1、 Introduction;
Switching power supply has obvious advantages such as low power consumption, high efficiency and small volume. It has been widely used in electrical products and electronic equipment. According to the output voltage stabilizing control mode of the circuit, switching power supply can be divided into three types: pulse width modulation (PWM), pulse frequency modulation (PFM) and pulse rate modulation (PWM). According to the trigger mode, switching power supply can be divided into self-excited type and other excited type, The switching power adapter explained in this article is pulse width modulation (PWM). It is an exciting switching power supply, which outputs the 12V DC regulated voltage commonly used in electrical products and electronic equipment, and the output rated current is 6A. It is suitable for the DC input power supply of LCD TV within 32 inches.
2、 Technical explanation of driving circuit of switching power adapter;
The drive chip ob2269 used in the switching power supply explained in this article adopts a unique design scheme, which is that the power supply system has high cost performance and can meet the requirements of the masses.
Ob2269 adopts the traditional current mode design and has the following characteristics;
▲ low standby power consumption: the design of low-power intermittent working mode can not only make the whole system easy to realize the latest recommendations of the International Energy Agency under no-load.
▲ noise free operation: audio noise will not appear under light load and full load. The optimized system design can make the system work quietly in any working state.
▲ lower starting current: VIN / VDD starting current is as low as 4ua, which can effectively reduce the loss of system starting circuit and shorten the starting time of the system.
▲ lower working current: the working current is about 2.3ma, which can effectively reduce the loss of the system and improve the efficiency of the system.
▲ built in OCP compensation: the built-in OCP compensation function makes the OCP curve of the system tend to be flat in the whole voltage range without increasing the cost, so as to improve the cost performance of the system.
▲ sound protection function: it has overvoltage protection function (OVP), over temperature protection function (OTP), undervoltage protection function (UVLO) and output overload protection function (OLP), combined with sound protection function.
▲ MOSFET soft drive: it can effectively improve the EMI of the system.
2269 features of the built-in system: it can effectively reduce EMI and reduce EMI.
3、 Electrical schematic diagram of switching power adapter;
Post time: Mar-17-2022
