Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

design of rectifier for ultra low input power

Status
Not open for further replies.

arezu

Newbie level 4
Joined
Apr 19, 2016
Messages
6
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
47
Hi,
I want to design a rectifier using schottky diode (HSMS285x) for an ultra low input power (-20dBm) at 700MHz.
It is strange that efficiency is better with single diode than voltage doubler circuit or/and bridge diode, although half-wave is lost in single diode circuit!!!
but on high input power level (>10dBm), efficiency is direct proportion to the number of stages and diodes However, on the low input power level is in the inverse proportion.
why?!!
 

Even a Schottky loses a large portion of the waveform before
it begins to conduct, and the penalty applies at each stage in
a multiplier ladder. The only good rectifier for very low amplitude
inputs is a zero-VT MOSFET and even this will suffer on the
leak-back phase. A synchronous rectifier would be best but
that's a chicken / egg deal, can't work until the commutation
circuitry has powered up.

A resonant input circuit may help you, ringing up until the
diode starts to steal energy from the tank. A resonant
transformer with voltage gain, even better.
 

You cannot have a diode rectifier that rectifies without a forward drop or does not have a reverse leakage. That is forbidden by Maxwell's demon.

To rectify ultra low input power (perhaps much lower than the room temperature) you will need a source of energy- in terms of jargon, you will be needing active circuits.
 

The best signal diode for low level, high frequency signals is often a Back Diode (a tunnel diode operated in the reverse direction).
It has a very low forward drop at small currents. and it has a square-law characteristic which means the output rectified DC voltage is proportional to the signal power (the square of the voltage).
The are used extensively in a satellite system I worked on for detecting microwave signals in the GHz region.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top