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High Accuracy, µPower, Over-Voltage Detector with Glitch Suppressor Using LTC1541 and LTC6994

An overvoltage detector which suppresses glitches is constructed from the LTC®1541 micropower op amp + comparator + voltage reference and LTC6994-1 TimerBlox® delay block/debouncer. In this circuit, the LTC1541 comparator detects power rail overvoltage conditions (including glitches). The built-in op amp inverts this signal and drives the LTC6994-1 which debounces the active low overvoltage signal to suppress glitches shorter than a given delay period. The delay period is set by a single resistor at the SET pin. The supply of LTC1541 and LTC6994-1 can be Vin or 2.5V - 5.5V voltage source. The accuracy of the circuit depends on the LTC1541 variations of the Vref, Vtrip, Vhysteresis and Vos voltages.

High Accuracy, µPower, Over-Voltage Detector with Glitch Suppressor

The LTC6994 is a programmable delay block with a range of 1µs to 33.6 seconds. The LTC6994 is part of the TimerBlox family of versatile silicon timing devices. A single resistor, RSET, programs an internal master oscillator frequency, setting the LTC6994’s time base. The input-to-output delay is determined by this master oscillator and an internal clock divider, NDIV, programmable to eight settings from 1 to 221. The output follows the input after delaying the rising and/or falling transitions. The LTC6994-1 will delay the rising or falling edge. For easy configuration of the LTC6994, download the TimerBlox Designer Tool. The LTC6994 is available in 6-pin ThinSOT and DFN packages.

The LTC1541/LTC1542 combine a micropower amplifier, comparator and bandgap reference in an 8-pin package. The part operates from a single 2.5V to 12.6V or dual ±1.25V to ±6.3V supply with a typical supply current of 5µA. Both the op amp and comparator feature a common mode input voltage range that extends from the negative supply to within 1.3V of the positive supply. The op amp output stage swings from rail-to-rail. The comparator's inverting input is internally connected to the reference output. The LTC1541is available in DFN, MSOP and SO packages.

 


Software

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.