Honeywell Information Systems Italia

Gianpaolo Montorfano

Giuseppe Baroni

A multiple output switching power supply wherein the voltage at a main output which couples to a main secondary winding of a transformer is regulated by pulse width modulation of the current flowing in the primary winding of the transformer and wherein the voltage at an auxiliary output which couples to an auxiliary secondary winding of the transformer is regulated by pulse width modulation of the current flowing in the auxiliary winding. The pulse width modulation is performed in synchronism with a preestablished turn-on delay of the control switches which control current pulses in the primary winding as to the turn-on of the switches which control current pulses in the auxiliary winding. Besides avoiding the need for a filter between the auxiliary winding and the related control switch, this form of synchronization reduces switching power losses, current spikes and induced radio frequency emission.

Multiple outputs switching power supply

This invention pertains to a power FET control circuit which operates at higher switching frequencies for reducing the output voltage ripple. The control circuit provides two pulse control signals each shifted 180.degree. out of phase, each of such signals having a fixed frequency and a duty-cycle ratio which varies up to a maximum of 50%.

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Milan, Italy

Gianpaolo Montorfano