Low voltage LED drive from 120VAC line

A method for converting line voltage to provide an independent power supply source, comprising the steps of:

• rectifying and filtering A.C. line voltage if required, to provide a DC voltage source;
• connecting the DC voltage source to the primary winding of a first transformer;
• tapping the DC voltage source through a dropping resistor so as to charge a capacitor and provide a start-up low voltage power supply for operating a pulse width modulating integrated circuit;
• pulse modulating the start-up low voltage at a frequency above 1,000 Hz;
• driving an on/off switching device in the first transformer primary winding at the frequency, so as to drive the first transformer;
• supplanting the start-up voltage power supply with power taken from the first transformer secondary winding;
• and
• providing an independent supply source of up to 36VDC from the first transformer output.

A method according to 10, and further comprising the steps of:

• connecting the DC voltage source to the primary winding of a second transformer;
• providing pulse width modulating and switching circuits powered by the independent power supply source for the second transformer input circuit,
• switching the DC voltage to the second transformer “Off” and “On”, in a selected pulse width modulated mode of from 0% to more than 60% “on-time”, at a frequency rate above 1,000 Hz;
• connecting the second transformer output to a power dissipating load;
• filtering the second transformer output through a “buck” stage to permit pulse width control in excess of 60% “on-time”;
• and
• controlling second transformer output to the power dissipating load at any selected level from zero to maximum by varying the “on-time” percentage from 0% to above 60% at the frequency rate.

A method for converting line voltage to provide an independent power supply source, comprising the steps of:

• rectifying the AC line voltage to provide a DC voltage power source;
• tapping the AC line voltage source to charge a capacitor so as to provide a AC low voltage source;
• rectifying the AC low voltage to provide DC low voltage;
• paralleling the DC low voltage across a zener diode and a capacitor selected to regulate the DC voltage level as necessary for operating integrated circuits;
• connecting the DC voltage power source to the primary winding of a transformer;
• providing pulse width modulating and switching circuits powered by the independent supply source;,
• switching the DC voltage connected to the primary of the transformer “Off” and “On”, in a selected pulse width modulated mode of from 0% to more than 60% “on-time”, at a frequency rate above 1,000 Hz;
• connecting the transformer output to a power dissipating load;
• filtering the transformer output through a “buck” stage to permit pulse width control in excess of 60% “on-time”;
• and
• controlling transformer output to the power dissipating load at any selected level from zero to maximum by varying the “on-time” percentage from 0% to above 60% at the frequency rate.