LDMOS and MOSFET amplifier input protection unit.
This unit is intended to provide the anti-overshot protection to gates of transistors. The device has three stages of protection: -peak power Zener voltage suppressors limiting the maximum voltage level on amplifier input, -high speed relay disconnecting the input from signal source when input power rise above the preset level, -switching off the biase voltage to provide additional protection. Voltage suppressor Zener diodes has the limiting level 21V (approximately 8W input). Thanks to input attenuator the VSWR rise just slightly when diodes are clamping the signal. If input power occasionally rise to very high level, the comparator-trigger circuit switches off the 5 ms release time relay, thus disconnecting the input out of power. This power level is trimpot tuneable. This trigger controls the BIAS circuit also through transistor key. The input power source (i.e. transceiver) stays connected to attenuator, so nothing happens to it output. When system is triggered, indicating LED goes on. It is necessary to disconnect the supply voltage in order to set to initial state.Do not use microcontroller as a HI SWR protection device, it is too slow. Get your own valid XHTML YouTube embed code Get your own valid XHTML YouTube embed code Get your own valid XHTML YouTube embed codeDetailed product information can be downloaded here dropmefiles.com/1D3KU
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