CN103428964A - Switching circuit with delay function - Google Patents

Abstract

The invention discloses a switch circuit with a delay function, which comprises a section switch unit, a normal state switch for performing normal on/off lamp control on an illumination load, a delay turn-off unit and a delay control switch for turning on or off the delay turn-off function, wherein the delay turn-off unit comprises a first AC-DC power supply circuit, a delay circuit and a first relay controlled by the delay circuit, the delay circuit consists of a time base integrated circuit and a first peripheral circuit, and the delay turn-off unit has the delay turn-off function of continuously turning on the illumination load after the normal state switch is turned off and automatically turning off the illumination load after the set turn-on time, so that illumination for a period of time can be continuously provided for a user after the user turns off the lamp, and convenience is brought to the life of the user. The delayed extinguishing time is adjustable and more flexible; the section switch unit is used for controlling the normal switch and the delay control switch in a section mode, so that the control can be realized through one power switch, and the use by a user is facilitated.

Description

Switching circuit with delay function

technical field

The invention relates to the field of switching power supplies, in particular to a switching circuit with a function of delaying light-off.

Background technique

Each lamp will be equipped with a switch, which controls the lighting and extinguishing of the lamp. There are many types of lamp switches, the most common of which are key switches and pull-down switches. The power of the lamp can be turned on by pressing or pulling down the switch to light up the lamp. Turn on the lighting function of the lamp, and then cut off the power supply of the lamp by pressing or pulling down the switch again, so that the lamp is extinguished, and the lighting function of the lamp is turned off. In daily life, if there is no remote control switch or other lighting, in a dark environment, after turning off the lights, there will be no lights, and we can only feel in the dark, which will bring a lot of inconvenience to our lives.

Therefore, how to design a lamp switch circuit that can still have a lighting function for a period of time after the lamp is turned off is a technical problem to be solved urgently in the industry.

Contents of the invention

The main purpose of the present invention is to provide a switch circuit with a delay function, aiming to realize that after the user turns off the light, the lamp can still provide lighting for the user for a period of time, and the lamp will automatically turn off after this period of time, so as to improve the life of the user. Bring convenience.

The present invention proposes a switch circuit with a delay function, which includes a normal switch that can be connected to the lighting load and is used to normally close or disconnect the power supply, a delay shutdown unit, and a delay function connected to the delay shutdown unit. The delay control switch; the delay shutdown unit includes a first AC-DC power supply circuit, a delay circuit and a first relay controlled by the delay circuit, the delay circuit is composed of a time base integrated circuit and a first peripheral circuit, The first peripheral circuit includes a first capacitor and a first current-limiting resistor, the first current-limiting resistor is connected in series with the first capacitor, and the positive pole of the output terminal of the first AC-DC power supply circuit is connected to the first The positive pole of the capacitor is electrically connected, and the negative pole of the output terminal of the first AC-DC power supply circuit is electrically connected to the negative pole of the first current limiting resistor; the pins of the time base integrated circuit include a power supply positive pole pin, a power supply Negative terminal pin, trigger input terminal pin, output terminal pin, reset terminal pin, control terminal pin, threshold terminal pin and discharge terminal pin, the power supply positive terminal pin and reset terminal of the time base integrated circuit The pin is electrically connected to the positive pole of the output terminal of the first AC-DC power supply circuit, and is electrically connected to the positive pole of the coil of the first relay; the negative pole pin of the power supply and the control terminal pin of the time base integrated circuit Electrically connected to the negative output terminal of the first AC-DC power supply circuit; the trigger input terminal pin and the threshold terminal pin of the time base integrated circuit are electrically connected between the first capacitor and the first Between the current-limiting resistors, it is connected to the negative pole of the first capacitor; the output terminal pin of the time base integrated circuit is connected to the negative pole of the coil of the first relay, and the contact end of the first relay is used to connect with the negative pole of the first capacitor. Lighting load connection.

Preferably, the delay shutdown unit further includes an LED indicator for displaying that the delay function is turned on, the anode of the LED indicator is connected to the anode of the output terminal of the first AC-DC power supply circuit, and the LED indicates The negative pole of the lamp is connected to the negative pole of the output terminal of the first AC-DC power supply circuit, and a second current limiting resistor is connected in series with the positive pole of the LED indicator light.

Preferably, the first AC-DC power supply circuit is composed of a first step-down circuit, a first bridge rectifier circuit and a first filtering and stabilizing circuit electrically connected in sequence.

Preferably, the first peripheral circuit further includes a first diode for discharging the first capacitor and a second capacitor for anti-interference, the first diode and the first The capacitor is connected in series and connected in parallel with the first current limiting resistor; the second capacitor is connected in series with the control terminal pin of the time base integrated circuit.

Preferably, the first capacitor is an electrolytic capacitor, and the second capacitor is a ceramic chip capacitor.

Preferably, a second diode that can form a short-time freewheeling circuit with the first relay is connected in antiphase and parallel at both ends of the coil of the first relay, and the second diode can be a switching diode, a rectifier diode or fast recovery diode.

Preferably, the normal switch is a second relay, the delay control switch is a third relay, and a section switch unit for controlling the second relay and the third relay is also included. the

Preferably, the section switch unit is a TC2608 section switch unit, including a power switch, a second AC-DC power supply circuit electrically connected to the power switch, and an electrical connection with the output end of the second AC-DC power supply circuit. The connected model is the segment control IC of TC2608 and the second peripheral circuit matched with the segment control IC, the coil end of the second relay is electrically connected with the first output end of the segment control IC, the The contact end of the second relay can be connected to the lighting load, the coil end of the third relay is electrically connected to the second output end of the segment control IC, and the contact end of the third relay is connected to the first The input terminal connection of the AC-DC power supply circuit.

Preferably, a third diode that can form a short-time freewheeling circuit with the second relay is connected in antiphase and parallel at both ends of the coil of the second relay, and antiphase and parallel is connected at both ends of the coil of the third relay A fourth diode that can form a short-time freewheeling circuit with the third relay, and the third diode and the fourth diode can be set as switching diodes, rectifier diodes or fast recovery diodes.

The switch circuit with delay function of the present invention includes a normal switch, a delay turn-off unit and a delay control switch. The normal switch is used to connect with the lighting load to control the lighting load on and off normally. The delay control switch is connected to the input terminal of the delay turn-off monolith, and the delay control switch is closed so that the delay turn-off monolith is powered on, thereby enabling the delay turn-off function. The delay turn-off unit has the function of delaying the lighting load to continue to light up after the normal switch is turned off, and automatically turns off the lighting load after the set lighting time, which can continue to provide users with a period of time after the user turns off the light. High-quality lighting brings convenience to users' lives.

When using the delayed light-off function, the normal switch is turned off, the delay control switch is closed, and the AC power is connected, and the 220V AC is stepped down, rectified, filtered, and stabilized by the first AC-DC power supply circuit to output a smooth DC power supply, and the supply delay circuit; the first capacitor is charged through the first current-limiting resistor. At this time, the first capacitor is a conductor. Since the voltage across the first capacitor cannot change abruptly, the threshold terminal pin of the time-base integrated circuit is at a high level, and the circuit is activated. Reset, its output pin outputs low level, which is equivalent to turning on the negative pole of the first relay, so that the coil circuit of the first relay is turned on, the armature of the first relay is pulled in, and the moving contact and the static contact are pulled in , the circuit is self-locked, so that the lighting load is turned on, the lighting load is lit, and the lighting load continues to emit light, providing lighting for the user, which is convenient for the user to use. As the first capacitor continues to be charged, the voltage at both ends of the first capacitor gradually increases, and the level of the trigger input pin of the time-base integrated circuit will continue to decrease. When it drops to 1/3 of the power supply, the circuit will flip and set. Its output terminal pin outputs high level, and the output terminal pin is a positive voltage, so the coil circuit of the first relay is disconnected, the first relay is de-energized and released, the moving contact jumps to release the self-locking, and the lighting load is disconnected. Open, the lighting load is automatically extinguished, and the lighting load is disconnected from the power supply, which is very safe. After the lighting load is disconnected, the electric energy stored in the first capacitor is discharged through the internal resistance of the time base integrated circuit and the first diode, so as to prepare for the next delayed turn off of the light.

The delay shutdown unit also includes an LED indicator light for displaying that the delay function is turned on, the positive pole of the LED indicator light is connected to the positive pole of the output terminal of the first AC-DC power supply circuit, and the negative pole of the LED indicator light is connected to the first AC-DC power supply circuit Connect to the negative pole of the output end of the LED indicator, and connect a second current-limiting resistor in series with the positive pole of the LED indicator. After the delay control switch is closed and the power is turned on, the LED indicator lights up normally through the second current-limiting resistor current limit, which is used to display the delay function. Has been turned on, informing the user that the delayed light off function is in use.

The LED indicator light in series and the second current limiting resistor are connected in parallel with the first capacitor, and the delay extinguishing time in the present invention can be realized by changing the capacity of the first capacitor or the resistance value of the second current limiting resistor. Enlarging the capacity of the first capacitor or the resistance value of the second current-limiting resistor increases the delay extinguishing time; on the contrary, reducing the capacity of the first capacitor or reducing the resistance value of the second current-limiting resistor shortens the delay time.

In the present invention, a section switch unit is added, and the section switch unit is used for section control of the normal switch and the delay control switch, so that it can be controlled by a power switch, which is convenient for users to use. the

Description of drawings

Fig. 1 is the circuit schematic diagram of the switching circuit with delay function of the present invention;

Fig. 2 is the pin function comparison diagram of the time base integrated circuit in the switching circuit with delay function of the present invention;

Fig. 3 is a pin function comparison diagram of the TC2608 segment control IC in the switch circuit with delay function of the present invention.

The realization of the purpose of the present invention, functional characteristics and advantages will be further described in conjunction with the embodiments and with reference to the accompanying drawings.

Detailed ways

It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Referring to Fig. 1, Fig. 2 and Fig. 3, an embodiment of the switch circuit with delay function of the present invention is proposed, and the switch circuit with delay function includes a normal switch for normally closing or disconnecting the power supply which can be connected with the lighting load K3, a delay off unit and a delay control switch K4 connected to the delay off unit for enabling the delay function. The normal switch K3 is used to connect with the lighting load to control the lighting load on and off normally. The delay control switch K4 is connected to the input terminal of the delay turn-off monolith, and the delay control switch K4 is closed so that the delay turn-off monolith is powered on, thereby enabling the delayed turn-off function; otherwise, the delay control switch K4 is turned off, so that the delay turn-off The single chip is disconnected from the power supply, and the delayed light off function is turned off. The delayed turn-off unit has the function of delaying the lighting load to continue to light up after the normal switch K3 is turned off, and automatically turns off the lighting load after the set lighting time. It can continue to provide users with a period of time after the user turns off the light The lighting of time brings convenience to the life of users.

The delay shutdown unit includes a first AC-DC power supply circuit, a delay circuit and a first relay K2 controlled by the delay circuit. The first AC-DC power supply circuit is used to convert the AC power into a smooth DC power supply for the delay circuit. . The first AC-DC power supply circuit is composed of a first step-down circuit, a first bridge rectifier circuit and a first filtering and stabilizing circuit which are electrically connected in sequence. The first step-down circuit is used for stepping down the input high-voltage alternating current. The first step-down circuit is composed of the first step-down capacitor C1 and the first discharge resistor R1. The first step-down capacitor C1 will generate capacitive reactance at a certain frequency of the AC signal, thereby limiting the maximum operating current of the delay circuit and realizing the limit Flow Buck. The first step-down capacitor C1 is a polypropylene capacitor, which is small in size, economical, reliable and high in efficiency. The first discharge resistor R1 is connected in parallel with both ends of the first step-down capacitor C1, and is used to provide a discharge path for the first step-down capacitor C1, so that the first step-down capacitor C1 can be discharged after the first step-down capacitor C1 stops working. The electric energy stored at both ends of the piezoelectric capacitor C1. The input terminal of the first bridge rectifier circuit is connected with the output terminal of the first step-down circuit, and the first bridge rectifier circuit is composed of four rectifier diodes D1, D2, D3 and D4, which are used to convert the AC voltage into unidirectional pulsation the DC voltage. The first filtering and voltage stabilizing circuit is composed of an electrolytic capacitor C2 and a voltage stabilizing diode D5. The electrolytic capacitor C2 is connected to the output end of the first bridge rectifier circuit, and is used to filter out the rectified unidirectional pulsating DC voltage. The AC component makes it a smooth DC voltage; the Zener diode D5 is connected in parallel with both ends of the electrolytic capacitor C2 for voltage stabilization. When the delay shutdown unit is working, the input high-voltage alternating current is stepped down by the first step-down circuit and then output to the first bridge rectifier circuit, rectified by the first bridge rectifier circuit, and outputs a unidirectional pulsating DC voltage, which is then electrolyzed The capacitor C2 and the regulator diode D5 filter and stabilize the voltage to output a smooth DC voltage for the delay circuit.

The delay circuit is composed of the time base integrated circuit IC1 and the first peripheral circuit matched with the time base integrated circuit IC1, the first peripheral circuit includes the first capacitor C3 and the first current limiting resistor R3, the first current limiting resistor R3 and the first capacitor C3 is connected in series, the positive pole of the output terminal of the first AC-DC power supply circuit is electrically connected to the positive pole of the first capacitor C3, and the negative pole of the output terminal of the first AC-DC power supply circuit is electrically connected to the negative pole of the first current limiting resistor R3. The time base integrated circuit IC1 is a 555 time base integrated circuit IC1, which includes 8 pins, pin 1 is the negative pin 1 of the power supply, pin 2 is the trigger input pin 2, and pin 3 is the output pin 3 , pin 4 is reset terminal pin 4, pin 5 is control terminal pin 5, pin 6 is threshold terminal pin 6, pin 7 is discharge terminal pin 7, pin 8 is power supply positive pin 8. The positive power supply pin 8 and the reset terminal pin 4 of the time base integrated circuit IC1 are electrically connected to the positive output end of the first AC-DC power supply circuit, and are electrically connected to the positive coil of the first relay K2; the time base integrated circuit The negative power supply pin 1 of IC1 and the control terminal pin 5 are electrically connected to the negative output terminal of the first AC-DC power supply circuit; the trigger input terminal pin 2 of the time base integrated circuit IC1 and the threshold terminal pin 6 are electrically connected Connected between the first capacitor C3 and the first current limiting resistor R3, and connected to the negative pole of the first capacitor C3; the output terminal pin 3 of the time base integrated circuit IC1 is connected to the coil negative pole of the first relay K2, and the first relay K2 The contact terminal K2-1 is used to connect with the lighting load.

When using the delayed light-off function, the normal switch K3 is turned off, the delay control switch K4 is closed, and the AC power is connected, and the 220V AC is stepped down, rectified, filtered, and stabilized by the first AC-DC power supply circuit to output a smooth DC power supply. supply delay circuit. The first capacitor C3 is charged through the first current-limiting resistor R3. At this time, the first capacitor C3 is a conductor. Since the voltage across the first capacitor C3 cannot change abruptly, the threshold terminal pin 6 of the time-base integrated circuit IC1 presents a high voltage. Ping, the circuit is reset, and its output pin 3 outputs a low level, which is equivalent to turning on the negative pole of the first relay K2, so that the coil circuit of the first relay K2 is turned on, the armature of the first relay K2 is attracted, and the contactor The point terminal K2-1 pulls in, the circuit is self-locked, and thus the lighting load is turned on, the lighting load is lit, and the lighting load continues to emit light, providing lighting for the user, which is convenient for the user. As the first capacitor C3 continues to charge, the voltage across the first capacitor C3 gradually rises, and the level of the trigger input pin 2 of the time-base integrated circuit IC1 will continue to drop. When it drops to 1/3 of the power supply, the circuit Turn over and set, the output pin 3 outputs high level, and the output pin 3 is a positive voltage, so the coil circuit of the first relay K2 is disconnected, the first relay K2 is de-energized and released, and the contact terminal K2-1 The self-locking is released by jumping off, so that the lighting load is disconnected, the lighting load is automatically extinguished, and the lighting load is completely disconnected from the power supply, which is very safe. After the lighting load is disconnected, the electric energy stored in the first capacitor C3 is discharged through the internal resistance of the time-base integrated circuit IC1 to prepare for the next delayed turn-off of the light.

Wherein, the first peripheral circuit further includes a first diode D6 for discharging the first capacitor C3 and a second capacitor C4 for anti-interference, the first diode D6 is connected in series with the first capacitor C3, and It is connected in parallel with the first current limiting resistor R3, and is used to provide a discharge channel for the electric energy stored in the first capacitor C3 together with the internal resistance of the time base integrated circuit IC1, so as to accelerate the discharge speed of the first capacitor C3. The second capacitor C4 is connected in series with the control terminal pin 5 of the time-base integrated circuit IC1, and the control terminal pin 5 of the time-base integrated circuit IC1 is connected in series with the second capacitor C4 and then connected to the negative output terminal of the first AC-DC power supply circuit. for anti-interference. In this embodiment, the first diode D6 is a switching diode, the first capacitor C3 is an electrolytic capacitor, and the second capacitor C4 is a ceramic chip capacitor.

The delay shutdown unit also includes an LED indicator light for displaying that the delay function is turned on, the positive pole of the LED indicator light is connected to the positive pole of the output terminal of the first AC-DC power supply circuit, and the negative pole of the LED indicator light is connected to the first AC-DC power supply circuit Connect to the negative pole of the output end of the LED indicator light, and connect a second current-limiting resistor R2 in series with the positive pole of the LED indicator light. After the delay control switch K4 is closed and the power is turned on, the LED indicator light is limited by the second current-limiting resistor R2 and normally emits light. The display delay function has been turned on, prompting the user to use the delayed light off function, which is convenient for the user to understand the use status of the lamp.

The LED indicator light connected in series and the second current limiting resistor R2 are connected in parallel with the first capacitor C3, and the delay extinguishing time in the present invention can be realized by changing the capacity of the first capacitor C3 or the resistance value of the second current limiting resistor R2. Increase the capacity of the first capacitor C3 or the resistance value of the second current-limiting resistor R2, and the delay extinguishing time will be longer; otherwise, reduce the capacity of the first capacitor C3 or reduce the resistance value of the second current-limiting resistor R2, and the delay time will become longer. short. The delay extinguishing time can be adjusted according to customer requirements, and the adjustment range is between 15S~60min. The design is flexible and can meet the customer's requirements for delay time.

A second diode D7, which can form a short-time freewheeling circuit with the first relay K2, is connected in antiphase and parallel to both ends of the coil of the first relay K2. The second diode D7 can be a switching diode, a rectifier diode or a fast recovery diode. The second diode D7 in this embodiment is a switching diode. The second diode D7 is used to protect the time base integrated circuit IC1 itself. At the moment when the first relay K2 changes from pull-in to release, the coil of the first relay K2 will form a short-time delay through the second diode D7. The freewheeling circuit prevents the current in the coil from changing abruptly, thereby avoiding the generation of counter electromotive force in the coil and ensuring the safety of the time-base integrated circuit IC1.

In the present invention, a segmented switch unit is added, which is used to control the normal switch K3 and the delay control switch K4 in segments, so that they can be controlled by a power switch K1, which is convenient for users.

The normal switch K3 is the second relay K3, the delay control switch K4 is the third relay K4, and the section switch unit is the TC2608 section switch unit. The TC2608 section switch unit includes a power switch K1 for connecting to the mains, a second AC-DC power circuit electrically connected to the power switch K1, and a model electrically connected to the output end of the second AC-DC power circuit. The segment control IC2 of TC2608 and the second peripheral circuit matched with the segment control IC2. The power switch K1 is a contact switch, which is the main switch of the switch circuit, and is used to control the power on and off of the segment switch unit. When the power switch K1 is turned off, the whole circuit is disconnected from the power supply. The second AC-DC power supply circuit is composed of a second step-down circuit, a second bridge rectifier circuit and a second filtering and stabilizing circuit. The second step-down circuit is composed of a second step-down capacitor C5 and a second discharge resistor R4. The second step-down capacitor C5 is a polypropylene capacitor, which is used to step down the input 220V high-voltage alternating current; the second discharge resistor R4 connected in parallel to both ends of the second step-down capacitor C5, providing a discharge path for the second step-down capacitor C5, so that after the second step-down capacitor C5 stops working, the electric energy stored at both ends of the second step-down capacitor C5 is discharged . The input terminal of the second bridge rectifier circuit is connected with the output terminal of the second step-down circuit, and the second bridge rectifier circuit is composed of four rectifier diodes D8, D9, D10 and D11, which are used to convert the AC voltage into unidirectional pulsation the DC voltage. The second filtering and voltage stabilizing circuit is composed of an electrolytic capacitor C6, a third bleeder resistor R5 and a voltage stabilizing diode D12. The electrolytic capacitor C6 is connected to the output end of the second bridge rectifier circuit for filtering out the The AC component in the unidirectional pulsating DC voltage makes it a smooth DC voltage; the Zener diode D12 is connected to the output end of the second bridge rectifier circuit for voltage stabilization. The third bleed resistor R5 is connected in parallel with both ends of the electrolytic capacitor C6 to provide a bleed path for the electrolytic capacitor C6. When the power switch K1 is closed, the input 220V high-voltage AC is stepped down by the second step-down circuit and then output to the second bridge rectifier circuit, rectified by the second bridge rectifier circuit, outputting a unidirectional pulsating DC voltage, and then electrolyzed Capacitor C6 and regulator diode D12 filter and stabilize the voltage to output smooth DC voltage for TC2608 subsection control IC2.

TC2608 segmented control IC2 includes 8 pins, which are called according to the function of the pins: power negative pin 1, first output pin 2, reset pin 3, clock input pin 4, power positive pin 5 , a mode selection pin 6 , a third output pin 7 and a second output pin 8 . The second peripheral circuit includes three resistors R6, R7, R8, one diode D13 and three capacitors C7, C8, C9.

Resistor R6 is a current limiting resistor, and the output end of the second bridge rectifier circuit is connected to diodes D12, D13 and resistor R8 via R6. Diode D13 is connected to positive power supply pin 5 of TC2608 subsection control IC2, capacitor C7, capacitor C8, and resistor R7 for step-down and current-limiting. The other end of the resistor R8 is connected to the clock input terminal pin 4 of the TC2608 segment control IC2, and is used to provide a high level to the clock input terminal pin 4. The pin 4 of the clock input terminal is connected to a capacitor C9 and connected to the negative pole of the power supply through the capacitor C9. The capacitor C9 is used for anti-interference. The power supply negative pin 1, reset terminal pin 3, mode selection pin 6, and third output terminal pin 7 of TC2608 segmented control IC2 are all connected to the other end of capacitor C7, capacitor C8, and resistor R6 and connected to the negative pole of the power supply , Capacitor C7 and capacitor C8 function as a filter, and resistor R7 is a discharge resistor, which is used to provide a power discharge channel for capacitor C7 and capacitor C8.

The coil end of the second relay K3 is electrically connected to the first output pin 2 of the TC2608 segmented control IC2, and the contact end K3-1 of the second relay K3 is used to connect with the lighting load; the coil end of the third relay K4 is connected to the The second output terminal pin 8 of the TC2608 segment control IC2 is electrically connected, and the contact terminal K4-1 of the third relay K4 is connected to the input terminal of the first AC-DC power supply circuit. When the power switch K1 is closed for the first time, the TC2608 subsection control IC2 controls the first output terminal pin 2 to output a low level, and connects the coil circuit of the second relay K3, so that the contact terminal K3-1 of the second relay K3 absorbs close, so that the lighting load is turned on normally; when the power switch K1 is turned off and closed, the TC2608 subsection control IC2 controls the first output pin 2 to output a high level, and controls the second output pin 8 to output a low level, so that the second output pin 8 outputs a low level. The second relay K3 is disconnected, and the coil circuit of the third relay K4 is connected, so that the contact terminal K4-1 of the third relay K4 is pulled in, and the delay circuit forms a loop, thereby enabling the function of delaying turning off the light. To sum up, when the user is using the lamp normally, the power switch K1 can be turned on or off normally; if the user wants to use the delayed turn-off function, the user only needs to turn off and turn on the power switch K1 after turning on the power switch K1 for the first time You can start the delayed light off function, which is easy to operate.

A third diode D14, which can form a short-time freewheeling circuit with the second relay K3, is connected in antiphase and parallel to both ends of the coil of the second relay K3, and a third diode D14 that can be connected in antiphase and parallel to the coil of the third relay K4 The relay K4 forms the fourth diode D15 of the short-time freewheeling circuit, and the third diode D14 and the fourth diode D15 can be switching diodes, rectifier diodes or fast recovery diodes. Both the third diode D14 and the fourth diode D15 are used to protect the TC2608 section control IC2 itself. At the moment when the second relay K3 changes from pull-in to release, the coil of the second relay K3 will pass through the third Diode D14 forms a short-time freewheeling circuit, so that the current in the coil does not cause a sudden change, thereby avoiding the generation of counter electromotive force in the coil, and ensuring the safety of TC2608 segmental control IC2; At the moment of release, the coil of the third relay K4 will form a short-time freewheeling circuit through the fourth diode D14, so that the current in the coil will not change suddenly, thereby avoiding the generation of counter electromotive force in the coil, ensuring that the TC2608 points segment controls the safety of IC2.

The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural transformations made by using the description of the present invention and the contents of the accompanying drawings, or directly or indirectly used in other related technical fields, are all The same reasoning is included in the patent protection scope of the present invention.

Claims (9)

1. A switching circuit with a delay function, characterized in that it includes a normal switch for normally closing or disconnecting a power supply that can be connected to a lighting load, a delay off unit and a unit connected to the delay off unit for Turn on the delay control switch of the delay function; the delay shutdown unit includes a first AC-DC power supply circuit, a delay circuit and a first relay controlled by the delay circuit, and the delay circuit is composed of a time base integrated circuit and a first peripheral Circuit composition, the first peripheral circuit includes a first capacitor and a first current-limiting resistor, the first current-limiting resistor is connected in series with the first capacitor, and the positive pole of the output terminal of the first AC-DC power supply circuit is connected to the The positive pole of the first capacitor is electrically connected, the negative pole of the output terminal of the first AC-DC power supply circuit is electrically connected to the negative pole of the first current limiting resistor; the pins of the time base integrated circuit include the positive pole lead of the power supply Pin, power negative pin, trigger input pin, output pin, reset pin, control pin, threshold pin and discharge pin, the positive power pin of the time base integrated circuit The pin of the reset terminal is electrically connected to the positive pole of the output terminal of the first AC-DC power supply circuit, and is electrically connected to the positive pole of the coil of the first relay; the negative pole pin of the power supply of the time base integrated circuit and the control The terminal pin is electrically connected to the negative output terminal of the first AC-DC power supply circuit; the trigger input terminal pin and the threshold terminal pin of the time base integrated circuit are electrically connected between the first capacitor and the Between the first current-limiting resistor, it is connected to the negative pole of the first capacitor; the output terminal pin of the time base integrated circuit is connected to the negative pole of the coil of the first relay, and the contact terminal of the first relay For connection to lighting loads. 2. The switch circuit with delay function according to claim 1, characterized in that, the delay turn-off unit also includes an LED indicator for displaying that the delay function is turned on, and the positive pole of the LED indicator is connected to the The positive pole of the output terminal of the first AC-DC power supply circuit is connected, the negative pole of the LED indicator light is connected with the negative pole of the output terminal of the first AC-DC power supply circuit, and a second current limiting is connected in series with the positive pole of the LED indicator light resistance. 3. The switch circuit with delay function according to claim 2, characterized in that, the first AC-DC power supply circuit is composed of a first step-down circuit, a first bridge rectifier circuit and a first The filter voltage regulator circuit is composed. 4. The switch circuit with delay function according to claim 1, characterized in that, the first peripheral circuit further comprises a first diode for discharging the first capacitor and a The first diode is connected in series with the first capacitor and parallel with the first current limiting resistor; the second capacitor is connected in series with the control terminal pin of the time base integrated circuit. 5. The switch circuit with delay function according to claim 4, wherein the first capacitor is an electrolytic capacitor, and the second capacitor is a ceramic chip capacitor. 6. The switch circuit with delay function according to claim 1, characterized in that, a second coil that can form a short-time freewheeling circuit with the first relay is connected in antiphase and parallel at both ends of the coil of the first relay. A diode, the second diode can be a switching diode, a rectifying diode or a fast recovery diode. 7. The switch circuit with delay function according to any one of claims 1 to 6, characterized in that, the normal switch is a second relay, the delay control switch is a third relay, and also includes a A section switch unit controlling the second relay and the third relay. 8. The switch circuit with delay function according to claim 7, characterized in that, the segment switch unit is a TC2608 segment switch unit, comprising a power switch, a second AC-DC electrically connected with the power switch A power supply circuit, a section control IC of model TC2608 electrically connected to the output end of the second AC-DC power supply circuit, and a second peripheral circuit matched with the section control IC, the coil end of the second relay It is electrically connected with the first output terminal of the subsection control IC, the contact terminal of the second relay can be connected with the lighting load, and the coil terminal of the third relay is connected with the second output terminal of the subsection control IC. Electrically connected, the contact end of the third relay is connected to the input end of the first AC-DC power supply circuit. 9. The switch circuit with delay function according to claim 8, characterized in that, a third relay that can form a short-time freewheeling circuit with the second relay is connected in antiphase and parallel at both ends of the coil of the second relay. A diode, a fourth diode that can form a short-time freewheeling circuit with the third relay is connected in antiphase and parallel at both ends of the coil of the third relay, and the third diode and the fourth Diodes can be set as switching diodes, rectifier diodes or fast recovery diodes.

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