Module of WK283R3S-33M power source seals series to be not sealed fill, its are main technical parameter: VOUT=3. 3 V, VIN=18 V~36 V, POUT=33 W, SI/Sv=0. 5 ％ , η =85 ％ , VP-P=100 MV. The appearance of module of this power source is 1/4 brick, its are main the characteristic is outputted for low-pressure big electric current module, efficient the power density that is 4 bricks of 1 ／ to be able to raise module with value of low ripple voltage, bulk.
2 circuit develop attacks
The power source develop that power of module of DC-DC power source is 30 W often chooses sheet to be stimulated rightly pit-a-pat type and stimulate type instead, module of this power source has develop to attack ／ of simple, input outputs the advantage such as electric segregation.
Power change-over circuit chooses the odd decorous transformer that stimulate type, circuit simple, application is convenient, apply to low-pressure big electric current to output a circumstance. This circuit is in charge of with switch of a power only and transformer is circled make simple, reliability is high. Stimulate type transformer to be compared instead with Chan Duan, although increased diode of follow on current and filter wave inductance, but transformer leakage magnetism voltage of ripple of small, output is low, efficiency is tall.
Requirement of this power source is efficient, the loss of its power source basically is switch loss, transformer loss, output commutate loss. Circuit of this power source uses Qian of nondestructive bad news circuit and synchronous commutate technology.
3 crucial technologies
Raise switch frequency to be able to reduce the volume of capacitance of wave of magnetic component, filter, conduce to systematic miniaturization. But as switch frequency rise, switch loss increases, medicinal powder hot area increases instead the miniaturization of block up system. Increase switch frequency, carry efficiency changeless the key that increasing even is this system design. Accordingly, must realize systematic design according to new technology, high-powered component and high-powered data.
3. 1 synchronous commutate
In power transformation of low-pressure big electric current implement in, if use traditional common diode or Xiaoteji diode commutate, as a result of its guide is connected pressure fall big, diode is pressed fall for 0. 4 V, when carrying 10 A electricity, loss is 0. 10 × of 4 × 0. 62=2. 48W. This is had to power source of a 33 W 2. The rectification consume of 48 W is very big. Rectification loss criterion
Make the main loss of transformer, cannot satisfy power source of switch of big electric current of systematic low pressure the requirement of efficient, minor volume.
Time of power MOSFET switch is short, input impedance is tall, these characteristics make MOSFET makes power transformation of low-pressure big electric current implement parts of an apparatus of first selection commutate. Power MOSFET is parts of an apparatus of a kind of voltage control, regard rectification as component, demand control voltage is as phasic as what need rectification voltage maintain synchronous ability to fulfil rectification function, call synchronous commutate circuitry.
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