External energy storage power supply system for portable terminals

Abstract

The utility model discloses a portable terminal external energy storage power supply unit and four way power automatic switching circuit, including external energy storage unit and equipment host, and external energy storage unit and equipment host communicate and power supply, and the power supply interface is VCC_5V and GND port, and external energy storage unit carries out 5V power supply to equipment host, and external energy storage unit and equipment host communicate through a single bus, are used for transmission external energy storage unit residual capacity information, the utility model discloses that portable gas alarm adds external energy storage unit, through simple docking can increase portable gas alarm endurance time, provides four way power automatic switching circuit, and the circuit adopts the intrinsic safety design, can make portable gas alarm long -time work in the inflammable and explosive environment.

Description

Technical Field

[0001] This utility model belongs to the field of electronic technology, specifically relating to an external energy storage power supply system for a portable terminal. Background Technology

[0002] Confined space work refers to a special working environment where work is carried out in a closed or semi-closed space. Confined spaces may contain potential hazards such as harmful gases, toxic gases, or flammable gases, including methane, hydrogen sulfide, and carbon monoxide. Gas detectors can detect leaks of these gases early to prevent emergencies such as poisoning, explosions, or fires. Before entering a confined space, workers typically need to perform gas testing to ensure that the gas and environment within the space meet safety standards. However, existing portable gas detectors are usually small in size and have poor battery life, making continuous monitoring of the gas environment in confined spaces impossible. Confined spaces are often temporary work sites without fixed power supply, requiring workers to repeatedly enter the confined space for safety monitoring, significantly increasing the probability of workers being exposed to potential hazards. Therefore, an external energy storage unit is used to expand the battery capacity of portable devices, providing four power sources and an automatic switching circuit. The four power sources are automatically switched according to different power input states, improving the working time of the portable gas detector. Utility Model Content

[0003] In view of this, the present invention provides an external energy storage power supply system for portable terminals, which adds an external energy storage unit to portable gas alarms. Through simple connection, the battery life of portable gas alarms can be increased. It provides a four-way power automatic switching circuit. The circuit adopts intrinsically safe design, which enables portable gas alarms to work for a long time in flammable and explosive environments.

[0004] An external energy storage power supply system for a portable terminal includes an external energy storage unit and a device host. The external energy storage unit communicates and supplies power to the device host. The power supply interface is a VCC_5V and a GND port. The external energy storage unit supplies 5V power to the device host. The external energy storage unit and the device host communicate through a single bus to transmit the remaining power information of the external energy storage unit.

[0005] Furthermore, the external energy storage unit includes a first power supply and a second power supply. The first power supply is directly supplied with 5V from the outside, and the second power supply is supplied with 5V after being boosted by the lithium battery pack of the external energy storage unit. The external energy storage unit has a power switching circuit inside to complete the switching between the first power supply and the second power supply.

[0006] Furthermore, the device host includes a third power supply, a fourth power supply, a boost / buck circuit, a control circuit, a wireless / voice drive circuit, and a sensor drive circuit. The third power supply is the host's charging interface, which adopts a TYPE-C interface design. It charges the host's energy storage battery while providing 5V operating power to the host. The third power supply has the third power supply priority. The fourth power supply is the energy storage battery, which has three interfaces: a charging interface, a discharging interface, and GND. The fourth power supply output interface boosts the voltage and outputs 5V to power the host. The fourth power supply has the lowest power supply priority. The host has an internal power switching circuit to switch between the third and fourth power supplies.

[0007] Furthermore, the automatic switching circuit between the first and second power supplies consists of three MOSFETs and a current-limiting resistor. The NMOS transistor is designated Q8, and the PMOS transistors are designated Q2 and Q5. The first power supply is an external 5V DC power supply. The first power supply is connected to the gates of Q8 and Q2, and the source of Q2. The source of Q8 is grounded, and the drain of Q8 is connected to the gate of Q8. The drain of Q5 is connected to the drain of Q2. If the first power supply is present, the source and drain of Q8 are in a conducting state. The drain of Q8 is also grounded, pulling down the gate of Q5, thus turning off Q2, and the second power supply does not provide power.

[0008] Furthermore, the automatic switching circuit between the third and fourth power supplies uses a charging chip for circuit switching.

[0009] Furthermore, the four-way automatic power switching circuit includes five MOSFETs and current-limiting resistors. The NMOS transistors are designated Q6, Q7, and Q9, and the PMOS transistors are designated Q3 and Q4. When all four power supplies are present, MOSFET Q8 is turned on, pulling down the gate of PMOS transistor Q5. Then, MOSFETs Q2 and Q4 are turned off, and the second, third, and fourth power supplies are automatically disconnected, with the first power supply powering the portable terminal. When the first power supply is not supplying power, and the other three power supplies are present, MOSFET Q2 is turned on, MOSFET Q4 is turned off, the second power supply is supplied, and the third and fourth power supplies are disconnected, with the system using the second power supply. When the first and second power supplies are not supplying power, and the other two power supplies are present, the third power supply is supplied, and MOSFET Q1 is not turned on. At this time, the supply voltage is USB_VCC minus the voltage drop of diode D1. When only the fourth power supply is supplying power, MOSFET Q1 is turned on, and the fourth power supply boosts the voltage to power the device.

[0010] Beneficial effects:

[0011] 1. This utility model simply connects an external energy storage unit to a portable gas alarm, providing four power supply options and an automatic switching circuit, thus improving the battery life of the portable gas alarm. It can significantly increase the device's runtime.

[0012] 2. This utility model automatically switches between four power sources by using different power input states, which improves the reliability and flexibility of power supply.

[0013] 3. The power automatic switching circuit of this utility model adopts an intrinsically safe design, which enables the portable gas alarm to work for a long time in flammable and explosive environments. Attached Figure Description

[0014] Figure 1 This is a block diagram of a portable terminal external energy storage power supply unit and a four-way power automatic switching circuit according to the present invention.

[0015] Figure 2 This is a circuit diagram illustrating an embodiment of the portable terminal external energy storage power supply unit and a four-way power automatic switching circuit according to the present invention.

[0016] Figure 3 This is a schematic diagram of the automatic switching circuit between the first power supply and the second power supply in this embodiment.

[0017] Figure 4 This is a schematic diagram of the four-way power supply automatic switching circuit in this embodiment.

[0018] Figure 5 This is a power supply switching flowchart of an external energy storage power supply unit and a four-way power automatic switching circuit for a portable terminal according to the present invention. Detailed Implementation

[0019] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0020] This utility model adds an external energy storage power supply unit to a portable terminal, and provides a portable terminal external energy storage power supply unit and a four-way power automatic switching circuit. The four power supplies on the input side are a directly connected 5V DC power supply, an external energy storage battery, a host energy storage battery, and a host charging interface.

[0021] The 5V DC power supply connected to the external energy storage is the primary power supply. It can be connected to a 5V DC power supply in places with DC power supply conditions to continuously power the device. The primary power supply has the highest priority. After the primary DC power supply is connected, the portable gas alarm will only use this power supply for power.

[0022] The external energy storage battery is the second power source. It is used in places where there is no DC power supply. After the external energy storage battery boosts and regulates the voltage, it supplies power to the equipment. Its priority is second only to the first power source.

[0023] The main unit's charging interface is a third power source, providing power to the main unit's energy storage battery and operating power to the main unit. This interface should not be used to directly supply power in flammable or explosive environments.

[0024] The main unit's energy storage battery is the fourth power source. When the above three power sources are not supplying power, this level of power source is used. The main unit's energy storage battery boosts and regulates the voltage to supply power to the main unit.

[0025] See Figure 1 The structural diagram shows that this utility model comprises two parts: an external energy storage unit and a device host. The external energy storage unit communicates and supplies power to the device host, with power supply interfaces including VCC_5V and GND ports. The external energy storage unit supplies 5V power to the device host. Communication between the external energy storage unit and the device host is via a single bus for transmitting information about the remaining power level of the external energy storage unit. The external energy storage unit includes two power supplies: a first power supply and a second power supply. The first power supply is a direct external 5V power supply using a DC 5.5*2.1mm round plug. The second power supply is a 5V power supply boosted from the lithium battery pack of the external energy storage unit. The external energy storage unit has an internal power switching circuit to switch between the first and second power supplies. The first power supply has the highest power supply priority, followed by the second power supply. The main unit also includes two power supplies, boost / buck circuits, control circuits, wireless / voice drive circuits, and sensor drive circuits. The two power supplies in the main unit are the third and fourth power supplies. The third power supply is the main unit's charging interface, which uses a TYPE-C interface design. It can charge the main unit's energy storage battery while providing 5V operating power to the main unit. The third power supply has the third power supply priority. The fourth power supply is the energy storage battery equipped in the main unit. It has three interfaces: a charging interface, a discharging interface, and GND. The fourth power supply output interface outputs 5V after boosting to power the device. The fourth power supply has the lowest power supply priority. The main unit has an internal power switching circuit to switch between the third and fourth power supplies. The third power supply has a higher priority than the fourth power supply. The fourth power supply has the lowest priority in this circuit. When the other three power supplies are not providing power, this power supply is used.

[0026] See Figure 2 The circuit diagram of this utility model consists of five parts: a second power supply and boost regulator circuit, a first power supply and automatic switching circuit between the first and second power supplies, a third power supply and battery charging circuit and automatic switching circuit between the third and fourth power supplies, and a four-way automatic power supply switching circuit. The second power supply and boost regulator circuit uses a battery power boost chip to boost the voltage of a single lithium battery to 5V, forming the second power supply. The third power supply and battery charging circuit and automatic switching circuit between the third and fourth power supplies uses a battery charging chip to power the device while the battery is charging.

[0027] like Figure 3As shown, the first power supply and the automatic switching circuit between the first and second power supplies are as follows: This part mainly consists of three MOSFETs and a current-limiting resistor. The NMOS is designated Q8, and the PMOS is designated Q2 and Q5. The first power supply is an external 5V DC power supply. The first power supply is connected to the gates of Q8 and Q2, and the source of Q2. The source of Q8 is grounded, and the drain of Q8 is connected to the gate of Q8. The drain of Q5 is connected to the drain of Q2. If the first power supply is present, the source and drain of Q8 are in a conducting state. The drain of Q8 is also grounded, which pulls the gate of Q5 low, so Q2 is turned off, and the second power supply does not supply power. Figure 3 Main components and connections:

[0028] NMOS Q8: Gate and drain are shorted, source is grounded, and the first power supply (5V DC) is connected to its gate-drain node.

[0029] PMOS Q2: The source is connected to the first power supply, the gate is connected to the gate-drain node of Q8, and the drain is connected to the drain of Q5.

[0030] PMOS Q5: The drain is connected to the drain of Q2, and the gate is connected to the drain of Q8 (therefore controlled by the switching state of Q8).

[0031] Working principle:

[0032] When the first power source is present:

[0033] The gate and drain voltages of Q8 are 5V, and its source is grounded, therefore V GS =5V. When NMOS Q8 enters the on state, its drain (short-circuited with the gate) is grounded through the source, which makes the drain voltage of Q8 close to 0V.

[0034] When the drain voltage of Q8 is 0V, the gate voltage of Q5 is low (GND). Since Q5 is a PMOS and its source voltage is the first power supply (5V), therefore V GS =V G V S =-5V, Q5 is turned on.

[0035] When Q5 is turned on, it pulls the drain of Q2 down to near 0V. At this time, the V of Q2... GS =0V 5V = -5V, PMOS Q2 is off.

[0036] When the primary power source is unavailable:

[0037] Q8 cannot be turned on because its drain and gate are no longer 0V. The gate of Q5 is not pulled low (it may be floating or kept at a high level), and Q5 is no longer turned on.

[0038] When the gate of oQ2 returns to a high level, V GS This turns on Q2, connecting the second power supply.

[0039] Logical function:

[0040] The existence of the first power source determines the output state of the second power source.

[0041] When the first power supply is present, Q8 and Q5 are turned on, eventually turning off Q2, thus turning off the second power supply.

[0042] When the first power supply is not available, Q8 is not turned on, Q5 is turned off, Q2 is turned on, and the second power supply provides power.

[0043] like Figure 4 As shown, the four-way automatic power switching circuit operates on the same principle as the first and second power automatic switching circuit. This circuit includes five MOSFETs and current-limiting resistors. The NMOS transistors are designated Q6, Q7, and Q9, and the PMOS transistors are designated Q3 and Q4. When all four power supplies are present, MOSFET Q8 is turned on, pulling down the gate of PMOS transistor Q5. Then, MOSFETs Q2 and Q4 are turned off, automatically disconnecting the second, third, and fourth power supplies, and using the first power supply to power the portable terminal. When the first power supply is not providing power, and the other three power supplies are present, MOSFET Q2 is turned on, MOSFET Q4 is turned off, the second power supply is activated, and the third and fourth power supplies are disconnected, with the system using the second power supply. When the first and second power supplies are not providing power, and the other two power supplies are present, the third power supply is activated, and MOSFET Q1 is not turned on. The supply voltage at this time is USB_VCC minus the voltage drop across diode D1. When only the fourth power supply is available, MOSFET Q1 is turned on, and the fourth power supply boosts the voltage to power the device.

[0044] Figure 4 The main components

[0045] 1. Power input:

[0046] oEX_BAT: Input after switching between the first and second power supplies.

[0047] oBAT_5V: Input after switching between the third and fourth power supplies.

[0048] 2. MOSFETs and their functions:

[0049] oQ3, Q4 (P-channel MOSFETs): Control the switching between EX_BAT and BAT_5V.

[0050] oQ6, Q7, Q9 (N-channel MOSFETs): Used for logic control to ensure that P-channel MOSFETs are correctly turned on or off.

[0051] 3. Resistor network:

[0052] R11, R13, R16, R17: Provide gate drive voltage division and pull-up / pull-down functions.

[0053] oR22: Used as a load resistor or drain pull-down resistor.

[0054] 4. Output terminal:

[0055] oOUT_5V: The stable output terminal of the circuit, with an output voltage of 5V.

[0056] Logical Analysis

[0057] 1. When EX_BAT exists (the input after switching between the first and second power supplies takes precedence):

[0058] oEX_BAT provides a voltage divider signal to the gate of Q3 through resistor R16.

[0059] oQ6 is pulled low through GND to ensure that the gate voltage of Q3 is lower than the source voltage, thus turning on Q3.

[0060] After oQ3 is turned on, the EX_BAT voltage is directly supplied to the EX_BAT1 node.

[0061] At this point, R17 pulls the gate voltage of Q4 high, turning off Q4 and preventing BAT_5V power supply.

[0062] Result: EX_BAT provides a stable voltage for OUT_5V.

[0063] 2. When EX_BAT does not exist (input after switching to the third or fourth power supply):

[0064] When EX_BAT fails (voltage drops to 0 or is disconnected), Q3 turns off due to loss of gate drive.

[0065] oQ6 also fails to conduct due to a lack of drive signal.

[0066] At this point, R11 and R13 pull the gate voltage of Q4 low, and Q4 turns on.

[0067] After Q4 is turned on, BAT_5V supplies power to OUT_5V through Q4.

[0068] Result: The circuit automatically switched to backup power.

[0069] See Figure 5 When four power supplies are present at the same time, the first power supply is compared with the second power supply in terms of priority, the third power supply is compared with the fourth power supply in terms of priority, and finally the four power supplies are compared in terms of priority, and the power supply with the highest priority is selected to supply power to the load.

[0070] In summary, the above are merely preferred embodiments of this utility model and are not intended to limit the scope of protection of this utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.

Claims

1. An external energy storage power supply system for a portable terminal, characterized in that, It includes an external energy storage unit and a device host. The external energy storage unit communicates and supplies power to the device host. The power supply interface is VCC_5V and GND port. The external energy storage unit supplies 5V power to the device host. The external energy storage unit and the device host communicate through a single bus to transmit the remaining power information of the external energy storage unit. The external energy storage unit includes a first power supply and a second power supply. The first power supply is directly supplied with 5V from the outside, and the second power supply is supplied with 5V after being boosted by the lithium battery pack of the external energy storage unit. The external energy storage unit has a power switching circuit inside to complete the switching between the first power supply and the second power supply. The main unit includes a third power supply, a fourth power supply, a boost / buck converter circuit, a control circuit, a wireless / voice driver circuit, and a sensor driver circuit. The third power supply is the main unit's charging interface, using a TYPE-C interface design. It charges the main unit's energy storage battery while providing 5V operating power to the main unit. The third power supply has the third power supply priority. The fourth power supply is the energy storage battery, which has three interfaces: a charging interface, a discharging interface, and GND. The fourth power supply output interface boosts the voltage and outputs 5V to power the main unit. The fourth power supply has the lowest power supply priority. The main unit has an internal power switching circuit to switch between the third and fourth power supplies. The automatic switching circuit between the first and second power supplies consists of three MOSFETs and a current-limiting resistor. The NMOS transistor is designated Q8, and the PMOS transistors are designated Q2 and Q5. The first power supply is an external 5V DC power supply. The first power supply is connected to the gates of Q8 and Q2, and the source of Q2. The source of Q8 is grounded, and the drain of Q8 is connected to the gate of Q8. The drain of Q5 is connected to the drain of Q2. If the first power supply is present, the source and drain of Q8 are in a conducting state. The drain of Q8 is also grounded, which pulls the gate of Q5 low, so Q2 is turned off, and the second power supply does not supply power. The automatic switching circuit between the third and fourth power supplies uses a charging chip for circuit switching. The four-way power automatic switching circuit includes five MOSFETs and current-limiting resistors. The NMOS transistors are designated Q6, Q7, and Q9, and the PMOS transistors are designated Q3 and Q4. When all four power supplies are present, MOSFET Q8 is turned on, pulling down the gate of PMOS transistor Q5. Then, MOSFETs Q2 and Q4 are turned off, and the second, third, and fourth power supplies are automatically disconnected, with the first power supply powering the portable terminal. When the first power supply is not supplying power, and the other three power supplies are present, MOSFET Q2 is turned on, MOSFET Q4 is turned off, the second power supply is supplied, and the third and fourth power supplies are disconnected, with the system using the second power supply. When the first and second power supplies are not supplying power, and the other two power supplies are present, the third power supply is supplied, and MOSFET Q1 is not turned on. At this time, the supply voltage is USB_VCC minus the voltage drop of diode D1. When only the fourth power supply is supplying power, MOSFET Q1 is turned on, and the fourth power supply boosts the voltage to power the device.

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