Converter regulation by controlled conduction overlap

A power supply circuit comprising a transformer including,

• a first transformer winding having first and second end terminals,
• first and second switching devices coupled to said first and second end terminals, respectively,
• signal monitoring means to monitor an output signal of the power supply,
• bias control means responsive to said signal monitoring means to periodically bias said first and second switching devices alternately nonconducting and simultaneously conducting for a controlled time duration each cycle of operation, said bias control means operating to render each of said first and second switching devices conducting during each cycle of operation for a time duration in excess of one-half of a time period of each cycle of operation and nonconducting during each half cycle of operation for a time duration less than one-half of a time period of each cycle of operation, and
• current limiting means to limit current flow in said first and second switching devices whereby the controlled time duration of simultaneously conducting intervals of said first and second switching devices controls the output signal of said power supply in order to maintain a predetermined regulated output signal magnitude to continuously energize a load at an output of said power supply.

A power supply circuit comprising,

• a power transformer including at least a primary winding having a center tap and two end terminals,
• first and second switching devices,
• an inductor connected to said center tap and having sufficient inductance to limit peak transient currents of said power transformer and said first and second switching devices,
• signal detection means coupled to monitor a signal reflective of the signal magnitude conducted by said first and second switching devices,
• conductive control means coupled to operate said first and second switching devices in a cyclic mode of operation and responsive to said signal detection means and operating to control the time duration of conductivity of the first and second switching devices during each cycle of operation, said conductive control means biasing each of said first and second switching devices in a conducting state during each cycle of operation for a time duration greater than one-half of the time period of each cycle of operation, and in a nonconducting state during each cycle of operation for a time duration less than one-half of the time period of each cycle of operation, whereby said first and second switching devices are alternately in a nonconduction state and simultaneously in a conduction state, the state of simultaneous conduction having a controlled time duration wherein the controlled time duration of simultaneous conduction is utilized to regulate the signal monitored by said signal detection means in order to maintain a predetermined regulated signal output to continuously energize a load at an output of said power supply

Power supply regulation means comprising:

• means to periodically bias first and second switching devices alternately nonconducting and simultaneously conducting;
• means to monitor a signal to be regulated whose magnitude is responsive to conduction in said first and second switching devices;
• said means to bias responsive to said means to monitor and including:
• means to establish a periodic cycle;
• means coupled to a reference signal to compare said signal to be regulated to said reference signal;
• and
• means to control an interval of simultaneous conduction of said first and second switching devices in response to said means to compare, said means to control operating to render each of said first and second switching devices conducting during each periodic cycle of operation for a time interval in excess of one-half the time period of each periodic cycle of operation and nonconducting during each periodic cycle of operation for a time interval less than one-half of the time period of each periodic cycle of operation in order to maintain a predetermined regulated output signal magnitude to continuously energize a load at an output of said power supply.