Converters: Voltage to Frequency, Page 1
Voltage Controlled Oscillators (VCO)
Last Updated on: Monday, April 21, 2008 04:37 AM

VCO; Voltage to Frequency Converters:  #'s - A     B - K     L - U    V - Z

• 40KHz Voltage to Frequency Converter
  This circuit was designed to frequency modulate a 40KHz carrier, using human voice frequencies.  A common flip/flop is used at the core of the circuit.

• 200MHz - 400MHz VOLTAGE controlled OSCILLATOR
  If you need a clean emitter coupled logic (ECL) type signal between 200MHz and 400MHz this circuit works fine. It uses four voltage controlled capacitors to change the frequency.

• Air Transparency Monitor, Xenon Flash Receiver
  I designed this circuit many years ago to monitor the quality of a mile long column of air for future optical communications experiments. The transmitter system (circuit 72 below) uses a powerful xenon flash in conjunction with a large 12 inch fresnel lens at the transmitter end and a matching 12 inch lens with a PIN photo diode at the receiver. The receiver system was connected to a weather station and a computer to collect the changes in intensity of the light flashes under different weather conditions. It has the potential for a 30+ mile range. I have also used this system to conduct cloud bounce experiments.

• Air Transparency Monitor, Xenon Flash Receiver, Page 2
  This is Page 2 of the receiver circuit Air Transparency Monitor, Xenon Flash Receiver

• CMOS SCHMITT TRIGGER IC MAKES VCO
  By changing the supply voltage fed to a classic 4584 Schmitt trigger type oscillator, the oscillator frequency can be changed over a range of 50:1.  A 74HCU04 inverter is used at the output of the 4584 to maintain a constant TTL logic level signal.

• Light to Frequency Converter
  This circuit uses a CMOS version of the classic 555 timer, to form a light intensity to frequency converter.  A small PIN photo diode is used as the light detector.  The pulses produced are short, so in some applications you may want to stretch them or feed them through a flip/flop to produce a square wave signal.  Although the circuit shown is designed for a 5v supply, it could operate from almost any voltage from 3v to 15v.

• Voltage to Frequency Converter + 1uS LED Pulse Driver
  This circuit receives the signal from the above amplifier and launches powerful 1uS infrared light pulses from a low cost LED that are frequency modulated by the audio information. The 10KHz center frequency of the pulse stream is low enough so a standard infrared LED can emit ten times more light than conventional long pulse techniques. The circuit is described in more detail in the transmitter section of my Handbook of Optical Through the Air Communications.

• Wide Band Zero Cross Detector
  This circuit was designed to convert a low amplitude 40KHz signal into a clean square wave signal.  It will work with inputs as small as 5mv peak-to-peak or as large as 3 volts peak to peak.  The input frequency can range from a few kilohertz to about 150KHz.

0.02% V/F Converter Consumes Only 26 µA:  07/04/96 EDN-Design Ideas / (added 11/05) 

10 Khz VFC uses Charge Pump Variation:  04/09/98 EDN-Design Ideas / (added 3/03)  

10.58 to 10.74 MHz VFO Oscillator :  Electronic Circuit design (added 02/05)

2-Way Multiplexed LCD Drive and Low Cost A/D-Converter using V/F Techniques with COP8 Microcontrollers:  National Semiconductor Application Note   (app note added 6/06)

A Design and Manufacturing Guide for the Lead Frame Chip Scale Package (LFCSP):  AN-772 Analog Devices Application Notes  (app note added 2/06)

Acceleration to Frequency Circuits:  AN-411 Analog Devices Application Notes  (app note added 2/06)

AN-214: Ground Rules for High Speed Circuits:  AN-214 Analog Devices Application Notes  (app note added 2/06)  Layout and Wiring Are Critical in Video Converter Circuits.

AN-276: Analog-to-Digital Conversion by using V/F Converters:  AN-276 Analog Devices Application Notes  (app note added 2/06)

AN-277: Applications for the AD537 Voltage to Frequency Converter:  AN-277 Analog Devices Application Notes  (app note added 2/06)

AN-278: Operation and Applications of the AD654 IC V-to-F Converter:  AN-278 Analog Devices Application Notes  (app note added 2/06)

AN-279: Using the AD650 Voltage-to-Frequency Converter as a Frequency-to-Voltage Converter:  AN-279 Analog Devices Application Notes  (app note added 2/06)

AN-280: Mixed Signal Circuit Technologies:  AN-280 Analog Devices Application Notes  (app note added 2/06)  Considers problems which arise when reality (& Murphy)   intervene in a design which orwise seems satisfactory in terms of ory and modeling.

AN-343: Circuit Ideas for IC Converters:  AN-343 Analog Devices Application Notes  (app note added 2/06)

AN-349: Keys to Longer Life for CMOS:  AN-349 Analog Devices Application Notes  (app note added 2/06)  Here's How CMOS Can be Protected Against Abuse

AN-361: Ask the Applications Engineer (V/F Converters):  AN-361 Analog Devices Application Notes  (app note added 2/06)

AN-411: Acceleration to Frequency Circuits:  AN-411 Analog Devices Application Notes  (app note added 2/06)

AN-772: A Design and Manufacturing Guide for the Lead Frame Chip Scale Package (LFCSP):  AN-772 Analog Devices Application Notes  (app note added 2/06)

AN795: Voltage-To-Frequency/Frequency-To-Voltage Converter:  Microchip Application Note Published 12-Nov-02   (app note added 2/06)

AN967: Bidirectional VF Control of Single and 3-Phase Induction Motors using the PIC16F72:  Microchip Application Note Published 27-Jan-05   (app note added 6/06)

Analog-to-Digital Conversion by using V/F Converters:  AN-276 Analog Devices Application Notes  (app note added 2/06)

AN-C: V/F Converter ICs Handle Frequency-To-Voltage Needs:  National Semiconductor Application Note   (app note added 2/06)

AN-D: Versatile Monolithic V/Fs can Compute as Well as Convert with High Accuracy:  National Semiconductor Application Note   (app note added 2/06)

Applications for the AD537 Voltage to Frequency Converter:  AN-277 Analog Devices Application Notes  (app note added 2/06)

Ask the Applications Engineer (V/F Converters):  AN-361 Analog Devices Application Notes  (app note added 2/06)