CN112865229A - Charging protection circuit and wireless earphone - Google Patents
Charging protection circuit and wireless earphone Download PDFInfo
- Publication number
- CN112865229A CN112865229A CN202110039483.6A CN202110039483A CN112865229A CN 112865229 A CN112865229 A CN 112865229A CN 202110039483 A CN202110039483 A CN 202110039483A CN 112865229 A CN112865229 A CN 112865229A
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- Prior art keywords
- battery
- charging
- management
- ntc
- voltage value
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- 238000001514 detection method Methods 0.000 abstract description 13
- 238000010586 diagram Methods 0.000 description 4
- 238000005070 sampling Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
Images
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/0031—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits using battery or load disconnect circuits
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H1/00—Details of emergency protective circuit arrangements
- H02H1/0007—Details of emergency protective circuit arrangements concerning the detecting means
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H5/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection
- H02H5/04—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature
- H02H5/042—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal non-electric working conditions with or without subsequent reconnection responsive to abnormal temperature using temperature dependent resistors
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/18—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for batteries; for accumulators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/0029—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries with safety or protection devices or circuits
- H02J7/00309—Overheat or overtemperature protection
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R1/00—Details of transducers, loudspeakers or microphones
- H04R1/10—Earpieces; Attachments therefor ; Earphones; Monophonic headphones
- H04R1/1025—Accumulators or arrangements for charging
Abstract
The invention provides a charging protection circuit and a wireless earphone, wherein the charging protection circuit comprises a charging management IC and a battery with an NTC (negative temperature coefficient) arranged inside; the BAT end of the charge management IC is connected with the positive electrode of the battery, the negative electrode of the battery is connected with the GND end of the charge management IC, and the TS end of the charge management IC is connected with the NTC interface of the battery; the charge management IC is configured to: calculating an NTC voltage value of the battery according to the charging data acquired in real time and the equivalent resistance value of the connecting wire, and stopping charging the battery when the NTC voltage value of the battery is judged to exceed a preset threshold range; the charging data comprises charging current and TS terminal voltage value of the charging management IC, and the equivalent resistance value of the connecting wire is the equivalent resistance value of the connecting wire between the cathode of the battery and the GND terminal of the charging management IC. The invention can solve the problem of inaccurate battery temperature detection caused by large line loss of the connecting line, thereby effectively improving the battery temperature detection precision.
Description
Technical Field
The invention relates to the technical field of circuits, in particular to a charging protection circuit and a wireless earphone.
Background
The current electronic products on the market have the condition that the battery is far away from the NTC used for detecting the temperature of the battery, so that the problem of inaccurate temperature detection is caused by long connecting wires.
For example, in a wireless earphone, if a battery and a PCB (electronic circuit board) are placed on the same side, the thickness of the whole earphone is increased, and in order to make the appearance of the earphone as thin as possible, a battery is usually placed on one side of the earphone, and a PCB is placed on the other side of the earphone.
The PCB includes chips such as a charge management IC (charge control IC) and an MCU, and in an application scenario where the connection line between the charge management IC and the battery is long and the impedance is large, a large charging current may cause a large voltage difference between the NTC voltage detected by the charge management IC and the actual NTC, which may cause erroneous determination of the charge management IC, and may result in that the charging cannot be stopped when the specified temperature is exceeded. The battery has a chargeable temperature range, and when the temperature is too low or too high, the battery is still charged, and the battery can be damaged.
Disclosure of Invention
The invention aims to provide a charging protection circuit and a wireless earphone, so as to solve the problem of inaccurate battery temperature detection caused by large line loss of a connecting line, and effectively improve the battery temperature detection precision.
In order to solve the above technical problem, the present invention provides a charging protection circuit, which includes a charging management IC and a battery with an NTC built therein;
the BAT end of the charging management IC is connected with the positive electrode of the battery, the negative electrode of the battery is connected with the GND end of the charging management IC, and the TS end of the charging management IC is connected with the NTC interface of the battery;
the charge management IC is configured to: calculating an NTC voltage value of the battery according to the charging data acquired in real time and the equivalent resistance value of the connecting wire, and stopping charging the battery when judging that the NTC voltage value of the battery exceeds a preset threshold range; the charging data comprises charging current and a TS terminal voltage value of the charging management IC, and the equivalent resistance value of the connecting wire is the equivalent resistance value of the connecting wire between the cathode of the battery and the GND terminal of the charging management IC.
Further, the NTC voltage value of the battery is calculated in the following manner:
Vntc＝Vts-Icharge*R4；
wherein Vntc represents an NTC voltage value of the battery, Vts represents a TS terminal voltage value of the charge management IC, Icharge represents the charging current, and R4 represents an equivalent resistance value of a connection line connecting a negative electrode of the battery and a GND terminal of the charge management IC.
Further, the charging protection circuit further comprises an MCU, and the MCU is connected with the charging management IC through an I2C interface.
In order to solve the same technical problem, the invention also provides a wireless headset, which comprises a first headset assembly, a second headset assembly, a connecting part and any one of the charging protection circuits;
one end of the connecting part is connected with the first earphone component, the other end of the connecting part is connected with the second earphone component, the charging management IC is arranged in the first earphone component, the battery is arranged in the second earphone component, and a connecting line between the charging management IC and the battery is laid in the connecting part.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a charging protection circuit and a wireless earphone, wherein the charging protection circuit comprises a charging management IC and a battery with an NTC (negative temperature coefficient) arranged inside; the BAT end of the charging management IC is connected with the positive electrode of the battery, the negative electrode of the battery is connected with the GND end of the charging management IC, and the TS end of the charging management IC is connected with the NTC interface of the battery; the charge management IC is configured to: calculating an NTC voltage value of the battery according to the charging data acquired in real time and the equivalent resistance value of the connecting wire, and stopping charging the battery when judging that the NTC voltage value of the battery exceeds a preset threshold range; the charging data comprises charging current and a TS terminal voltage value of the charging management IC, and the equivalent resistance value of the connecting wire is the equivalent resistance value of the connecting wire between the cathode of the battery and the GND terminal of the charging management IC. The invention can solve the problem of inaccurate battery temperature detection caused by large line loss of the connecting line, thereby effectively improving the battery temperature detection precision.
Drawings
Fig. 1 is a schematic structural diagram of a charge protection circuit according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of voltage versus temperature provided by an embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating a variation of a charging current of a battery according to an embodiment of the present invention;
FIG. 4 is a diagram of software logic provided in accordance with an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, an embodiment of the present invention provides a charging protection circuit, which includes a charging management IC and a battery with an NTC built therein;
the BAT end of the charging management IC is connected with the positive electrode of the battery, the negative electrode of the battery is connected with the GND end of the charging management IC, and the TS end of the charging management IC is connected with the NTC interface of the battery;
the charge management IC is configured to: calculating an NTC voltage value of the battery according to the charging data acquired in real time and the equivalent resistance value of the connecting wire, and stopping charging the battery when judging that the NTC voltage value of the battery exceeds a preset threshold range; the charging data comprises charging current and a TS terminal voltage value of the charging management IC, and the equivalent resistance value of the connecting wire is the equivalent resistance value of the connecting wire between the cathode of the battery and the GND terminal of the charging management IC.
In a specific embodiment, the charging current may also be obtained by sampling a voltage of a sampling resistor connected in series to the battery charging path through an ADC (analog-to-digital conversion module). Icharge ═ U sample voltage/R sample resistance.
Further, the NTC voltage value of the battery is calculated in the following manner:
Vntc＝Vts-Icharge*R4；
wherein Vntc represents an NTC voltage value of the battery, Vts represents a TS terminal voltage value of the charge management IC, Icharge represents the charging current, and R4 represents an equivalent resistance value of a connection line connecting a negative electrode of the battery and a GND terminal of the charge management IC.
Further, the charging protection circuit further comprises an MCU, and the MCU is connected with the charging management IC through an I2C interface.
In order to solve the same technical problem, the invention also provides a wireless headset, which comprises a first headset assembly, a second headset assembly, a connecting part and any one of the charging protection circuits;
one end of the connecting part is connected with the first earphone component, the other end of the connecting part is connected with the second earphone component, the charging management IC is arranged in the first earphone component, the battery is arranged in the second earphone component, and a connecting line between the charging management IC and the battery is laid in the connecting part.
Referring to fig. 1, based on the above scheme, in order to better understand the charging protection circuit provided by the embodiment of the present invention, the following detailed description is provided:
the reference numbers are as follows:
u1: the controller is a controller which can read and configure parameters related to the charging management IC by the MCU through an I2C interface (SCL, SDA);
u2: the charging management IC is used for managing the functions of charging current, temperature protection and the like of the battery;
u3: a battery having an NTC built therein;
r2: a connecting line equivalent resistance from the battery anode BAT + to the BAT pin of the charge management IC;
r3: equivalent resistance of a connecting line from the NTC of the battery to a TS pin of the charging management IC;
r4: battery negative electrode BAT-equivalent resistance of connecting wire to ground leg GND of charge management IC;
r1: an NTC built in the battery;
5V: a charging voltage of the charger;
ichar: the charge current flows through BAT output with the path U2, passes through R2, is input to BAT + and returns to GND of U2 from BAT-;
ur 4: voltage drop across R4 due to charging current Its, Ur4 ═ Icharge R4;
its: the constant current source inside the U2 outputs a fixed current, typically about 75uA, to the NTC resistor R1.
It should be noted that, where R1 is a thermistor, the resistance value changes with the temperature change, the TS pin of U2 outputs a fixed current, and U2 obtains the corresponding temperature through the voltage value Vts on the TS.
For example: the temperature value corresponding to the TS voltage of a certain chip is shown in fig. 2, and this corresponding relationship between the temperature and the voltage can be configured by software, and a more accurate corresponding relationship can be obtained by an actual temperature test.
The voltage value Vts on the TS pin is Its × R3+ Its × R1+ Its × R4+ Ur4, and Its × R3+ Its × R4+ Ur4, which may cause errors for temperature detection, may be ignored since Its is of the uA class, while Icharge is of the hundreds of milliamperes, and may cause a large voltage drop. The error caused cannot be ignored for the accuracy of temperature detection, and particularly, the larger the resistance of the connecting wire, the larger the error becomes.
Since the charging current varies during the charging of the battery, as shown in fig. 3:
ur4 is varied by Icharge in order to cancel this error in Ur4 at different charging currents. We chose a charge management IC that could read the charging current in real time, and the resistance R4 to the connection line is a controllable impedance, of known value, so we can calculate Ur 4.
It should be noted that, according to the actual measurement result, the error of the wire rod with impedance less than 50 milli-ohms is acceptable, and beyond this parameter, the error is relatively large. The problem of excessive impedance usually occurs when the headset wires are relatively long.
As shown in fig. 4, the logic in software is as follows:
1. reading charging current Icharge;
2. reading the voltage Vts of the Ts pin;
3. acquiring an actual NTC voltage Vntc-Vts-Ur 4;
4. whether the temperature corresponding to Vntc is too high or too low;
5. if yes, stopping charging; if not, returning to repeatedly execute the steps 1-4.
Compared with the prior art, the temperature detection method and the temperature detection device can solve the problem of inaccurate temperature detection caused by relatively high impedance of the connecting wire, and improve the detection precision.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention.
Claims (4)
1. A charging protection circuit is characterized by comprising a charging management IC and a battery with a built-in NTC;
the BAT end of the charging management IC is connected with the positive electrode of the battery, the negative electrode of the battery is connected with the GND end of the charging management IC, and the TS end of the charging management IC is connected with the NTC interface of the battery;
the charge management IC is configured to: calculating an NTC voltage value of the battery according to the charging data acquired in real time and the equivalent resistance value of the connecting wire, and stopping charging the battery when judging that the NTC voltage value of the battery exceeds a preset threshold range; the charging data comprises charging current and a TS terminal voltage value of the charging management IC, and the equivalent resistance value of the connecting wire is the equivalent resistance value of the connecting wire between the cathode of the battery and the GND terminal of the charging management IC.
2. The charge protection circuit of claim 1, wherein the NTC voltage value of the battery is calculated by:
Vntc＝Vts-Icharge*R4；
wherein Vntc represents an NTC voltage value of the battery, Vts represents a TS terminal voltage value of the charge management IC, Icharge represents the charging current, and R4 represents an equivalent resistance value of a connection line connecting a negative electrode of the battery and a GND terminal of the charge management IC.
3. The charge protection circuit according to claim 1, further comprising an MCU connected to the charge management IC via an I2C interface.
4. A wireless headset comprising a first earpiece assembly, a second earpiece assembly, a connection component, and the charge protection circuit of any one of claims 1-3;
one end of the connecting part is connected with the first earphone component, the other end of the connecting part is connected with the second earphone component, the charging management IC is arranged in the first earphone component, the battery is arranged in the second earphone component, and a connecting line between the charging management IC and the battery is laid in the connecting part.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110039483.6A CN112865229A (en) | 2021-01-12 | 2021-01-12 | Charging protection circuit and wireless earphone |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202110039483.6A CN112865229A (en) | 2021-01-12 | 2021-01-12 | Charging protection circuit and wireless earphone |
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| Publication Number | Publication Date |
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| CN112865229A true CN112865229A (en) | 2021-05-28 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202110039483.6A Pending CN112865229A (en) | 2021-01-12 | 2021-01-12 | Charging protection circuit and wireless earphone |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116625538A (en) * | 2023-07-24 | 2023-08-22 | 张家港华捷电子有限公司 | PCB preset circuit, pull-up type NTC sampling circuit and pull-down type NTC sampling method |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| WO2011113089A1 (en) * | 2010-03-16 | 2011-09-22 | Design And Industry Pty Ltd | A wireless headset assembly |
| CN206313957U (en) * | 2016-12-12 | 2017-07-07 | 成都三零瑞通移动通信有限公司 | A kind of flash disk bluetooth earphone |
| CN108063480A (en) * | 2017-12-28 | 2018-05-22 | 国网江苏省电力有限公司电力科学研究院 | A kind of autonomous activation of terminal Ni-MH battery, management of charging and discharging system and method |
| CN211128116U (en) * | 2019-11-21 | 2020-07-28 | 深圳艾创力科技有限公司 | Control system based on bluetooth headset intelligence storehouse and bluetooth of which box charges |
| CN212063548U (en) * | 2020-05-20 | 2020-12-01 | 深圳市力得鑫电子有限公司 | Wired charging box for Bluetooth headset |
-
2021
- 2021-01-12 CN CN202110039483.6A patent/CN112865229A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2011113089A1 (en) * | 2010-03-16 | 2011-09-22 | Design And Industry Pty Ltd | A wireless headset assembly |
| CN206313957U (en) * | 2016-12-12 | 2017-07-07 | 成都三零瑞通移动通信有限公司 | A kind of flash disk bluetooth earphone |
| CN108063480A (en) * | 2017-12-28 | 2018-05-22 | 国网江苏省电力有限公司电力科学研究院 | A kind of autonomous activation of terminal Ni-MH battery, management of charging and discharging system and method |
| CN211128116U (en) * | 2019-11-21 | 2020-07-28 | 深圳艾创力科技有限公司 | Control system based on bluetooth headset intelligence storehouse and bluetooth of which box charges |
| CN212063548U (en) * | 2020-05-20 | 2020-12-01 | 深圳市力得鑫电子有限公司 | Wired charging box for Bluetooth headset |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116625538A (en) * | 2023-07-24 | 2023-08-22 | 张家港华捷电子有限公司 | PCB preset circuit, pull-up type NTC sampling circuit and pull-down type NTC sampling method |
| CN116625538B (en) * | 2023-07-24 | 2023-10-27 | 张家港华捷电子有限公司 | PCB preset circuit and lithium battery NTC voltage sampling method |
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Application publication date: 20210528 |