Electronic product lithium battery protection method

Abstract

The invention discloses a method for protecting a lithium battery of an electronic product, which is characterized in that the electronic product protects the lithium battery through a lithium protection chip U1 in a product circuit, when the electronic product exits from a protected mode, a VM pin and a GND pin are in a connected state through a circuit arranged outside the lithium protection chip U1, the battery current flows out from a battery positive electrode B +, and the lithium battery is protected. After passing through a product circuit, the current flows to a VM pin and then flows to a battery cathode B-through a GND pin of the lithium protection chip U1, and the lithium protection chip U returns to a normal working state; the circuit arranged outside the lithium protection chip U1 is provided with a key K, and the VM pin and the GND pin are in a connected state through the key K. In conclusion, the lithium protection chip is activated through the key, and the user experience is improved with lower cost on the basis of not greatly changing and designing a circuit of an electronic product.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium battery protection, and in particular to a lithium battery protection method for electronic products. Background Art

[0002] In the field of general consumer electronic products, if lithium batteries are used, there will be lithium battery protection chips, namely the so-called lithium protection chips. For example, the common Mitsumi MM3280 series lithium battery protection chips are available. The main function of the lithium protection chip is: when the lithium battery is working, if it encounters overcharge, over-discharge, overcurrent, low voltage, etc., the lithium protection chip actively cuts off the external output of the lithium battery to protect the battery or the entire circuit. At the same time, consumer electronic products are usually exported and sold to other countries. It usually takes a long time from transportation and sale to the actual receipt, unpacking and use by consumers. This time can be as short as half a year or as long as 1 to 2 years. Such a long time requires lithium battery-powered electronic products to enter an extremely low power consumption state. The current method is generally to actively trigger the lithium protection chip when the product leaves the factory, so that the lithium battery enters the "lithium protection mode" or the "protection mode" of the lithium battery. At this time, the power consumption is about nanoampere level, which greatly reduces the energy consumption of electronic products.

[0003] After the lithium battery of an electronic product is in protection mode, if you want to restart the work, you need to exit the protection mode of the lithium battery. Currently, the most common method to exit the protection mode is to charge the lithium battery. Figure 1 As shown, the circuit principle of the existing lithium battery protection chip is as follows: the positive electrode B+ of the battery is connected to the VDD pin of the lithium battery protection chip U, the negative electrode B- of the battery is connected to the GND pin of the lithium battery protection chip U, and the ground signal of the product circuit is connected to the VM pin of the lithium battery protection chip U. Among them, the positive electrode B+ and GND are used to power the lithium battery protection chip U. Figure 2 As shown, under normal working conditions, the VM pin and the GND pin are connected, and the battery current flows out from the positive electrode B+ of the battery, passes through various components in the product circuit, flows to the VM pin, and then flows to the negative electrode B- of the battery through the GND pin of the lithium battery protection chip U.

[0004] When the lithium battery protection chip U is in the protected state, the VM pin inside the lithium battery protection chip U is disconnected from the GND pin, and the current loop of the entire lithium battery protection chip U is cut off to protect the battery and avoid risks such as over-discharge, over-charge, short circuit, and overheating. Therefore, the protection feature of the lithium battery protection chip is used to make the entire circuit system enter an extremely low power consumption mode to achieve long-term storage. That is, when the product leaves the factory, the VM pin inside the lithium battery protection chip U is disconnected from the GND pin, so that the lithium battery protection chip U is in the protected state.

[0005] Normally, the condition for the lithium battery protection chip U to exit the "protection mode" is: charging voltage > (battery voltage - 0.5V). The charging voltage is the voltage difference between VDD and VM, and the battery voltage is the voltage difference between VDD and GND. Assuming the battery voltage is 4.0V, the minimum charging voltage of 3.5V is enough to activate the lithium battery protection chip. Therefore, when it is necessary to exit the lithium battery protection mode, the common technical solution is to charge the entire system.

[0006] Based on the above, in the prior art, if the lithium battery is to be taken out of the protection mode, it needs to be charged to exit the protection mode. However, for some electronic products (such as smart watches, etc.), consumers prefer to use them immediately after unpacking them. In this way, the existing method of exiting the lithium protection mode by charging is difficult to meet the needs of consumers. In view of this, the present invention proposes the following technical solution. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a lithium battery protection method for electronic products in view of the shortcomings of the prior art. The present invention activates the lithium battery protection chip by pressing a button, thereby improving the user experience at a relatively low cost without significantly changing the circuit design of the electronic product.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions: the electronic product lithium battery protection method is as follows: the electronic product protects the lithium battery through the lithium protection chip U1 in the product circuit, the positive electrode B+ of the lithium battery is connected to the VDD pin of the lithium protection chip U, the negative electrode B- of the lithium battery is connected to the GND pin, and the ground signal end of the product circuit is connected to the VM pin of the lithium protection chip U1. When the lithium protection chip U1 is in the protected mode, the VM pin inside the lithium protection chip U1 is disconnected from the GND pin, the current loop of the lithium protection chip U1 is cut off, and the circuit system of the entire electronic product enters the low power consumption mode. When exiting the protected mode, the VM pin and the GND pin are connected through the circuit set outside the lithium protection chip U1, the battery current flows out from the positive electrode B+ of the battery, passes through the product circuit, flows to the VM pin, and then flows to the negative electrode B- of the battery through the GND pin of the lithium protection chip U1, and the lithium protection chip U resumes the normal working state; the circuit set outside the lithium protection chip U1 has a button K, and the VM pin and the GND pin are connected through the button K.

[0009] Furthermore, in the above technical solution, the button K and the capacitor C are arranged in series between the ground signal terminal and the negative electrode B- of the lithium battery, and the product circuit is that the pull-up power supply output by the lithium protection chip U1 is connected between the button K and the capacitor C.

[0010] Furthermore, in the above technical solution, the product circuit is connected between the button K and the capacitor C through a resistor R1. Alternatively, a resistor R2 is provided between the button K and the ground signal terminal.

[0011] Furthermore, in the above technical solution, the key K is a key that the electronic product itself has, that is, the key K directly utilizes the existing keys of the electronic product and is not separately provided.

[0012] Furthermore, in the above technical solution, the product circuit adopts a Bluetooth control circuit, which is usually mainly composed of a Bluetooth control chip.

[0013] Furthermore, in the above technical solution, one end of the key K is connected to the signal control pin in the Bluetooth control circuit, so that the key K can still be used as the original function key of the product.

[0014] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art: First, for the existing lithium-ion battery chip, the present invention does not need to activate the lithium-ion battery chip to exit the protection mode by charging, but sets a circuit outside the lithium-ion battery chip, and triggers the conduction of the circuit by pressing a button to connect the VM pin and the GND pin, thereby activating the lithium-ion battery chip to exit the protection mode. In this way, after receiving the electronic product, consumers can directly press the button to use it, without spending time to activate the lithium-ion battery chip to exit the protection mode by charging.

[0015] Secondly, the button for activating the lithium battery protection chip of the present invention can directly adopt the original related function button of the electronic product. When the lithium battery protection chip is activated by the button to exit the protection mode, the button will restore the original function, and the circuit of the electronic product will return to normal operation without leakage and other problems.

[0016] In summary, the present invention activates the lithium battery protection chip by pressing a button, thereby improving the user experience at a relatively low cost without significantly changing the circuit design of the electronic product. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is the circuit schematic diagram of the existing lithium battery protection chip; Figure 2 This is the circuit working principle diagram of the existing lithium battery protection chip; Figure 3 is a circuit schematic diagram of Embodiment 1 of the present invention; Figure 4 It is a circuit schematic diagram of the second embodiment of the present invention. DETAILED DESCRIPTION

[0018] The present invention is further described below in conjunction with specific embodiments and drawings.

[0019] The present invention is a method for protecting lithium batteries in electronic products, wherein the electronic products are electronic products with lithium batteries such as smart watches, smart bracelets, and mobile phones. Figure 3 As shown, the protection method is as follows: a lithium battery protection chip U1 is set in the circuit of the electronic product, and the electronic product protects the lithium battery through the lithium battery protection chip U1. The working principle of the lithium battery protection chip U1 is as follows: the positive electrode B+ of the lithium battery is connected to the VDD pin of the lithium battery protection chip U1, the negative electrode B- of the lithium battery is connected to the GND pin, and the ground signal end of the product circuit is connected to the VM pin of the lithium battery protection chip U1.

[0020] When the product leaves the factory, the lithium battery chip U1 is set to the protection mode. At this time, the VM pin and GND pin inside the lithium battery chip U1 are disconnected, the current loop of the lithium battery chip U1 is cut off, and the circuit system of the entire electronic product enters a low-power protection mode to cope with the long time from when the electronic product leaves the factory to when it enters the hands of consumers.

[0021] As described in the background technology, existing electronic products with lithium battery protection chip U1 need to exit the protection mode, and are usually activated by charging mode, so that the charging voltage is greater than (battery voltage - 0.5V). The method adopted by the present invention does not require activation by charging, but is directly implemented by a circuit set outside the lithium battery protection chip U1.

[0022] like Figure 3 As shown, by pressing button K, the VM pin and the GND pin are connected, and the battery current flows out from the positive electrode B+ of the battery, passes through the product circuit, flows to the VM pin, and then flows to the negative electrode B- of the battery through the GND pin of the lithium battery protection chip U1, and the lithium battery protection chip U1 returns to normal working state.

[0023] Specifically, the button K and capacitor C are connected in series between the ground signal terminal and the negative electrode B- of the lithium battery. The product circuit VDD_IO is connected between the button K and the capacitor C through a resistor R1, that is, the pull-up power output by the lithium battery protection chip U1 is connected between the button K and the capacitor C.

[0024] After adopting the present invention, when the product leaves the factory, the lithium battery chip U1 is set to the protected mode. At this time, the VM pin inside the lithium battery chip U1 is disconnected from the GND pin, the current loop of the lithium battery chip U1 is cut off, and the circuit system of the entire electronic product enters a low-power protection mode. The pull-up power output of the product circuit VDD_IO is 0, and the power at the button K is also 0, and the system will not leak electricity.

[0025] In addition, the present invention is mainly applied to consumer electronic products such as smart watches. In general, the buttons of such electronic products all have special functions. If a button K is set separately to activate the lithium battery protection chip, the circuit of the entire product will be greatly modified. Therefore, the present invention can directly use the existing buttons of electronic products to activate the lithium battery protection chip. The reason why this method can be implemented is that the general function buttons in existing electronic products need to be connected to the main control chip in the product circuit as signal control pins at both ends. That is, usually one end of the general buttons of electronic products is grounded, and the other end is connected to the power supply through a pull-up resistor. Therefore, the button K in the present invention can directly use the existing buttons in electronic products without being set separately.

[0026] The following is an example of a Bluetooth connection button in an electronic product: the product circuit of the electronic product is a Bluetooth control circuit, which is mainly composed of a Bluetooth chip. The button K is connected to the VDD_IO terminal of the Bluetooth chip, and the button K is connected to the signal control pin of the Bluetooth chip through the k_detect terminal. When the lithium battery protection chip U1 is in protection mode, the pull-up power VDD_IO output by the Bluetooth chip is 0, the power at the k_detect terminal is 0, and the system will not leak electricity.

[0027] When the electronic product needs to exit the protection mode, press button K. When button K is pressed, capacitor C can conduct current and can be considered to be in a short-circuit state (capacitor C can conduct AC signals and isolate DC signals). The VM pin and the GND pin are short-circuited, which means that the activation conditions of the lithium protection chip mentioned above are met (that is, the charging voltage mentioned above > (battery voltage - 0.5V)).

[0028] When the lithium battery protection chip U1 exits the lithium battery protection mode, the whole system starts to work normally. The voltage on the VDD_IO of the Bluetooth chip can generally be 3.3V or 1.8V (depending on the product). At this time, the voltage at the k_detect terminal is the voltage of VDD_IO, and the whole circuit system will not leak electricity.

[0029] After the lithium battery protection chip U1 exits the lithium battery protection mode, the entire system starts to work normally. When the button K is pressed again, the voltage at the k_detect terminal will be pulled down, so the detection of the button K is normal, and there will be no leakage at this time. The entire lithium battery protection chip U1 will not have any extra redundant actions, the button K can still realize the original function, and the entire product circuit works normally.

[0030] The present invention utilizes the key K of the existing electronic product. When the key K is pressed, the lithium security chip U1 is activated, and the entire circuit resumes normal operation without causing leakage and other problems.

[0031] See Figure 4As shown, this is the second embodiment of the present invention. The difference between the second embodiment and the first embodiment is that a resistor R2 is provided between the button K and the ground signal terminal, and the button K is connected to the signal control pin of the Bluetooth chip through the k_detect terminal. After the button K is pressed, the lithium battery protection chip U1 can also be activated. After the lithium battery protection chip U1 is activated, when the button K is not pressed again, the system will not leak electricity, and the k_detect terminal is at a low level. When the button K is pressed again, the pin at the k_detect terminal is at a high level, and the system will not leak electricity, and it is in normal operation.

[0032] Of course, the above description is only a specific embodiment of the present invention and is not intended to limit the scope of implementation of the present invention. All equivalent changes or modifications made according to the structure, characteristics and principles described in the patent application scope of the present invention should be included in the patent application scope of the present invention.

Claims

1. A lithium battery protection method for electronic products. The protection method is as follows: the electronic product protects the lithium battery through the lithium battery protection chip U1 in the product circuit. The positive electrode B+ of the lithium battery is connected to the VDD pin of the lithium battery protection chip U, and the negative electrode B- of the lithium battery is connected to the GND pin. The ground signal end of the product circuit is connected to the VM pin of the lithium battery protection chip U1. When the lithium battery protection chip U1 is in the protected mode, the VM pin inside the lithium battery protection chip U1 is disconnected from the GND pin, the current loop of the lithium battery protection chip U1 is cut off, and the circuit system of the entire electronic product enters the low power consumption mode. The characteristics are as follows: When exiting the protected mode, the VM pin and the GND pin are connected through the circuit set outside the lithium protection chip U1. The battery current flows out from the positive electrode B+ of the battery, passes through the product circuit, flows to the VM pin, and then flows to the negative electrode B- of the battery through the GND pin of the lithium protection chip U1. The lithium protection chip U returns to normal working state; The circuit arranged outside the lithium-ion battery protection chip U1 has a button K, through which the VM pin and the GND pin are connected.

2. The method for protecting lithium batteries of electronic products according to claim 1, characterized in that: The button K and the capacitor C are connected in series between the ground signal terminal and the negative electrode B- of the lithium battery, and the product circuit is that the pull-up power output by the lithium protection chip U1 is connected between the button K and the capacitor C.

3. The method for protecting lithium batteries of electronic products according to claim 2, characterized in that: The product circuit is connected between the button K and the capacitor C via a resistor R1.

4. The method for protecting lithium batteries of electronic products according to claim 2, characterized in that: A resistor R2 is arranged between the button K and the ground signal terminal.

5. The method for protecting lithium batteries of electronic products according to any one of claims 2 to 4, characterized in that: The button K is a button that the electronic product itself has, that is, the button K directly utilizes the existing button of the electronic product and is not separately provided.

6. The method for protecting a lithium battery of an electronic product according to claim 5, characterized in that: The product circuit adopts a Bluetooth control circuit.

7. The method for protecting a lithium battery of an electronic product according to claim 6, characterized in that: One end of the button K is connected to a signal control pin in the Bluetooth control circuit.

Images