[SOLVED] Understanding function of circuit

[kiwi101]

Hey guys, the following circuit was attached to a boost convertor and is used to provide a 2 MHz frequency square waves to the Boost Convertor. My issue is when looking at the circuit, I realized I don't fundamentally understand how it achieves that.
1) So for example I understand that the second Op-amp is an integrator (since it has a capacitor in feedback) and integrates whatever signal comes to it, but the signal at the point after second opamp is triangle waveform and signal at point "out" is a square waveform. Why? How does this third op-amp further integrate the triangle waveform?
2)Why is their a current source between the inverting and non-inverting terminal of the first two OP-Amps?
3) What is the point of the feedback resistor of 47K between the first two op-amps?

Please help me to understand this circuit so I can begin to read functionality of circuits.
Thanks

 

[FvM]

1. The third OP is acting as a comparator (the integral of a triangle would be hardly a square wave, by the way).
2. It's a voltage rather than a current source.
3. The first OP forms a schmitt-trigger. The overall feedback is negative, the combination with the schmitt-trigger makes an astable oscillator.

 

[kiwi101]

Thanks guys!