CN204794261U - A charging circuit and portable power source for portable power source - Google Patents

Abstract

The utility model discloses a charging circuit for a mobile power supply and a mobile power supply, a charging interface for receiving an external input power supply, a discharge interface for an external load, a built-in battery for storing electric energy, and a charging interface for detecting the charging The detection circuit of the plug state of the interface and the discharge interface; when the detection circuit detects that there is an input power supply on the charging interface, it cuts off the current output of the battery to the discharge interface; the input power is connected to discharge The power supply pin of the interface charges the load when a load is connected to the discharge interface. By designing the mobile power supply, when there is an input power supply, it directly uses the external input power supply to charge the load inserted into the mobile power supply, thereby reducing the power dissipation of the mobile power supply, reducing the heat generation of the mobile power supply, and ensuring that the internal power supply of the mobile power supply The performance of the electronic device will not be degraded due to the high working temperature, which improves the reliability of the mobile power supply.

Description

Charging circuit for mobile power supply and mobile power supply

technical field

The utility model belongs to the technical field of charging and discharging circuits, and in particular relates to a circuit design suitable for a charging circuit of a mobile power supply.

Background technique

With the increasing popularity of wearable electronic products, their types are becoming more and more diverse, and their functions are becoming more and more diversified, and people use the wearable electronic products more and more frequently. Since wearable electronic products are generally small in size, the space reserved for batteries inside is very limited, and it is impossible to use larger batteries to power such electronic products. Limited by the volume of the battery, the capacity of the battery will not be too large, which will greatly limit the battery life of wearable electronic products and require frequent charging.

In order to facilitate consumers to charge wearable electronic products or other portable digital products, mobile charging devices (or mobile power for short) have emerged as the times require. This type of mobile power supply is small in size and easy to carry, so it can supplement power for such loads (such as wearable electronic products, digital products, etc.) anytime and anywhere to meet consumers' needs for continuous use of such electronic products.

The current mobile power supply, considering the safety issue, the battery capacity is generally designed within 2200mAh, and it can charge two to three small-capacity loads when fully charged. When the battery power of the mobile power supply is exhausted, an external input power supply is required to supplement the power for the mobile power supply. During the period when the mobile power supply is supplementing power, sometimes it is necessary for the mobile power supply to charge the load connected to it at the same time. In this case, most of the existing mobile power supplies adopt the design method of "charging while discharging", that is, while using an external input power source to charge the built-in battery of the mobile power supply, the built-in battery of the mobile power supply is controlled as an external load. Charge. This "charging while discharging" design method will not only reduce the charging efficiency, but also generate a large power dissipation on the mobile power supply, resulting in serious heating of the mobile power supply. When the operating temperature of the mobile power supply rises, it will affect the performance of the electronic devices inside the mobile power supply, and the higher the operating temperature, the lower the performance of the electronic devices, which seriously affects the performance and reliability of the mobile power supply.

Contents of the invention

The purpose of this utility model is to provide a charging circuit for a mobile power supply. When the mobile power supply is connected to an external input power supply and a load at the same time, the traditional charging mode of "charging while discharging" is changed, and the external input power supply is directly connected to the charging circuit. Charge the load, thereby improving the charging efficiency and reducing the heat generated by the mobile power supply.

In order to solve the above-mentioned technical problems, the utility model adopts the following technical solutions to achieve:

A charging circuit for a mobile power supply, including a charging interface for receiving external input power, a discharging interface for external loads, a built-in battery for storing electric energy, and a plug for detecting the charging interface and the discharging interface state detection circuit; the detection circuit cuts off the current output of the battery to the discharge interface when it detects that there is an input power supply on the charging interface; the input power supply is connected to the power pin of the discharge interface. When a load is connected to the discharge interface, the load is charged.

In order to control the battery to stop charging the load plugged into the discharge interface when the input power is connected, the utility model proposes the following three optimal design schemes:

Option 1: Connect the battery to a boost circuit, and when the detection circuit detects that there is an input power supply connected to the charging interface, the output signal controls the boost circuit to stop running, so as to cut off the power supply of the battery to the The current output of the above discharge interface.

As a preferred circuit design of the detection circuit, an NMOS transistor is arranged in the detection circuit, the gate of the NMOS transistor receives the input power supply, the source is grounded, and the drain is connected to the enabling of the boost circuit. pin, the boost circuit stops running when the potential of its enable pin is low.

In order to enable the built-in battery of the mobile power supply to charge the external load normally when there is no input power supply, the utility model is also provided with a control circuit in the detection circuit, and the control circuit is connected to the status pin of the discharge interface and The power supply pin, when it is detected that a load is connected to the charging interface and the load is not fully charged, outputs a high-level control signal to the enable pin of the boost circuit to control the boost circuit in the absence of When the input power is connected, it is enabled to run, and the battery voltage is boosted to meet the charging requirements of the external load; when the control circuit detects that there is a load connected to the charging interface and the load is fully charged , setting the potential of the enable pin of the boost circuit to be low, and stopping charging the external load.

Solution 2, the battery is provided with a switch circuit in the path connected to the discharge interface, and when the detection circuit detects that there is an input power supply connected to the charging interface, the output signal controls the switch circuit to cut off the path , so as to cut off the current output of the battery to the discharge interface.

As a preferred circuit design of the switch circuit, a first PMOS transistor and a second PMOS transistor are arranged in the switch circuit, the current output by the battery is first transmitted to the source of the first PMOS transistor, and the first PMOS transistor The drain of the PMOS transistor is connected to the drain of the second PMOS transistor, the source of the second PMOS transistor is connected to the power supply pin of the discharge interface, and an antiparallel connection is connected between the source and the drain of each PMOS transistor. Parasitic diodes, the gates of the first PMOS transistor and the second PMOS transistor are connected to the detection circuit; as a preferred circuit design of the detection circuit, the detection circuit is provided with a first NMOS transistor and a second NMOS transistor The gate of the first NMOS transistor receives the input power, the source is grounded, and the drain is connected to the gate of the second NMOS transistor; the source of the second NMOS transistor is grounded, and the drain is connected to the first PMOS transistor and the second NMOS transistor. The grid of the two PMOS transistors.

In order to enable the built-in battery of the mobile power supply to charge the external load normally when there is no input power supply, the utility model is also provided with a control circuit in the detection circuit, and the control circuit is connected to the status pin of the discharge interface and Power supply pin, when a load is connected to the charging interface and the load is not fully charged, output a high-level control signal to the gate of the second NMOS transistor to control the second NMOS transistor when there is no input power It is turned on when it is connected, and the current path between the battery and the external load is connected, and the battery is used to charge the load; when the control circuit detects that there is a load connected to the charging interface and the load is fully charged When powering on, set the gate potential of the second NMOS transistor to be low, cut off the current path between the battery and the external load, and stop the battery from charging the external load, so as to save battery power.

Solution 3: Connect the battery to the input terminal of a boost circuit, the output terminal of the boost circuit is connected to the power supply pin of the discharge interface through a switch circuit, and the detection circuit detects that there is an input terminal on the charging interface. When the power supply is connected, the output signal controls the step-up circuit to stop running and controls the switch circuit to turn off, so as to cut off the current output of the battery to the discharge interface.

As a preferred circuit design of the switch circuit, a first PMOS transistor and a second PMOS transistor are arranged in the switch circuit, the source of the first PMOS transistor is connected to the output terminal of the boost circuit, and the first PMOS transistor The drain of the transistor is connected to the drain of the second PMOS transistor, the source of the second PMOS transistor is connected to the power supply pin of the discharge interface, and an antiparallel parasitic is connected between the source and the drain of each PMOS transistor. Diodes, the gates of the first PMOS transistor and the second PMOS transistor are connected to the detection circuit; as a preferred circuit design of the detection circuit, a first NMOS transistor and a second NMOS transistor are arranged in the detection circuit, The gate of the first NMOS transistor receives the input power, the source is grounded, and the drain is respectively connected to the enable pin of the boost circuit and the gate of the second NMOS transistor; the source of the second NMOS transistor The drain is connected to the gates of the first PMOS transistor and the second PMOS transistor.

In order to enable the built-in battery of the mobile power supply to charge the external load normally when there is no input power supply, the utility model is also provided with a control circuit in the detection circuit, and the control circuit is connected to the status pin of the discharge interface and The power supply pin, when it is detected that a load is connected to the charging interface and the load is not fully charged, the control signal outputting a high level is transmitted to the enable pin of the boost circuit and the second The gate of the NMOS transistor controls the boost circuit to enable operation, boosts the battery voltage to the charging voltage value required by the external load, and simultaneously controls the second NMOS transistor to turn on, so that the first PMOS transistor Connect the current path between the battery and the discharge interface with the second PMOS tube to charge the external load; when the control circuit detects that a load is connected to the charging interface and the load is fully charged and setting the enable pin of the boost circuit and the gate potential of the second NMOS transistor to be low, so that the battery stops charging the external load, so as to save battery power.

Based on the circuit design of the above-mentioned charging circuit, the utility model also proposes a mobile power supply using the above-mentioned charging circuit design, including a charging interface for receiving external input power, a discharging interface for external loads, and a built-in battery for storing electric energy. A battery and a detection circuit for detecting the plug-in status of the charging interface and the discharging interface; when the detecting circuit detects that the charging interface has an input power supply, it cuts off the current from the battery to the discharging interface Output: the input power is connected to the power supply pin of the discharge interface, and when a load is connected to the discharge interface, the load is charged.

Compared with the prior art, the advantages and positive effects of this utility model are: the utility model directly uses the external input power supply to charge the load inserted into the mobile power supply through the design of the mobile power supply when the input power supply is connected, without Then the external load is charged by the built-in battery of the mobile power supply, which can significantly reduce the power dissipation of the mobile power supply, reduce the calorific value of the mobile power supply, and ensure that the electronic devices inside the mobile power supply will not be affected by their performance due to excessive operating temperature. The decline of the power bank improves the reliability of the mobile power supply. At the same time, compared with the traditional "charging while discharging" charging mode, the charging circuit of the utility model can significantly improve the charging efficiency of the mobile power supply, accelerate the charging speed of the load, and the circuit design is simple and easy to implement.

After reading the detailed description of the embodiments of the utility model in conjunction with the accompanying drawings, other features and advantages of the utility model will become clearer.

Description of drawings

Fig. 1 is the circuit schematic diagram of the first embodiment of the charging circuit proposed by the utility model;

Fig. 2 is the circuit schematic diagram of the second embodiment of the charging circuit proposed by the utility model;

Fig. 3 is a schematic circuit diagram of a third embodiment of the charging circuit proposed by the present invention.

Detailed ways

Below in conjunction with accompanying drawing, the specific embodiment of the present utility model is described in further detail.

In order to solve the problems that the existing mobile power supply adopts the charging mode of "charging while discharging", which leads to the reduction of charging efficiency of the mobile power supply, large power dissipation and serious heat generation, the utility model proposes a mobile power supply in the case of an external input power supply. , directly use the connected input power to supply power to the external load of the mobile power supply, and then charge the built-in battery of the mobile power supply after the load is fully charged; or, use the connected input power to directly charge the external load at the same time as the mobile The built-in battery of the power supply is charged, so that the charging efficiency can be guaranteed to reach more than 70%, and the charging speed of the load can be improved.

In order to achieve the above design purpose, it is necessary to design a detection circuit in the mobile power supply to check the plug-in status of the charging interface and discharge interface on the mobile power supply, and then control the mobile power supply according to the actual plug-in status of the input power supply and the external load. When the battery in the charging interface has an input power supply, it stops charging the load connected to the charging interface, and only when there is no input power supply on the charging interface and a load is inserted on the discharge interface, the built-in mobile power supply The battery charges the external load to ensure the charging efficiency of the battery.

The specific circuit design and working principle of the charging circuit in the mobile power supply proposed by the utility model will be described in detail below through three specific embodiments.

Embodiment 1, as shown in FIG. 1 , in this embodiment, a charging interface USB_1 for external input power and a discharge interface USB_2 for external load are designed on the mobile power supply. The discharge interface USB_2 can be provided with one channel or multiple channels. In order to enable the input power supply USB_IN connected through the charging interface USB_1 to directly charge the external load, this embodiment connects the power supply pin VBUS of the charging interface USB_1 with the power supply pin Vbus of the discharge interface USB_2, so that the input power supply VBUS_IN can be connected to After being connected to the mobile power supply, it is directly transmitted to the external load through the power pin Vbus of the discharge interface USB_2 to charge it. In order to prevent the internal current of the mobile power supply from being fed back to the input power supply VBUS_IN, this embodiment connects an anti-reverse bias diode D1 in series on the power supply pin VBUS of the charging interface USB_1, and utilizes the reverse cut-off characteristic of the anti-reverse bias diode D1. Ensure that the charging current of the input power supply USB_IN is normally delivered to the discharge interface USB_2, and at the same time prevent the mobile power supply from charging the external input power supply in reverse.

In order to control the built-in battery of the mobile power supply to stop charging the external load when the input power supply USB_IN is connected to the charging interface USB_1, this embodiment sets a detection circuit in the mobile power supply. In this embodiment, for the case where the output voltage of the built-in battery is lower than the charging voltage required by the external load, a boost circuit BOOST and an NMOS transistor Q1 are provided in the detection circuit. Connect the input terminal VIN of the boost circuit BOOST to the positive pole BATTERY+ of the battery, the output terminal VOUT is connected to the power supply pin Vbus of the discharge interface USB_2, the enable terminal EN is connected to the drain of the NMOS transistor Q1, and the source of the NMOS transistor Q1 The pole is grounded, and the gate receives the input power supply USB_IN, and the input power supply USB_IN can be divided by a voltage divider circuit composed of voltage divider resistors R4 and R5, and then transmitted to the gate of the NMOS transistor Q1 to control The NMOS transistor Q1 is turned on when there is an input power supply USB_IN, and then pulls down the potential of the enable terminal of the boost circuit BOOST to control the boost circuit BOOST to stop running, so as to achieve the design purpose of cutting off the battery from charging the external load.

In this embodiment, the boost circuit BOOST may be formed by discrete components, or an integrated chip may be directly selected for circuit design, which is not specifically limited in this embodiment.

In order to enable the built-in battery of the mobile power supply to charge the external load normally when there is no input power USB_IN on the charging interface USB_1 and an external load is inserted on the discharge interface USB_2, and to automatically stop the charging process after the external load is fully charged , In this embodiment, a control circuit is also provided in the detection circuit, including a controller MCU, a pull-up resistor R1, a sampling resistor, a current detection chip U1 and other parts. Connect the status pin Shield of the discharge interface USB_2 to the DC power supply VCC through the pull-up resistor R1, or connect it in series with the resistor R2 to the DC power supply VCC through the pull-up resistor R1. The DC power supply VCC can be provided directly by a battery inside the mobile power supply, or after the voltage of the battery is regulated and transformed by a voltage regulator. For the case where the resistor R2 is not configured, the status pin Shield of the discharge interface USB_2 can be directly connected to the controller MCU, such as one of the GPIO ports PI02 of the MCU; for the case where the resistor R2 is configured, the resistor R2 can be connected with the pull-up resistor The middle node of R1 is connected to the GPIO port PI02 of the controller MCU, because when an external load is inserted into the discharge interface USB_2, the internal circuit of the load will pull down the potential of the status pin Shield of the discharge interface USB_2 or directly ground it , and then make the potential of the PI02 port of the controller MCU jump from the high level when the load is not inserted to the low level after the load is inserted. The controller MCU can accurately judge whether there is a load inserted on the mobile power supply according to the high and low level changes of its PI02 port, and when it detects that a load is inserted, it outputs a high-level control signal VEN to the boost circuit through its PI01 port The enable terminal EN of BOOST, when there is no input power supply USB_IN, controls the boost circuit BOOST to enable operation, and uses the built-in battery of the mobile power supply to charge the external load.

In order to detect the charging state of the load, this embodiment connects a sampling resistor R3 in series with the power supply pin Vbus of the discharge interface USB_2, connects the current detection chip U1 to both ends of the sampling resistor R3, and detects the potential at both ends of the sampling resistor R3 difference, and then according to the detected potential difference combined with the resistance value of the sampling resistor R3, the magnitude of the charging current can be calculated. When the current detection chip U1 detects that the charging current is less than the preset lower limit, it feeds back a high-level signal I _OUT _CUR to another IO port AI01 of the controller MCU to notify the controller that the MCU is fully charged. When the controller MCU detects that the load is fully charged, it sets the control signal VEN output through its PI01 port to low level to control the boost circuit BOOST to stop running, and then controls the battery to stop charging the external load to save battery power. .

The specific working principle of the mobile power supply of this embodiment will be described in detail below with reference to FIG. 1 .

After the mobile power supply is started and running, the controller MCU automatically detects whether there is a load inserted into the charging interface USB_2. If no load is inserted, the control signal VEN is set to low level, and the boost circuit BOOST is controlled to be in an inactive state. At this time, if there is no input power supply USB_IN connected to the charging interface USB_1 of the mobile power supply, the mobile power supply is in the standby state; The input power USB_IN charges the built-in battery of the power bank. Specifically, a power management chip can be built in the mobile power supply and connected between the charging interface USB_1 and the battery to control the charging process of the battery.

During the period when the input power supply USB_IN is connected to the charging interface USB_1, if a load is inserted into the discharge interface USB_2 of the mobile power supply, at this time, the controller MCU sets the output control signal VEN to a high level, but at this time , due to the existence of the input power supply USB_IN, the gate voltage of the NMOS transistor Q1 is high and enters a saturated conduction state, and then pulls down the potential of the enable terminal EN of the boost circuit BOOST, and controls the boost circuit BOOST to maintain an inactive state. Prevent the external load from being charged by the built-in battery of the mobile power supply, and use the external input power USB_IN to directly charge the load. That is, the input power USB_IN connected through the charging interface USB_1 of the mobile power supply is transmitted to the external load through the anti-reverse bias diode D1 and the sampling resistor R3 to charge the external load.

In the process of using the input power supply USB_IN to charge the external load, the input power supply USB_IN can be used to simultaneously charge the built-in battery of the mobile power supply, or the built-in battery of the mobile power supply can be charged after the external load is fully charged. When the latter design method is adopted, the controller MCU can be used to detect the charging state of the external load, that is, the charging current of the load is detected through the sampling resistor R3 and the current detection chip U1, and when the charging current is less than the preset lower limit value, it is judged The load is fully charged, and then controls the power management chip connected between the input power supply USB_IN and the battery to start running, and starts to charge the built-in battery of the mobile power supply.

When the controller MCU detects that there is a load inserted on the discharge interface USB_2, but there is no input power supply USB_IN on the charging interface USB_1, at this time the NMOS transistor Q1 is in the cut-off state because its gate voltage is low, and the controller MCU because of The potential of the PI02 port changes from high level to low level and outputs a high level control signal VEN through its PI01 port, and then controls the boost circuit BOOST to enable operation, and after the battery voltage is boosted, the output charging voltage ( For example, 5V, etc.) to charge the load via the discharge interface USB_2. After the load is fully charged, the controller MCU sets the control signal VEN to a low level, controls the boost circuit BOOST to stop running, and then stops the charging process to save battery power.

In this embodiment, the charging interface USB_1 and the discharging interface USB_2 may be USB interfaces commonly used in the industry at present. In order to facilitate consumers to distinguish, a USB socket can be selected as the charging interface USB_1, and a USB plug can be selected as the discharging interface USB_2. Of course, this embodiment is not limited to the above examples.

Embodiment 2, as shown in FIG. 2 , in this embodiment, a charging interface USB_1 for external input power and a discharge interface USB_2 for external load are also designed on the mobile power supply. After the power supply pin VBUS of the charging interface USB_2 is connected in series with the anti-reverse bias diode D1, the power supply pin Vbus of the discharge interface USB_2 is connected. When the input power supply USB_IN is connected to the charging interface USB_1, the load inserted into the discharge interface USB_2 is directly Charge.

In order to control the built-in battery of the mobile power supply to stop charging the external load when the input power supply USB_IN is connected to the charging interface USB_1, this embodiment first designs a switch in the path where the battery is connected to the power pin Vbus of the discharge interface USB_2 circuit, the switch circuit can be formed by connecting two PMOS transistors, or directly adopt a reverse series PMOS pair transistor Q3 for circuit design. Of course, other electronic devices with switching functions can also be used to connect between the battery and the power pin Vbus of the discharge interface USB_2 to control the charging current output by the battery on and off.

In this embodiment, a PMOS pair transistor Q3 in reverse series is used as an example for illustration. The charging voltage VBAT output by the battery (the charging voltage VBAT can be the voltage directly output by the battery, or the voltage after the battery voltage is converted, as long as the voltage value of the charging voltage VBAT can meet the charging requirements of the external load. Can) transmit to the source of the first PMOS transistor in the PMOS pair Q3, the drain of the first PMOS transistor is connected to the drain of the second PMOS transistor, and the source of the second PMOS transistor is connected to the power supply pin Vbus of the discharge interface USB_2 , or connect to the power supply pin Vbus of the discharge interface USB_2 through the sampling resistor R3. In each PMOS transistor, a parasitic diode D2, D3 is provided, and the parasitic diode D2, D3 is connected in antiparallel between the source and the drain of the PMOS transistor, that is, the cathode of the parasitic diode D2, D3 is connected to the PMOS transistor. The source, the anodes of the parasitic diodes D2 and D3 are connected to the drains of the PMOS transistors, the gates of the two PMOS transistors are connected to the detection circuit, and the detection circuit is used to control the on-off of the two PMOS transistors.

The detection circuit of this embodiment is provided with a first NMOS transistor Q1, a second NMOS transistor Q2 and a control circuit, and the control circuit can follow the design method of the control circuit in Embodiment 1, that is, it includes a controller MCU, a pull-up The main parts such as resistor R1, sampling resistor R3 and current detection chip U1 are used to realize the insertion detection of an external load and the detection and judgment of whether the load is fully charged. For the specific connection relationship of the control circuit, refer to the relevant description in the first embodiment.

Use the input power supply USB_IN connected through the charging interface USB_1 to perform on-off control on the first NMOS transistor Q1. Specifically, the gate of the first NMOS transistor Q1 can be connected to the voltage dividing resistors R4 and R5, and the voltage dividing resistors R4 and R5 can be used to control the After the input power supply USB_IN is divided, it is applied to the gate of the first NMOS transistor Q1 to control the first NMOS transistor Q1 to be turned on and off. The source of the first NMOS transistor Q1 is grounded, and the drain is connected to the gate of the second NMOS transistor Q2. The gate of the second NMOS transistor Q2 is connected to the PI01 port of the controller MCU at the same time, and receives the control signal VEN output by the controller MCU. The source of the second NMOS transistor Q2 is grounded, the drain is connected to the gate of the PMOS pair transistor Q3, and the drain of the PMOS pair transistor Q3 is connected through a resistor R6.

The specific working principle of the mobile power supply of this embodiment will be described in detail below with reference to FIG. 2 .

After the mobile power supply is started and running, the controller MCU judges whether there is a load inserted into the charging interface USB_2 according to the high or low level state of its PI02 port. If there is no load inserted, it sets the control signal VEN to a low level to control the second NMOS tube. Q2 is turned off, and then the PMOS transistor Q3 is kept in the off state, cutting off the current path from the battery to the charging interface USB_2. At this time, if there is no input power supply USB_IN connected to the charging interface USB_1 of the mobile power supply, the mobile power supply is in the standby state; The input power USB_IN charges the built-in battery of the power bank. Specifically, a power management chip can be built in the mobile power supply and connected between the charging interface USB_1 and the battery to control the charging process of the battery.

During the period when the input power supply USB_IN is connected to the charging interface USB_1, if a load is inserted into the discharge interface USB_2 of the mobile power supply, at this time, the controller MCU sets the output control signal VEN to a high level, but at this time , due to the existence of the input power supply USB_IN, the gate voltage of the first NMOS transistor Q1 is high and enters a saturated conduction state, and then the gate potential of the second NMOS transistor Q2 is pulled down, so that the second NMOS transistor Q2 is in an off state, Control the PMOS to keep the transistor Q3 in the off state, prevent the external load from being charged by the built-in battery of the mobile power supply, and use the external input power supply USB_IN to directly charge the load. That is, the input power USB_IN connected through the charging interface USB_1 of the mobile power supply is transmitted to the external load through the anti-reverse bias diode D1 and the sampling resistor R3 to charge the external load. At this time, due to the existence of the parasitic diode D3, the input power USB_IN can be prevented from flowing to the battery through the PMOS transistor Q3.

When the controller MCU detects that there is a load inserted into the discharge interface USB_2, but there is no input power supply USB_IN connected to the charging interface USB_1, at this time the first NMOS transistor Q1 enters the cut-off state because its gate voltage is low, and the controller MCU then Because the potential of the PI02 port changes from high level to low level, the high level control signal VEN is output through the PI01 port, and then the second NMOS transistor Q2 is controlled to be saturated and turned on, and the gate potential of the PMOS transistor Q3 is lowered. , control the conduction of the PMOS transistor Q3, connect the charging circuit between the battery and the discharge interface USB_2, and use the battery to charge the external load. After the load is fully charged, the controller MCU sets the control signal VEN to a low level, controls the second NMOS transistor Q2 to turn off, and then turns off the PMOS transistor Q3 to stop the charging process of the battery to the external load to save battery power.

Embodiment 3, as shown in FIG. 3 , in this embodiment, a charging interface USB_1 for external input power and a discharge interface USB_2 for external load are also designed on the mobile power supply. After the power supply pin VBUS of the charging interface USB_2 is connected in series with the anti-reverse bias diode D1, the power supply pin Vbus of the discharge interface USB_2 is connected. When the input power supply USB_IN is connected to the charging interface USB_1, the load inserted into the discharge interface USB_2 is directly Charge.

In order to control the built-in battery of the mobile power supply to stop charging the external load when the input power supply USB_IN is connected to the charging interface USB_1, this embodiment designs a boost in the path where the battery is connected to the power pin Vbus of the discharge interface USB_2 The circuit BOOST and a switch circuit, the boost circuit BOOST can be formed by discrete components, or integrated chips can be directly selected for circuit design. The input terminal VIN of the boost circuit BOOST is connected to the positive pole BATTERY+ of the battery, the output terminal VOUT is connected to the switch circuit, and connected to the power pin Vbus of the discharge interface USB_2 through the switch circuit. Connect the enable end EN of the boost circuit BOOST and the control end of the switch circuit to the detection circuit, and use the detection circuit to control the working state of the boost circuit BOOST and the on-off state of the switch circuit.

In this embodiment, the switching circuit can be designed in the same manner as the switching circuit in Embodiment 2, that is, two PMOS transistors or a PMOS pair transistor Q3 or other switching elements that have a switching function and support the passage of a large current are designed. made. In this embodiment, a PMOS transistor Q3 is still used as an example for illustration, and its connection relationship is different from that of Embodiment 2 only in that the source of the first PMOS transistor is connected to the output terminal VOUT of the boost circuit BOOST.

The detection circuit of this embodiment can be designed in the same manner as the detection circuit in Embodiment 2, that is, the gate of the first NMOS transistor Q1 is connected to the input power supply USB_IN through the voltage dividing resistors R4 and R5, the source is grounded, and the drain is connected to The gate of the second NMOS transistor Q2. Connect the gate of the second NMOS transistor Q2 to the enable terminal EN of the boost circuit BOOST and the PI01 port of the controller MCU to receive the control signal VEN output by the controller MCU. The source of the second NMOS transistor Q2 is grounded, the drain is connected to the gate of the PMOS pair transistor Q3, and the drain of the PMOS pair transistor Q3 is connected through a resistor R6.

The specific working principle of the mobile power supply of this embodiment will be described in detail below with reference to FIG. 3 .

After the mobile power supply is started and running, the controller MCU judges whether there is a load inserted into the charging interface USB_2 according to the high and low level status of its PI02 port. If there is no load inserted, the control signal VEN is set to low level to control the boost circuit BOOST It is in the non-working state, and controls the second NMOS transistor Q2 to be cut off, and then keeps the PMOS transistor Q3 in the off state, so as to cut off the current path from the battery to the charging interface USB_2. At this time, if there is no input power supply USB_IN connected to the charging interface USB_1 of the mobile power supply, the mobile power supply is in the standby state; The input power USB_IN charges the built-in battery of the power bank.

During the period when the input power supply USB_IN is connected to the charging interface USB_1, if the controller MCU detects that a load is inserted into the discharge interface USB_2 of the mobile power supply, at this time, the controller MCU sets the output control signal VEN to a high voltage. However, at this time, due to the existence of the input power supply USB_IN, the gate voltage of the first NMOS transistor Q1 is high and enters a saturated conduction state, and then pulls down the EN potential of the enable terminal EN of the boost circuit BOOST, and makes the second The gate potential of the NMOS transistor Q2 is low. Since the enable terminal EN of the boost circuit BOOST is at a low level, the boost circuit BOOST stops operating, and at the same time, because the gate potential of the second NMOS transistor Q2 is low, the second NMOS transistor Q2 is in an off state, and then controls the PMOS The tube Q3 is kept in the off state to block the charging path from the battery to the external load, and the external input power supply USB_IN is used to directly charge the load.

When the controller MCU detects that there is a load inserted into the discharge interface USB_2, but there is no input power supply USB_IN connected to the charging interface USB_1, at this time the first NMOS transistor Q1 enters the cut-off state because its gate voltage is low, and the controller MCU then Because the potential of the PI02 port changes from high level to low level, a high level control signal VEN is output through its PI01 port, and then the booster circuit BOOST is controlled to enable operation, and the second NMOS transistor Q2 is saturated and turned on. The gate potential of the PMOS pair transistor Q3 is pulled down to control the PMOS pair transistor Q3 to be turned on. At this time, after the battery voltage is boosted and transformed by the boost circuit BOOST, it passes through the source and drain of the first PMOS in the PMOS transistor Q3 and the parasitic diode D3 of the second PMOS transistor, and is transmitted to the discharge terminal via the sampling resistor R3. The interface USB_2 charges the load inserted into the discharge interface USB_2. After the load is fully charged, the controller MCU sets the control signal VEN to a low level, controls the booster circuit BOOST to stop running, and controls the second NMOS transistor Q2 to cut off, and then turns off the PMOS transistor Q3 to stop the battery from connecting the load to the outside. Charging process to save battery power.

In the process of using the input power supply USB_IN to charge the external load, the input power supply USB_IN can also be used to simultaneously charge the built-in battery of the mobile power supply, or the built-in battery of the mobile power supply can be charged after the external load is fully charged. For the charging interface USB_1 and the discharging interface USB_2, the USB interfaces generally used in the industry can also be selected. In order to facilitate consumers to distinguish, a USB socket can be selected as the charging interface USB_1, and a USB plug can be selected as the discharging interface USB_2. Of course, this embodiment is not limited to the above examples.

Of course, the NMOS transistors Q1 and Q2 in the detection circuit can also be replaced by NPN transistors, thyristors or other switching elements, which is not specifically limited in this embodiment.

The mobile power charging circuit proposed by the utility model has the advantages of simple structure, low cost, reliable performance and low power consumption, and is suitable for application in various mobile power products.

Of course, the above description is not a limitation of the present utility model, and the present utility model is not limited to the above-mentioned examples. Those of ordinary skill in the art may make changes, modifications, additions or replacements within the essential scope of the present utility model. It should also belong to the protection scope of the present utility model.

Claims (10)

1. A charging circuit for a mobile power supply, comprising a charging interface for receiving an external input power supply, a discharge interface for an external load, a built-in battery for storing electric energy, and a device for detecting the charging interface and the discharging interface A detection circuit for a plugged state; it is characterized in that: the detection circuit cuts off the current output of the battery to the discharge interface when it detects that the input power is connected to the charging interface; the input power is connected to the discharge interface When a load is connected to the discharge interface, the power supply pin charges the load. 2. The charging circuit for a mobile power supply according to claim 1, wherein the battery is connected to a boost circuit, and the detection circuit outputs The signal controls the step-up circuit to stop running, so as to cut off the current output of the battery to the discharge interface. 3. The charging circuit for mobile power according to claim 2, characterized in that: an NMOS transistor is arranged in the detection circuit, the gate of the NMOS transistor receives the input power, the source is grounded, The drain is connected to the enable pin of the boost circuit, and the boost circuit stops running when the potential of the enable pin is low. 4. The charging circuit for mobile power supply according to claim 1, characterized in that: the battery is provided with a switch circuit in the path connected to the discharge interface, and the detection circuit detects that the charging interface is connected to the charging circuit. When the input power is connected, the output signal controls the switch circuit to cut off the path, so as to cut off the current output of the battery to the discharge interface. 5. The charging circuit for mobile power supply according to claim 4, characterized in that: The switch circuit is provided with a first PMOS transistor and a second PMOS transistor, the current output by the battery is transmitted to the source of the first PMOS transistor, and the drain of the first PMOS transistor is connected to the drain of the second PMOS transistor , the source of the second PMOS tube is connected to the power supply pin of the discharge interface, and an antiparallel parasitic diode is connected between the source and drain of each PMOS tube, and the first PMOS tube and the second PMOS tube The gate is connected to the detection circuit; A first NMOS transistor and a second NMOS transistor are arranged in the detection circuit, the gate of the first NMOS transistor receives the input power supply, the source is grounded, and the drain is connected to the gate of the second NMOS transistor; The source of the transistor is grounded, and the drain is connected to the gates of the first PMOS transistor and the second PMOS transistor. 6. The charging circuit for mobile power supply according to claim 5, characterized in that: a control circuit is also provided in the detection circuit, the control circuit is connected to the status pin and the power pin of the discharge interface, and the When it is detected that a load is connected to the charging interface and the load is not fully charged, output a high-level control signal to the gate of the second NMOS transistor. 7. The charging circuit for a mobile power supply according to claim 1, wherein the battery is connected to an input terminal of a boost circuit, and the output terminal of the boost circuit is connected to the power supply of the discharge interface through a switch circuit pin, when the detection circuit detects that there is an input power supply on the charging interface, the output signal controls the step-up circuit to stop running and controls the switch circuit to turn off, so as to cut off the discharge of the battery to the Interface current output. 8. The charging circuit for mobile power according to claim 7, characterized in that: A first PMOS transistor and a second PMOS transistor are arranged in the switch circuit, the source of the first PMOS transistor is connected to the output terminal of the boost circuit, and the drain of the first PMOS transistor is connected to the drain of the second PMOS transistor , the source of the second PMOS tube is connected to the power supply pin of the discharge interface, and an antiparallel parasitic diode is connected between the source and drain of each PMOS tube, and the first PMOS tube and the second PMOS tube The gate is connected to the detection circuit; A first NMOS transistor and a second NMOS transistor are arranged in the detection circuit, the gate of the first NMOS transistor receives the input power supply, the source is grounded, and the drain is respectively connected to the enable pin of the boost circuit and the gate of the second NMOS transistor; the source of the second NMOS transistor is grounded, and the drain is connected to the gates of the first PMOS transistor and the second PMOS transistor. 9. The charging circuit for mobile power supply according to claim 8, characterized in that: a control circuit is also provided in the detection circuit, the control circuit is connected to the status pin and the power pin of the discharge interface, and the When it is detected that a load is connected to the charging interface and the load is not fully charged, output a high-level control signal and transmit it to the enable pin of the boost circuit and the gate of the second NMOS transistor respectively . 10. A mobile power supply, characterized in that it is provided with a charging circuit for a mobile power supply according to any one of claims 1 to 9.