Internet of Things Device and Battery Powered Circuit Thereof

Abstract

The present invention provides an Internet of Things device and a battery power supply circuit thereof. The voltage of the battery is compared with the default over-discharge voltage to generate a comparison signal. The battery protection circuit is coupled to the battery and the comparison circuit. The battery supplies power to the load through the battery protection circuit, and determines whether to cut off the power supply path from the battery to the load according to the comparison signal, wherein when the battery voltage decreases from greater than the default over-discharge voltage to less than the default over-discharge voltage, the battery protection circuit cuts off the power supply path from the battery to the load, and when the battery voltage increases from less than the default over-discharge voltage to greater than the default over-discharge voltage, the battery protection circuit does not conduct the power supply path.

Description

Technical Field

[0001] The present invention relates to an electronic device, and in particular to an Internet of Things device and a battery power supply circuit thereof. Background Art

[0002] Generally speaking, most of the batteries used in IoT devices are disposable batteries, so the main thing to do is to monitor the battery discharge status to prevent the battery from continuing to discharge in the low-voltage over-discharge area and causing battery overheating. Battery overheating will shorten the battery life, and even worse, it may catch fire and cause safety issues, so how to ensure that the battery is not discharged in the over-discharge area is a very important issue. Summary of the invention

[0003] The present invention provides an Internet of Things device and a battery power supply circuit thereof, which can ensure the safety of battery use.

[0004] The battery power supply circuit of the present invention includes a battery, a comparison circuit and a battery protection circuit. The comparison circuit is coupled to the battery, and compares the voltage of the battery with the default over-discharge voltage to generate a comparison signal. The battery protection circuit is coupled to the battery and the comparison circuit. The battery supplies power to the load through the battery protection circuit, and determines whether to cut off the power supply path from the battery to the load based on the comparison signal, wherein when the battery voltage decreases from greater than the default over-discharge voltage to less than the default over-discharge voltage, the battery protection circuit cuts off the power supply path from the battery to the load, and when the battery voltage increases from less than the default over-discharge voltage to greater than the default over-discharge voltage, the battery protection circuit does not conduct the power supply path.

[0005] The Internet of Things device of the present invention includes a communication circuit and a battery power supply circuit. The battery power supply circuit supplies power to the communication circuit. The battery power supply circuit includes a battery, a comparison circuit and a battery protection circuit. The comparison circuit is coupled to the battery and compares the voltage of the battery with the default over-discharge voltage to generate a comparison signal. The battery protection circuit is coupled to the battery and the comparison circuit. The battery supplies power to the communication circuit through the battery protection circuit, and determines whether to cut off the power supply path from the battery to the communication circuit based on the comparison signal, wherein when the battery voltage decreases from greater than the default over-discharge voltage to less than the default over-discharge voltage, the battery protection circuit cuts off the power supply path from the battery to the communication circuit, and when the battery voltage increases from less than the default over-discharge voltage to greater than the default over-discharge voltage, the battery protection circuit does not conduct the power supply path.

[0006] Based on the above, the battery protection circuit of the embodiment of the present invention can cut off the power supply path from the battery to the load when the battery voltage decreases from greater than the default over-discharge voltage to less than the default over-discharge voltage, and does not conduct the power supply path from the battery to the load when the battery voltage increases from less than the default over-discharge voltage to greater than the default over-discharge voltage. This can effectively prevent the battery voltage from rebounding after the power supply path is cut off, causing the battery to enter the over-discharge area again for discharge, and effectively improve the safety of battery use.

[0007] In order to make the above features and advantages of the present invention more clearly understood, embodiments are given below with reference to the accompanying drawings for detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 is a schematic diagram of a battery power supply circuit according to an embodiment of the present invention;

[0009] Figure 2 is a schematic diagram of an Internet of Things device according to an embodiment of the present invention;

[0010] Figure 3 is a schematic diagram of a three-terminal regulator according to an embodiment of the present invention;

[0011] Figure 4 is a schematic diagram of an Internet of Things device according to another embodiment of the present invention;

[0012] Figure 5 is a schematic diagram of an Internet of Things device according to another embodiment of the present invention. DETAILED DESCRIPTION

[0013] Figure 1 is a schematic diagram of a battery power supply circuit according to an embodiment of the present invention, please refer to Figure 1 . The battery power supply circuit 100 may include a battery protection circuit 102, a comparison circuit 104 and a battery 106. The battery protection circuit 102 is coupled to the battery 106, the comparison circuit 104 and the load 108. The comparison circuit 104 is also coupled to the battery 106. The battery 106 may be, for example, a disposable battery, but is not limited thereto. The battery 106 may power the load 108 through the battery protection circuit 102. The comparison circuit 104 may compare the discharged voltage of the battery 106 with the default over-discharge voltage to generate a comparison signal Va. The battery protection circuit 102 may determine whether to cut off the power supply path from the battery 106 to the load 108 based on the comparison signal Va. For example, the battery protection circuit 102 may cut off the power supply path from the battery 106 to the load 108 when the battery voltage decreases from greater than the default over-discharge voltage to less than the default over-discharge voltage to prevent the battery 106 from discharging in the over-discharge area.

[0014] In addition, the battery protection circuit 102 does not conduct the power supply path from the battery 106 to the load 108 even after the battery voltage rises from less than the default over-discharge voltage to greater than the default over-discharge voltage. Thus, when the voltage of the battery 106 rebounds to greater than the default over-discharge voltage because the load 108 no longer draws the load from the battery 106, the battery protection circuit 102 still does not conduct the power supply path from the battery 106 to the load 108, so as to prevent the battery 106 from entering the over-discharge area again for discharge. The aforementioned mechanism can prevent the battery 106 from repeatedly entering the over-discharge area for discharge, thereby improving the safety of the battery.

[0015] In some embodiments, the comparison circuit 104 may also compare the temperature of the battery 106 (or the surrounding area of ​​the battery) with a default temperature to generate a comparison signal Va. When the temperature of the battery 106 is greater than the default temperature, the battery protection circuit 102 may cut off the power supply path from the battery 106 to the load 108 according to the comparison signal Va, thereby further improving the safety of the battery.

[0016] Figure 2 1 is a schematic diagram of an Internet of Things device according to an embodiment of the present invention. In this embodiment, a battery power supply circuit 100 is applied to an Internet of Things device. Figure 1 The load 108 of the embodiment can be, for example, a communication circuit 208 of an IoT device in this embodiment, but is not limited thereto. In addition, in this embodiment, the battery protection circuit 102 can include a power supply control circuit 202, a PNP transistor Q1, NPN transistors Q2, Q3, and resistors R4, R5, and the comparison circuit 104 can include a voltage divider circuit 204, a resistor R3, and a three-terminal regulator 206.

[0017] Among them, the emitter terminal and the collector terminal of the PNP transistor Q1 are coupled to the battery 106 and the communication circuit 208 respectively, the resistor R4 is coupled between the base terminal of the PNP transistor Q1 and the power supply control circuit 202, the collector terminal and the emitter terminal of the NPN transistor Q3 are coupled to the resistor R4 and the ground respectively, the base terminal of the NPN transistor Q3 is coupled to the collector terminal of the NPN transistor Q2, the resistor R5 is coupled between the collector terminal of the PNP transistor Q1 and the collector terminal of the NPN transistor Q2, the base terminal of the NPN transistor Q2 is coupled to the output terminal of the comparison circuit 104 (that is, the cathode terminal of the three-terminal regulator 206), and the emitter terminal of the NPN transistor Q2 is coupled to the ground. In addition, in the comparison circuit 104, the voltage divider circuit 204 is coupled to the battery 106 and the reference terminal of the three-terminal regulator 206, the cathode terminal and the anode terminal of the three-terminal regulator 206 are respectively coupled to the base terminal of the NPN transistor Q2 and the ground, and the resistor R3 is coupled between the battery 106 and the cathode terminal of the three-terminal regulator 206. The three-terminal regulator 206 can be implemented by a TL431 chip, for example, but is not limited thereto.

[0018] The power supply control circuit 202 can respond to the power supply control signal to turn on the PNP transistor Q1. In this embodiment, the power supply control circuit 202 can be implemented by the power switch SW1. The power switch SW1 can be controlled by the power supply control signal to enter the on state to pull down the base voltage of the PNP transistor Q1 and turn on the PNP transistor Q1. The power supply control signal can, for example, respond to the user's pressing operation on the power button and be provided to the power switch SW1 to turn on the power switch SW1. The power button can be a physical button or a virtual button displayed on a touch display. After the PNP transistor Q1 enters the on state and then enters the off state, responding to the end of the pressing operation, the power switch SW1 returns to the off state. After the power switch SW1 returns to the off state, the NPN transistor Q3 can enter the on state as the PNP transistor Q1 is turned on. In addition, the on state of the NPN transistor Q2 is controlled by the comparison signal Va output by the comparison circuit 104. When the battery 106 does not enter the over-discharge area and supplies power normally, the NPN transistor Q2 is in the off state. In this way, when the battery 106 does not enter the over-discharge region and supplies power normally, the battery 106 can supply power to the communication circuit 108 through the PNP transistor Q1 .

[0019] The voltage divider circuit 104 can divide the voltage of the battery 106 to generate a divided voltage V1. In this embodiment, the voltage divider circuit 104 may include resistors R1 and R2 connected in series between the battery 106 and the ground. The divided voltage V1 is generated at a common connection point of the resistors R1 and R2. The three-terminal regulator 206 can compare the divided voltage V1 with a reference voltage and generate a comparison signal Va at the cathode end of the three-terminal regulator 206. In other words, the three-terminal regulator 206 can be as follows: Figure 3 As shown, it includes an NPN transistor Q4 and a comparator A1, the positive input terminal of the comparator A1 is coupled to the output terminal of the voltage divider circuit 204 to receive the divided voltage V1, the negative input terminal of the comparator A1 is coupled to the reference voltage VR, the output terminal of the comparator A1 is coupled to the base terminal of the NPN transistor Q4, and the collector terminal and the emitter terminal of the NPN transistor Q4 are respectively coupled to the resistor R3 and the ground. The conduction state of the NPN transistor Q4 is controlled by the comparator A1. When the divided voltage V1 is greater than the reference voltage VR, the comparator A1 turns on the NPN transistor Q4, so that the voltage of the comparison signal Va is pulled down, and at this time, the NPN transistor Q2 is controlled by the comparison signal Va and is in the off state.

[0020] In addition, when the divided voltage V1 is less than the reference voltage VR, the NPN transistor Q4 is in the off state, so the comparison signal Va can be maintained at a high voltage level, and at this time, the NPN transistor Q2 is controlled by the comparison signal Va and is in the on state, so that the voltage at the collector terminal of the NPN transistor Q2 is pulled down. The low voltage at the collector terminal of the NPN transistor Q2 will cause the NPN transistor Q3 and the PNP transistor Q1 to enter the off state, thereby cutting off the power supply path of the battery 106 to the communication circuit 208. By appropriately designing the resistance values ​​of the resistors R1 and R2 and the voltage value of the reference voltage VR at the negative input terminal of the comparator A1, the corresponding default over-discharge voltage can be designed for batteries 106 of different specifications, and when the voltage of the battery 106 is lower than the default over-discharge voltage, the voltage divider circuit 104, the three-terminal regulator 206, the NPN transistors Q2 and Q3 and other components can be triggered to turn off the PNP transistor Q1 to prevent the battery 106 from discharging in the over-discharge area. Since the PNP transistor Q1 and the power switch SW1 are both in the off state, even if the voltage of the battery 106 rebounds due to no longer being drawn by the communication circuit 208, the PNP transistor Q1 cannot be turned on, thereby preventing the battery 106 from discharging in the over-discharge area, effectively improving the safety of the battery 106.

[0021] It is worth noting that in some embodiments, the resistor R2 of the voltage divider circuit 204 can be implemented, for example, with a negative temperature coefficient thermistor, which can be configured next to the battery 106, for example, within 3 cm of the battery 106, to sense the temperature of the battery 106. When the temperature of the battery 106 is greater than the default temperature, the three-terminal regulator 206 can generate a high voltage level comparison signal Va according to the divided voltage V1 on the common junction of the resistor R1 and the resistor R2, so as to turn on the NPN transistor Q2, thereby turning off the PNP transistor Q1, cutting off the power supply path of the battery 106 to the communication circuit 208, and preventing the battery 106 from discharging and causing the temperature to continue to rise, thereby further improving the safety of the battery 106. In addition, Figure 2 In the embodiment, the resistors R3 , R4 and R5 are non-essential components and can be selectively removed as required.

[0022] Figure 4 is a schematic diagram of an Internet of Things device according to another embodiment of the present invention. Figure 2The difference between the embodiments is that the power supply control circuit 402 of the embodiment is implemented by a PNP transistor Q5 and a capacitor C1, the emitter terminal and the collector terminal of the PNP transistor Q5 are coupled to the resistor R4 and the ground respectively, the base terminal of the PNP transistor Q5 is coupled to the output terminal of the comparison circuit 104 (i.e., the cathode terminal of the three-terminal regulator 206), and the capacitor C1 is coupled between the base terminal of the PNP transistor Q5 and the ground. In the embodiment, the comparison signal Va can charge the capacitor C1, and generate a power supply control signal on the capacitor C1. When the battery 106 does not enter the over-discharge area and supplies power normally, the comparison signal Va is a low voltage level, so the power supply control signal is also a low voltage level, so that the PNP transistor Q5 is in a conducting state, thereby pulling down the base terminal voltage of the PNP transistor Q1, so that the PNP transistor Q1 enters a conducting state. In this way, the battery 106 can supply power to the communication circuit 208 through the PNP transistor Q1. At this time, the NPN transistor Q2 is in the off state because the comparison signal Va is at a low voltage level, and the base terminal of the NPN transistor Q3 is at a high voltage level in response to the conduction of the PNP transistor Q1, so the NPN transistor Q3 is in the on state.

[0023] When the voltage of the battery 106 is lower than the default over-discharge voltage, the comparison signal Va will turn to a high voltage level, and the power supply control signal will also turn to a high voltage level to turn off the PNP transistor Q5. In addition, the NPN transistor Q2 responds to the high voltage level of the comparison signal Va and enters the on state, thereby pulling down the base terminal voltage of the NPN transistor Q3, so that the NPN transistor Q3 enters the off state. When both the PNP transistor Q5 and the NPN transistor Q3 are in the off state, the base terminal of the PNP transistor Q1 turns to a high voltage level and the PNP transistor Q1 enters the off state, thereby cutting off the power supply path of the battery 106 to the communication circuit 208. Since the capacitor C1 has a high capacitance value (for example, 10mF, but not limited to this), even if the voltage of the battery 106 rebounds due to the stop of being drawn by the communication circuit 208, the PNP transistor Q5 cannot be turned on, and the battery 106 can be prevented from discharging in the over-discharge area, thereby effectively improving the safety of the battery 106.

[0024] It is worth noting that in some embodiments, the comparison circuit 104 may further include a capacitor for preventing the battery 106 from entering the over-discharge region again due to battery voltage rebound. Figure 5is a schematic diagram of an Internet of Things device according to another embodiment of the present invention. In this embodiment, the comparison circuit 104 further includes a capacitor C2, and the capacitor C2 is coupled between the common connection point of the resistor R1 and the resistor R2 and the ground. In this way, when the power supply path of the battery 106 to the communication circuit 208 is cut off, and the voltage of the battery 106 rebounds due to the stop of being drawn by the communication circuit 208, the battery 106 needs to additionally charge the capacitor C2, thereby ensuring that the comparison signal Va is maintained at a high voltage level, and preventing the voltage of the battery 106 from being greater than the default over-discharge voltage and turning on the power supply path of the battery 106 to the communication circuit 208 again.

[0025] In summary, the battery protection circuit of the embodiment of the present invention can cut off the power supply path from the battery to the load when the battery voltage decreases from greater than the default over-discharge voltage to less than the default over-discharge voltage, and does not conduct the power supply path from the battery to the load when the battery voltage increases from less than the default over-discharge voltage to greater than the default over-discharge voltage. This can effectively prevent the battery voltage from re-entering the over-discharge area for discharge due to voltage rebound after the power supply path is cut off, effectively improving the safety of the battery. In some embodiments, the battery protection circuit can also cut off the power supply path from the battery to the load when the battery temperature is greater than the default temperature, which can further improve the safety of the battery.

[0026] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Any person skilled in the art may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the claims.

Claims

1. A battery powered circuit, characterized in that: include: Battery; A comparison circuit, coupled to the battery, compares the voltage of the battery with a default over-discharge voltage to generate a comparison signal; as well as A battery protection circuit is coupled to the battery and the comparison circuit, wherein the battery supplies power to the load through the battery protection circuit, and determines whether to cut off the power supply path from the battery to the load according to the comparison signal, wherein when the voltage of the battery decreases from greater than the default over-discharge voltage to less than the default over-discharge voltage, the battery protection circuit cuts off the power supply path from the battery to the load, and when the voltage of the battery increases from less than the default over-discharge voltage to greater than the default over-discharge voltage, the battery protection circuit does not conduct the power supply path, and the battery protection circuit includes: A first PNP transistor, an emitter terminal and a collector terminal of which are respectively coupled to the battery and the load; A first NPN transistor, a collector terminal and an emitter terminal of which are respectively coupled to the base terminal of the first PNP transistor and to ground; a second NPN transistor, whose collector terminal and emitter terminal are respectively coupled to the collector terminal of the first PNP transistor and the ground, and whose base terminal is coupled to the comparison circuit; and The power supply control circuit is coupled to the base terminal of the first PNP transistor, and turns on the first PNP transistor according to a power supply control signal. The first NPN transistor turns off the first PNP transistor in response to the voltage of the battery being lower than the default over-discharge voltage.

2. The battery powered circuit according to claim 1, characterized in that: The comparison circuit comprises: a voltage dividing circuit coupled to the battery and dividing the voltage of the battery to generate a divided voltage; and A three-terminal regulator, whose cathode terminal and anode terminal are respectively coupled to the output terminal of the comparison circuit and the ground, and the reference terminal of the three-terminal regulator is coupled to the divided voltage. The three-terminal regulator compares the divided voltage with the reference voltage and generates the comparison signal at the output terminal of the comparison circuit.

3. The battery powered circuit according to claim 2, characterized in that: The power supply control circuit comprises: a second PNP transistor, whose emitter terminal and collector terminal are respectively coupled to the base terminal of the first PNP transistor and the ground, and the base terminal of the second PNP transistor is coupled to the cathode terminal of the three-terminal regulator; and The capacitor is coupled between the base terminal of the second PNP transistor and the ground, and responds to the voltage of the cathode terminal of the three-terminal regulator to provide the power supply control signal at the base terminal of the second PNP transistor.

4. The battery powered circuit according to claim 3, characterized in that: The voltage divider circuit comprises: A first resistor, a first end of which is coupled to the battery; and The second resistor is coupled between the second end of the first resistor and the ground. A common junction of the first resistor and the second resistor is coupled to a reference end of the three-terminal regulator. The second resistor is a negative temperature coefficient thermistor.

5. The battery powered circuit according to claim 2, characterized in that: The three-terminal regulator comprises: a comparator, whose positive and negative terminals are respectively coupled to the voltage divider circuit and the reference voltage; and The transistor is coupled between the output terminal of the comparison circuit and the ground. The control terminal of the transistor is coupled to the output terminal of the comparator and is turned on by the comparator when the divided voltage is greater than the reference voltage.

6. The battery powered circuit according to claim 2, characterized in that: The comparison circuit further comprises: The capacitor is coupled between the output terminal of the voltage divider circuit and the ground.

7. An Internet of Things device, characterized in that: include: Communication circuits; as well as A battery power supply circuit is used to supply power to the communication circuit, and the battery power supply circuit includes: Battery; A comparison circuit coupled to the battery, comparing the voltage of the battery with a default over-discharge voltage to generate a comparison signal; and A battery protection circuit is coupled to the battery and the comparison circuit, wherein the battery supplies power to the communication circuit through the battery protection circuit, and determines whether to cut off the power supply path from the battery to the communication circuit according to the comparison signal, wherein when the voltage of the battery decreases from greater than the default over-discharge voltage to less than the default over-discharge voltage, the battery protection circuit cuts off the power supply path from the battery to the communication circuit, and when the voltage of the battery increases from less than the default over-discharge voltage to greater than the default over-discharge voltage, the battery protection circuit does not conduct the power supply path, and the battery protection circuit includes: A first PNP transistor, an emitter terminal and a collector terminal of which are respectively coupled to the battery and the communication circuit; A first NPN transistor, a collector terminal and an emitter terminal of which are respectively coupled to the base terminal of the first PNP transistor and to ground; a second NPN transistor, whose collector terminal and emitter terminal are respectively coupled to the collector terminal of the first PNP transistor and the ground, and whose base terminal is coupled to the comparison circuit; and The power supply control circuit is coupled to the base terminal of the first PNP transistor, and turns on the first PNP transistor according to a power supply control signal. The first NPN transistor turns off the first PNP transistor in response to the voltage of the battery being lower than the default over-discharge voltage.

8. The Internet of Things device according to claim 7, characterized in that: The comparison circuit comprises: a voltage dividing circuit coupled to the battery and dividing the voltage of the battery to generate a divided voltage; and A three-terminal regulator, whose cathode terminal and anode terminal are respectively coupled to the output terminal of the comparison circuit and the ground, and the reference terminal of the three-terminal regulator is coupled to the divided voltage. The three-terminal regulator compares the divided voltage with the reference voltage and generates the comparison signal at the output terminal of the comparison circuit.

9. The Internet of Things device according to claim 8, characterized in that: The power supply control circuit comprises: a second PNP transistor, whose emitter terminal and collector terminal are respectively coupled to the base terminal of the first PNP transistor and the ground, and the base terminal of the second PNP transistor is coupled to the cathode terminal of the three-terminal regulator; and The capacitor is coupled between the base terminal of the second PNP transistor and the ground, and responds to the voltage of the cathode terminal of the three-terminal regulator to provide the power supply control signal at the base terminal of the second PNP transistor.

10. The Internet of Things device according to claim 9, characterized in that: The voltage divider circuit comprises: A first resistor, a first end of which is coupled to the battery; and The second resistor is coupled between the second end of the first resistor and the ground. A common junction of the first resistor and the second resistor is coupled to a reference end of the three-terminal regulator. The second resistor is a negative temperature coefficient thermistor.

11. The Internet of Things device according to claim 8, characterized in that: The three-terminal regulator comprises: a comparator, whose positive and negative terminals are respectively coupled to the voltage divider circuit and the reference voltage; and The transistor is coupled between the output terminal of the comparison circuit and the ground. The control terminal of the transistor is coupled to the output terminal of the comparator and is turned on by the comparator when the divided voltage is greater than the reference voltage.

12. The Internet of Things device according to claim 8, characterized in that: The comparison circuit further comprises: The capacitor is coupled between the output terminal of the voltage divider circuit and the ground.

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