On-chip LNK616PG of LinkSwitch-II family firms Power Integrations can be designed very simple battery charger with mains supply, which can operate in either stabilizing the voltage and current stabilization mode. The device can be used for charging mobile phones or other electronic devices that consume less than 5 watts.
LNK616PG chip was developed for use in the budget of low-voltage chargers and network adapters. This controller provides precise control of output voltage and current for a small number of external components, and characteristically, without the use of optocouplers.
LNK616PG has built a 700-volt key transistor and a control circuit that provides high efficiency over the entire range of output currents and low power consumption without load.
The rich range of protective functions of the chip and is LNK616PG such as automatic restart after a short circuit or open circuit elements of feedback. Safety under all operating conditions is provided having an additional thermal protection hysteresis.
In the scheme LNK616PG used on the input side flyback pulse converter.
Input AC voltage is rectified by diodes D1 … D4. A DC voltage smoothing capacitors C1 and C2. Inductors L1 and L2, together with capacitors C1 and C2 form a filter to reduce electromagnetic interference.
The rectified and filtered voltage is applied to one of the conclusions of the primary winding of the transformer T1. The second conclusion is switched internal MOSFET transistor chip U1. Snubber circuit, consisting of a diode D5, resistors R3, R4 and capacitor C3 limits the spikes that occur at the drain of the transistor at the time of switching.
Voltage secondary winding of the transformer T1 is rectified by diode D7 and smoothing capacitors C7 and C8. To improve the efficiency as a Schottky diode D7 is taken. The output voltage is stabilized by controlling the internal switching MOSFET transistor, and the stabilization of the output current by varying the switching frequency. Sensor output voltage is a separate bias winding of the transformer T1.
Resistor R9 provides a minimal load for the regime in the absence of consumption. The circuit can be used pulse transformers of the type Santronics SNXR1346, Ice Components TP07161 type or Precision, Inc Type 019-6120-00R.
Description of the transformer Ice Components TP07161 can take here .
Thus, the scheme presented expensive charger that operates from a wide range of input voltages from 85 to 265, and provides a regulated 5-V with maximum current of 1 A.