TP2014 datasheet(14/21 Pages) 3PEAK

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TP2011/TP2012/TP2014

Ultra-Low Power 200nA, 1.6V, RRIO, Push-Pull Output Comparators

Typical Applications

IR Receiver

The TP2011 is an ideal candidate to be used as an infrared receiver shown in Figure 7. The infrared photo diode

creates a current relative to the amount of infrared light present. The current creates a voltage across RD. When this

voltage level cross the voltage applied by the voltage divider to the inverting input, the output transitions. Optional Ro

provides additional hysteresis for noise immunity.

VDD

TP2011

Figure 7. IR Receiver

Relaxation Oscillator

A relaxation oscillator using TP2011 is shown in Figure 8. Resistors R1 and R2 set the bias point at the comparator's

inverting input. The period of oscillator is set by the time constant of R4 and C1. The maximum frequency is limited by

the large signal propagation delay of the comparator. TP2011’s low propagation delay guarantees the high frequency

oscillation.

If the inverted input (VC1) is lower than the non-inverting input (VA), the output is high which charges C1 through R4 until

VC1 is equal to VA. The value of VA at this point is







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 VA1=2VDD /3, and VA2= VDD/3

The capacitor C1 now discharges through R4, and the voltage VC decreases till it is equal to VA2, at which point the

comparator switches again, bringing it back to the initial stage. The time period is equal to twice the time it takes to

discharge C1 from 2VDD/3 to VDD/3. Hence the frequency is:

ln2

Freq





TP2014 데이터시트(PDF) 14 Page - 3PEAK INC.