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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: December 25, 2017 01:47 PM

Circuits Designed by Dave Johnson, P.E.

1us LED Pulse Driver + Voltage to Frequency ConverterThis 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 . . . Hobby Circuit designed by David A. Johnson P.E.-March, 1999

200Mhz-400Mhz Voltage Controlled Oscillator (VCO)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. . . Circuit by David Johnson P.E.-March, 1999

40Khz Voltage to Frequency ConverterThis 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. . . Circuit by David A. Johnson P.E.-December, 2004

CMOS Schmitt Trigger IC Makes VCOBy 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. . . Circuit by Dave Johnson P.E.-December, 2002

ELC signal between 200Mhz-400MhzIf 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 . . . Hobby Circuit designed by David A. Johnson P.E.-March, 1999




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

0.01% Voltage to Frequency Converter -  The LTC6943 is a monolithic, charge-balanced, dual switched capacitor instrumentation building block.  A pair of switches alternately connects an external capacitor to an input voltage and then connects the charged capacitor across an output port.  The internal switches have a break-before-make action.  An internal clock is provided___ Linear Technology/Analog Devices App Note, Mar 31, 2010

0.02% V/F Converter Consumes Only 26 µA -  07/04/96 EDN-Design Ideas Figure 1  shows a voltage-to-frequency  (V/F] converter that produces a 0- to 10-kHz output for an input range of 0 to 5V.  Linearity of the converter is 0.02%, and gain drift is 60 ppm/8C.  The maximum current consumption is only 26 �A, 100 times lower than currently available units.  To understand the circuit's operation, assume__ Circuit Design by Jim Williams, Linear Technology, Milpitas, CA

10 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

1-Hz to 100-MHz VFC features 160-dB dynamic range -  09/01/05 EDN-Design Ideas Transform voltage to current over wide frequency, amplitude__ Circuit Design by Jim Williams, Linear Technology Corp

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

200Mhz-400Mhz Voltage Controlled Oscillator (VCO) -  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. . . Circuit by David Johnson P.E.-March, 1999

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. . . Circuit by David A. Johnson P.E.-December, 2004

8 pin µC forms one-chip Programmable VCO -  09/24/98 EDN-Design Ideas NOTE :  multiple circuits, scoll to this one.  The circuit in Figure 1 uses a Microchip 8-pin µC  (PIC12C671]as a voltage-controlled oscillator  (VCO].  Because  PIC12C671 has an internal 4-MHz oscillator, four-channel 8-bit A/D converters, and built-in power-reset circuitry, you need no external components to configure  VCO.  The µC reads two analog inputs through AN0 and AN1__ Circuit Design by Yongping Xia, Teldata Inc, Los Angeles, CA

AN14Designs for High Performance Voltage-to-Frequency Converters -  Linear Technology AN14 __ Designed by Jim WilliamsMar 1st, 1986

AN15Circuitry for Single Cell Operation -  Linear Technology AN15 __ Designed by Jim WilliamsNov 1st, 1985

Build a PIC Controlled DDS VFO 0 to 6 MHz -  This is NOT meant as a detailed building instruction for a DDS VFO.  It is only a few fragments from my experimental work in the shack.  This is "as is" information.  It may contain errors.   However, my own prototype works very well. __ Designed by Johan Bodin, SM6LKM

Circuit 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 designed to be driven from current-steering DACs to enable a modulated voltage source to control the devices__ Circuit Design by Ali Mehmed, Nokia UK Ltd, Southwood, UK

Circuitry for Single Cell Operation -  Linear Technology AN15 __ Designed by Jim WilliamsNov 1st, 1985

CMOS inverter VCO tunes octave to UHF -  11/19/98 EDN-Design Ideas NOTE :  File contain several designs.  Scroll to find this one.  A robust and versatile vco provIdeas a stable output to 300 MHz (Figure 1).  The circuit's simplicity, unconditional stability, and consistent high-drive capability over an octave make the oscillator ideal for many applications, such as synthesized sources, local oscillators, and transmitters.  The AHC logic family (Texas Instruments, www.ti.com) makes the circuit's performance possible.  AHC is a relatively new line of CMOS logic whose high speeds and good noise performance allow oscillator operation into regions in which bipolar-junction-transistor and FET designs prevail.__ Circuit Design by Shawn Stafford, AM Communications Inc, Quakertown, PA  

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. . . Circuit by Dave Johnson P.E.-December, 2002

Design Formulas 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

Designs for High Frequency Voltage-To-Frequency Converters -  AN14 A variety of high performance V/F circuits is presented.  Included are a 1Hz to 100MHz design, a quartz-stabilized type and a 0.0007) % linear unit.  Other circuits feature 1.5V operation, sine wave output an nonlinear transfer functions.  A separate section examines the trade-offs and advantages of various approaches to V/F conversion.  __ Linear Technology/Analog Devices

Designs for High Performance Voltage-to-Frequency Converters -  Linear Technology AN14 __ Designed by Jim WilliamsMar 1st, 1986

DPP adds versatility to VFC -  14-Nov-02 EDN-Design Ideas The basic VFC(voltage-to-frequency converter] in Figure 1 comprises an integrator(IC1] and a Schmitt-trigger circuit(IC2].  The integrator converts the dc input voltage, VIN , to a linear voltage ramp, and the Schmitt trigger sets the limits of the integrator's output voltage.  Feedback around both circuits provIdeas the condition for oscillation__ Circuit Design by Chuck Wojslaw, Catalyst Semiconductor, Sunnyvale, CA

Dramatically Increase the Frequency Range of RC-Based Voltage-Controlled Oscillators -  09/21/12 EDN-Design Ideas Add a varactor to a voltage-controlled oscillator to increase the tuning range.  A typical voltage-to-frequency converter—also known as a VCO (voltage-controlled oscillator)—IC has a simple linear tuning characteristic relating input voltage to output frequency.  It is usually of the form F=kV/RC, where RC is the time constant of the associated timing resistor and capacitor.  The output frequency range of these parts varies, but few, if any, tune over the entire range with one set of RC timing components.  If you change the timing ratio as the input voltage changes, however, you can magnify the tuning range to take advantage of nearly the entire frequency range in one implementation.  __ Circuit Design by Shawn Stafford, Pittsburgh, PA

Eight-pin µC forms one-chip programmable VCO -  09/24/98 EDN-Design Ideas NOTE :  multiple circuits, scoll to this one.  The circuit in Figure 1 uses a Microchip 8-pin µC  (PIC12C671]as a voltage-controlled oscillator  (VCO].  Because  PIC12C671 has an internal 4-MHz oscillator, four-channel 8-bit A/D converters, and built-in power-reset circuitry, you need no external components to configure  VCO.  The µC reads two analog inputs through AN0 and AN1__ Circuit Design by Yongping Xia, Teldata Inc, Los Angeles, CA

ELC signal between 200Mhz-400Mhz -  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 . . . Hobby Circuit designed by David A. Johnson P.E.-March, 1999

Exponential Voltage-to-Frequency Converter for Music Synthesizers -  Logarithmic characteristic of BJT is used to provide an exponential control effect on V/F function.  By using a multiple transistor array, a thermal stabilization circuit assures a constant operating point for the log function.  __ Linear Technology/Analog Devices App Note, Jun 21, 2011

Field Effect Transistor as a Voltage Controlled Resistor  -  An FET can be used as a voltage controlled resistor (vcr) where the resistance between the drain and source is controlled by the gate-source voltage,  __

Hippasian nonlinear VFC stretches dynamic range -  19-Feb-09 EDN-Design Ideas A voltage-to-frequency converter uses square roots to extend dynamic range by orders of magnitude__ Circuit Design by W Stephen Woodward, Chapel Hill, NC

Inexpensive VFC Features Good Linearity & Dynamic Range -  12/01/11  EDN-Design Ideas A voltage to frequency converter circuit builds on the work of two analog greats.  __ Circuit Design by Jordan Dimitrov, Toronto, ON, Canada

Inverters form three-phase VCO -  08/04/01 EDN-Design Ideas You sometimes need an inexpensive VCO that can produce evenly spaced three-phase outputs over a wide frequency range.  You could use tracking all-phase filters with only one oscillator, but this technique is difficult to implement and offers limited range.  Other methods, such as using a DSP, are feasible, but they're complex and expensive__ Circuit Design by Al Dutcher, AL Labs, West Deptford, NJ

Inverting latches make Simple Circuit VCO -  06/19/97 EDN-Design Ideas The output frequency of the simple VCO in Figure 1, which is synthesized from inverting latch stages, is tunable to an integer multiple of the input frequency by selecting which output phases feed back to the input multiplexer.  The circuit__ Circuit Design by Ed Nielson, VLSI Technology, Sophia Antipolis, France


Circuits:  #'s - K      L - Z


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