Patent ID: 7301288

Claim:
A buck power supply circuit for providing regulated current to a load, comprising: first and second switching devices connected in series in a half-bridge arrangement; first and second drivers for said first and second switching devices, respectively; an inductor connected at one end to a connection point between said first and second switching devices and at the other end providing an output voltage to said load; a feedback circuit connected to said load for providing a feedback voltage representative of output current in said load; a comparator connected to both of said first and second drivers through a logic network, providing hysteretic control of said drivers such that said output voltage to said load and thereby said load current is maintained between upper and lower limits, said feedback voltage being fed back to said comparator for establishing said upper limit of said output voltage; a reference voltage circuit connected to said comparator for establishing said lower limit of said output voltage; and an enable circuit connected to said comparator for receiving an enable signal, said enable circuit being operable for setting said output voltage at a selected value.