Product Highlights

The function optimized by the cost of minimum system

Completely integrated short -circuit and interruption automatic restart

Circle protection

Self -partial pressure Power supply-save transformer auxiliary winding

and related partial pressure power components

Precision tolerance and neglected temperature changes

Key parameters simplify the design and reduce the cost [123 [123 ]

The high -maximum switching frequency allows very low

Magnetic flux density transformer design, in fact,

A listening noise

frequency shake greatly reduced EMI [123 [123 ]

Packaging with large climbing to high -voltage pins

Switch solution with the least number of components

It is much better than linear/RCC

The system cost is low In the RCC, discrete PWM, and other

integrated solution

The universal input range can run globally

Simple opening/level control-no loop compensation

No partial pressure winding-simpler, lower-cost transformers

High-frequency switch-smaller, lower cost

Very low number of components quantity -The higher reliability and single -sided printed circuit board

high bandwidth provides rapid opening, no over -adjustment and good transient load response

Flowing operation can inhibit the frequency ripple of the line

Built -in current limit and lag heat shutdown

Protection

Ecological intelligence #174; very energy saving

empty load consumption lt; 300 mw, none Partial pressure winding

265 VAC input

Meets the requirements of the California Energy Commission (CEC) Energy Department

Star and EU requirements

Application

[ 123] Mobile phone/rope phone, PDA, digital camera charger, MP3/portable audio equipment, shaver, etc.

Spare and auxiliary power supply

Instructions

Linkswitch HF integrates 700 V power MOSFET, oscillator, simple switch control solution, high voltage switch current #174; Table 1 Essence Note: 1. A typical continuous power supply under non -ventilation conditions at a closed adapter measured at an ambient temperature of 50 ° C. 2 The maximum practicality has a continuous power sink in the open frame design with sufficient calories and measures in an environment of 50 ° C. three. Packing: P: DIP-8B, G: SMD-8B. Regarding lead -free packaging options, 4 For the design without Y capacitor, the available power may be lower (refer to key applications precautions). Power supply, frequency jitter, cyclical current limitation, and the heat shutdown circuit on a single -piece integrated circuit. The power of entrepreneurial work comes directly from the pipeline of the duct, eliminating the need for bias winding and related circuits. The maximum switching frequency of 200 KHz allows low -throughput transformer design, which almost eliminates the paint transformer structure of the simple noise control scheme. The high -efficiency operation high switching frequency is due to the optimization of the switching characteristics of the integrated circuit and the small capacitor power MOSFET. Full -integrated security automatic restart circuit output power restrictions During the failure circuit or opening of the loop to reduce the number of components and the cost of secondary feedback circuits. The frequency of the internal oscillator is the jitter to significantly reduce the peak and the average electromagnetic interference, and minimize the filtering cost.

Pointing function description

Drainage (D) Sales: Power MOSFET Demonstration. Provide internal operation startup and steady -state operating current.

Wing (BP) pin: 0.1 μF The internal point of the connection point of an external bypass container generated 5.8 V power supply.

Feedback (FB) pin: During normal work, the switch of the power MOSFET is controlled by this pin. The current greater than 49μA is transmitted to the pin.

Source quotation: The pin is the power MOSFET power connection. It is also the grounding reference of bypass and feedback. The switch of the controller. Unlike the traditional PWM (pulse width modulator) controller, Linkswitch HF uses simple opening/off control to adjust the output voltage. Linkswitch high -frequency controller includes oscillator, feedback (detection and logic) circuit, 5.8 V registered, bypass pins, excessive temperature protection, frequency jitter, current limit circuit, frontier faint, and a 700 volt power MOSFETT MOSFETT Essence The link switch HF includes an additional automatic restart circuit.

oscillator

The typical oscillator frequency is set to an average value of 200 kilo internally. The oscillator generates two signals: the maximum duty cycle signal (DCMAX) and the clock signal indicate the beginning of each cycle. Linkswitch high -frequency oscillator contains the following circuits to introduce a small amount of frequency jitter, usually a 16 kHz peak peak and minimize EMI. The modulation rate frequency jitter is set to 1.5 kHz to optimize EMI to reduce whether it is the average emissions or the peak emissions. The frequency should be used to measure the decrease of the tither the leaky waveform. The waveform diagram 4 shows the frequency of the link switch HFTrends.

Feedback input circuit

The feedback input circuit at the FB pins is set to 1.65 V. When the current inputs the current of the pin exceeds 49 μA, the logic electric low (disable) is generated at the output terminal of the feedback circuit. This output is at the clock signal at the beginning of each cycle. If the power of MOSFET is high, the cycle (enable) should be kept off (disabled). Because the sampling is just at each cycle, the follow -up change of the FB pin voltage or current is ignored in the rest of the cycle.

5.8V regulator and 6.3V parallel voltage pliers

5.8 V registered bypass capacitors are charged from the drain voltage, as long as the MOSFET is turned off. The internal power supply voltage node high -frequency connection switch with this bypass is. When the MOSFET is connected, the link switch HF exhausts the energy stored in the barrier container. The low power consumption of very internal circuits allows the connection switch HF to continue to run from the current consumption from the current. 0.1 μF bypass electricity value is enough for high -frequency decoupling and energy storage. In addition, there is also a 6.3 V pauses. When the current provides current to the bypass, the bypass feet are 6.3V pins through the external resistor. This helps the link switch high frequency through the external bias winding to reduce the air -load power consumption of less than 50MW.

Winging pinhopper pressure

The underwriting voltage circuit of bypass pins will fail the power supply as the cross -footing voltage below 4.85V, MOSFET. Once the bypass pins voltage drops below 4.85 volts, it must be rose back to 5.8 volts to enable (open) power MOSFET.

Excessive protection

The temperature of the sensor of the heat shutdown circuit. The threshold is set to 142 ° C, and the typical value is 75 ° C behind. When the mold temperature rises to the threshold (142 ° C) above, the power MOSFET is disabled and kept for disable until the mold temperature drops by 75 ° C. At this time, it is re -enabled.

current limit

current in the current -limiting circuit detection power MOSFET. When the current exceeds the internal threshold (ILIMIT), the power MOSFET is closed at the remaining time of this cycle. The short -term comparator has been opened after cutting -edge anti -hidden circuit inhibitory current limit power MOSFET. The setting of the front edge rushing time is that the current peak is caused by the reverse recovery time of the capacitor and rectifier.

Automatically restart

If the output overload and other failures occur, the output high -frequency switch or short -circuit automatic restart operation. When the FB pin is pulled up, the oscillator is reset. If the FB pin is not pulled up for 30 milliseconds, the power MOSFET switch is turned off of 650 milliseconds. Automatically restart alternately to enable and disable the power MOSFET, until the failure state has been excludedEssence

Application Example

2.4 WCC/CV charger adapter Figure 5 is A 5.7 V, 400 ma, constant voltage, constant current (CV/CC) battery charger. The input bridge formed by the diode D1-D4 is used for the input voltage of rectifier AC electricity. Then the rectified AC power was filtered out of the storage capacitor C1 and C2. The resistor RF1 is a fire prevention, the easy melting line is winding, the role of the melting wire and the surge current, and the π filter consisting of C1, C2, and L1, the differential mold noise decayer. This simple EMI filtering, plus frequency jitter connecting switch HF (U1), small value Y1 capacitor (CY1), shielding winding in T1, and secondary side RC buffer (R5, C5), allow design satisfaction to meet two two Indoasia and radiation EMI limit. CY1's low -value is very important to meet the requirements of low -frequency leakage of the line, in this case lt; 10μA. The input voltage of the rectifier and filtering is applied to the one -side T1 winding. On the other side of the transformer one side is driven by U1 integrated MOSFET. The diode D5, C3, and R1R3 form a primary clamping network. This limits the drain voltage caused by the peak leakage. The R3 allows the resistor to use slowly, and the low -cost rectifier diode restricts the reverse D5 when the U1 is connected. The choice of slow -paced diode improves efficiency and conducts electromagnetic interference. The output rectifier is provided by the Schottky diode D6. The low -level positive voltage provides a high -efficiency range and low ESR capacitor C6 during the entire operation to minimize the output voltage ripples. In the constant voltage (CV) mode, the output voltage is transmitted by the Qina diode VR1 and the PNP transistor to transmit the base voltage problem 1. Q1's VBE is divided into R7 value setting deviation through VR1 current (~ 2.7 ma). When the output voltage exceeds the threshold voltage determined by Q1 and VR1, the Q1 is connected, and the current flows through the LED of U2. As a LED current increase, the current feedback feedback pins increase, and the further switching cycle of U1 is disabled. In a very light load, almost all switching cycles will be disabled, providing lower effective switching frequency and empty load consumption. During the load transient state, the R6 and R8 ensure that the amount of Q1 is not exceeded when R4 prevents C4 discharge. Resistance R9 and R10 form a constant current (CC) sensing circuit. About 400 mAh or more, the voltage passing voltage through the sensing resistance exceeds the optocoupler diode, the voltage is about 1 V. The current through LED is determined by the output current and CC control to control the CV feedback circuit. CC keeps control even in the case of short -circuited output.

Key application precautions

Link switch HF design precautions

Output power table

Maximum output power table (Table 1) indicates the maximum The actual continuous output power level is obtained under the following assumptions:

1. For the 85 volt AC voltage, the minimum DC input voltage is 90 volt or higher input, or 240 V or higher, for 230 VAC input or 115 VAC band voltage multipliers. The input capacitance value should be large enough to meet these AC input standard design.

2. 5.5V output with Schottky rectifier diode.

3. Suppose the efficiency is 70%.

4.fosc (min) and Ilimit (min) work frequency.

5. Only voltage output (no second -side constant current circuit).

6. Continuous mode operation (0.6 ≤kp ≤ 1).

7. This part is a copper area with sufficient copper welding of the plate installation and source to maintain the source pins temperature equal to or below 100 ° C.

8. The environmental temperature of the open frame design is the internal case temperature of 50 ° C adapter. The temperature is designed at 60 ° C. Below 1, KP is a ratio of a ripple to a peak. Higher than 1, KP is the ratio of the primary MOSFET to the interruption time of the secondary diodes. Working at a lower effective switching frequency can simplify the limit of conduction and radiation electromagnetic interference, especially the design of a safe Y capacitor must be eliminated. By using the low -load frequency, the primary inductance value is higher than the power transmission. However, this lower operating frequency will be lower than these values u200bu200bas shown in Table 1.

Listening noise

The application of frequency jump working in short -wave link switches can generate audio components in the transformer. In order to limit the generation of this listening noise, the transformer should make the peak peak of the magnetic rhotians below 1250 Gauss (125 metric tons). Following this guide and using the standard transformer soaking production technology almost eliminates listening noise. Higher flux density, but carefully evaluating the noise that can be heard is the possible performance. The sample before the design of the transformer is approved. Ceramic capacitors using Z5U and other media may also generate audio noise in clamp circuits. If this is in this case, try to replace them with a different capacitor, such as polyester film type. See Figure 6 for Linkswitch HF layout to obtain high -frequency connection switches.

Single -point grounding

Use a single -point grounding connecting electric container using the input filter to connect to the copper source area.

Wingrsen container (CBP)

The barrier pipe pipe football container should be as close as possible to the bypass and source. The main circuit area capacitor and transformer of the input filter in one circuit area should be as smaller as possible together with the connection switch HF. One clamping of the primary clamp circuit is used to limit the peak voltage and the leaky foot is turning. This can be realized by using the RCD card hoop (as shown in the figure) in Figure 5) or Zina (~ 200V)Wind a winding with diode pliers. In all cases, in order to minimize the electromagnetic interference, we should pay attention to minimizing the circuit path from the clamp component to the transformer and the connection switch HF.

Thermal factors

The copper area below the link switch HF not only play a single point ground, but also can be used as a heat sink. Because this area is connected to the quiet source node, this area should be maximized to connect the good heat dissipation of the switch HF. It is also suitable for the cathode of the output diode.

Y -type capacitors

The placement of the Y -type capacitor shall directly input the public/reflux terminal of the secondary side of the secondary side of the positive polarity transformer from the primary input filter capacitor. Such a current is placed on the current of the high -intensity of the route from the chain switch high -frequency device. Note that if you enter π (C, L, C) EMI filter, and then the filter should be placed in the input filter capacitor.

Optical coupling

Physically -coupled to the link switch HF to minimize the main edge tracking length. Keep a large current, and the high -pressure leakage and clamping trajectory away from the optocoupler to prevent the noise from increasing noise. In order to obtain the best performance, the output diode connects secondary winding, output diode, and output filter capacitors should be minimized. In addition, sufficient copper should provide a diode used for heat dissipation in the anode and cathode. It is best to be at a quiet cathode terminal. A large anode area can increase high -frequency radiation EMI.

Quick Design Examination Form

Like any power design, all connection switch HF design should be verified on the test table to ensure that in the worst case, it will not exceed the specifications. This strong recommendation is at least the following tests:

1. Maximum drain voltage -Verification of VDS does not exceed the maximum input voltage and peak (overload) output is 675 V power.

2. Maximum leakage current-At the highest environmental temperature, the maximum input voltage and peak output (overload) power, check whether the drain-waveform has signs of signs of saturation and excessive front-edge current peak startup. Repeat the above steps in a stable state and verify Figure 6. Recommended layout of high -frequency anti -fixing switches. The cutting -edge peak event is lower than the end of TLEB (minute). In any case, the maximum displacement current should be lower than the absolute maximum value rating.

3. Thermal inspection-In the specified maximum output power, the minimum input voltage and the highest ambient temperature, confirmed that it does not exceed the temperature specifications to connect to the switch HF, transformers, output diode and output capacitors. The part of the RDS (ON) of sufficient heat link switch HF AS should be left to partial changes in the data table. At the low -line and maximum power, the high -frequency source pins temperature of the maximum link switch is 100 ° C to consider these changes.

Absolute maximum rated value (1,5)

[12]3] Discost voltage -0.3 volt to 700 volts

Peak drain current 400 mAh (750 mAh) (2)

Feedback voltage-0 to 9 volts

] Feedback current 100 mAh

Writing voltage -0.3 volt to 9 volts

Storage temperature -65 ° C to 150 ° C

Work knot temperature (3)- 40 ° C to 150 ° C

Lead temperature (4) 260 degrees Celsius

Note:

1. Refer to all the voltage of the power supply, TA u003d 25 ° C.

2. When the drain voltage is less than 400V.

3. Usually restricted by internal circuits.

4.1/16 inches. 5 seconds come out of the box.

5. The maximum rated value can be adopted, one by one, which will not cause permanent damage to the product. Extended time exposure to absolute maximum rated values u200bu200bmay affect product reliability

heat impedance

Heat impedance: P or G packaging:

[θja) 70 ° C 70 ° C /W (2); 60 ° C/W (3)

(θjc) (1) 11 ° C/w

Note:

1. Measurement on the pin 2 (source) of the interface.

2. Welded to 0.36 square inch. (232 square millimeters) 2 ounces (610 grams/square meter) copper.

3. Welded to 1 square inch. (645 square millimeters) 2 ounces (610 grams/square meter) copper.

Note: A. When the feedback foot voltage ≥2V (MOSFET is not equal), the sum of the total current consumption is the sum of IS1 and IDSS. When the feedback foot is short -circuited to the power supply (MOSFET switch), the sum of IS2 and IDSS.

B. Because the output MOSFET is a switch, it is difficult to isolate the switching current from the power current. Another method is to measure the wires of the bypass when 6V.

C. Wingrsen pin starts the charging waveform and see the typical performance characteristics chapter Figure 14.

D. This current is only used to provide optional optical coupling feet connected between bypass and feedback instead of any other external circuits.

E. The current limit of other DI/DT values, please refer to Figure 13.

F. This parameter is guaranteed by the design.

G,This parameter is derived by features.

H, the automatic restart time has the same temperature characteristics as the oscillator (with frequency)