CN112636455A - Power supply device for conference terminal and conference terminal equipment - Google Patents

Power supply device for conference terminal and conference terminal equipment Download PDF

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Publication number
CN112636455A
CN112636455A CN202011594921.7A CN202011594921A CN112636455A CN 112636455 A CN112636455 A CN 112636455A CN 202011594921 A CN202011594921 A CN 202011594921A CN 112636455 A CN112636455 A CN 112636455A
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China
Prior art keywords
power supply
branch
switching
mos
power
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CN202011594921.7A
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Chinese (zh)
Inventor
凌宏强
范建根
张洪伟
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Sundial Technology Shanghai Co Ltd
Suzhou Keda Technology Co Ltd
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Sundial Technology Shanghai Co Ltd
Suzhou Keda Technology Co Ltd
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Priority to CN202011594921.7A priority Critical patent/CN112636455A/en
Publication of CN112636455A publication Critical patent/CN112636455A/en
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
    • H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
    • H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
    • H02J9/068—Electronic means for switching from one power supply to another power supply, e.g. to avoid parallel connection
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
    • Y02B70/30—Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S20/00—Management or operation of end-user stationary applications or the last stages of power distribution; Controlling, monitoring or operating thereof
    • Y04S20/20—End-user application control systems

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  • Business, Economics & Management (AREA)
  • Emergency Management (AREA)
  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Direct Current Feeding And Distribution (AREA)

Abstract

The application relates to a power supply unit and meeting terminal equipment for conference terminal, including parallel connection's first power supply branch road and second power supply branch road, first power supply branch road inserts power adapter as power supply through first power supply input, second power supply branch road inserts POE-PD as power supply through second power supply input, still includes: the first MOS switching tube is connected in series in the first power supply branch; the second MOS switch tube is connected in series in a second power supply branch circuit; and the power supply switching module is used for controlling the conduction and the cut-off of the first MOS switching tube and the second MOS switching tube according to the accessed power supply and controlling the second MOS switching tube to be always in a cut-off state when the power adapter is accessed for power supply. The problems that an existing power supply device is large in power consumption and large in load terminal voltage drop are solved.

Description

Power supply device for conference terminal and conference terminal equipment
Technical Field
The application relates to a power supply device for a conference terminal and conference terminal equipment, and belongs to the field of power supply equipment.
Background
The conference terminal product uses two power supply modes of power adapter and POE _ PD, can the power supply of exclusive use power adapter, also can the power supply of exclusive use POE _ PD, when both are plugged in simultaneously, preferentially use power adapter power supply.
As shown in fig. 1, in the prior art, the processing mode of preferentially using power-adaptive power supply is implemented by adding a power diode to each of the power supply paths of the power adapter and the POE _ PD.
However, the power diode has a forward conduction voltage drop, so that the power diode has dissipation power consumption, thereby causing temperature rise and reduction of power utilization rate, and the power diode is particularly obvious under a high-power load. Because the power adapter is a standard outsourcing part, the amplitude of the output voltage cannot be adjusted, in order to realize that the power adapter is preferentially used for supplying power when the power adapter and the power adapter are plugged simultaneously, the diode on the power adapter passage can be preferentially conducted only by reducing the POE _ PD output voltage. However, by doing so, the current value of the POE _ PD power supply is further increased, so that when the POE _ PD is used alone, the power dissipation of the diode on the POE _ PD power supply path is larger. Also, when supplying a large capacitive load, the starting current is too high, resulting in the need for a power diode with a higher current rating.
Disclosure of Invention
The application provides a power supply unit and meeting terminal equipment for meeting terminal, can solve among the prior art to the power supply unit of meeting terminal product, because of the great power loss that power diode brought on the power supply route, the problem of the load terminal voltage that brings during the power switching.
The application provides the following technical scheme:
in a first aspect of the embodiments of the present application, a power supply device for a conference terminal is provided, where the power supply device includes:
the power supply system comprises a first power supply branch and a second power supply branch which are connected in parallel, wherein the first power supply branch is connected with a power adapter through a first power supply input end to serve as a power supply, and the second power supply branch is connected with a POE-PD through a second power supply input end to serve as a power supply;
the first MOS switching tube is connected in series in the first power supply branch and is used for controlling the on-off of the first power supply branch;
the second MOS switch is connected in series in the second power supply branch and used for controlling the on-off of the second power supply branch;
and the power supply switching module is used for controlling the conduction and the cut-off of the first MOS switching tube and the second MOS switching tube according to the accessed power supply and controlling the second MOS switching tube to be always in a cut-off state when the power adapter is accessed for power supply.
The technical scheme of this application adopts the MOS switch tube to replace power diode, because MOS pipe conduction voltage drops for a short time, reduces the consumption, reduces the voltage drop of load end when the power supply switches.
Further, according to the power supply device of the first aspect of the embodiment of the present application, the power supply switching module includes:
the input end of the first driving circuit is connected with a first power supply input end, and the control signal output end of the first driving circuit is connected with the control end of the first MOS switch tube and used for controlling the on-off of the first MOS switch tube according to the power supply signal of the first power supply input end;
the input end of the second driving circuit is connected with a second power supply input end, and the control signal output end of the second driving circuit is connected with the control end of the second MOS switch tube and used for controlling the on-off of the second MOS switch tube according to the power supply signal of the second power supply input end;
and the input end of the switching mutual exclusion circuit is connected with the first power supply input end, the control output end of the switching mutual exclusion circuit is connected with the second driving circuit, the switching mutual exclusion circuit is used for disconnecting the control of the second driving circuit on the second MOS switch tube when the power adapter is connected to supply power, and the second MOS switch tube is always in a cut-off state.
According to the technical scheme, the switching mutual exclusion circuit is arranged, so that the second driving circuit is disconnected when the power adapter is connected to supply power, the second driving circuit loses control over the second MOS switch circuit, the second MOS switch circuit is cut off, only the power adapter supplies power, and the power adapter is guaranteed to be preferentially used for supplying power under the condition that the power adapter is connected.
Further, according to the power supply apparatus described in the first aspect of the embodiment of the present application, the switching mutual exclusion circuit includes a fourth MOS switch tube (U4) and a switch control branch, and the fourth MOS switch tube (U4) is connected in series in the control loop of the second driving circuit;
the control input end of the switch control branch is connected with the first power supply input end, and the control output end of the first switch control branch is connected with the control end of the fourth MOS switch tube (U4) and used for controlling the on-off of the fourth MOS switch tube (U4).
The switching mutual exclusion circuit of this application sets up the fourth MOS switch tube to with the fourth MOS switch tube series connection in second drive circuit's control circuit, can break off the fourth MOS switch tube immediately like this under the condition that power adapter inserts, make the second drive circuit disconnection, POE-PD's power supply route disconnection guarantees that power adapter preferentially supplies power.
Further, according to the power supply apparatus in the first aspect of the embodiment of the present application, the first driving circuit includes two mutually exclusive conducting first switching branches and a second switching branch;
the input end of the first switch branch is connected with the first power supply input end, the output end of the first switch branch is connected with the control end of the second switch branch, and the output end of the first switch branch is grounded through a resistor (R8);
the input end of the second switch branch is connected with the source electrode of the first MOS switch tube, and the output end of the second switch branch is grounded through a series resistor (R9);
the grid electrode of the first MOS switching tube is connected to the output end of the second switching branch circuit through a series resistor (R10).
According to the technical scheme, when the power adapter is connected, the first switch branch circuit is kept connected and the second switch circuit is kept disconnected when the first switch branch circuit and the second switch branch circuit which are mutually exclusive are connected, so that the grid voltage of the first MOS switch tube can be quickly pulled down and then connected, and the power adapter power supply channel is ensured to be connected.
Further, according to the power supply apparatus in the first aspect of the embodiment of the present application, the second driving circuit includes a third switching branch and a fourth switching branch that are mutually exclusive and conductive;
the input end of the third switching branch is connected with the second power supply input end through a fourth MOS switching tube (U4), the output end of the third switching branch is connected with the control end of the fourth switching branch, and the output end of the third switching branch is grounded through a resistor (R11);
the input end of the fourth switching branch is connected with the source electrode of the second MOS switching tube, and the output end of the fourth switching branch is grounded through a series resistor (R12);
the grid electrode of the second MOS switch tube is connected to the output end of the second switch branch through a series resistor (R13).
According to the technical scheme, the POE-PD switch-on circuit has the advantages that when the POE-PD is connected, the fourth switch circuit is kept cut off, the grid voltage of the fourth MOS switch tube can be pulled down in time, and the POE-PD switch-on circuit is switched on quickly.
Further, according to the power supply apparatus of the first aspect of the embodiment of the present application, the switch control branch includes a first NPN transistor (Q1) and a second NPN transistor (Q2) that are mutually exclusive and conductive, and resistors (R5, R6);
the base electrode of the first NPN triode (Q1) is connected with the first power supply input end, the collector electrode of the first NPN triode (Q1) is connected with the base electrode of the second NPN triode (Q2) and then connected to the second power supply input end, the emitter electrode of the first NPN triode (Q1) is connected with the emitter electrode of the second NPN triode (Q2) and then grounded, the collector electrode of the second NPN triode (Q2) is connected to the second power supply input end through a resistor (R5), and the collector electrode of the second NPN triode (Q2) is connected with the grid electrode of the fourth MOS switching tube (U4) through a resistor (R6).
According to the technical scheme, the first NPN triode (Q1) and the second NPN triode (Q2) which are mutually exclusively conducted are arranged, so that the grid potential of the U4 is pulled high by the R5 under the condition that the power adapter is connected, the U4 is completely cut off, and the power adapter is ensured to supply power preferentially.
Further, according to the power supply apparatus in the first aspect of the embodiment of the present application, the first switch branch includes a first PNP triode, an emitter of the first PNP triode is connected to the first power input terminal, a collector of the first PNP triode is grounded through a series resistor (R8), and the collector of the first PNP triode is connected to a base of the first PNP triode;
the second switch branch comprises a diode (D4) and a second PNP triode, the anode of the diode (D4) is connected with the source electrode of the first MOS switch tube, the cathode of the diode (D4) is connected with the emitting electrode of the second PNP triode, and the base electrode of the second PNP triode is connected with the collecting electrode of the first PNP triode.
This application technical scheme is through setting up diode D4, ensures to control during first MOS switch tube switches on, and Q3B's projecting pole is in reverse bias all the time, thoroughly cuts off Q3B, and U1's grid voltage just can be as low as possible like this, guarantees that during power adapter inserts, first MOS switch tube maintains the on-state all the time.
Further, according to the power supply apparatus in the first aspect of the embodiment of the present application, the third switching branch includes a third PNP transistor and a resistor (R11), an emitter of the third PNP transistor is connected to the second power input terminal, a collector of the third PNP transistor is connected to ground through a series resistor (R11), and a collector of the third PNP transistor is connected to a base of the third PNP transistor;
the fourth switch branch comprises a diode (D5) and a fourth PNP triode, the anode of the diode (D5) is connected with the source electrode of the second MOS switch tube, the cathode of the diode (D5) is connected with the emitting electrode of the fourth PNP triode, and the base electrode of the second PNP triode is connected with the collecting electrode of the first PNP triode.
This application technical scheme is through setting up diode D5, ensures to control the second MOS switch tube and switches on the period, and Q3D's projecting pole is in reverse bias all the time, thoroughly cuts off Q3D, and U2's grid voltage can be as low as possible like this, guarantees only to connect POE _ PD supply period, and the second MOS switch tube maintains the on-state all the time.
Further, according to the power supply device of the first aspect of the embodiment of the present application, the power supply device further includes a slow start circuit, the slow start circuit includes a third MOS switch tube and a slow start control circuit, the third MOS switch tube is connected in series in a power supply path between the power supply output end and the load, and the slow start control circuit is configured to delay conduction of the third MOS switch tube.
This application technical scheme is through slowly starting protecting against shock electric current.
A second aspect of the embodiments of the present application provides a conference terminal device, including the power supply apparatus described in the first aspect of the embodiments of the present application.
The beneficial effect of this application lies in: this application adopts the MOS switch tube to replace the power diode in former power supply route, has extremely low pressure drop when the MOS switch tube is in complete conducting state, compares the high pressure drop of original power diode, can reduce power dissipation loss.
This application is when selecting the preferential power supply of power adapter, realizes through switching the MOS switch tube on two power supply branch roads, and when the MOS switch tube switched on, there was not the pressure drop hardly, has improved the power supply efficiency, reduces the energy consumption, and the pressure value of load end power falls within 5% when realizing the switching of route between power adapter and POE _ PD.
The foregoing description is only an overview of the technical solutions of the present application, and in order to make the technical solutions of the present application more clear and clear, and to implement the technical solutions according to the content of the description, the following detailed description is made with reference to the preferred embodiments of the present application and the accompanying drawings.
Drawings
Fig. 1 is a schematic structural diagram of a conventional power supply apparatus;
fig. 2 is a schematic structural diagram of a power supply device according to an embodiment of the present application;
fig. 3 is a schematic circuit diagram of a power supply device according to an embodiment of the present application.
Detailed Description
The following detailed description of embodiments of the present application will be described in conjunction with the accompanying drawings and examples. The following examples are intended to illustrate the present application but are not intended to limit the scope of the present application.
Fig. 2 is a power supply unit for conference terminal that this application embodiment provided, as shown in fig. 2, power supply unit includes two way power supply branches, first power supply branch and second power supply branch promptly, first power supply branch and second power supply branch parallel connection, first power supply branch adopts power adapter as power supply, second power supply branch adopts POE-PD as power supply.
The first power supply branch comprises a first power supply input end, the first power supply input end is used for accessing a power adapter as a power supply, the second power supply branch comprises a second power supply input end, and the second power supply input end is used for accessing POE-PD as the power supply. The first power supply branch and the second power supply branch are both connected to a load (a conference terminal product) through a power supply output end, and double-path power supply of the load is achieved.
POE-PD and power adapter can both be alone for the load power supply, when POE-PD and power adapter cut in simultaneously, then preferentially adopt power adapter power supply.
Further, as shown in fig. 1, the power supply device further includes a first MOS switch tube and a second MOS switch tube, the first MOS switch tube is connected in series in the first power supply branch, and the second MOS switch tube is connected in series in the second power supply branch. When the first MOS switching tube works in a cut-off state, the first power supply branch is disconnected; when the second MOS switching tube works in a cut-off state, the second power supply branch is disconnected.
The embodiment realizes the power supply switching of the power adapter and the POE-PD by switching the on-off of the first MOS switch tube and the second MOS switch tube.
Further, power supply unit still includes power supply switching module, power supply switching module is used for switching the operating condition of first MOS switch tube and second MOS switch tube, specifically does:
under the condition that only POE-PD inserts the power supply, the power supply switching module controls the second MOS to open the light pipe and be in the on-state, and once detecting that power adapter inserts, the first MOS switch tube of control is switched on immediately, and control second MOS switch tube simultaneously ends.
Under the condition that only power adapter inserts the power supply, control first MOS switch tube and be in the on-state all the time to control second MOS switch tube and be in the off-state all the time, guarantee under the condition that power adapter inserts, whether POE-PD inserts the power supply, adopt power adapter power supply all the time.
Under the condition that the power adapter and the POE-PD are simultaneously connected to supply power, the first MOS switch tube is immediately controlled to be switched on, and the second MOS switch tube is controlled to be switched off.
Optionally, as shown in fig. 2, the power supply switching module includes a first driving circuit, a second driving circuit, and a switching mutual exclusion circuit.
Specifically, a control signal output end of the first driving circuit is connected to a control end of the first MOS switch tube, and is used for controlling the turn-off and turn-on of the first MOS switch tube. Meanwhile, the power supply end of the first driving circuit is connected with the first power supply input end, when the power adapter is connected, the first driving circuit is connected, and when the power adapter is disconnected, the first driving circuit is disconnected.
And the control signal output end of the second driving circuit is connected with the control end of the second MOS switch tube and is used for controlling the cut-off and the conduction of the second MOS switch tube. Meanwhile, the power supply end of the second driving circuit is connected with the second power supply input end, and when the POE-PD is connected, the second driving circuit is connected; when the POE-PD is disconnected, the second driving circuit is disconnected.
The power supply end of the switching mutual exclusion circuit is connected with the first power supply input end, and when the power adapter is connected to supply power, the switching mutual exclusion circuit is switched on; when the power adapter is disconnected, the switching mutual exclusion circuit is disconnected, and the control of the second driving circuit is lost. And the control signal output end of the switching mutual exclusion circuit is connected with the second driving circuit and is used for controlling the on-off of the second driving circuit.
Based on the circuit structure of the power supply switching module, the switching control of the first power supply branch and the second power supply branch in the embodiment of the present application is respectively completed by the first driving circuit, the second driving circuit and the switching mutex circuit. The method specifically comprises the following steps:
when only the power adapter is connected to supply power, the first driving circuit automatically sets the first MOS switch tube in a complete conduction state, and a power supply signal output by the power adapter is transmitted to the power output end through the first MOS switch tube.
At the moment, the switching mutual exclusion circuit sets the second driving circuit to be in a failure state no matter whether POE _ PD is accessed or not, and the second driving circuit controls disconnection of the second MOS switch tube, so that the second MOS switch tube is always in a cut-off state no matter whether POE _ PD is accessed or not.
When only POE _ PD is connected to supply power, because there is no power adapter, the first drive circuit is invalid by itself, and the first drive circuit is disconnected to the control of the first MOS switch tube, therefore, the first MOS switch tube works in a cut-off state.
At this moment, switch the exclusive circuit and also be in failure mode because there is not the access of power adapter to control to second drive circuit is invalid, and second drive circuit is in the activated state, and automatic setting of second MOS switch tube is in complete conducting state, and the power supply signal of POE _ PD output transmits to power output end through second MOS switch tube.
At this time, if the power adapter is accessed, after the switching mutual exclusion circuit obtains a power supply signal of the power adapter, the second driving circuit is set to be in a failure state, and the second MOS switch tube is changed from a complete conduction state to a cut-off state. Simultaneously, because power adapter's access, first drive circuit also switches on again, output control signal, with first MOS switch tube setting at complete conducting state, power supply is switched into power adapter by POE _ PD.
When the power adapter and the POE _ PD are simultaneously connected to supply power, the response speed of the switching mutual exclusion circuit is fastest, and the second driving circuit is immediately set to be in a failure state, so that the second MOS switch tube is in a cut-off state. Meanwhile, the first MOS switch tube is set in a complete conduction state by the first driving circuit, and a power supply signal output by the power adapter is transmitted to the power output end through the first MOS switch tube.
The power diode in the former power supply route is replaced to the MOS switch tube, has extremely low pressure drop when the MOS switch tube is in the complete conducting state, compares the high pressure drop of former power diode, can reduce power dissipation loss. In addition, this application is when selecting the preferential power supply of power adapter, realizes through switching the MOS switch tube on two power supply branch roads, and when the MOS switch tube switched on, there was not the pressure drop hardly, has improved the power supply efficiency, reduces the energy consumption, and the pressure value of load end power falls within 5% when realizing the route switching between power adapter and POE _ PD.
Optionally, the power supply device according to the embodiment of the present application is further provided with a slow start circuit, where the slow start circuit is disposed at the power supply output ends of the first power supply branch and the second power supply branch, and is configured to realize slow start of the load power supply path.
Specifically, the slow start circuit comprises a third MOS switch tube and a slow start control module, the slow start control module comprises a slow start control unit, the third MOS switch tube is connected in series between the power output end and the load, and a delay start mechanism is arranged in the slow start control unit and used for delaying the conduction of the third MOS switch tube after power is supplied, so that the power supply path of the load is started after the power supply switching module finishes switching.
Furthermore, the slow starting circuit is also provided with an external control unit, and the external control unit is used for on-off control of the slow starting circuit.
By arranging the slow starting circuit, the power supply path of the starting load can be delayed, and overlarge conduction impact current brought by the capacitive load when the capacitive load is supplied with power is avoided.
Fig. 3 shows a schematic circuit diagram of the power supply device according to the embodiment of the present invention, as shown in fig. 3, a P-channel MOS transistor U1 is adopted as the first MOS switch transistor of the embodiment of the present invention, a P-channel MOS transistor U2 is adopted as the second MOS switch transistor, and U1 and U2 in fig. 3 are both P-channel MOS transistors of NXP (enwispy) PMK35EP, where U1 is responsible for turning on and off the first power supply branch using the power adapter as the power supply, and U2 is responsible for turning on and off the second power supply branch using POE-PD as the power supply.
It should be noted that in other embodiments, an appropriate P-MOS model may be selected according to the input voltage and the rated operating current of the practical application. The embodiments of the present application will be described below with reference to a P-channel MOS transistor shown in fig. 3.
Optionally, referring to fig. 3, the first driving circuit of this embodiment includes a PNP transistor Q3A and a PNP transistor Q3B that are mutually exclusively turned on, resistors R8 to R10, a capacitor C1, and a diode D4.
Specifically, the emitter of the PNP triode Q3A is connected to the first power input terminal, the collector of the PNP triode Q3A is connected to the ground through the resistor R8, the base of the PNP triode Q3A is connected to the collector, the collector of the PNP triode Q3A is connected to the base of the PNP triode Q3B, the emitter of the PNP triode Q3B is connected to the source of the P-channel MOS transistor U1 through the diode D4 connected in the reverse direction, and the collector of the PNP triode Q3B is connected to the ground through the resistor R9. The drain electrode of the P-channel MOS tube U1 is connected with a first power supply input end, the source electrode of the P-channel MOS tube U1 is connected with a power supply output end, the grid electrode of the P-channel MOS tube U1 is connected with the collector electrode of the PNP triode Q3B through a resistor R10, a capacitor C1 is further connected between the grid electrode and the source electrode of the P-channel MOS tube U1, and the capacitor C1 is used for filtering.
In this embodiment, the PNP transistor Q3A and the PNP transistor Q3B are both array PNP transistors and have the same parameters.
When the power adapter is connected to supply power, the emitter of Q3A obtains a high potential and is immediately turned on, Q3B is in an off state, the resistor R9 pulls down the gate voltage of U1, and then U1 is fully turned on (V1gs is-12V), so that the first power supply branch is powered on to supply power to the load through the power adapter.
The function of D4 is to ensure that during the turn-on of U1, the emitter of Q3B is reverse biased and Q3B is completely turned off, so that the gate voltage of U1 can be as low as possible. In order to ensure that the Q3B is turned on, the gate voltage of the U1 is as close to the source voltage as possible, so the forward conduction voltage drop of the diode D4 is as small as possible, and for this reason, the schottky diode or the germanium transistor is used as the diode D4.
Optionally, referring to fig. 3, the second driving circuit of this embodiment includes a PNP transistor Q3C and a PNP transistor Q3D that are mutually exclusively turned on, resistors R11 to R13, a capacitor C2, and a diode D5.
Specifically, the emitter of the PNP triode Q3C is connected to the second power input terminal through the fourth MOS switch tube U4 communicated with P, the collector of the PNP triode Q3C is grounded through the resistor R11, the base of the PNP triode Q3C is connected to the collector, the collector of the PNP triode Q3C is connected to the base of the PNP triode Q3D, the emitter of the PNP triode Q3D is connected to the source of the P-channel MOS tube U2 through the diode D5 connected in the reverse direction, and the collector of the PNP triode Q3D is grounded through the resistor R12. The drain electrode of the P-channel MOS tube U2 is connected with the second power supply input end, the source electrode of the P-channel MOS tube U2 is connected with the power supply output end, the grid electrode of the P-channel MOS tube U2 is connected with the collector electrode of the PNP triode Q3D through a resistor R13, a capacitor C2 is further connected between the grid electrode and the source electrode of the P-channel MOS tube U2, and the capacitor C2 is used for filtering.
When the power adapter and the POE _ PD are connected simultaneously for supplying power, the drains of the U1 and the U2 are connected with an external power supply in order to prevent reverse power supply interference caused by the existence of diodes in U1 and U2. In this embodiment, the PNP transistor Q3C and the PNP transistor Q3D are both array PNP transistors and have the same parameters.
When the POE-PD is powered on, when U4 is turned on, the emitter of Q3C gets high, and is immediately turned on, and Q3D is in an off state, the resistor R12 pulls down the gate voltage of U2, and then U2 is fully turned on (V2gs ═ 12V), so that the second power supply branch is powered on to supply power to the load through the power adapter.
The function of D5 is to ensure that during the turn-on of U2, the emitter of Q3D is reverse biased and Q3D is completely turned off, so that the gate voltage of U2 can be as low as possible. In order to ensure that the Q3D is turned on, the gate voltage of the U2 is as close to the source voltage as possible, so the forward conduction voltage drop of the diode D5 is as small as possible, and for this reason, the schottky diode or the germanium transistor is used as the diode D5.
Optionally, referring to fig. 2, the switching mutex circuit includes an NPN transistor Q1 and an NPN transistor Q2 that are turned on mutually exclusively, a P-channel MOS transistor U4, resistors R1-R7, and a capacitor C3.
Specifically, the base of the NPN transistor Q1 is connected to the first power supply input terminal through the resistor R1, the collector of the NPN transistor Q1 is connected to the second power supply input terminal through the resistor R4 after being connected to the base of the NPN transistor Q2, the emitter of the NPN transistor Q1 is connected to the emitter of the NPN transistor Q2 and then grounded, and the collector of the NPN transistor Q2 is connected to the second power supply input terminal through the resistor R5.
The grid of U4 connects the collector of Q2 through resistance R6, and the source of U4 connects the second power supply input end, and the drain-source resistance of U4 passes through resistance R7 ground connection, and simultaneously, the drain-source resistance of U4 connects the emitter of PNP triode Q3C, and still is connected with electric capacity C3 between the grid of U4 and the source, plays the filtering role.
Under the condition that the first power supply input end is connected with a power adapter for supplying power, the base of Q1 is conducted due to obtaining forward bias voltage, and under the condition that Q1 is conducted, the voltage of the base of Q2 is 0, and Q2 is cut off; at this time, the gate potential of U4 is pulled high by the resistor R5, and U4 is turned off; after U4 is cut off, the emitter potential of Q3C is pulled down by a resistor R7, and Q3C is cut off; when Q3C is cut off, the base potential of Q3D is pulled low by the resistor R11, and Q3D is turned on; after the Q3D is turned on, the gate potential of the U2 is pulled high, the U2 is in an off state, and the second power supply branch is disconnected.
Optionally, referring to fig. 3, the slow start circuit includes an NPN transistor Q4, resistors R16 to R21, capacitors C5 to C7, and diodes D1 to D3.
Specifically, a third P-channel MOS tube U3 is connected in series in a power supply loop from a power supply output end to a load, a resistor R17 and a capacitor C5 are connected in parallel and then connected in series with R16 to form an RC charging loop, and C5 is connected with the power supply output end through a diode D1 in forward connection; the anode of the capacitor C6 is connected with the source of U3, the cathode of the capacitor C6 is connected with the gate of U3 through a diode D3 connected in the forward direction, and the cathode of the capacitor C6 is connected with the collector of Q4 through a series resistor R19; the anode of the capacitor C7 is connected with the drain of the U3, the cathode of the capacitor C7 is connected with the gate of the U3 through the resistor R21 which is connected in series, the gate of the U3 is grounded through the resistor R20, the source of the U3 is connected with the collector of the Q4 through the resistors R18 and R19 which are connected in series in sequence, the emitter of the Q4 is grounded, and the base of the Q4 is connected with the capacitor C5.
At the initial power-on, the base voltage of Q4 is 0, Q4 is in a cut-off state, the voltage across the capacitor C6 is 0, the gate-source voltage Vgs of U3 is 0, and U3 is in a cut-off state. The voltage of the power output end charges a capacitor C5 through an RC charging loop, Q4 is conducted after a period of RC charging delay time, the voltage of the power output end charges a capacitor C6 through a resistor R19 to delay the opening of U3, and when Vgs reaches the opening voltage of U3, U3 is opened.
When the U3 is turned on to the Miller stage, the complete conduction of the U3 is slowed down by the capacitor C7, the resistor R21 and the resistor R20, so that the excessive conduction surge current caused by the following capacitive load is avoided. The function of D3 is to ensure that U3 is not disturbed by the environment during the miller phase. When powered down, Q4 turns off, and C6 discharges through resistor R18, turning U3 off. In the embodiment, the magnitude of the conduction degree of the U4 is controlled by controlling the rising slope of the gate source voltage of the U3, so that the problem of overlarge starting current caused by a large capacitive load is solved.
The diode D2 is used for the external control to slowly start the circuit power-on and power-off access, and the access signal is high when the circuit is slowly started to power on, and low when the circuit is slowly started to power off.
Since the soft start channel is handled by a NXP PMK35EP (P-MOS) U3, the U3 source is connected to the supply output in order to prevent the body diode of U3(P-MOS) from going to the load supply before the soft start.
Based on the circuit schematic diagram shown in fig. 3, the specific working process of the embodiment of the present application is as follows:
when only the second power supply input terminal is connected with POE _ PD for supplying power and the power adapter is not connected, Q1 is cut off, Q2 is conducted, at the moment, the grid potential of U4 is pulled down by the resistor R6, and U4 is completely conducted; under the condition that U4 is turned on, the emitter potential of Q3C is equal to VCC voltage 12V, and the emitter of Q3C obtains positive bias voltage conduction; at this time, Q3D is in an off state, the gate voltage of U2 is pulled low by resistor R12, U2 is fully turned on (V2gs — 12V), the second power supply branch is powered on, and the load is supplied with power through POE-PD.
When the first power supply input end is connected to a power adapter for supplying power, an emitter of the Q3A obtains a high potential and is immediately turned on, the Q3B is in an off state, the resistor R9 pulls down a gate of the U1, the U1 is completely turned on (V1gs is-12V), the first power supply branch is powered on, and the load is supplied with power through the power adapter. At this time, when the power adapter supplies power, the base of the Q1 is turned on because of obtaining a forward bias voltage, and when the Q1 is turned on, the base voltage of the Q2 is 0, and the Q2 is turned off; the gate potential of U4 is pulled high by the resistor R5, and U4 is cut off; after U4 is cut off, the emitter potential of Q3C is pulled down by a resistor R7, and Q3C is cut off; when Q3C is cut off, the base potential of Q3D is pulled low by the resistor R11, and Q3D is turned on; after the Q3D is turned on, the gate potential of the U2 is pulled high, the U2 is in an off state, the second power supply branch is disconnected, and at this time, the power adapter is selected to supply power regardless of whether the POE _ PD is connected.
When the power adapter of the first power supply input end and the POE _ PD of the second power supply input end are simultaneously connected to supply power, similarly, the U2 is immediately cut off, and only the power adapter supplies power.
When the power adapter cuts off the power supply, Q3A is cut off immediately, Q3B is conducted, and after Q3B is conducted, the grid potential of U1 is pulled high, U1 is in a cut-off state, and the first power supply branch is cut off. Meanwhile, when the power adapter cuts off power supply, Q1 is cut off, Q2 is turned on, at this time, the gate potential of U4 is pulled low by the resistor R6, U4 is completely turned on, and as with the above analysis, the second power supply branch is powered on, and POE-PD starts to supply power.
To sum up, power supply unit of this application embodiment replaces power diode through setting up P channel MOS pipe, sets up the switching that the power supply switched the module and carries out power supply simultaneously, reduces the consumption, has improved the power supply efficiency, and the pressure value of load end power falls within 5% when realizing the route switching between power adapter and POE _ PD.
The embodiment of the present application further provides a conference terminal device, which includes the power supply apparatus in the above embodiment, and details are not repeated here.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. The utility model provides a power supply unit for conference terminal, includes parallel connection's first power supply branch road and second power supply branch road, first power supply branch road passes through first power supply input and inserts power adapter as power supply, second power supply branch road passes through second power supply input and inserts POE-PD as power supply, its characterized in that, power supply unit still includes:
the first MOS switching tube is connected in series in the first power supply branch and is used for controlling the on-off of the first power supply branch;
the second MOS switch is connected in series in the second power supply branch and used for controlling the on-off of the second power supply branch;
and the power supply switching module is used for controlling the conduction and the cut-off of the first MOS switching tube and the second MOS switching tube according to the accessed power supply and controlling the second MOS switching tube to be always in a cut-off state when the power adapter is accessed for power supply.
2. The power supply device for conference terminal according to claim 1, wherein said power supply switching module comprises:
the input end of the first driving circuit is connected with a first power supply input end, and the control signal output end of the first driving circuit is connected with the control end of the first MOS switch tube and used for controlling the on-off of the first MOS switch tube according to the power supply signal of the first power supply input end;
the input end of the second driving circuit is connected with a second power supply input end, and the control signal output end of the second driving circuit is connected with the control end of the second MOS switch tube and used for controlling the on-off of the second MOS switch tube according to the power supply signal of the second power supply input end;
and the input end of the switching mutual exclusion circuit is connected with the first power supply input end, the control output end of the switching mutual exclusion circuit is connected with the second driving circuit, the switching mutual exclusion circuit is used for disconnecting the control of the second driving circuit on the second MOS switch tube when the power adapter is connected to supply power, and the second MOS switch tube is always in a cut-off state.
3. The power supply device for conference terminal as claimed in claim 2, wherein said switching mutual exclusion circuit comprises a fourth MOS switch tube (U4) and a switch control branch, said fourth MOS switch tube (U4) is connected in series in the control loop of the second driving circuit;
the control input end of the switch control branch is connected with the first power supply input end, and the control output end of the first switch control branch is connected with the control end of the fourth MOS switch tube (U4) and used for controlling the on-off of the fourth MOS switch tube (U4).
4. The power supply device according to claim 1, wherein the first driving circuit comprises two mutually exclusive conducting first and second switching branches;
the input end of the first switch branch is connected with the first power supply input end, the output end of the first switch branch is connected with the control end of the second switch branch, and the output end of the first switch branch is grounded through a resistor (R8);
the input end of the second switch branch is connected with the source electrode of the first MOS switch tube, and the output end of the second switch branch is grounded through a series resistor (R9);
the grid electrode of the first MOS switching tube is connected to the output end of the second switching branch circuit through a series resistor (R10).
5. The power supply device for the conference terminal as claimed in claim 2, wherein the second driving circuit comprises a third switching branch and a fourth switching branch which are mutually exclusively conducted;
the input end of the third switching branch is connected with the second power supply input end through a fourth MOS switching tube (U4), the output end of the third switching branch is connected with the control end of the fourth switching branch, and the output end of the third switching branch is grounded through a resistor (R11);
the input end of the fourth switching branch is connected with the source electrode of the second MOS switching tube, and the output end of the fourth switching branch is grounded through a series resistor (R12);
the grid electrode of the second MOS switch tube is connected to the output end of the second switch branch through a series resistor (R13).
6. The power supply device for conference terminals according to claim 3, wherein the switch control branch comprises a first NPN transistor (Q1) and a second NPN transistor (Q2) which are mutually exclusively conductive, and resistors (R5, R6);
the base electrode of the first NPN triode (Q1) is connected with the first power supply input end, the collector electrode of the first NPN triode (Q1) is connected with the base electrode of the second NPN triode (Q2) and then connected to the second power supply input end, the emitter electrode of the first NPN triode (Q1) is connected with the emitter electrode of the second NPN triode (Q2) and then grounded, the collector electrode of the second NPN triode (Q2) is connected to the second power supply input end through a resistor (R5), and the collector electrode of the second NPN triode (Q2) is connected with the grid electrode of the fourth MOS switching tube (U4) through a resistor (R6).
7. The power supply device as claimed in claim 4, wherein the first switching branch comprises a first PNP transistor, an emitter of the first PNP transistor is connected to the first power input terminal, a collector of the first PNP transistor is connected to ground through a series resistor (R8), and a collector of the first PNP transistor is connected to a base of the first PNP transistor;
the second switch branch comprises a diode (D4) and a second PNP triode, the anode of the diode (D4) is connected with the source electrode of the first MOS switch tube, the cathode of the diode (D4) is connected with the emitting electrode of the second PNP triode, and the base electrode of the second PNP triode is connected with the collecting electrode of the first PNP triode.
8. The power supply apparatus for conference terminal as claimed in claim 5, wherein said third switching branch comprises a third PNP transistor and a resistor (R11), an emitter of said third PNP transistor being connected to said second power input terminal, a collector of said third PNP transistor being connected to ground via a series resistor (R11), a collector of said third PNP transistor being connected to a base;
the fourth switch branch comprises a diode (D5) and a fourth PNP triode, the anode of the diode (D5) is connected with the source electrode of the second MOS switch tube, the cathode of the diode (D5) is connected with the emitting electrode of the fourth PNP triode, and the base electrode of the second PNP triode is connected with the collecting electrode of the first PNP triode.
9. The power supply device according to claim 1, further comprising a slow start circuit, wherein the slow start circuit comprises a third MOS switch tube and a slow start control circuit, the third MOS switch tube is connected in series in a power supply path between the power supply output terminal and the load, and the slow start control circuit is configured to delay the conduction of the third MOS switch tube.
10. Conference terminal equipment, characterized in that it comprises a power supply device according to any one of claims 1-9.
CN202011594921.7A 2020-12-29 2020-12-29 Power supply device for conference terminal and conference terminal equipment Pending CN112636455A (en)

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CN116155249A (en) * 2023-04-20 2023-05-23 深圳市兆兴博拓科技股份有限公司 Drive circuit of beauty mask, beauty mask and use method

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