Main and auxiliary power supply identification circuit and main and auxiliary power supply circuit supporting lithium battery charging

Abstract

The utility model provides a main and auxiliary power supply identification circuit and a main and auxiliary power supply circuit supporting lithium battery charging. The main and auxiliary power supply identification circuit comprises a microcontroller MCU, a main power supply interface, an auxiliary power supply interface, a main and auxiliary power supply circuit and an identification circuit. The identification circuit comprises a triode, a resistor R2 and a resistor R3; the output end of the main and auxiliary power supply circuit is connected with a power supply pin of the MCU; the output end of the main and auxiliary power supply circuit is also sequentially connected with a resistor R3 and a triode and then grounded; a connection point between the resistor R3 and the triode is connected with a signal input pin of the microcontroller MCU; the base electrode of the triode is connected in series with a resistor R2 and then connected with a main power supply interface. Therefore, on the basis of the power supply circuit of the main power supply and the auxiliary power supply, which power supply supplies power can be identified, and corresponding operation can be carried out on the basis of the power supply circuit of the main power supply and the auxiliary power supply.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of rechargeable electronic products, and concretely relates to a main and auxiliary power supply power supply identification circuit and a main and auxiliary power supply power supply circuit supporting lithium battery charging. BACKGROUND

[0002] Most of the current electronic products support multi-power supply, and the common ones are embedded lithium battery power supply and external power adapter power supply, and the voltage range of single lithium battery can be 3.7V to 4.2V. Generally, there is a voltage difference between the lithium battery voltage and the external power adapter voltage, and the lithium battery voltage is less than the external power adapter voltage, so the external power supply port can also supply power for the lithium battery.

[0003] For the power supply mode of electronic products, an effective power supply mode is: when the external power adapter is not connected, the electronic product is powered by the embedded lithium battery; when the external power adapter is connected, the electronic product is powered by the external power supply. Therefore, the external power supply is called the main power supply, and the internal lithium battery is called the auxiliary power supply.

[0004] At present, for the charging of lithium batteries, due to the small voltage difference between the lithium battery and the external power supply, manufacturers often use multiple diodes in series to charge the lithium battery. This way, the circuit is unstable, which will affect the service life of the entire electronic product.

[0005] In addition, when the power consumption of the electronic product being charged is too large, if it is powered by the lithium battery at this time, the working time of the electronic product will be reduced due to the fixed capacity of the lithium battery. Therefore, how to identify which way to power the electronic product is particularly important. When it is identified that the lithium battery is powered, appropriate measures can be taken, such as reducing the power consumption of the electronic product.

[0006] In addition, for the automatic switching of the main and auxiliary power supplies, there are switching methods realized by using Schottky diodes or special power supply switching chips in the prior art. However, for the scheme using Schottky diodes, the circuit has a voltage drop, and the scheme using the power supply switching chip has a high cost.

[0007] In order to solve the above problems, people have been seeking an ideal technical solution. UTILITY MODEL CONTENTS

[0008] The utility model aims at the shortage of the prior art, and provides a main and auxiliary power supply power supply identification circuit and a main and auxiliary power supply power supply circuit supporting lithium battery charging, which can identify which power supply to power, and then make appropriate operations based on this. The circuit is simple, stable and reliable, easy to use, and the on-state voltage drop is basically negligible.

[0009] In order to achieve the above object, the utility model provides a kind of main and auxiliary power supply identification circuit, including microcontroller MCU, main power supply interface, auxiliary power supply interface, main and auxiliary power supply circuit and identification circuit;

[0010] The main and auxiliary power supply circuit includes main power supply circuit and auxiliary power supply circuit;

[0011] The main power supply interface is connected with the input end of the main power supply circuit;

[0012] The auxiliary power supply interface is connected with the input end of the auxiliary power supply circuit;

[0013] The output end of the main power supply circuit is connected with the output end of the auxiliary power supply circuit, and the corresponding connection point is used as the output end of the main and auxiliary power supply circuit;

[0014] The identification circuit includes a triode, a resistor R2 and a resistor R3;

[0015] The output end of the main and auxiliary power supply circuit is connected with the power supply pin of the microcontroller MCU;

[0016] The output end of the main and auxiliary power supply circuit is further connected with the resistor R3 and the triode in sequence, and then grounded;

[0017] The connection point between the resistor R3 and the triode is connected with the signal input pin of the microcontroller MCU;

[0018] The base of the triode is connected with the main power supply interface after being connected with the resistor R2 in series.

[0019] Optionally, the main power supply circuit includes a MOS tube Q1, and the auxiliary power supply circuit includes a MOS tube Q2;

[0020] The main power supply interface is connected with the output end of the main and auxiliary power supply circuit after being connected with the MOS tube Q1 in series;

[0021] The auxiliary power supply interface is connected with the output end of the main and auxiliary power supply circuit after being connected with the MOS tube Q2 in series;

[0022] The gate of the MOS tube Q1 and the gate of the MOS tube Q2 are both connected with the main power supply interface at one end, and connected with the ground through the resistor R1 at the other end.

[0023] The main and auxiliary power supply circuit includes two MOS tubes, and since the voltage drop after the MOS tube is turned on is basically negligible, compared with the switching mode realized by using a Schottky diode, the circuit of the scheme basically has no voltage drop, reduces power loss, is particularly suitable for the case that the voltage of the power supply is basically consistent with the output voltage, and the circuit of the scheme is more stable.

[0024] The utility model discloses the beneficial effects are:

[0025] When the base of the three-stage tube is high level, the IO port (signal input pin) of microcontroller MCU receives low level, and at this time, power supply is realized through the main power supply interface, when the base of the three-stage tube is low level, the IO port of microcontroller MCU receives high level, and at this time, power supply is not realized through the main power supply interface. Based on this, it can be judged that which power supply is powered, and then corresponding operation can be made based on this, for example, when it is judged that lithium battery power supply (power supply is not realized through the main power supply interface), the power consumption of electronic product can be reduced, so that the use time of electronic product is improved. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 It is the circuit schematic diagram of the utility model embodiment 1;

[0027] Figure 2 It is the circuit schematic diagram of the utility model embodiment 2;

[0028] Figure 3 It is the circuit schematic diagram of the utility model embodiment 3;

[0029] Figure 4 It is the structure block diagram of the utility model embodiment 4. DETAILED DESCRIPTION

[0030] The technical scheme of the utility model is further described in detail below through specific implementation.

[0031] The terms "first", "second", "third", "fourth" and the like in the description, claims, and drawings of the present application are used to distinguish similar objects, and do not necessarily have to be used to describe a particular order or sequence. It should be understood that the terms used in this way are interchangeable, and are only used to distinguish the objects with the same attributes in the description of the embodiments of the present application.

[0032] Embodiment 1

[0033] As Figure 1 shown, the embodiment provides a main and auxiliary power supply power supply identification circuit, including microcontroller MCU, main power supply interface, auxiliary power supply interface, main and auxiliary power supply circuit and identification circuit.

[0034] The main and auxiliary power supply circuit comprises a main power supply circuit and an auxiliary power supply circuit;

[0035] The main power supply interface is connected with the input end of the main power supply circuit;

[0036] The auxiliary power supply interface is connected with the input end of the auxiliary power supply circuit;

[0037] The output end of the main power supply circuit is connected with the output end of the auxiliary power supply circuit, and the corresponding connection point serves as the output end of the main and auxiliary power supply circuit;

[0038] The identification circuit comprises a triode, a resistor R2 and a resistor R3;

[0039] The output end of the main and auxiliary power supply circuit is connected with the power supply pin of the microcontroller MCU;

[0040] The output end of the main and auxiliary power supply circuit is further connected with the resistor R3 and the triode in sequence and then grounded;

[0041] The connection point between the resistor R3 and the triode is connected with the signal input pin (IO port) of the microcontroller MCU;

[0042] The base of the triode is further connected with the main power supply interface in series with the resistor R2.

[0043] Specifically, the triode is an NPN tube, the emitter of the triode is grounded, and the collector of the triode is connected with one end of the resistor R3.

[0044] It should be noted that when the main power supply interface has a main power supply inserted, wherein the main power supply can be a power supply after an adapter of a commercial power supply, the voltage of the main power supply interface is denoted as VIN1, the main power supply supplies power to the electronic product, the voltage Vo of the output end of the main and auxiliary power supply circuit is a high voltage (approximately equal to VIN1), the voltage of the base of the triode is VIN1, the triode is turned on, the collector of the triode is at a low level, and the detection pin (IO port) of the microcontroller MCU receives a low level. When the main power supply interface does not have a main power supply inserted, the auxiliary power supply supplies power to the electronic product, wherein the auxiliary power supply can be a lithium battery, the voltage of the auxiliary power supply interface is denoted as VIN2, the voltage Vo of the output end of the main and auxiliary power supply circuit is a high voltage (approximately equal to VIN2), the voltage of the base of the triode is approximately 0, the triode is cut off, the collector of the triode is at a high level, and the detection pin of the microcontroller MCU receives a high level.

[0045] Based on this, the microcontroller MCU can determine which power supply is used to power the electronic product by the high or low (level state) of the voltage of the collector of the triode. When the collector of the triode is low, the microcontroller MCU determines that the main power supply is used for power supply. When the collector of the triode is high, the microcontroller MCU determines that the auxiliary power supply is used for power supply. In other words, it is determined which power supply is used for power supply based on whether the main power supply is inserted. For example, if the auxiliary power supply is a lithium battery, when it is identified that the lithium battery is used for power supply, appropriate measures can be taken, such as reducing the power consumption of the electronic product to prolong the working time of the electronic product; when it is identified that the main power supply is used for power supply, the power consumption problem can be ignored (the power consumption of the electronic product can not be reduced). The circuit of this embodiment is simpler and more practical, and the corresponding working mode of this embodiment is more convenient.

[0046] Embodiment 2

[0047] As shown in Figure 2 The difference between this embodiment and embodiment 1 is that the specific implementation of the main and auxiliary power supply circuit is given: the main power supply circuit includes a MOS tube Q1, and the auxiliary power supply circuit includes a MOS tube Q2.

[0048] The main power supply interface connects the output end of the main and auxiliary power supply circuit after the MOS tube Q1 is connected in series.

[0049] The auxiliary power supply interface connects the output end of the main and auxiliary power supply circuit after the MOS tube Q2 is connected in series.

[0050] The gate of the MOS tube Q1 and the gate of the MOS tube Q2 are connected to one end of the main power supply interface, and the other end is connected to the ground through a resistor R1.

[0051] It should be noted that the voltage VIN2 is smaller than the voltage VIN1. When the main power supply is used (the main power supply interface has the main power supply inserted), the voltage VIN2 and the voltage VIN1 should satisfy the relationship that the MOS tube Q1 is turned on and the MOS tube Q2 is turned off.

[0052] Specifically, the MOS tube Q1 is an NMOS tube, and the MOS tube Q2 is a PMOS tube. The drain of the MOS tube Q1 is connected to the input end of the main power supply circuit, and the source of the MOS tube Q1 is connected to the output end Vo of the main and auxiliary power supply circuit. The drain of the MOS tube Q2 is connected to the input end of the auxiliary power supply circuit, and the source of the MOS tube Q2 is connected to the output end Vo of the main and auxiliary power supply circuit.

[0053] It should be noted that: when the main power supply interface has a main power supply inserted, the gate of the MOS tube Q1 is high level, the gate of the MOS tube Q2 is high level, the MOS tube Q1 is turned on, the MOS tube Q2 is turned off, the main power supply supplies power to the electronic product, and the voltage Vo of the output end of the main and auxiliary power supply circuit is high voltage (about equal to VIN1). When the main power supply interface does not have a main power supply inserted, the gate of the MOS tube Q1 is low level, the gate of the MOS tube Q2 is low level, the MOS tube Q1 is turned off, the MOS tube Q2 is turned on, the auxiliary power supply supplies power to the electronic product, and the voltage Vo of the output end of the main and auxiliary power supply circuit is high voltage (about equal to VIN2).

[0054] It should also be noted that when the main power supply interface does not have a main power supply inserted, the gate of the MOS tube Q2 is low level, and due to the parasitic capacitance of the MOS tube Q2, the MOS tube Q2 is turned on.

[0055] For the automatic switching of the main and auxiliary power supplies, there are switching modes realized by using Schottky diodes or special power supply switching chips in the prior art. Compared with these two modes, the circuit of the present scheme has no voltage drop, and the circuit is simple, stable, low in cost and easy to use, and is particularly suitable for situations where the supply voltage and the output voltage are basically consistent.

[0056] Embodiment 3

[0057] As shown in Figure 3 , the difference between the present embodiment and embodiment 2 is that the main and auxiliary power supply identification circuit further comprises a DC-DC power supply voltage stabilizing module.

[0058] The DC-DC power supply voltage stabilizing module is connected in series between the output end of the main and auxiliary power supply circuit and the first connection point, and the first connection point is the connection point of the resistor R3 and the power supply pin of the microcontroller MCU.

[0059] It should be noted that in this embodiment, the output port for supplying power to the electronic product can be the output end of the DC-DC power supply voltage stabilizing module, and the voltage thereof is denoted as VCC.

[0060] Embodiment 4

[0061] As shown in Figure 4 , the auxiliary power supply is a lithium battery. The difference between the present embodiment and any one of embodiments 1 to 3 is that a specific implementation of a main and auxiliary power supply circuit supporting lithium battery charging is given, which comprises a main power supply, a lithium battery, a lithium battery charging module, and a main and auxiliary power supply identification circuit according to any one of embodiments 1 to 3.

[0062] The main power supply connects a main power supply interface of the main power supply powered identification circuit, and the lithium battery connects a secondary power supply interface of the secondary power supply powered identification circuit.

[0063] One end of the lithium battery charging module is connected to the main power supply interface, and the other end is connected to the lithium battery.

[0064] It should be noted that when the main power supply interface has a main power supply inserted, the main power supply can be a power supply after an adapter of a commercial power supply, the main power supply supplies power to the electronic product, and the lithium battery charging module works, and the main power supply also charges the lithium battery through the lithium battery charging module. When the main power supply interface does not have a main power supply inserted, the lithium battery charging module does not work.

[0065] In one embodiment, the lithium battery charging module is realized by a general lithium battery charging integrated IC and its peripheral circuit. The lithium battery is a commercially available general rechargeable lithium battery, and the voltage range of a single lithium battery can be 3.7V~4.2V, and the lithium battery can be used in series or in parallel. Further, the voltage of the lithium battery should be less than the voltage of the main power supply interface after the main power supply is inserted.

[0066] In one embodiment, the MOS tube Q1 is selected as a 2N7002 NMOS tube, the MOS tube Q2 is selected as an AO3407 PMOS tube, and the triode is selected as an SS8050 NPN tube.

[0067] In one embodiment, the resistance R2 has a resistance value of 200Ω, the resistance R3 has a resistance value of 4.7kΩ, and the resistance R1 has a resistance value of 330kΩ.

[0068] In one embodiment, the lithium battery charging integrated IC can select a general lithium battery charging IC such as FM4057, LM3420 or TP4056, and the peripheral circuit can refer to the chip manual of the manufacturer. The DC-DC power supply stabilizing module (i.e. a DC-DC synchronous step-down stabilizing module) can select a general power supply stabilizing chip such as SY8088, SY8113 or BL9342, and the peripheral circuit can refer to the chip manual of the manufacturer.

[0069] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and not to limit them; although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the specific embodiments of the present application can be modified or some technical features can be replaced by equivalent ones; without departing from the spirit of the technical solutions of the present application, they should be covered in the technical solution range of the present application claimed.

Claims

1. A main / supplementary power supply identification circuit, characterized in that, Includes a microcontroller (MCU), a main power supply interface, a secondary power supply interface, a main and secondary power supply circuit, and an identification circuit; The main and auxiliary power supply circuits include a main power supply circuit and an auxiliary power supply circuit. The main power supply interface is connected to the input terminal of the main power supply circuit; The auxiliary power supply interface is connected to the input terminal of the auxiliary power supply circuit; The output terminal of the main power supply circuit is connected to the output terminal of the auxiliary power supply circuit, and the corresponding connection point serves as the output terminal of the main and auxiliary power supply circuits. The identification circuit includes a transistor, resistor R2, and resistor R3; The output terminal of the main and auxiliary power supply circuit is connected to the power supply pin of the microcontroller MCU; The output terminal of the main and auxiliary power supply circuit is also connected to the resistor R3 and the transistor in sequence and then grounded. The connection point between resistor R3 and transistor is connected to the signal input pin of microcontroller MCU. The base of the transistor is connected in series with the resistor R2 and then connected to the main power supply interface.

2. The main / supplementary power supply identification circuit according to claim 1, characterized in that, The main power supply circuit includes a MOSFET Q1, and the auxiliary power supply circuit includes a MOSFET Q2; The main power supply interface is connected in series with the MOS transistor Q1 and then connected to the output terminal of the main and auxiliary power supply circuits. The auxiliary power supply interface is connected in series with the MOS transistor Q2 and then connected to the output terminal of the main and auxiliary power supply circuit. The gates of both MOS transistors Q1 and Q2 are connected at one end to the main power supply interface and at the other end to ground through resistor R1.

3. The main / supplementary power supply identification circuit according to claim 2, characterized in that, It also includes a DC-DC power supply regulator module; The DC-DC power regulator module is connected in series between the output terminal of the main and auxiliary power supply circuit and the first connection point, which is the connection point between the resistor R3 and the power supply pin of the microcontroller MCU.

4. The main / supplementary power supply identification circuit according to claim 2, characterized in that: The MOSFET Q1 is selected as a 2N7002 NMOS transistor, the MOSFET Q2 is selected as an AO3407 PMOS transistor, and the transistor is selected as an SS8050 NPN transistor.

5. A main and auxiliary power supply circuit supporting lithium battery charging, characterized in that, Includes a main power supply, a lithium battery, a lithium battery charging module, and a main / secondary power supply identification circuit as described in any one of claims 1 to 4; The main power supply is connected to the main power supply interface of the main power supply identification circuit, and the lithium battery is connected to the auxiliary power supply interface of the auxiliary power supply identification circuit. One end of the lithium battery charging module is connected to the main power supply interface, and the other end is connected to the lithium battery.

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