Power supply USB output control circuit

Abstract

The utility model relates to a power supply USB output control circuit, a power supply comprises a battery pack, an on-off control circuit, an auxiliary power supply, an MCU processor, a USB protocol chip, a DC / DC conversion circuit and a USB port, the auxiliary power supply is connected with the MCU processor and the USB protocol chip and is used for supplying power to the MCU processor and the USB protocol chip, the USB port has a detection voltage, and the DC / DC conversion circuit is connected with the DC / DC conversion circuit. And the USB protocol chip is connected with a current sampling resistor at the output side of the DC / DC conversion circuit, when the electric equipment is inserted into the USB port, the voltage change is detected, and the USB protocol chip determines whether the electric equipment of the USB port is accessed or not according to the voltage change of the current sampling resistor, and controls the on-off of the fourth switch piece and the third switch piece according to whether the electric equipment is accessed or not. According to the application, the access of the electric equipment connected to the USB port is automatically detected, the access of the DC / DC conversion circuit can be automatically started, the operation of the DC / DC conversion circuit is stopped when no electric equipment exists at the USB port of the equipment, the no-load operation of the DC / DC conversion circuit is avoided, and the energy consumption is effectively saved.

Description

TECHNICAL FIELD

[0001] The utility model relates to power control technical field, concretely relates to a power USB output control circuit. BACKGROUND

[0002] With the development of photovoltaic products, the light storage all-in-one machine is more and more favored by the market due to its structural characteristics and functionality, and the small light storage all-in-one machine also welcomes its market explosion, wherein, the rich interface (USB, etc.) of the small light storage all-in-one machine can provide rich experience for users. Since the general use environment of the light storage all-in-one machine is an outdoor humid environment, the circuit with USB external charging needs to solve several problems.

[0003] 1. Solve the USB insertion detection problem, avoid the no-load loss caused by the cumbersome switch and forgetting to turn off;

[0004] During the use of the equipment, firstly, the light storage all-in-one machine switch and the USB port start switch button need to be turned on, and the start process is cumbersome, secondly, the internal circuit DC / DC conversion circuit is in the state of no-load operation, which forms a loss.

[0005] 2. Solve the waterproof problem and appearance processing problem caused by the USB switch button;

[0006] The USB switch button of the equipment needs to be waterproof, which leads to more troublesome production and processing, and also increases the production cost.

[0007] 3. Solve the problem caused by the safety requirement;

[0008] According to the requirements of safety standards IEC62109 and IEC62368, the light storage all-in-one machine needs to meet IEC62368 when used as a portable power supply, IEC62368 requires that the accessible voltage of the directly accessible part (USB is directly accessible) is within 60VDC, and the light storage all-in-one machine needs to meet IEC2109 when used in a humid environment, IEC62109 requires that the accessible voltage of the directly accessible part (USB is directly accessible) is within 35VDC. This also leads to more electrical restrictions when designing the light storage all-in-one machine, however, with the increasing power of the photovoltaic system involved in the light storage all-in-one machine, the photovoltaic system and the light storage all-in-one machine exceed the requirement of directly accessible voltage more and more, which leads to the fact that the existing light storage all-in-one machine is difficult to meet the safety requirement.

[0009] Therefore, how to design the structure of the power USB output control circuit so as to overcome the above defects is the technical problem to be solved by the present application. INVENTION CONTENTS

[0010] The utility model discloses a main purpose is to overcome above at least one defect, is to provide a kind of power supply USB output control circuit, it can optimize to remove traditional USB switch button, improve work safety and reliability, while, simplify manufacturing difficulty, reduce manufacturing cost.

[0011] To achieve the above object, the utility model adopts technical scheme:

[0012] The utility model provides a kind of power supply USB output control circuit, power supply includes battery pack, switch control circuit, auxiliary power supply, MCU processor, USB protocol chip, DC / DC conversion circuit, fourth switch piece, third switch piece and USB port, the switch control circuit with the battery pack, auxiliary power supply are all connected, for controlling the circuit on-off between the battery pack and auxiliary power supply, the battery pack is connected with the input side of DC / DC conversion circuit through the fourth switch piece, the output side of DC / DC conversion circuit is connected with USB port through the third switch piece, the access detection pin of USB protocol chip is connected with the USB port, the USB protocol chip is used to control the work of DC / DC conversion circuit and peripheral circuit according to whether the USB port has electrical equipment insertion, wherein, the auxiliary power supply is connected with the MCU processor and USB protocol chip, for the power supply for the work of MCU processor and USB protocol chip,

[0013] When electrical equipment is inserted into the USB port, the voltage of the access detection pin of the USB protocol chip changes, the USB protocol chip determines whether the electrical equipment of USB port is accessed according to the voltage change of the access detection pin, and controls the on-off of the fourth switch piece and the third switch piece according to whether the electrical equipment is accessed.

[0014] According to one of the embodiments of the utility model, the output pin of the MCU processor is connected with the fourth switch piece through the isolation control circuit, the communication pin of the MCU processor is connected with the USB protocol chip, and the MCU processor controls the on-off of the fourth switch piece according to the control signal fed back by the USB protocol chip.

[0015] According to one of the embodiments of the utility model, the isolation control circuit includes current-limiting resistor and isolation optocoupler, the output pin of the MCU processor is connected with the input side of the isolation optocoupler through the current-limiting resistor, and the output side of the isolation optocoupler is connected with the fourth switch piece.

[0016] According to one of the embodiments of the utility model, the DC / DC conversion circuit is flyback isolation DC / DC conversion circuit.

[0017] According to one of the embodiments of the present application, the detection voltage is 5V.

[0018] According to one of the embodiments of the present application, the detection voltage is from any one of the auxiliary power supply, MCU processor or USB protocol chip.

[0019] According to one of the embodiments of the present application, the detection voltage is from the auxiliary power supply, and the output end of the auxiliary power supply is connected with the output side of the DC / DC conversion unit through a reverse prevention diode, for forming the detection voltage of the USB port.

[0020] According to one of the embodiments of the present application, the output end of the auxiliary power supply is connected with the power supply pin of the MCU processor after being connected with a voltage stabilizing element in series.

[0021] According to one of the embodiments of the present application, a voltage reduction module is arranged in the USB protocol chip, and the high level output pin of the USB protocol chip is connected with the output side of the DC / DC conversion unit, for forming the detection voltage of the USB port.

[0022] According to one of the embodiments of the present application, the switch element is a relay, contactor, triode or MOS tube.

[0023] Compared with the prior art, the power supply USB output control circuit of the present application has the following advantages and beneficial effects:

[0024] The power supply USB output control circuit of the present application can realize automatic detection of the connection of the power consuming device connected with the USB port, simplifies the operation process, and can automatically start the DC / DC conversion circuit, and stop the operation of the DC / DC conversion circuit when there is no power consuming device connected with the USB port, thereby avoiding the no-load operation of the DC / DC conversion circuit and effectively saving energy consumption.

[0025] Further, the power supply USB output control circuit of the present application is designed to be isolated in multiple connection channels, so that the power supply can be used in any battery voltage system (including high battery voltage or high voltage system caused by other internal circuits), thereby improving the applicability of the device. BRIEF DESCRIPTION OF DRAWINGS

[0026] Some specific embodiments of the present application will be described in detail hereinafter with reference to the accompanying drawings in an exemplary and non-limiting manner. The same reference signs in the drawings indicate the same or similar components or parts. Those skilled in the art should understand that the drawings are not necessarily drawn to scale. In the drawings:

[0027] Figure 1is a structural schematic diagram of a power supply USB output control circuit according to the prior art;

[0028] Figure 2 is a structural schematic diagram of a power supply USB output control circuit according to one embodiment of the present application;

[0029] Figure 3 is a working flow schematic diagram of a power supply USB output control circuit according to one embodiment of the present application;

[0030] Figure 4 is a structural schematic diagram of a power supply USB output control circuit according to another embodiment of the present application. DETAILED DESCRIPTION

[0031] The technical solutions of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0032] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0033] Figure 1 is a USB external discharge control circuit diagram of a common portable power supply on the market at present, and its working principle is as follows:

[0034] The dashed box is a battery pack, SW1 is a power on / off button, and the auxiliary power is powered on after the on / off button SW1 is pressed to start. Then the auxiliary power supplies power to the MCU processor. The MCU processor is powered on. When the USB port needs to be connected and used by the power device, the USB switch button SW2 is pressed, the MCU processor sends a trigger signal to control the fourth switch M4 to be turned on through the triode Q1, the DC / DC conversion circuit starts to work and supplies power to the rear circuit (such as USB protocol chip and USB port, etc.), and the third switch M3 is opened after the USB protocol chip is powered on. When the power device that needs to be charged is connected to the USB port, the USB protocol chip can detect the voltage change of the USB port through the connection detection pin, and discharge externally through the USB port. When there is no need to discharge the external power device through the USB port, the USB switch button SW2 is pressed to disconnect, and the fourth switch M4 is turned off to stop the discharging process.

[0035] However, the USB external discharge control circuit of the prior art has several limitations:

[0036] 1. Since opening or stopping USB discharging needs manual operation of the switch, the operation is cumbersome and the experience is poor. If the user forgets to press the USB switch button SW2 when not charging, it will cause the DC / DC conversion circuit to be forgotten to be closed, which will cause the DC / DC conversion circuit to run under no load, resulting in unnecessary loss.

[0037] 2. For long-term outdoor use environment, the USB switch button SW2 needs waterproof treatment. The waterproof switch is generally large in size due to the existence of the sealing ring, and the appearance treatment is more troublesome, leading to difficult production and processing, and increasing the production cost.

[0038] 3. When the device is used as a portable power supply, IEC62368 requires that the accessible voltage be within 60VDC, and when the device is used as a light storage all-in-one machine in a humid environment, IEC62109 requires that the contact voltage be within 35VDC, which has more restrictions. However, as the power of the photovoltaic system involved in the light storage all-in-one machine continues to increase, the demand for photovoltaic systems and light storage all-in-one machines to exceed the directly accessible voltage is increasing, making it difficult for existing light storage all-in-one machines to meet the safety requirements.

[0039] The switch in the embodiments of the present application is an example of PMOS tube for electrically controlled on-off. It can be understood that the switch can also use relays, contactors, transistors and other electrically controllable electrical elements that can act as switches, which should also be included in the protection of the present application.

[0040] Embodiment 1:

[0041] This embodiment describes a power supply USB output control circuit, as shown in Figure 2As shown, the power supply includes a battery pack, a switching control circuit, an auxiliary power supply, an MCU processor, a USB protocol chip, a DC / DC conversion circuit, a fourth switch M4, a third switch M3 and a USB port, the switching control circuit is connected with the battery pack and the auxiliary power supply, and is used for controlling the circuit on-off between the battery pack and the auxiliary power supply, the battery pack is connected with the input side of the DC / DC conversion circuit through the fourth switch M4, the output side of the DC / DC conversion circuit is connected with the USB port through the third switch M3, the access detection pin of the USB protocol chip is connected with the USB port, the USB protocol chip is used for controlling the working of the DC / DC conversion circuit and the peripheral circuit according to whether the USB port has a power device inserted, wherein the auxiliary power supply is connected with the MCU processor and the USB protocol chip (the output end of the auxiliary power supply is connected with the power supply pin of the MCU processor through a series connection with a voltage stabilizing element), and can supply power for the working of the MCU processor and the USB protocol chip, the USB protocol chip is connected with the current sampling resistor of the output side of the DC / DC conversion circuit, the current sampling resistor is used for feeding back the current size when the USB port supplies power to the power device, and the current sampling resistor can also play a role of short circuit protection.

[0042] When the power device is inserted into the USB port, the voltage of the access detection pin of the USB protocol chip changes, the USB protocol chip determines whether the power device of the USB port is accessed according to the voltage change of the access detection pin, and controls the on-off of the fourth switch M4 and the third switch M3 according to whether the power device is accessed.

[0043] Generally, the USB protocol chip has a USB protocol function, when the power device is not inserted into the USB port, the access detection pins DP and DM of the USB protocol chip are low, when the external power device is inserted into the USB port, the level of the access detection pins DP and DM changes, at this time, it can be judged that the power device is accessed (after judging that the access, the main power circuit is controlled to be turned on), similarly, when the level of the access detection pins DP and DM changes to low again, it indicates that the power device is disconnected (after judging that the disconnection, the main power circuit is controlled to be turned off, and the no-load loss is saved).

[0044] In the embodiment, the auxiliary power supply provides the detection voltage for the USB port. Specifically, the output end of the auxiliary power supply is connected with the output side of the DC / DC conversion unit through a reverse prevention diode, and is used for forming the detection voltage of the USB port.

[0045] The output pin of the MCU processor is connected with the fourth switch M4 through an isolation control circuit, the MCU processor is connected with the communication pin of the USB protocol chip, and the USB protocol chip communicates with the MCU processor through an I2C protocol. The MCU processor controls the on-off of the fourth switch M4 according to the control signal fed back by the USB protocol chip. The isolation control circuit comprises a current-limiting resistor R3 and an isolation optocoupler U1, the output pin of the MCU processor is connected with the input side of the isolation optocoupler U1 through the current-limiting resistor R3, the output side of the isolation optocoupler U1 has two poles, one pole is connected with the negative pole of the battery pack, and the other pole is connected with the fourth switch M4, the fourth switch M4 is a PMOS tube, and the fourth switch M4 is connected in series between the positive pole of the battery pack and the DC / DC conversion circuit.

[0046] In the working process of the battery pack, the working process is as follows Figure 3The auxiliary power supply is connected with the output side of the DC / DC conversion unit, and provides a 5V detection voltage for the USB port. The presence of the detection voltage can provide a protocol detection basis for the USB powered device with power and the USB powered device without power. At this time, the DC / DC conversion circuit is not powered and does not work. When the MCU processor is powered on, when the powered device is connected to the USB port, the detection voltage changes due to the connected powered device, and the current sampling resistor R2 feeds back the change of the detection voltage to the USB protocol chip. When the USB protocol chip judges that the USB powered device is connected, the third switch M3 is closed, so as to avoid that the connected powered device pulls down the voltage of the auxiliary power supply. At the same time, the USB protocol chip sends a command to the MCU processor through the I2C protocol through the communication pin, and notifies the MCU processor. Then, the MCU processor outputs a high level through the current limiting resistor R3 to control the isolation optocoupler U1 to be turned on, so that the fourth switch M4 is opened, and the DC / DC conversion circuit starts to work. The MCU processor detects the voltage of the output side of the DC / DC conversion circuit through the internal ADC module, and when the DC / DC conversion circuit is started according to the voltage change, the MCU processor sends a command to control the USB protocol chip to open the third switch M3 again, and makes the DC / DC conversion circuit handshake with the USB powered device through the USB port, and starts to discharge externally. When the USB is unplugged, that is, the powered device is unplugged, the USB protocol chip notifies the MCU processor to stop discharging, and the MCU processor closes the fourth switch M4 through the isolation control circuit composed of R3 and U1, so as to disconnect the connection between the battery pack and the DC / DC conversion circuit, so as to achieve the purpose of closing the DC / DC conversion circuit. At the same time, the USB protocol chip keeps opening M3, so as to prepare for the next connection of the USB powered device.

[0047] Embodiment 2:

[0048] The power supply USB output control circuit of the embodiment optimizes the circuit described in embodiment 1, and the optimization is the specific structure of the DC / DC conversion circuit and the USB protocol chip.

[0049] The DC / DC conversion circuit is a flyback isolation DC / DC conversion circuit. As shown in Figure 4 C2, M1, T1, R1, D1 and C1 constitute a flyback isolation DC / DC conversion circuit, and a voltage reduction module is arranged in the USB protocol chip. The high level output pin of the USB protocol chip is connected with the output side of the DC / DC conversion unit, and is used to form the detection voltage of the USB port.

[0050] It can be understood that the detection voltage is from any one of the auxiliary power supply, MCU processor or USB protocol chip. The embodiment described is that a voltage reduction module is arranged in the USB protocol chip, and a larger voltage, for example, 10-20V, input by the auxiliary power supply can be reduced, so that the detection voltage of 5V is output to the USB port after the voltage reduction module achieves the voltage reduction purpose.

[0051] In conclusion, the power supply USB output control circuit can realize automatic detection of the access of the connected power consumption equipment at the USB port, simplifies the operation process, and can automatically start to realize the access of the DC / DC conversion circuit, and stop the work of the DC / DC conversion circuit when there is no power consumption equipment at the device USB port, thereby avoiding the no-load work of the DC / DC conversion circuit and effectively saving energy consumption.

[0052] Further, the power supply USB output control circuit is designed in isolation in the multiple connection channels, so that the power supply can be used in any battery voltage system (including high battery voltage or high voltage system caused by other internal circuits), and the device applicability is improved.

[0053] The above embodiments are only for illustrating the technical concept and characteristics of the utility model, and the purpose is to enable those skilled in the art to understand the content of the utility model and implement it, and it cannot limit the protection scope of the utility model. Any equivalent changes or modifications made according to the spirit and essence of the utility model should be covered within the protection scope of the utility model.

Claims

1. A power supply USB output control circuit, the power supply comprising a battery pack, a switch control circuit, an auxiliary power supply, an MCU processor, a USB protocol chip, a DC / DC conversion circuit, a fourth switch, a third switch and a USB port, the switch control circuit being connected with the battery pack and the auxiliary power supply, for controlling the circuit on-off between the battery pack and the auxiliary power supply, the battery pack being connected with the input side of the DC / DC conversion circuit through the fourth switch, the output side of the DC / DC conversion circuit being connected with the USB port through the third switch, the access detection pin of the USB protocol chip being connected with the USB port, the USB protocol chip being used for controlling the working of the DC / DC conversion circuit and peripheral circuit according to whether there is a power device inserted into the USB port, characterized in that, The auxiliary power supply is connected with the MCU processor and the USB protocol chip, and is used for supplying power for the working of the MCU processor and the USB protocol chip.

2. The power supply USB output control circuit of claim 1, wherein, The output pin of the MCU processor is connected with the fourth switch element through an isolation control circuit, and the communication pin of the MCU processor is connected with the USB protocol chip.

3. The power supply USB output control circuit of claim 2, wherein, The isolation control circuit comprises a current-limiting resistor and an isolation optocoupler, the output pin of the MCU processor is connected with the input side of the isolation optocoupler through the current-limiting resistor, and the output side of the isolation optocoupler is connected with the fourth switch element.

4. The power supply USB output control circuit of claim 1, wherein, The DC / DC conversion circuit is a flyback isolation DC / DC conversion circuit.

5. The power supply USB output control circuit of claim 1, wherein, The USB port is connected with a detection voltage, and the detection voltage is a 5V voltage.

6. The power supply USB output control circuit of claim 5, wherein, The detection voltage is from any one of the auxiliary power supply, the MCU processor or the USB protocol chip.

7. The power supply USB output control circuit of claim 5, wherein, The detection voltage is from the auxiliary power supply, and the output end of the auxiliary power supply is connected with the output side of the DC / DC conversion unit through a flyback diode, and is used for forming the detection voltage of the USB port.

8. The power supply USB output control circuit of any one of claims 1 to 7, wherein, The output end of the auxiliary power supply is connected with the power supply pin of the MCU processor through a series connection with a voltage stabilizing element.

9. The power supply USB output control circuit of any one of claims 1 to 7, wherein, The USB protocol chip is provided with a voltage reduction module, the high-level output pin of the USB protocol chip is connected with the output side of the DC / DC conversion unit, and is used for forming the detection voltage of the USB port.

10. The power supply USB output control circuit of claim 1, wherein, The switch element is a relay, a contactor, a triode or a MOS tube.

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