High frequency transformer is odd the core component of a switch power source, in view of this kind high frequency transformer has its specialty on the design, elaborate technically for this reduce its loss and the method that restrain frequency noise, can design personnel reference for high frequency transformer. Odd integrated circuit has a switch power supply tall compositive degree, tall sex price is compared, most the advantage such as index of brief periphery circuit, optimum behavior, can form efficient the power source of segregation formula switch of transformer of the frequency that do not have labour. In 1994 ～ 2001, what a variety of series such as Ⅱ of TOtch, TOtch- Ⅱ , TOtch-FX, TOtch-GX, Tintch, Tintch- rolled out in succession on international is odd a product of switch power source, already made development now the actor of power source of switch of medium, small-power, accurate switch power source and module of switch power source chooses integrated circuit. High frequency transformer is switch it is as important as what transmit to undertake energy stores in power source component, odd an actor bad of function of high frequency transformer in switch power source, have bigger effect to power source efficiency not only, and the other technology index that matters to power source directly and electromagnetism compatibility (EMC) . For this, efficient high frequency transformer should have dc loss and communication loss feeling of low, leakage the coupling capacitance between the distributinging capacitance of itself of small, winding and each winding wants small wait for a condition. The dc loss of high frequency transformer is caused by the cupreous loss of coil. To improve efficiency, answer to choose wider lead as far as possible, take Mm2 of ／ of 10A of ～ of current density J=4. The communication loss of high frequency transformer is caused by the loss of the hasten skin effect of high frequency electric current and magnetism core. When high frequency electric current carries wire, always be incline to passes at flowing from the surface, this meeting makes the effective and current area of lead is reduced, make the communication of lead equivalent impedance outclass cupreous resistor. High frequency electric current becomes inverse ratio to the square root of the penetrable ability of conductor and switch frequency, to reduce communication copper impedance, lead radius must not exceed high frequency electric current to be able to amount to 2 times of deepness. The relation curve that can offer chosen wire wire path and switch frequency is shown 1 times like the graph. Illustrate, when F=100kHz, lead diameter is theoretic desirable φ 0.
4mm. But to reduce hasten skin effect, actual and usable thinner lead is circled many times, and need not a wide lead is circled make. Must decrease leakage feeling to when designing high frequency transformer the smallest. Heal because of leakage feeling big, the aiguille voltage extent of generation heals tall, leakage pole clamp the loss of circuit heals big, this brings about power source loss of efficiency necessarily. Accord with the high frequency transformer of insulation and security standard to, quantity of its leakage feeling should be the 3 ％ of 1 ％ ～ that primary inductance measures when sub open a way. Want to reach the target under 1 ％ , in workmanship admiral is hard to come true. The following step can take when reducing leakage to feel: Reduce the NP of v/LIT all over the ground number of primary winding; The breadth that increases winding (choose EE magnetism core for example, in order to increase framework width B) ; Those who increase winding is tall, wide than; Reduce the insulation layer between each winding; Raise the coupling rate between winding.
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