L6562 may serve as the PFC pressure-rise pre-converter as well as the constitution conforms to IEC61000-3-2 the harmonic current limit standard 300W switching power supply (for example TV, table model PC monitoring device power source and so on); May also use in the high-end AC-DC adapter/battery charger, the entrance level server and the Web server and so on.
Figure 1
1 L6562 main feature
L6562 uses 8 pin DIP and the SO seal, chip electric circuit composition as shown in Figure 1. Compares with L6561, the L6562 internal multiplier has the THD minimizing special electric circuit, can the active control AC input current junction more distort and the erroneous amplifier output ripple distorts, thus provides the high power factor and very low THD. L6562 other characteristics are as follows:
* has the 10.3~22V wide supply voltage scope;
* has is lower than 70μThe starting current and is lower than 4mA the operating current, and includes the closure function, thus is suitable specially in controls remotely/closes the control, and can satisfy “the blue sky to cause”, “star of the energy” and “Energy 2000″ and so on standards;
* with the aid in the voltage error amplifier and ±1% internal precise voltage reference, may control PFC the DC output voltage and causes it to be highly stable;
* has the overvoltage protection function, can process when safely the start and the load separation produces overvoltage;
* inlays the RC low-pass filtering electric circuit in the electric current sensing foot, may reduce the exterior part quantity and the PCB area;
* has the source electric current/to fill the electric current for - the 600/800mA push-pull output stage, and has undervoltage locking 煟 to wink Zheng Taxi 犗 Lu and the 15V voltage clamp, but driver power MOSFET or IGBT, thus may cause the converter output to reach as high as 300W.
Figure 2
2 L6562 THD optimization electric circuits
In view of causes the reason which THD worsens, L6562 in its internal multiplier unit, has inserted the THD optimization special electric circuit. This electric circuit can process the energy which nearby the AC circuit voltage zero crossing agglomerates, thus after enabling the bridge-type rectifier’s high-pass filter electric capacity to discharge fully, reduces the junction more to distort, reduces THD.
Unifies in the high linear multiplier’s THD optimization electric circuit, the L6562 permission sheds in erroneous amplifier opposition input end 煟 Sang Weizhi Niu 牶 su tiao plays 煟 vast Greece stoppage of pay Niu 犞jian to connect the RC series compensation network, reduces the higher harmonic which the erroneous amplifier output ripple and the multiplier output. Compares with L6561, the L6562 performance has the obvious promotion, but the cost does not increase.
3 using electric circuit and PFC effect
Makes controller’s 80W TM with L6562 PFC pressure-rise converter electric circuit as shown in Figure 2. And, magnetic elements T1 selects the E25N 13×7 magnetic core, primary winding 105 circle 熡 vast Bolivia ×0.1mm twisted wire 牐 inductance value L elects is 0.7mH, the secondary 11 circle 熡 Meng Daiduan 0.1mm insulated conductor 牎 # ta bites the load to bite R50 which and the C3 composition series network step Niu Beitu Niu Cangjian connects serves as the erroneous amplifier’s ripple compensation, C23 serves as the slope compensation.
