Power Management IC Using PFM Technology

Green power management IC-ME8108 is a high-performance chip using pulse frequency modulation (PFM) technology. This chip is a low-power AC/DC switching power supply controller designed specifically for cost-effective battery chargers, power adapters and LED drivers. ME8108 has low power consumption, low startup current and low EMI, and the maximum efficiency can reach more than 80%. The startup voltage, output voltage and maximum power can be adjusted. This product uses pulse frequency modulation (PFM) technology to make the flyback circuit work in discontinuous current mode (DCM), and uses advanced primary side feedback control (PSR) technology to achieve precise control of constant voltage/constant current (CV/CC). It can achieve stable and reliable system operation without optocouplers, secondary feedback circuits and loop compensation circuits.

ME8108 contains 5V built-in voltage, voltage feedback and digital circuit, constant peak current setting circuit, leading edge blanking circuit, optimized transistor drive circuit, overvoltage protection circuit, open circuit protection circuit, PFM control and constant voltage and constant current adjustment circuit.

ME8108 package and pinout

ME8108 Pin Description

Internal structure diagram of ME8108

Features and advantages of ME8108

* The use of pulse frequency modulation (PFM) technology can achieve high-precision constant voltage and constant current compared to pulse width modulation (PMW) technology, and the efficiency of pulse frequency modulation (PFM) IC under light load can be very high, so the ME8108 system will be easier to pass the energy standard Energy Star EPS 2.0.

* The primary feedback control mode is used for constant current and constant voltage. Optocoupler and secondary feedback loop are not required, and loop compensation circuit can be omitted, but the system can still maintain loop stability.

* ME8108 can make the system always work in discontinuous mode with a fixed primary peak current, and provide different loads by adjusting the switching frequency, so that the system can present a linear frequency reduction characteristic from full load to light load.

* The startup current of ME8108 is very small, so the VCC voltage can quickly reach the undervoltage lockout threshold value to achieve fast startup; and in the application system, a larger startup resistor can be used to meet the startup current requirement of the chip, reducing energy consumption.

* ME8108 has excellent EMI characteristics. The built-in frequency jitter technology design can effectively improve the EMI characteristics of the system and reduce the EMI cost of the system.

* Built-in LEB leading edge blanking function can save an external RC network for the system and reduce system cost.

* ME8108 uses soft start control to reduce the output voltage overshoot at the moment of power on, which effectively suppresses the high current when the system is powered on and reduces the impact of the high current when the system starts on the system power consumption.

* ME8108 integrates a complete set of protection function modules, such as overvoltage protection, open circuit protection, and short circuit protection. Therefore, the ME8108 system is highly reliable and there is no need to add additional protection circuits under abnormal circumstances.

* The power supply designed with ME8108 will not produce audio noise regardless of no load, light load or full load. The optimized system design can make the system work quietly in any working state.

Typical application solutions of ME8108

ME8108 can be widely used in various low-power AC/DC switching power supply solutions, such as mobile phone chargers, power adapters, etc. In addition, since the chip integrates a constant current function, it can also be widely used in low-power LED drive solutions.

ME8108 typical application circuit

ME8108 Application Examples

As portable electronic devices become more and more popular, portable chargers, adapters and other related accessories will become more and more popular among consumers. In the future, power solutions will inevitably develop in the direction of low cost, low power consumption, easy to carry, high performance and high reliability. The high-performance green power PFM control chip ME8108 conforms to this trend. Using this chip, you can build an AC/DC converter solution that uses very few external components and maintains high performance within a wide AC voltage input range.