help! Is this a peak current mode or some else control mode

[mastericke]

i am confused by this famous HV9910 diagram, is this a peak current control mode, why it don't need a ramp current conpensation!

is it a open loop?

 

[eem2am]

The ramp is provided by the current sense resistor.

its an on off controller, but is unusual because it has an oscillator. -therefore we cannot name it a hystetic controller.

but you can see staight away how it works......soon as current goes above reference, the switch turns off .