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Comparator Detects position of peaks & valleys in a waveform
05/24/07 EDN-Design Ideas Simple comparator circuit locates peaks and valleys of a waveform in time__ Circuit Design by Marián Štofka, Slovak University of Technology, Bratislava, Slovakia
Comparator Directly Controls Power-MOSFET Gate
11/03/11 EDN-Design Ideas Circuit switching point is independent of unregulated FET voltage. It is common practice to power a MOSFET with a comparator and with an unregulated voltage and to power the comparator driving it from a regulated one (Figure 1). Many loads are insensitive to driving voltage, so it would be a waste of money and power to use a regulated supply to drive the FET. It is also common practice to add resistors R1 and R2 to the comparator to put hysteresis in the operation, making the circuit less susceptible to noise, especially with slowly changing signals.__ Circuit Design by Peter Demchenko, Vilnius, Lithuania
Comparator Exhibits Temporary Hysteresis
10/14/00 EDN-Design Ideas Noise and interference can be significant problems when you transform a signal from a sine wave to a square wave. When the sine wave crosses the reference level, a comparator can exhibit uncertainty, or jitter. A common method to eliminate comparator uncertainty is to introduce positive feedback by using a resistor divider at the comparator's output. The drawback of this method is that the resulting hysteresis produces an offset that's a function of the state of the comparator.__ Circuit Design by Victor Axenenko, CSRI, St Petersburg, Russia
Comparator has Independent Trip Voltages
07/22/99 EDN-Design Ideas For an inverting amplifier with hysteresis, resistors R A , R B , and R F determine the crossover voltages (Figure 1). Unfortunately, using three resistors to set the upper and lower trip voltages creates a dependence between the two trip voltages: It's impossible to set one voltage without affecting the other.__ Circuit Design by Gregory Billiard
Comparator has programmable limits
EDN-Design Ideas July 8, 1998 This circuit combines a dual buffered D/A converter and dual four-input comparator to configure a comparator circuit with a digitally programmable window center and width.__ Circuit Design by Michele Frantisek, Brno, Czech RepublicJuly 8, 1998
Comparator Improves Regulator's Efficiency
04/28/94 EDN-Design Ideas The UC384X family of current-mode PWM regulators requires a current shunt or some other component to develop a voltage proportional to the output current. This shunt must develop a 1V signal at full load. For off-line supplies, the 1V requirement is not hard to meet because of the high voltage on the supply's dc bus. However, if you want__ Circuit Design by Cristophe Basso, European Synchrotron Radiation Facility, Grenoble, France
Comparator provides stable hysteresis
03/18/99 EDN-Design Ideas Unless a voltage-comparator circuitis sampling an extremely clean signal, the comparator always requires some hysteresis. Traditional comparator circuits obtain the required hysteresis by using positive feedback derived from the ratio of two resistors. The voltage at the noninverting input is the superposition of a fraction of the input and output voltages, each divided by its respective resistor ratio. With an inverting comparator, the noninverting input usually connects to a voltage reference with reasonably low impedance, and you can choose the hysteresis-setting resistors without concern for loading.__ Circuit Design by Fernando Garcia, Lucent Technologies, Brownsville, TX
Comparator uses signal-dependent hysteresis
EDN-Design Ideas March 26, 1998 [ NOTE
: File has multiple design, scroll for this one.] Sometimes, you need to distinguish between two voltages, using some hysteresis in the decision. When the levels of the compared signals vary over a wide range (for example, a few orders of magnitude), the hysteresis width should vary similarly to ensure a constant ratio between hysteresis width and signal level__ Circuit Design by P Krehlik and L Sliwczynski, University of Mining and Metallurgy, Krakow, Poland
Comparators form 3 to 5V or 5 to 3V translator/transceive
09/02/96 EDN-Design Ideas In many recent systems, you often need to interface 3V signals with higher voltages within the system. In some cases, it's necessary to interconnect 3 and 5V open-collector transceivers. Figure 1 shows one example, in which multiple multidrop communications devices interconnect. In systems where no control lines are available for interfacing, the__ Circuit Design by Robert Hanrahan, National Semiconductor, Woodcliff Lake, NJ
Cooling Fan Thermostat (12v)
This circuit will turn on a 12v DC powered cooling fan when the air temperature reaches a certain high temperature and will keep the fan turned on until the temperature drops below a second lower level. Both the high and low temperatures are both adjustable . . . Hobby Circuit designed by Dave Johnson P.E.-February, 2011
Current Indicator for Battery Chargers
This circuit was inspired by a company needing a DC current indicator light which was small enough to be molded into a medium size 28v rechargeable battery assembly. They specified that they wanted the circuit to turn on the LED indicator light with 500ma or more of battery charge current. . . Circuit by David A. Johnson P.E.-January, 2011
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