LPV7215MFSLASHNOPB datasheet(17/28 Pages) TI1

17 / 28 page

VA2 =

VCC (R2||R3)

R1 + (R2||R3)

VA1 =

VCC.R2

R2 + R1||R3

LPV7215

www.ti.com

SNOSAI6I – SEPTEMBER 2005 – REVISED APRIL 2013

Figure 40. IR Receiver

SQUARE WAVE GENERATOR

A typical application for a comparator is as a square wave oscillator. The circuit in Figure 41 generates a square

wave whose period is set by the RC time constant of the capacitor C1 and resistor R4. The maximum frequency

is limited by the large signal propagation delay of the comparator and by the capacitive loading at the output,

which limits the output slew rate.

Figure 41. Square Wave Oscillator

Consider the output of Figure 41 to be high to analyze the circuit. That implies that the inverted input (VC) is

lower than the non-inverting input (VA). This causes the C1 to be charged through R4, and the voltage VC

increases until it is equal to the non-inverting input. The value of VA at this point is

If R1 = R2 = R3 then VA1 = 2VCC/3

At this point the comparator switches pulling down the output to the negative rail. The value of VA at this point is

If R1 = R2 = R3 then VA2 = VCC/3

Submit Documentation Feedback

Product Folder Links: LPV7215

LPV7215MF/NOPB Datasheet(PDF) 17 Page - Texas Instruments