Patent ID: 7336122

Claim:
A low power high side current monitor comprising: an input terminal; a load terminal; a current sensing element coupled to the input terminal and the load side terminal; an operational amplifier having a non-inverting input coupled to the load terminal; a first resistor coupled to the input terminal and an inverting input of the operational amplifier; a first transistor having a first terminal coupled to the first resistor and the inverting input of the operational amplifier and a second terminal coupled to an output of the operational amplifier; a second resistor coupled to a third terminal of the first transistor and to ground; and a second transistor having a first terminal coupled to the operational amplifier, a second terminal coupled to a voltage source, and a third terminal coupled to ground, wherein the second transistor is a single depletion mode PMOS transistor eliminating a need for a shunt regulator coupled to the operational amplifier and allowing the current monitor to operate at voltage levels from approximately 10 V to approximately 450V with minimal power dissipation.