Auxiliary power supply for switch-mode power supplies
A combined voltage regulator and snubber circuit generally has a voltage regulator device in parallel with the energy storage element of the snubber circuit operatively connectable in series with a leakage inductance current path; the leakage inductance being part of a magnetic component utilized in a switch-mode power supply having an input voltage source, controllable semiconductor switches, freewheeling semiconductor switches, feedback controller, reactive energy storage components and a load; the voltage regulator generally providing constant or variable voltage to the gate driver of the controllable semiconductor and/or feedback controller.
1. A switch-mode power supply comprising:
a transformer having at least two transformer inputs and a load output;
a plurality of converter cells connected to each other and configured to receive a voltage input, at least one of the plurality of converter cells comprising:
an input capacitor across the voltage input of the converter cell,
a snubber circuit comprising an energy storage device and a reverse-biased diode connected in series with the energy storage device, one of the transformer inputs connected in parallel with the snubber circuit,
a switch driven by a gate driver and controlling a current through the transformer, and
a voltage regulator having a plurality of voltage regulator inputs and a regulated output; the regulated output of the voltage regulator connects to voltage rails of a gate driver, a first voltage regulator input among the plurality of voltage regulator inputs for a first converter cell among the plurality of converter cells connects across the input capacitor, and a second voltage regulator input among the plurality of voltage regulator inputs for a second converter cell among the plurality of converter cells connects in parallel across the snubber circuit for of a prior converter cell among the plurality of converter cells;
a low-dropout regulator, and
an auxiliary winding on the at least one transformer input for providing an auxiliary voltage to the low-dropout regulator for providing power to the voltage regulator of the at least one of the converter cells.
2. The switch-mode power supply according to claim 1 , wherein the snubber circuit of the first converter cell comprises a resistive element in parallel with the energy storage device of the first converter cell.
3. The switch-mode power supply according to claim 1 , wherein the energy storage device comprises a capacitor.
4. The switch-mode power supply according to claim 1 , further comprising a load connected to the load output of the transformer.
5. The switch-mode power supply according to claim 4 , further comprising a feedback controller monitoring the connected load output of the transformer in comparison to a reference voltage.
6. The switch-mode power supply according to claim 5 , the feedback controller comprising a subtraction block, a compensator, and a multiple-output pulse-width modulator (MPWM) generator controlling the gate driver of each converter cell.
7. A switch-mode power supply comprising:
a transformer having at least two transformer inputs and a load output;
a converter cell, the converter cell comprising:
a converter cell input capacitor;
a snubber circuit comprising an energy storage device and a diode connected in series with the energy storage device, wherein a first transformer input among the at least two transformer inputs is connected in parallel with the snubber circuit;
a switch driven by a gate driver and controlling a current through the first transformer input; and
a voltage regulator having two inputs and a regulated output, the regulated output of the voltage regulator connected to the gate driver, one input of the voltage regulator connected in parallel across a snubber circuit of a previous converter cell, another input of the voltage regulator connected in parallel across the converter cell input capacitor;
a low-dropout regulator; and
an auxiliary winding on the at least one transformer input for providing an auxiliary voltage to the low-dropout regulator for providing power to the voltage regulator of a low-side converter cell voltage regulator.