Patent ID: 9444345
Filing Date: 2016-09-13
CPC Classification: H02M,Y02B

Claim Text:
1. A switch mode power supply, comprising: a transformer having a winding; a power switch responsive to a switch mode control signal and coupled to said transformer for producing periodic voltage pulses in said transformer such that, in a normal load mode of operation, switching operation in said power switch is uninterrupted; a first rectifier coupled to said transformer for rectifying said periodic voltage pulses to produce a first rectified voltage that is coupled to a load circuit, said first rectified voltage producing a load current in said load circuit; a second rectifier coupled to said transformer for rectifying periodic voltage pulses in said winding to produce second rectified voltage pulses at an output of said second rectifier such that an average value of said second rectified voltage pulses at said second rectifier output is indicative of said load current in the normal load mode of operation; a control circuit responsive to said first rectified voltage for generating said switch mode control signal that is coupled to said power switch to regulate said first rectified voltage; a sensor coupled to said second rectifier output for sensing said average value of said second rectified voltage pulses to generate an output signal; and a comparator coupled to said sensor and responsive to said sensor output signal, the comparator further coupled to said power switch for cyclically disabling said power switch from producing said periodic voltage pulses in said transformer when said magnitude of said sensor output signal is less than a threshold of the comparator.