Case Sharing: High-Speed Hair Dryer Application-The Application of Orient Thyristor Optocoupler and Transistor Optocoupler

As shown in the following picture: High-speed hair dryer

 

The Orient OR-M3053L-TP-G thyristor output optocoupler is used to drive thyristors,600V IFT 5mA SOP4 package.           

 

Orient OR-354B-TP-G transistor optocoupler. used for zero-crossing detection and range detection. SOP4 package

 

Product Introduction of OR-M30XX Orient Thyristor Optocoupler

1.Product List

Non-zero-crossing products	VDRM ≥ 400V	VDRM ≥ 600V	VDRM ≥ 800V
IFT ≤ 20mA	OR-M3020	OR-M3050	OR-M3070
IFT ≤ 15mA	OR-M3021	OR-M3051	OR-M3071
IFT ≤ 10mA	OR-M3022	OR-M3052	OR-M3072
IFT ≤ 5mA	OR-M3023	OR-M3053	OR-M3073
IFT ≤ 3mA	OR-M3024	OR-M3054	OR-M3074

 

Zero-crossing products	VDRM ≥ 400V	VDRM ≥ 600V	VDRM ≥ 800V
IFT ≤ 20mA	OR-M3040	OR-M3060	OR-M3080
IFT ≤ 15mA	OR-M3041	OR-M3061	OR-M3081
IFT ≤ 10mA	OR-M3042	OR-M3062	OR-M3082
IFT ≤ 5mA	OR-M3043	OR-M3063	OR-M3083
IFT ≤ 3mA	OR-M3044	OR-M3064	OR-M3084

 

2.Introduction to Electrical Properties

1).Trigger Current (IFT）

The trigger current (IFT) refers to the minimum current required for IR to conduct when the PT terminal is triggered to turn on. It is an important parameter that needs to be considered when applying customer circuits.

Therefore. when designing. the trigger current provided by the circuit to the thyristor optocoupler must be greater than the IFT of the thyristor optocoupler to ensure that the optocoupler can be triggered and started normally.

a.The influence of temperature on IFT

As shown in Figure 1, the influence of temperature on IFT is that when the temperature keeps rising, IFT will show a slow downward trend within the specification range.

 

Figure 1 The influence of temperature on IFT

 

2). Critical rise rate of off-state voltage (dv/dt)

The critical rise rate of the off-state voltage of the thyristor optocoupler is expressed as follows.

dv/dt=0.63×E1/τ unit  V/μS

       τ=RW×C unit μS

E1：VDM=2/3VDRM ，RW：Adjustable resistor ，C：Capacitor,used to generate exponential waveforms

From this formula, it can be seen that its dv/dt parameters are mainly important parameters of the PT-terminal thyristor chip itself, which affect the application performance of the optocoupler after packaging.

Figure 2 Schematic diagram of dv/dt testing

 

 

3).Introduction to Other Parameters

Off-state repetitive peak current IDRM: The forward and reverse peak leakage current passing through PT when the PT terminal is in the blocked state and subjected to the off-state repetitive peak voltage VDRM.

Blocking repetitive peak current 2IDRM2: In the energized state, when the PT terminal is in the blocked state and is subjected to the off-state repetitive peak voltage VDRM, the forward and reverse peak leakage current through the PT.

On-state peak voltage VTM: When the PT terminal is in the conducting state, the voltage passing through PT is called the on-state peak voltage.

Holding current IH: The minimum current required to keep the PT terminal in a continuously conducting state after the thyristor optocoupler is turned on.

 

4).Circuit Recommendation

Thyristor optocouplers can be isolated for AC load control, provided that the load is relatively small (about 50 mA or less). For larger currents (up to several amperes), a thyristor optocoupler is combined with a high-power thyristor for AC load control. The following figure shows the basic circuit configuration. Rs and C are components of the buffer circuit, which prevent the thyristor optocoupler switch failure by shielding noise, while the varistor absorbs any surge voltage from the powerline.

Figure 3 Control circuit of a single thyristor optocoupler

Figure 4 Thyristor optocoupler and high-power thyristor control circuit

 

 

5).Application Fields

Small household appliances: hair dryers, health care kettles, dimmable lights, speed-regulating fans, audio systems, toy devices, radio remote controls, etc

Large household appliances: air conditioners, televisions, refrigerators, washing machines, sound and light circuits, timing controllers, cameras and industrial controls, etc

Figure 5 shows the application schematic diagram of the Orient thyristor optocoupler for hair dryer

Figure 6 shows the application principle diagram of the Orient thyristor optocoupler for dimming lamps