US Patent 7872372 Power circuit

A device for delivering a desired power to a load comprises a voltage detection module, a comparator module, a power regulation module, and a current source. The voltage detection module generates a voltage signal based on a voltage across the load. The comparator module compares a first value based on the voltage signal to a power reference signal. The power reference signal is based on the desired power. The power regulation module generates a digital code based on the comparison. The current source provides a current to the load. The current is based on a predetermined constant current and a second value. The second value is based on the digital code.