As custom device for this circuit, Fuji Electric has commercialized the M-Power 2 containing an IC and two power MOSFETs and this device has been well received for use in power supplies for flat panel televisions. To support even larger power supplies, this device has been developed having a lower ON resistance and featuring improved controlled IC functionality.
UTSource F9222L Features
3-No arm-short by lower frequency side operation
4-High efficiency during light load operation
Feature 1 and 2 above provide the same benefit as the conventional current resonant frequency.However feature 3 and 4 are difficult to achieve with the frequency control method and the significant benefit of the present method is the ability to provide these the countermeasures and improvements easily.
It has three main regions. Main board, logic board and Y board are the three areas. In region 2, there are 6 pins;
In region 1, there are 12 pins which are PS-ON, STBY, GND, Vamp, D5.3V ,GND_15V.
In region 3, there are 3 pins that are Vs, GND, Vg (D15V) and Va.
During period 1, when Q1 is ON and Q2 is off, the current flows through Cr to PI and supplies power to the load. Output control voltage is implemented by feeding back to the control IC the signal forms the output voltage regulator as voltage reference. During period 2, when Q2 is ON, the polarity of Vp1 inverts from positive to negative. During period 3, after the discharge is completed, the Q2 diode body begins to conduct. At this time , zero voltage switching becomes active when Q2 turns ON. The gate voltage turn-on voltage is moderated by a resistance connected to Q2 terminal and the circuit is set such that the ZVS will become active and prevent Q1 and Q2 from turning on both simultaneously.
Control IC functions
The control Ic which is specially developed for multi-oscillated control has some general functions.One is computation function to control pulse width modulation. The other is protection funtion by latched shutdown against the overcurrent, load short circuit, overheat and undervoltage lockout.Also the latched shutdown function of overcurrent protection and overheat protection is provided with the timer setting.
The power MOSFET is used in SUPERFAP-G series power MOSFETS having the characteristics of low resistance and high switching speed and aims to reduce loss and protect overheating.
- The current detection method has been changed from plus to minus and the influence of power MOSFETs drive current have been eliminated.
- The current detection terminal is separated from the power MOSFETs terminal and the externally attached filter can be desighned freely in accordance with the power supply specifications.
- Two GND terminals are provided which lessened the influence of control on IC and the pattern of layout has been made easier to design.
- Used in compensation circuit for light load burst.