Three functional forms of intelligent switch

1879 year , Edison, the great God of technology, invented the electric lamp by improving the filament with carbon filament , At the same time, the electric lamp holder and switch were also invented . today , Electric lighting has a history of more than 100 years , Electrical switch from the earliest pull switch to modern intelligent switch , Size of switch 、 Industrial shape design 、 There has been a disruptive revolution in Electronic Technology .

Intelligent switch ( Foreign name ”Smart Switch”) The term in the encyclopedia is interpreted as ” Using the combination and programming of control board and electronic components , To realize the circuit intelligent switch control unit ”.

In the smart home scene , Intelligent switch is used to realize circuit intelligent switch control . There are many kinds and functions of intelligent switch products , The author To the following 3 The electronic design composition and working principle of two common types of wireless intelligent switch products are discussed .

Single live wire intelligent switch

The product and wiring application of single live wire intelligent switch are shown in the figure below ： In the wiring environment, there is only single live wire

The single live wire intelligent switch and the lamp are connected in series in the zero live wire , Single fire power taking needs to take part of the current from the lamp circuit under the two working conditions of off state and on state of the lamp to supply power to the power taking unit of the intelligent switch 、 Power conversion unit 、 The control unit and the wireless communication unit work .

The single live wire intelligent switch consists of a structure 、 Electronics is composed of two units . The basic circuit composition of the electronic unit of the single live wire intelligent switch includes ： Closed power take-off circuit 、 Open power take-off circuit 、 Switch circuit 、 Power conversion circuit 、 wireless communication SOC circuit .

PS：<< A series of articles on single fire line design 1~10>> It can be obtained from the hardware bear official account

Zero fire line intelligent switch

The product and wiring application of zero fire wire intelligent switch are shown in the figure below ： Introduce zero line in wiring environment

The zero fire line intelligent switch supplies power to the internal circuit by the zero fire line , The lighting is controlled by controlling the on-off of the live wire through the electronic switching device .

Take zero fire line intelligent switch as an example , The basic circuit composition of its electronic unit includes ：AC-DC Power Supply 、 Switch and its driving circuit 、 Power conversion circuit 、 wireless communication SOC circuit .

AC-DC Power Supply ： Convert AC to DC for proper product operation . Power architecture usually has non isolated power supply （Buck、Buck-Boost、Boost etc. ） And isolated power supply （ Flyback, etc ） Two topologies .

Switch and its driving circuit ： Used to control the conduction of the live wire / Turn off . Switching devices are usually made of thyristors 、MOS tube 、IGBT device 、 Relay, etc , Among them, thyristor 、 The relay is more general .

Power conversion circuit ： take AC-DC The DC output from the power supply is converted into a suitable for wireless communication SOC The operating voltage of the circuit . Usually used LDO perhaps DC-DC circuit , This part of the circuit can be tailored according to practical application .

wireless communication SOC circuit ： Integrated inside the chip MCU and RF function .MCU Be responsible for realizing the product working logic and function ,RF Responsible for receiving and transmitting wireless signals .

Intelligent dimming switch

Dimming switch is developed to meet people's different needs for light brightness at different times . By controlling and changing the thyristor /MOS The phase angle of the tube is used to control the conduction degree of the alternating current , That is to change the effective value of the input voltage , Dimming is achieved by changing the voltage .

There are two dimming control modes ： Front tangent dimming 、 Back edge tangential dimming .

Front tangent dimming ： From AC phase 0 Start , Chopping the input voltage , To a certain phase moment Conduction , only Yes Input voltage .

Back edge tangential dimming ： From AC phase 0 Start , Chopping the input voltage , To a certain phase moment Turn off , only nothing Input voltage .

Take the zero fire line intelligent dimming switch as an example , The basic circuit composition of its electronic unit includes ：AC-DC Power Supply 、 Dimming switch and its driving circuit 、 AC zero detection circuit 、 Power conversion circuit 、 wireless communication SOC circuit .

AC-DC Power Supply ： Convert AC to DC for proper product operation . Power architecture usually has non isolated power supply （Buck、Buck-Boost、Boost etc. ） And isolated power supply （ Flyback, etc ） Two topologies .

Dimming switch and its driving circuit ： It is used to control and adjust the conduction of AC phase angle / Turn off ratio . Switching devices are usually made of thyristors 、MOS tube 、IGBT Components, etc ; Thyristor can only be used in leading edge phase cutting because of its conduction characteristics ;MOS tube /IGBT Both can be used in leading edge tangency and trailing edge tangency .

AC zero detection circuit ： Used to detect alternating current 0 phase , For wireless communications SOC Provide reference signal to control AC conduction / Turn off the phase angle .(PS:<< Talking about 5 Class zero crossing detection circuit >> It can be obtained from the hardware bear official account )

Power conversion circuit ： take AC-DC The DC output from the power supply is converted into a suitable for wireless communication SOC The operating voltage of the circuit . Usually used LDO perhaps DC-DC circuit , This part of the circuit can be tailored according to practical application .

wireless communication SOC circuit ： Integrated inside the chip MCU and RF function .MCU Be responsible for realizing the product working logic and function ,RF Responsible for receiving and transmitting wireless signals .

Intelligent switch as a basic electrical product , Suitable for household use 、 Commercial and other fields , At present, the types of wireless communication in China include WiFi、ZigBee、 bluetooth , And abroad there are Z-wave、Matter. These different communication schemes have their own advantages and disadvantages , for example ,WiFi It is suitable for most home areas with existing routers , No additional gateway configuration ; Bluetooth requires a gateway , It is suitable for ad hoc networking of hundreds of devices , It is suitable for large-scale centralized control , And in 2019 In the form of the rapid rise of smart speakers , The smart speaker is basically equipped with Bluetooth gateway function ;ZigBee Need extra ZigBee gateway , It is also applicable to ad hoc networks of hundreds of devices , At low power consumption 、 Low delay 、 Large capacity has stronger advantages .

As a basic electrical category , The service life of the switch in the user's home is expected to be up to 7-8 In the above . For smart home enterprises , Such a frequently used product also plays a role of high user viscosity 、 The strategic significance of traffic entrance . Therefore, smart home companies can basically be called smart switch companies , Like green rice 、 Euribo 、 Bo Lian 、 beauty 、 Morgan et al . so to speak , Smart switches are the industry's top priority “ A strategist must fight ” A category of .

In specific usage scenarios , The user can remotely control the switch 、 Time switch 、 Countdown switch 、 Voice control and other operations . These features look bland , But in fact, when you really go deep into the industry , Want to make the smart switch stable 、 Durability is not an easy thing . Later, we will explain the details and key points of intelligent switch design in other chapters , Including all kinds of... You may encounter “ pit ”！