#intellectual control

Traditionally, switching power supply (SMPS) Realize with a fundamental analog control cycle, but digital signal controller (DSC) Technical latest development makes the design which adopts the digital controlling mechanism very practical and economic, however, it is estimated digital control technique will be applied to the advanced products at first, because in the advanced products, it is very obvious and direct that this technology gets the advantage. But a lot of analog power supply it employs to be can from minimum, most cheap microcontroller (MCU) too Obtain a lot of advantages in configurated ability and intelligence offered, in fact, there are 4 independent numerically controlled stages in the power at least, they are controlled by an opening/closing, p control disposition, control figure feedback total digital control, among them on off control has some advantages attracting people's attention at stage. Through making the traditional switching power supply MOSFET driver export void switched input to turn over, puls e-width modulation (PWM) Technology can be used for operation time of the control power supply, namely from 0% to the operation time (Fig. 1) of 100% of the increase power slowly ,This method allows the flexible one " Soft turn on " ,Surge current by usually appearing while preventing the switching power supply from starting. Even minimum MCU have 4 common the intersection of I/O and port at least and than employ the intersection of demand and large computational capability much, can, from straight extension to 2 or multi-output, the mechanism support simultaneous control a plurality of the intersection of switch and stabilizator concept this, thus make the output sequence very accurate, in addition, if MCU has comparator and voltage reference on slice, then they can realize effectively voltage shortage is locked-in or carry out tracing, so as to ensure two are exported and risen with the identical slope. Another it increases intelligence for power to be to utilize internal the intersection of Shaker and ( 4MHz) of MCU as to simple method . This Shaker can be used as the clock source of PWM generator of the switch stabilizator, such as the intersection of Microchip and at a high speed PWM control device MCP1630 of Company ' Fig. 2) . In the example here, the clock of MCU is exported (usually divided by 4 reference clocks which get 1MHz) Connect and input to the vibration of PWM generator, if MCU has PWM port on slice, it can be used as the input source of the stabilizator PWM of the switch, thus control duty ratio and frequency better. The internal Shaker of MCU is usually by the compensatory RC circuit of temperature, and generally normalize original acquiescence when being dispatched from the factory, but the design engineer can utilize the calibrate register (OSCAL) of MCU Shaker ,Regulate the oscillator frequency at any time through the software, this function contributes to meeting FCC and other administrative organs to force specifiedly to radiate the requirement. Utilize the simple pseudo-random sequence to change OSCAL to set up, mains frequency can be changed within the range of about 600MHz to 1.2MHz, if adopt the Linear Feedback Shift Register, only need several line codes and realize the random number generator very easily. This kind of technology that is widely known by the people only needs to carry on little programming and work to 8 MCUs, deal with detune to the internal Shaker through this way, the energy of the power can be launched in one very in the wide-range, thus reduce the launching energy of single frequency 20dB. From: Microchip Company