds a predetermined current value during charging, the constant current charging module (540) is used. The charge current is controlled to be maintained substantially at a predetermined current value.
The charging device according to claim 1, wherein said secondary battery is a secondary battery used in a mobile phone, and said charging device is a universal charging adapted to charge a secondary battery used in a plurality of mobile phones. Device.
The charging device according to claim 1 or 2, wherein said charging means includes a charging circuit of said secondary battery, and said charging circuit is provided with a driving MOS transistor for controlling a charging current of said secondary battery ( M1);

The constant temperature charging module (330) includes:

a triode (Q1) for sampling a feedback temperature signal;

a first operational amplifier (OA1) for performing a comparison operation;

A first strobe (M3) is controlled by an output of the first operational amplifier (OA1) to selectively output a temperature feedback signal to a gate of the drive MOS transistor (M1).
The charging device according to claim 3, wherein said triode is a PNP/NPN type triode, and an emitter of said triode (Q1) is connected to a constant current source ( Ib ), said triode (Q1) The base and collector are grounded, and the emitter base voltage ( Vbe ) of the transistor having a negative temperature coefficient is input to the first input terminal of the first operational amplifier (OA1).
The charging device according to claim 3, wherein the second input terminal of the first operational amplifier (OA1) is connected to the first reference voltage, and the size of the first reference voltage is set to determine The predetermined temperature value is stated.
The charging device according to claim 3, wherein said first strobe (M3) is a PMOS/NMOS transistor, and a gate and a drain of said PMOS/NMOS transistor are coupled to said first operation An output of the amplifier (OA1), a source of the PMOS/NMOS transistor is coupled to a gate of the driving MOS transistor.
The charging device according to claim 1 or 2, wherein said charging means includes a charging circuit of said secondary battery, and said charging circuit is provided with a driving MOS transistor for controlling a charging current of said secondary battery ( M1);

The constant current charging module (540) includes:

a sampling MOS transistor (M2) for sampling a charging current in the charging circuit;

a resistor (R) connected in series with the sampling MOS transistor (M2);

a second operational amplifier (OA2) for performing a comparison operation;

a second strobe (M5) controlled by an output of the second operational amplifier (OA2) to selectively output a charging current feedback signal to the driving MOS transistor (M1) and the sampling MOS transistor (M2) The gate of ).
The charging device of claim 7, wherein the constant current charging module (540) further comprises:

Third operational amplifier (OA3), and

Third MOS transistor (M4);

The drain of the driving MOS transistor (M1) is connected to the first input terminal of the third operational amplifier (OA3), and the drain of the sampling MOS transistor (M2) is simultaneously connected to the third operational amplifier (OA3) a second input terminal and a source of the third MOS transistor (M4), and an output terminal of the third operational amplifier (OA3) is coupled to a gate of the third MOS transistor (M4).
A charging apparatus according to claim 7, wherein said sampling MOS transistor (M2) is a MOS transistor which is scaled down with respect to said driving MOS transistor (M1).
A charging apparatus according to claim 9, wherein said sampling MOS transistor (M2) and said driving MOS transistor (M1) are both PMOS transistors.
The charging device according to claim 7, wherein a voltage signal across said resistor (R) is fed back to a two-input terminal of said second operational amplifier (OA2), said second operational amplifier (OA1) The first input terminal is coupled to the second reference voltage, and the predetermined current value is determined by setting the magnitude of the second reference voltage.
The charging device according to claim 7, wherein the second strobe (M5) is a PMOS/NMOS transistor, and a gate and a drain of the PMOS/NMOS transistor are coupled to the second operation An output of the amplifier (OA2), a source of the PMOS/NMOS transistor is coupled to a gate of the driving MOS transistor (M1) and the sampling MOS transistor (M2).
The charging device according to claim 1 or 2, wherein the charging device further comprises:

Reference current and reference voltage module (111),

Battery polarity detection module (112),

Power-on detection module (114),

Trickle charge detection module (117),

Charging saturation detection module (116),

Short circuit protection module (118), and/or

Internal oscillator (115).
The charging device according to claim 2, wherein said predetermined temperature value is about 120 °C.
A charging device according to claim 2 or 12, wherein said predetermined current value is about 500 mA.