PWM controller for an electrical load

Claim 1

A pulse width modulation controller comprising: first, second and third comparators having respective inverting and non-inverting inputs and an output thereof, said inverting input of said first comparator and said non-inverting input of said second comparator defining first and second input voltage lines respectively, said non-inverting input of said first comparator being coupled to said inverting inputs of said second and third comparators defining a current node and said non-inverting input of said third comparator being coupled to an offset voltage source with respect to a reference voltage line; latching means having set, reset and output terminals thereof, said set and reset terminals being coupled to said output of said first and third comparators respectively. first and second switching means having respective first and second current carrying electrodes and a control electrode thereof, said latching means output terminal and said output of said second comparator being coupled to said control electrodes of said first and second switching means respectively, each having said first current carrying electrodes thereof coupled to said reference voltage line and said second current carrying electrodes coupled to said current node and an output voltage line respectively; a current source coupling a supply voltage line to said current node; and a capacitor coupling said current node to said reference voltage line.