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Converters: Voltage to Frequency
Voltage Controlled Oscillators (VCO)

Converters -- Main Page

Voltage to Frequency Converters:  #'s - K     L - Z

 

Last Updated: November 30, 2017 07:38 AM

Circuits Designed by Dave Johnson, P.E.

Light to Frequency ConverterThis 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 . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2008

VCO from CMOS Schmitt Trigger ICBy 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 . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002

Voltage to Frequency Converter + 1us LED Pulse DriverThis 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. . . Circuit by David Johnson P.E.-March, 1999

Voltage to Frequency Converter -40KhzThis 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 . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2004


Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

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 . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2008

Light to Frequency Converter -  Fout = –1.4kHz per microampere of photo diode current, IPD.  The LTC6990 is a precision silicon oscillator with a programmable frequency range of 488Hz to 2MHz. ___ Linear Technology/Analog Devices App Note, Jun 16th 2010

Low power voltage-to-frequency converter makes a wireless probe for testing an inductive power supply -  26-May-05 EDN-Design Ideas Inductive pickup measures low-power circuit's supply__ Circuit Design by Francis Rodes, Eliane Garnier, and Salma Alozade, ENSEIRB Talence, France

Low-Power voltage-to-frequency converter makes a wireless probe for testing an inductive power supply -  05/26/05  EDN-Design Ideas Inductive pickup measures low-power circuit's supply__ Circuit Design by Francis Rodes, Eliane Garnier, and Salma Alozade, ENSEIRB Talence, France

Multilayer Capacitor Doubles as Varactor -  20-Mar-03 EDN-Design Ideas Correct voltage drop and phase shift in transmission linesThe main purpose for building the circuit in Figure 1 is to study the idiosyncrasies of X5R, Z5U, and Y5V multilayer ceramic capacitors.  The circuit is also an inexpensive VCO(voltage-controlled oscillator] with only five components.  Many types of ceramic capacitors for surface-mount placement are on the market__ Circuit Design by Susanne Nell, Breitenfurt, Austria

NE555 Timer Sparks Low-Cost Voltage-To-Frequency Converter -  02/21/08  EDN-Design Ideas The combination of an NE555 timer and a Miller integrator yields a voltage-to-frequency converter that costs less than 50 cents__ Circuit Design by Gyula Diószegi and János Nagy, Divelex Ltd, Budapest, Hungary

Performs High-Speed Voltage-To-Current, Current-To-Current Conversion -  07/25/02  EDN-Design Ideas The circuit in Figure 1performs active voltage-to-current conversion or acts as a variable-gain current mirror with high precision and bandwidth.  A typical application is testing high-speed ICs or other devices that have inputs des__ Circuit Design by Ali Mehmed, Nokia UK Ltd, Southwood, UK

Programmable Clock Oscillator -  PIC-Tock video clock using a PIC16C61.Voltage controller oscillator that was designed as a wide range oscillator to generate clock pulses for a stepper motor drive system, frequency could be varied over1,000,000:1 __ Designed by Richard Torrens

Series-LC-Tank VCO Breaks Tuning-Range Records -  10/20/11  EDN-Design Ideas A series tank circuit allows you a 4-to-1 frequency range.__ Circuit Design by Louis Vlemincq, Belgacom, Evere, Belgium

Simplify Classic V/I Converter -  01/20/00 EDN-Design Ideas Figure 1 shows a classic voltage-to-current (V/I) converter.  You can select the resistor values such that the output current in the load, R L , varies only with the input voltage, V IN , and is independent of R L .  The circuit is widely used in industrial instruments for supplying a 4- to 20-mA signal.  __ Circuit Design by Dudley Nye

Single transistor pump -  This is a simple circuit that can produce a staircase voltage output given a periodic pulse input __

Ten Khz VFC uses Charge Pump Variation 04/09/98 EDN-Design Ideas -   (Several circuits included, scroll to find this one)  A diode-capacitor charge pump is the starting point for many voltage-to-frequency-converter  (VFC] designs.  The circuit in Figure 1 uses a variation on that classic theme to achieve linearity less than 0.05%, micropower operation of approximately 10-�A total draw from a 5 to 36V rail, and bipolar-input capability__ Circuit Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC

Universal Watchdog Fully Controls µ Preset -  05/25/95 EDN-Design Ideas Many µPs contain internal watchdog timers, and you may wonder why you need another stand-alone circuit.  Unfortunately, more highly integrated functions have preset parameters that you may want to change.  Also, internal watchdogs are generally a simple combination of a flip-flop and a timer.  If the program does not start properly on the first try, the timer is of no use because the program never turns on the watchdog.  This watchdog catches exactly this condition__ Circuit Design by Terje Kvinge, Nera AS, Kokstad, Norway

V/F Converter Draws Flea Power -  04/24/97 EDN-Design Ideas The V/F converter in Figure 1 is unique because it draws less than 30 µA from one unregulated supply while converting bipolar input voltages.  It produces three CMOS -compatible, 0to 10-kHz outputsone (F+]that becomes active when the input voltage is positive, another (F­]that takes__ Circuit Design by W Stephen Woodward, University of North Carolina, Chapel Hill, NC

V/I converter accommodates grounded loA - D -  06/10/99 EDN-Design Ideas (PDF has many circuits listed, scroll to find this one)    The voltage-to-current(V/I]converter in Figure 1 uses three common op amps, two medium-power transistors, and only a few passive components.  The first op amp(IC1]inverts the sum of voltages VIN and VOUT to V1=-(VIN+VOUT].  The second op amp(IC2]and transistors Q1 and Q2 invert this voltage to__ Circuit Design by Michele Frantisek, Brno, Czech Republic

V/I Curve Tracer -  The V/I Curve Tracer is an indispensable tool for troubleshooting circuits and testing components.  The circuit traces the current versus voltage curve for the component under test on an ordinary oscilloscope.  The peak-to-peak test voltage __ Contact: Charles Wenzel of Wenzel Associates, Inc.

VCO from CMOS Schmitt Trigger IC -  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 . . . Hobby Circuit designed by David A. Johnson P.E.-March, 2002

VCO Has Digitally Programmable Center Frequency -  04/25/96 EDN-Design Ideas The circuits in Figure 1 illustrates a narrowband VCO, which has a digitally programmable center-frequency ratio of greater than 2-to-1.  With a VCO having center-frequency ratio(F HIGH/FLOW]of greater than 2-to-1, you can derive any output frequency by simple binary division__ Circuit Design by Paul Sofianos, Motorola LICD, Chandler, AZ

VCO produces positive & negative output frequencies -  12/25/03  EDN-Design Ideas The circuit in Figure 1 is a quadrature-output VCO that provIdeas both positive and negative output frequencies, depending on the polarity of the control-voltage input.  The circuit provIdeas a function that designers traditionally im__ Circuit Design by Henry Walmsley, Farnborough, UK

VCO supply touts low noise -  10/28/99 EDN-Design Idea   Many portable RF products use VCOs to generate the RF carrier frequency.  These applications often require low-noise VCO power-supply voltages that are higher than the primary battery voltage.  Many designs use a DC/DC converter powering a low-noise linear __ Circuit Design by Ted Henderson

VCO uses programmable logic -  14-Nov-02 EDN-Design Ideas A VCO(voltage-controlled oscillator] is an analog circuit, so you cannot find it in the libraries for the design of digital programmable chips.  When you need such a circuit for synchronization or clock multiplication, you need to find a circuit that works with the standard digital functions, such as AND and NAND__ Circuit Design by Susanne Nell, Breitenfurt, Austria

VCO using the TL431 reference -  10/10/13  EDN-Design Ideas The ubiquitous TL431 voltage reference has found something else it’s good at__ Circuit Design by R O Ocaya

Versatile Power Supply -  Using this circuit, you can obtain the following voltages (approx.) at a current limited to one ampere: 3.3V, 5V, 6V, 9V, 12V and 15V.  The AC mains is stepped down by transformer...___ Electronics Projects for You

VFC makes Simple Circuit capacitance meter -  06/07/01 EDN-Design Ideas When you develop the prototype of a circuit using capacitors or when you replace an old, defective capacitor with a new one, you often need to know the value of the capacitor you use or replace.  At times, the values printed on the capacitors are no longer readable.  Also, the wide tolerance__ Circuit Design by K Suresh, Indira Gandhi Centre for Atomic Research, Kalpakkam, India

Volt/F Converter Draws Flea Power -  04/24/97 EDN-Design Ideas The V/F converter in Figure 1 is unique because it draws less than 30 µA from one unregulated supply while converting bipolar input voltages.  It produces three CMOS -compatible, 0to 10-kHz outputsone (F+]that becomes active when the input voltage is positive, another (F­]that takes__ Circuit Design by W Stephen Woodward, University of North Carolina, Chapel Hill, NC

Voltage Controlled Switch using 555 -  In this circuit the 555 timer is used in a novel way, as a voltage controlled switch.   __ Designed by Miroslav Adzic

Voltage Controls Sine-Wave Frequency -  08/17/95 EDN-Design Ideas The circuit in Fig 1 generates a 50-Hz to 1-kHz sinusoidal waveform that exhibits lower than 60-dB THD.  The input voltage controls the output frequency with the relationship 1 kHz/V.  The output amplitude is invariant with frequency over the entire operating range.  IC1 is a V/F converter__ Circuit Design by Yongping Xia, EBT Inc, Torrance, CA

Voltage to Frequency Converter -  This voltage to frequency converter circuit has an oscillator that is voltage controlled and has a small, 0.5% deviation.  IC1 function as a multivibrator and produces rectangular impulses with equal width.  The width of the impulses depend on R4, P1 and C1.  With P1 we can do fine adjustments of the output frequency.  The output __ Designed by Popescu Marian

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. . . Circuit by David Johnson P.E.-March, 1999

Voltage to Frequency Converter -40Khz -  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 . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2004

Voltage-Controlled Resistor -  A common request from SPICE users is a voltage-controlled resistor.  Although there's no SPICE component that directly models this device, you can easily put one together.  There's several ways to do it.  You can even extend the device to model more complex resistance functions like RTDs and thermistors (spice design)  __

Voltage-To-Current Converter Makes a Flexible Current Reference -  18-Sep-03 EDN-Design Ideas The voltage-to-current converter in Figure 1 can both source and sink current.  The circuit isflexible than some traditional current references that require different topologies for current sourcing and sinking.  Also, you can easily adjust the value of the current reference by simply adjusting the circuit's input voltage__ Circuit Design by Art Kay, Texas Instruments, Tucson, AZ


Circuits:  #'s - K      L - Z


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