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Oscillators:  Voltage Controlled (VCO)
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Oscillator Circuits -- Main Page

 

Last Updated: October 09, 2017 03:39 PM

Circuits Designed by Dave Johnson, P.E. :

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 Dave 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 Johnson P.E.-December, 2004

AIR Transparency Monitor, Xenon Flash Receiver - I designed this receiver 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. . . Circuit by David A. Johnson P.E.-June, 2000

AIR Transparency Monitor-Pg2 - This is Page 2 of the receiver circuit AIR TRANSPARENCY MONITOR, XENON FLASH RECEIVER. . . Circuit by Dave Johnson P.E.-June, 2000

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


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

"Chloroplast" - Type 1 (Voltage Controlled) Solar Engine -  These designs are based on the Motorola MC34164-* micro power undervoltage sensing ICs.  They're pretty efficient, work at higher voltages than most solar engines, and can provide voltages for other logic circuits (say, a microprocessor).  This page hosts the original Chloroplast by Craig Maynard, as well as some Chloroplast variants by Wilf Rigter. __ Designed by Wilf Rigter

"MicroPower" - Type 1 (Voltage Controlled) Solar Engine -  Ken Huntington's fairly complex, but very efficient "micropower" solar engine design.  No 1381s or ICs needed. __ Designed by Ken Huntington

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

1381-based - Type 1 (Voltage Controlled) Solar Engine -  Two simple solar engine designs using a 1381* voltage discriminator. __ Designed by Wilf Rigter

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 Dave Johnson P.E.-March, 1999

300 to 500 Mhz VCO -  The datasheet says this VCO covers 300 to 500 Mhz,  in this test setup with one coil it covers 350 to 475 Mhz with the controlling voltage.  The output should be about -10dBm, but it's -20dBm.  The stability and sideband noise was not good enough for my HAM radio project, sorry.   But I'm sure it will be perfect to be used with a PLL. __ Designed by Thomas Scherrer OZ2CPU

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 Johnson P.E.-December, 2004

555 VCO -  By adjusting the voltage on pin 5, (the CONTROL pin) the frequency of the oscillator can be adjusted quite considerably.  __ 555-Timer

8-pin µC forms one-chip programmable VCO -  09/24/98 EDN-Design Ideas - NOTE :  multiple circuits, scroll 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

90 MHz voltage controlled oscillator for FM Band  -  Notice the abundance of 2N4401, 1 k resistors and 330 Ohm resistors? That's because I have a lot of each.  2N4401's weren't intended to be used as varactors, but they work just fine.  Don't be afraid to experiment with the parts you have on hand.  Build this on a ground plane board.  Layout is important.   __ Designed by Dick Cappels

AIR Transparency Monitor, Xenon Flash Receiver -  I designed this receiver 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. . . Circuit by David A. Johnson P.E.-June, 2000

AIR Transparency Monitor-Pg2 -  This is Page 2 of the receiver circuit AIR TRANSPARENCY MONITOR, XENON FLASH RECEIVER. . . Circuit by Dave Johnson P.E.-June, 2000

AN-45-001  Automated load measurement of VCO's -  AN-450-01 App Note__ MiniCircuits.com

AN-45-002  Line Stretchers Ease VCO Load-Pull Testing -  AN-450-02 App Note__ MiniCircuits.com

AN-95-003  Glossary of VCO terms -  AN-95-003 Application Note__ MiniCircuits.com

AN-95-004  Wide Modulation Bandwidth Measurements -  AN-95-004 Application Note__ MiniCircuits.com

AN-95-005  How VCO Parameters Affect Each Other -  AN-95-005 Application Note__ MiniCircuits.com

AN-95-006  Optimizing VCO/PLL Evaluations & PLL Synthesizer Designs -  AN-95-006 Application Note__ MiniCircuits.com

Analog Voltage Controls Digital Potentiometer -  03/20/08  EDN-Design Ideas - A microcontroller with an internal ADC controls a digital potentiometer via an I2C interface __ Circuit Design by Hrishikesh Shinde, Maxim Integrated Products, Dallas, TX

Analyze LED characteristics with PSpice -  01/18/01 EDN-Design Ideas - Recent advances in LED technology have led to LEDs' widespread use in outdoor-signal applications, such as in traffic and railroad signals.  A typical LED signal consists of an LED array and a power supply.  When a low-voltage power supply is desirable or mandatory, series/parallel combinations of LEDs become inevitable __ Circuit Design by Sam Mollet, GE Harris Harmon Railway Technology, Grain Valley, MO

Arduino LFO Waveform Generator -  This project uses an Arduino microprocessor and a DAC0808 8 bit parallel DAC to produce arbitrary low frequency oscillator (LFO) waveforms.  These waveforms are useful for driving a tremolo/vibrato circuit in a guitar amplifier such as the Lil Tiger or a phaser effect such as the Liquidator __ Designed by G. Forrest Cook

Arduino LFO Waveform Generator V2 -  This project uses an Arduino microprocessor and a MAX522 8 bit serial DAC to produce arbitrary low frequency oscillator (LFO) waveforms.  These waveforms are useful for driving a tremolo/vibrato circuit in a guitar amplifier such as the Lil Tiger or the Hammonator 2RVT.  This is a second generation version of this project, see the first version for reference. __ Designed by G. Forrest Cook

Automated load measurement of VCO's -  AN-450-01 App Note__ MiniCircuits.com

Behavioral Spice Model Emulates VCO -  07/06/95 EDN-Design Ideas - A behavioral model treats a circuit as a black box, which you can describe using an equation or table.  Listing 1 is a Microsemi PSpice behavioral model that simulates the operation of a voltage-controlled oscillator (VCO].  The output signal of a VCO is VO= (2ăfOt], where A is the amplitude, t is the time variable __ Circuit Design by Dr. Bashir Al-Hashimi, Staffordshire University, Stafford, UK

Characterizing & minimizing VCO phase noise -  Application Note__ MiniCircuits.com

Circuit Biases VCOS for Cable and -  11/20/97 EDN-Design Ideas - PLLs are useful in a variety of applications, most notably cable and TV tuners. __ Circuit Design by Ravindra Ambatipudi, National Semiconductor Corp, Santa Clara, CA

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 provide as 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

Constant Temperature -  This circuit is a generic low power temperature controller that can be used for stabilizing temperature sensitive electronic circuits.  It was built to stabilize a radio frequency VFO (Variable Frequency Oscillator) for ham radio applications.  The circuit has also been used to lower the drift of a Ramsey FM10a micropower FM transmitter __ Designed by G. Forrest Cook

DAC & Op Amp provide variable-control voltage -  12/06/01 EDN-Design Ideas - Early DACs contained standard R-2R ladder networks, and produced a negative output voltage.  These early DACs, such as the MAX7837/7847 and the MAX523, require both positive and negative supply rails to accommodate their negative output.  With the transition to single-supply ICs, however, many modern DACs operate with a single supply rail and an inverted R-2R ladder network __ Circuit Design by Chad Olson, Maxim Integrated Products, Sunnyvale, CA

Design features of a synthesizer using Mini-Circuits VCOs -  Application Note__ MiniCircuits.com

Designing VCOs & Buffers using the UPA family of Dual Transistors 3/99  -  App Note  Doc #927__ California Eastern Laboratories

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 provide as 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

DSSSE - Type 1 (Voltage Controlled) Solar Engine -  If you had time to experiment with the ALF type SE circuit you may have discovered some of its shortcomings with regard to a Power Smart Head adaptation. The problem is that HCMOS gates are power hungry when used as SE voltage comparators when the analog input voltage is near the CMOS switching threshold. If an HCMOS gate is used without sampling, the chip supply current can be as high as 70mA with the comparator input voltage near the trigger threshold (Vcc / 2). __ Designed by Wilf Rigter


Voltage Controlled Oscillators:   #'s - D      E - S       T - Z

 


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