Switch-mode power supplies including three-level LLC circuits for low line and high line operation

A method of operating a switch-mode power supply including a pair of input terminals, a pair of output terminals, at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals, and at least two PFC circuit switches coupled in a voltage doubler power factor correction (PFC) circuit coupled between the pair of input terminals and the three-level LLC circuit, the method comprising:

• operating the at least two PFC circuit switches of the voltage doubler PFC circuit to increase a voltage input received at the pair of input terminals and supply the increased voltage to the three-level LLC circuit;
• and
• operating the at least four switches of the three-level LLC circuit to supply a DC voltage output to the pair of output terminals;
• wherein operating the at least two PFC switches includes:
• supplying a first PFC voltage output to the three-level LLC circuit arrangement when the voltage input is within a specified low line voltage range;
• and
• supplying a second PFC voltage output to the three-level LLC circuit arrangement when the voltage input is within a specified high line voltage range;
• and
• wherein:
• the power supply includes a first reference and a second reference;
• the method further comprises sensing the voltage input and determining whether the sensed voltage input is within the specified low line voltage range or the specified high line voltage range;
• and
• operating the at least two PFC circuit switches includes operating the at least two PFC circuit switches according to a first voltage reference when the voltage input is within the specified low line voltage range and operating the at least two PFC circuit switches according to a second voltage reference when the voltage input is within the specified high line voltage range.

A method of operating a switch-mode power supply including a pair of input terminals, a pair of output terminals, at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals, and at least two PFC circuit switches coupled in a voltage doubler power factor correction (PFC) circuit coupled between the pair of input terminals and the three-level LLC circuit, the method comprising:

• operating the at least two PFC circuit switches of the voltage doubler PFC circuit to increase a voltage input received at the pair of input terminals and supply the increased voltage to the three-level LLC circuit;
• and
• operating the at least four switches of the three-level LLC circuit to supply a DC voltage output to the pair of output terminals;
• wherein operating the at least two PFC switches includes:
• supplying a first PFC voltage output to the three-level LLC circuit arrangement when the voltage input is within a specified low line voltage range;
• and
• supplying a second PFC voltage output to the three-level LLC circuit arrangement when the voltage input is within a specified high line voltage range;
• and
• wherein operating the at least four switches of the three-level LLC circuit includes:
• operating the at least four switches of the three-level LLC circuit arrangement in a first mode of operation when the voltage input is within the specified low line voltage range;
• and
• operating the at least four switches of the three-level LLC circuit arrangement in a second mode of operation when the voltage input is within the specified high line voltage range.

A switch-mode power supply, comprising:

• a pair of input terminals for receiving an alternating current (AC) or direct current (DC) voltage input from an input power source;
• a pair of output terminals for supplying a direct current (DC) voltage output to a load;
• at least four switches coupled in a three-level LLC circuit arrangement between the pair of input terminals and the pair of output terminals;
• and
• a voltage doubler power factor correction (PFC) circuit coupled between the pair of input terminals and the three-level LLC circuit;
• and
• a control circuit coupled to operate the at least four switches to supply the DC voltage output to the load;
• and
• wherein:
• the voltage doubler PFC circuit is configured to supply a first PFC voltage output to the three-level LLC circuit arrangement when the voltage input is within a specified low line voltage range;
• the voltage doubler PFC circuit is configured to supply a second PFC voltage output to the three-level LLC circuit arrangement when the voltage input is within a specified high line voltage range;
• the second PFC voltage output is greater than the first PFC voltage output;
• the specified low line voltage range is different than the specified high line voltage range;
• the voltage doubler PFC circuit includes at least two PFC circuit switches, the control circuit includes a first voltage reference and a second voltage reference, the first voltage reference is different than the second voltage reference, and the control circuit is configured to:
• receive a sensed input voltage and determine whether the sensed input voltage is within the specified low line voltage range or the specified high line voltage range;
• operate the at least two PFC circuit switches according to the first voltage reference when the voltage input is within the specified low line voltage range;
• and
• operate the at least two PFC circuit switches according to the second voltage reference when the voltage input is within the specified high line voltage range.