CN212304869U - Main and standby power supply switching circuit - Google Patents
Main and standby power supply switching circuit Download PDFInfo
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- CN212304869U CN212304869U CN202021912157.9U CN202021912157U CN212304869U CN 212304869 U CN212304869 U CN 212304869U CN 202021912157 U CN202021912157 U CN 202021912157U CN 212304869 U CN212304869 U CN 212304869U
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- 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
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- 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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Abstract
The utility model discloses a activestandby power supply switching circuit, it includes switching transistor, controllable accurate steady voltage source, output feedback module and AC feedback module. The main and standby power supply switching circuit is arranged among the AC-DC power supply module, the battery power supply module and the power supply output end and controls the power supply mode of the power supply output end according to the AC voltage signal and the output voltage of the battery power supply module. The main power supply and standby power supply switching circuit has the functions as follows: when the AC voltage signal is greater than the threshold value, the AC-DC power supply module is preferentially adopted to supply power to the power supply output end, and when the AC voltage signal is less than the threshold value and the output voltage of the battery power supply module is normal, the battery power supply module is used to supply power to the power supply output end. The power supply mode can be switched to the battery power supply module only through the AC-DC power supply module, and the battery power supply module cannot independently supply power, so that the battery power supply module cannot supply power in the product transportation process, and the loss caused by battery discharge in the product transportation process can be avoided.
Description
Technical Field
The utility model belongs to the technical field of the electron, in particular to activestandby power supply switching circuit.
Background
The fire-fighting emergency lighting system mainly comprises accident emergency lighting, an emergency exit sign and an indicator light, and is an emergency lighting device which is arranged for guiding trapped people to evacuate or developing fire-fighting rescue actions after a normal lighting power supply is cut off when a fire disaster happens. In order to ensure high reliability of the emergency lamp in case of an accident, the emergency lamp needs to have an alternating current power supply mode as a main power supply and a battery power supply mode as a standby power supply. In the event of an accident, the ac power supply system is usually cut off or disabled, and therefore the power supply system needs to be switched to battery power.
The existing main/standby power switching mode generally needs to use an MCU to sample input/output signals to judge the working state of the main/standby power and then send signals to control the switching circuit to work. The MCU control circuit is influenced by the working environment and can possibly send out error signals (soft errors occur in the MCU with certain probability in the long-term operation process), in addition, the MCU is used, the sampling of the MCU is delayed, the delay of the main and standby power switching can be caused, the circuit is complex, the reliability is low, a plurality of components and parts are provided, and the cost is high.
SUMMERY OF THE UTILITY MODEL
The utility model aims at providing a activestandby power supply switching circuit, the device detect AC voltage signal and battery power module's output voltage signal through the circuit that adopts analog device to constitute to this switching of control power supply mode has solved the problem that the delay that adopts MCU sampling control to lead to is high, the reliability is low.
The technical scheme of the utility model be, a activestandby power supply switching circuit for the setting is between AC-DC power module, battery power module and power supply output, activestandby power supply switching circuit includes:
the source electrode of the switching transistor is connected with the output end of the battery power supply module, the drain electrode of the switching transistor is connected with the anode of a diode, and the cathode of the diode is connected with the power supply output end; the power supply output end is connected with the output end of the AC-DC power supply module;
the cathode of the controllable precise voltage-stabilizing source is connected with the grid electrode of the switching transistor through a first resistor, and the anode of the controllable precise voltage-stabilizing source is grounded;
the input end of the output feedback module is connected with the power supply output end, and the output end of the output feedback module is connected with the reference end of the controllable precise voltage-stabilizing source; when the voltage of the power supply output end is in a normal range, the open-circuit voltage of the output end of the output feedback module is larger than the breakover voltage of the controllable precise voltage-stabilizing source;
the input end of the AC feedback module is connected with the output end of the AC voltage signal detection module, and the output end of the AC feedback module is connected with the reference end of the controllable precise voltage-stabilizing source; when the AC voltage signal is greater than the threshold value, the AC feedback module pulls down the voltage of the reference end of the controllable precise voltage-stabilizing source to make the voltage not conducted;
and the output feedback module or the AC feedback module is internally provided with an energy storage capacitor, and the energy storage capacitor is used for driving the controllable precise voltage stabilization source to be conducted and enabling the switching transistor to be conducted when the AC voltage signal is reduced to be below a threshold value and the power supply mode of the power supply output end is switched to the battery power supply module by the AC-DC power supply module.
The utility model discloses a further improvement lies in, output feedback module includes first node, first node pass through the second resistance with controllable accurate steady voltage source's reference end is connected, between first node and the earthing terminal parallelly connected have zener diode, third resistance, fourth resistance and filter capacitance; an adjustable resistor is connected between the power supply output end and the first node.
The utility model discloses a further improvement lies in, the AC feedback module includes second node and third node; a sixth resistor and a second diode are connected between the second node and the reference end of the controllable precise voltage-stabilizing source; the anode of the second diode is connected with the reference end; the emitter of the second transistor is grounded, the base of the second transistor is connected with the output end of the AC voltage signal detection module through an eighth resistor, and the collector of the second transistor is connected with the second node; a seventh resistor is connected between the second node and the third node; the third node is connected with the output end of the AC-DC power supply module through a first diode, and the cathode of the first diode is connected with the third node.
The utility model discloses a further improvement lies in, energy storage capacitor connects between third node and earthing terminal.
The utility model discloses a further improvement lies in, AC voltage signal detection module includes rectification filter module and opto-coupler; the input end of the rectification filtering module is connected with the AC voltage signal input end of the AC-DC power supply module; the input end of the optocoupler is connected with the output end of the rectifying and filtering module; the positive pole of the output end of the optical coupler is connected with a VCC end, and the negative pole of the output end of the optical coupler is the output end of the AC voltage signal detection module; and the input-output characteristic of the rectification filtering module meets the condition that the optical coupler is in a conducting state when an AC voltage signal at the AC voltage signal input end is higher than a threshold value.
The utility model has the advantages that:
(1) the voltage feedback and the switching action of the circuit are realized by analog devices, so that the circuit has better reliability under the long-term operation condition, and soft errors of a digital system caused by environmental factors are avoided; in addition, compared with a low-frequency digital system (MCU), a system formed by analog devices has the advantages of faster response, fewer elements and lower cost;
(2) the power supply mode can be switched to the battery power supply module only through the AC-DC power supply module, and the battery power supply module cannot independently supply power, so that the battery power supply module cannot supply power in the product transportation process, and the loss caused by battery discharge in the product transportation process can be avoided.
Drawings
Fig. 1 is a circuit diagram of a main/standby power supply switching circuit;
fig. 2 is a circuit diagram of an AC voltage signal detection module.
Detailed Description
As shown in fig. 1, an embodiment of the present invention provides a main/standby power switching circuit, which is configured between an AC-DC power supply module, a battery power supply module, and a power supply output terminal, and controls a power supply mode of the power supply output terminal according to an AC voltage signal and an output voltage of the battery power supply module. The main power supply and standby power supply switching circuit has the functions as follows: when the AC voltage signal is greater than the threshold value, the AC-DC power supply module is preferentially adopted to supply power to the power supply output end, and when the AC voltage signal is less than the threshold value and the output voltage of the battery power supply module is normal, the battery power supply module is used to supply power to the power supply output end.
In order to realize the above functions, the main/standby power supply switching circuit includes: a switching transistor Q1, a controllable precision voltage regulator TL431, an output feedback module 10, and an AC feedback module 20. Specifically, the method comprises the following steps:
the switch transistor Q1 is a PMOS transistor, the source electrode of the switch transistor Q1 is connected with the output end of the battery power supply module, the drain electrode of the switch transistor Q1 is connected with the anode of a diode D3, and the cathode of the diode D3 is connected with the power supply output end; the power supply output end is connected with the output end of the AC-DC power supply module. When the switching transistor Q1 is turned on, the battery power supply module supplies power to the power supply output terminal.
In some embodiments, controllable precision voltage regulator TL431 is model number TL 431. The internal reference voltage of the TL431 is 2.5V, and when the voltage of the reference terminal (R pole) is greater than 2.5V, conduction is performed between the cathode K and the anode a of the TL 431. The cathode of the controllable precise voltage-stabilizing source is connected with the grid of a switching transistor Q1 through a first resistor R1, and the anode of the controllable precise voltage-stabilizing source is grounded.
The input end of the output feedback module 10 is connected to the power supply output end, and the output end thereof is connected to the reference end R of the controllable precise voltage regulator TL 431. And when the voltage of the power supply output end is in a normal range, the open-circuit voltage of the output end of the output feedback module is larger than the breakover voltage of the controllable precise voltage-stabilizing source.
The output feedback module 10 has various embodiments, and in one specific embodiment, the output feedback module 10 includes a first node a. The first node a is connected to the reference terminal R of the controllable precision voltage regulator TL431 through a second resistor R2. A zener diode ZD1, a third resistor R3, a fourth resistor R4, and a filter capacitor C1 are connected in parallel between the first node a and the ground GND. An adjustable resistor R5 is connected between the power supply output end and the first node a.
During the power supply process of the battery power supply module, the output voltage of the battery power supply module is continuously reduced, and the battery overdischarge adversely affects the service life of the battery power supply module, so that the input-output characteristic of the output feedback module 10 is adjusted by the adjustable resistor R5, and when the battery is overdischarged, the output voltage of the output feedback module 10 is lower than the on-state voltage of the controllable precise voltage regulator TL431, so that the switching transistor Q1 is turned off, and the battery power supply module stops supplying power.
In another embodiment, the output feedback module 10 can be implemented by using an operational amplifier and a voltage divider circuit. The operational amplifier can realize the amplification function of any proportion by matching with a specific feedback loop, which is equivalent to the voltage division by adopting a resistance network.
The input end of the AC feedback module 20 is connected to the output end of the AC voltage signal detection module, and the output end of the AC feedback module 20 is connected to the reference end R of the controllable precision voltage regulator TL 431; when the AC voltage signal for supplying power to the AC-DC power supply module is greater than the threshold, the AC feedback module 20 pulls down the reference terminal voltage of the controllable precise voltage regulator TL431 to make it non-conductive. At this time, the AC-DC power supply module supplies power to the power supply output terminal, and the switching transistor Q1 is in an off state.
The output feedback module 10 or the AC feedback module 20 is provided with an energy storage capacitor, and the energy storage capacitor is used for driving the controllable precise voltage stabilization source TL431 to be conducted when the AC voltage signal is reduced below the threshold value and the power supply mode of the power supply output end is switched from the AC-DC power supply module to the battery power supply module, and conducting the switching transistor, thereby achieving the purpose of switching the power supply mode.
To implement the functionality of the AC feedback module 20, the AC feedback module includes a second node b and a third node c. A sixth resistor R6 and a second diode D2 are connected between the second node b and the reference terminal R of the controllable precision voltage regulator TL431, and the anode of the second diode D2 is connected to the reference terminal R. The emitter of the second transistor Q2 is grounded, its base is connected to the output terminal of the AC voltage signal detection module through the eighth resistor R8, and its collector is connected to the second node b. A seventh resistor R7 is connected between the second node b and the third node c. The third node c is connected to the output terminal of the AC-DC power supply module through a first diode D1, and the cathode of the first diode D1 is connected to the third node c.
In one embodiment, the energy storage capacitor EC1 is connected between the third node c and the ground GND. In other embodiments, the energy storage capacitor EC1 may also be connected between the supply output terminal and the ground terminal GND.
The operation of the embodiment shown in fig. 1 is described below with reference to the accompanying drawings:
the main and standby power supply switching circuit defaults to adopt an AC-DC power supply module to supply power to the power supply output end. When an AC voltage signal (commercial power) for supplying power to the AC-DC power supply module is normal, the AC-DC power supply module outputs a direct current voltage to supply power to the power supply output end, and simultaneously charges the energy storage capacitor EC 1. The AC voltage signal detection module outputs a high level, so that the emitter and the collector of the second transistor Q2 are turned on, the cathode of the second diode D2 is grounded through the second transistor Q2, the output voltage of the AC feedback module 20 (reference terminal R) is clamped to about 0.7V, the cathode K and the anode a of the controllable precise voltage stabilization source TL431 are not turned on, the switching transistor Q1 is in a turned-off state, and the battery power supply module does not supply power to the outside. At this time, the zener diode ZD1 in the output feedback module 10 plays a role of clamping, and protects the reference terminal R of the controllable precision voltage regulator TL 431.
When the AC voltage signal is lower than the threshold (the commercial power is under-voltage or disconnected), the AC-DC power supply module stops working, and the AC voltage signal detection module outputs a high-resistance state, so that the second transistor Q2 is not conducted, and the second diode D2 loses the clamping function. When an AC voltage signal is just powered off, because energy is stored in the energy storage capacitor EC1, the voltage does not disappear, the resistance values of the resistors in the AC feedback module 20 and the output feedback module 10 meet that the voltage of the reference end R of the controllable precise voltage-stabilizing source TL431 is greater than 2.5V under the power supply action of the energy storage capacitor EC1, so that the cathode K and the anode a of the controllable precise voltage-stabilizing source TL431 are conducted, the resistor R9 is connected between the source and the gate of the switching transistor Q1, the resistor R9 and the first resistor R1 divide the voltage, and the switching transistor Q1 is conducted, so that the power supply mode of the power supply output end is switched from the AC-DC power supply module to the battery power supply module.
After the power supply mode is switched, the output feedback module 10 continuously detects the output voltage, when the battery power is normal, the output feedback module 10 continuously maintains that the voltage of the reference end R of the controllable precise voltage-stabilizing source TL431 is greater than 2.5V, so that the battery power supply module continuously supplies power until the power in the battery power supply module is exhausted, and the voltage of the reference end R of the controllable precise voltage-stabilizing source TL431 is lower than 2.5V. During the power supply of the battery power supply module, the voltage of the energy storage capacitor EC1 gradually decreases until a steady state (the same as the voltage of the reference terminal R) is entered.
In this embodiment, the power supply mode can only be switched from the AC-DC power supply module to the battery power supply module, and the battery power supply module cannot independently supply power, so that the battery power supply module does not supply power during product transportation, and thus, loss caused by battery discharge during product transportation can be avoided.
As shown in fig. 1 and 2, in this embodiment, the AC voltage signal detection module includes a rectification filter module and an optical coupler. The input end of the rectifying and filtering module is connected with the AC voltage signal input end of the AC-DC power supply module and used for receiving the AC voltage signal. The input end of the optical coupler is connected with the output end of the rectifying and filtering module. The positive pole of output of opto-coupler connects VCC end, and the output negative pole of opto-coupler is AC voltage signal detection module's output.
The rectifying and filtering module is composed of a resistor R10, a resistor R11, a capacitor C11 and a diode D11 and is used for half-wave rectification, voltage division and filtering. The input-output characteristic of the rectification filter module meets the condition that when an AC voltage signal at an AC voltage signal input end is higher than a threshold value, the optical coupler is in a conducting state.
The foregoing has described in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be devised by those skilled in the art in light of the teachings of the present invention without undue experimentation. Therefore, the technical solutions that can be obtained by a person skilled in the art through logic analysis, reasoning or limited experiments based on the prior art according to the concepts of the present invention should be within the scope of protection defined by the claims.
Claims (4)
1. A master-slave power supply switching circuit is used for being arranged among an AC-DC power supply module, a battery power supply module and a power supply output end, and is characterized by comprising:
the source electrode of the switching transistor is connected with the output end of the battery power supply module, the drain electrode of the switching transistor is connected with the anode of a diode, and the cathode of the diode is connected with the power supply output end; the power supply output end is connected with the output end of the AC-DC power supply module;
the cathode of the controllable precise voltage-stabilizing source is connected with the grid electrode of the switching transistor through a first resistor, and the anode of the controllable precise voltage-stabilizing source is grounded;
the input end of the output feedback module is connected with the power supply output end, and the output end of the output feedback module is connected with the reference end of the controllable precise voltage-stabilizing source; when the voltage of the power supply output end is in a normal range, the open-circuit voltage of the output end of the output feedback module is larger than the breakover voltage of the controllable precise voltage-stabilizing source;
the input end of the AC feedback module is connected with the output end of the AC voltage signal detection module, and the output end of the AC feedback module is connected with the reference end of the controllable precise voltage-stabilizing source; when the AC voltage signal is greater than the threshold value, the AC feedback module pulls down the voltage of the reference end of the controllable precise voltage-stabilizing source to make the voltage not conducted;
and the output feedback module or the AC feedback module is internally provided with an energy storage capacitor, and the energy storage capacitor is used for driving the controllable precise voltage stabilization source to be conducted and enabling the switching transistor to be conducted when the AC voltage signal is reduced to be below a threshold value and the power supply mode of the power supply output end is switched to the battery power supply module by the AC-DC power supply module.
2. The main/standby power switching circuit according to claim 1, wherein the output feedback module comprises a first node, the first node is connected with the reference terminal of the controllable precision voltage regulator through a second resistor, and a zener diode, a third resistor, a fourth resistor and a filter capacitor are connected in parallel between the first node and a ground terminal; an adjustable resistor is connected between the power supply output end and the first node.
3. The main/standby power switching circuit according to claim 1, wherein the AC feedback module includes a second node and a third node; a sixth resistor and a second diode are connected between the second node and the reference end of the controllable precise voltage-stabilizing source; the anode of the second diode is connected with the reference end; the emitter of the second transistor is grounded, the base of the second transistor is connected with the output end of the AC voltage signal detection module through an eighth resistor, and the collector of the second transistor is connected with the second node; a seventh resistor is connected between the second node and the third node; the third node is connected with the output end of the AC-DC power supply module through a first diode, and the cathode of the first diode is connected with the third node.
4. The main/standby power switching circuit according to claim 3, wherein said energy storage capacitor is connected between said third node and ground.
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| CN202021912157.9U CN212304869U (en) | 2020-09-04 | 2020-09-04 | Main and standby power supply switching circuit |
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| CN202021912157.9U CN212304869U (en) | 2020-09-04 | 2020-09-04 | Main and standby power supply switching circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112018878A (en) * | 2020-09-04 | 2020-12-01 | 柏宜照明（上海）股份有限公司 | Main and standby power supply switching circuit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112018878A (en) * | 2020-09-04 | 2020-12-01 | 柏宜照明（上海）股份有限公司 | Main and standby power supply switching circuit |
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