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
Ten-Cent Charge Pump Provides LCD Bias
Designing a product for low-power battery operation usually means maximizing the battery life by operating the circuit on as low of a supply voltage as possible. This design used a custom LCD but, due to the number of display segments (160) , a __
Touch Switch Exciter
If you have hundreds of touch switches that need an excitation signal, then this circuit is what you need. Its 20KHz 20v peak to peak output signal can supply up to 3 watts of touch switch excitation power . . . Hobby Circuit designed by David Johnson P.E.-February, 2002
Tripler converts 5 to 15V
08/17/00 EDN-Design Ideas By configuring a charge-pump voltage doubler as a tripler, you can readily derive 15V from 5V(Figure 1). A 15V rail is useful for powering op amps, LCD-bias circuits and other low-current applications. The connections shown configure the IC1 voltage doubler as a tripler. The no-load output voltage of the circuit is approximately 3VIN2VD,__ Circuit Design by Ken Yang, Maxim Integrated Products, Sunnyvale, CA
Ultra Pure 125kHz Sine Wave Signal Source
For some RFID systems operating at 125KHz, a very low distortion signal source reference is needed. The circuit shown on this page produces a 10-volt peak-to-peak signal into a 50-ohm load, with a distortion of only 0.01%. . . Circuit by David A. Johnson P.E.-February, 2002
Very Low Power Astable Multivibrator
This classic circuit draws only 200 nanoamps from a 1.5v supply. . . Circuit by Dave Johnson P.E.-June, 2000
Very Low Power Gated Crystal Oscillator
The circuit gates the output of a continuously operating 32KHz crystal oscillator to the input of a C-MOS buffer when clock pulses are needed. The technique gets around the problem of a slow starting crystal oscillator by keeping the oscillator going and switching on a transistor power stage only as needed. . . Circuit by David Johnson P.E.-June, 2000
Voltage Boost to Series Regulator provided by Capacitor - This circuit adds some capacitors and diodes to a traditional transformer type series regulator circuit to extend the normal operating range. It can insure regulation during low line voltage conditions or it can squeeze a few more watts out of a plug-in-the-wall power adapter power supply . . . Hobby Circuit designed by Dave Johnson P.E.-January, 1998
Voltage Inverter II
This simple and inexpensive circuit can produce a dual (positive and negative) voltage from a single supply input. It is therefore extremely useful for powering opamp and other circuits that require a dual voltage from a single battery. The circuit will operate at an input voltage from around 5V to 20V and produce a output from +-2.5V to +-10V. __ Contact: IQ Technologies |