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CMOS Peak Detector using Diode Connected MOSFET
 An active type peak detector using OP-amp and transistor has high performance, however active type is too
complicate structure which control and suppress the errors.
 Actually many of active type peak detectors employee complicate error compensation circuit.
VDD
ENC
CC
Ci
Switching Time Controller
Vin
Qch
Voff
C gd
Cd
Ch
< Active Type Simple Peak Detector and Error Sources >
< Example of Complicated Structure of Peak Detector >
 Input error sources : Parasitic capacitance
 Input parasitic capacitance
 Coupling capacitance
 MOSFET error sources
 Gate-to-drain capacitance
 Drain capacitance
 Channel charge Qch
 Offset error calibrated using multiple switches
 Additional control circuits and power consumption
 Another error or problem generated by additional circuits
 Inadequate structure for multi-channel system
CMOS Peak Detector using Diode Connected MOSFET
 In a communication system, sometimes an input signal need to be rectified in order to use as the system power.
 General rectifying circuit uses diodes, however, we cannot use a diode due to its forward voltage drop which
cause input signal loss.
 We suggest passive peak detector using diode connected MOSFET which has advantages of diode peak detector and also has active
peak detector.
 Our peak circuit shows only 1.2 % loss when the amplitude of input is 1 V. On the other hands, diode peak detector has almost 50 %
loss at the same condition.
1.5
1.0
Diode Output
Input Signal
1.0
0.5
Amplitude [ V ]
Amplitude [ V ]
1.5
Input Signal
Output of Proposed Circuit
0.0
-0.5
0.5
0.0
-0.5
-1.0
-1.0
-1.5
-1.5
0.0
1.0x10
-7
Time [s]
2.0x10
-7
3.0x10
-7
0.0
1.0x10
-7
2.0x10
-7
3.0x10
Time [s]
-7
4.0x10
-7
5.0x10
-7