Low power, dual output AC/DC and DC/DC converter

An AC/DC and DC/DC converters comprising:

• a first input terminal to receive an input voltage;
• a first output terminal to supply a first output voltage, of a first sign;
• a second output terminal to supply a second output voltage, of a second sign opposite to said first sign;
• a controlled switch, connected between said first input terminal and a first intermediate node;
• a first component, connected between said first intermediate node and said first output terminal;
• and
• a second component, connected between said first intermediate node and a second intermediate node, wherein one of said first and second components comprises an inductive element and another of said first and second components comprises a unidirectional current conducting element, thereby forming a dual voltage generating circuit connected between said second intermediate node and said second output terminal, wherein the dual voltage generating circuit is coupled to use at least part of an energy supplied by the inductive element to generate the second output voltage during a recirculation phase.

A method for AC/DC and DC/DC conversion, comprising the steps of:

• supplying an input voltage to an output filter comprising an inductive component in a first operating step;
• filtering said input voltage to generate a first output voltage, of a first sign;
• interrupting said step of supplying an input voltage;
• causing a recirculation current to flow through said inductive element in a second operating step, said recirculation current being associated to a recirculation energy;
• acquiring, in said second operating step, at least part of said recirculation energy;
• and
• accumulating said part of the recirculation energy in a storage element to generate a second output voltage, of a second sign opposite to said first sign, directly from said part of the recirculation energy.

A converter, comprising:

• a switch having a control terminal, input terminal coupled to an input node of the converter, and an output terminal;
• a first device having a first terminal coupled to the output terminal of the switch, and a second terminal coupled to a first output node of the converter;
• a second device having a first terminal coupled to the first terminal of the first device, and a second terminal coupled to a second output node of the converter;
• an energy recovery device having a first terminal coupled to the second terminal of the second device and to the second output node of the converter, and a second terminal coupled to a reference line;
• a first charge storage device having a first terminal coupled to the second terminal of the first device, and a second terminal coupled to the reference line;
• a second charge storage device having a first terminal coupled to the second output node of the converter, and a second terminal coupled to the reference line;
• and
• a variable load control circuit having a first terminal coupled to the first output node of the converter, a second terminal coupled to the second output node of the converter, and a third terminal coupled to the reference line wherein the energy recovery device is coupled to use at least part of an inductor energy provided from either one of the first or second devices to generate an output voltage at the second output node of the converter during a recirculation phase.

An apparatus, comprising:

• a first input terminal to receive an input voltage;
• a first output terminal to supply a first output voltage, of a first sign;
• a second output terminal to supply a second output voltage, of a second sign opposite to said first sign;
• a controlled switch, connected between said first input terminal and a first intermediate node;
• a first component, connected between said first intermediate node and said first output terminal;
• a second component, connected between said first intermediate node and a reference potential line, one of said first and second components comprising an inductive element and another of said first and second components comprising a unidirectional current conduction element that is open in a conduction phase of said controlled switch and closed in a recirculation phase;
• and
• a dual voltage generator circuit, coupled to said inductive element and connected to said second output terminal, wherein said dual voltage generator circuit comprises a voltage generator having a Zener diode, connected to said inductive element in said recirculation phase, and a capacitive element, connected between said Zener diode and said second output terminal, wherein
• said dual voltage generator circuit is connected between said second component and said reference potential line, and forms, with said second component, a second intermediate node, wherein
• said Zener diode being connected between said second intermediate node and said reference potential line, and said capacitive element being connected between said reference potential line and said second output terminal, and wherein
• said first component comprises an inductor and said second component comprises a diode having a cathode connected to said first intermediate node, and an anode connected to said second intermediate node, and wherein said Zener diode has an anode connected to said second intermediate node and a cathode connected to said reference potential line.

An apparatus, comprising:

• a first input terminal to receive an input voltage;
• a first output terminal to supply a first output voltage, of a first sign;
• a second output terminal to supply a second output voltage, of a second sign opposite to said first sign;
• a controlled switch, connected between said first input terminal and a first intermediate node;
• a first component, connected between said first intermediate node and said first output terminal;
• a second component, connected between said first intermediate node and a reference potential line, one of said first and second components comprising an inductive element and another of said first and second components comprising a unidirectional current conduction element that is open in a conduction phase of said controlled switch and closed in a recirculation phase;
• and
• a dual voltage generator circuit, coupled to said inductive element and connected to said second output terminal, wherein said dual voltage generator circuit comprises a voltage generator having a Zener diode, connected to said inductive element in said recirculation phase, and a capacitive element, connected between said Zener diode and said second output terminal, wherein
• said dual voltage generator circuit is connected between said second component and said reference potential line, and forms, with said second component, a second intermediate node, wherein
• said Zener diode being connected between said second intermediate node and said reference potential line, and said capacitive element being connected between said reference potential line and said second output terminal, and wherein
• said first component comprises a diode having a cathode connected to said first intermediate node and an anode connected to said first output, and said second component comprises an inductor, and wherein said Zener diode has a cathode connected to said second intermediate node, and an anode connected to said reference potential line.

An apparatus, comprising:

• a switch having a control terminal, an input terminal coupled to an input node, and an output terminal;
• a first device having a first terminal coupled to the output terminal of the switch, and a second terminal coupled to a first output node;
• a second device having a first terminal coupled to the first terminal of the first device, and a second terminal coupled to a second output node;
• an energy recovery device having a first terminal coupled to the second terminal of the second device and to the second output node, and a second terminal coupled to a reference node;
• a first charge storage device having a first terminal coupled to the second terminal of the first device, and a second terminal coupled to the reference node;
• a second charge storage device having a first terminal coupled to the second output node, and a second terminal coupled to the reference node;
• and
• a variable load control circuit having a first terminal coupled to the first output node, a second terminal coupled to the second output node, and a third terminal coupled to the reference node, wherein the variable load control circuit includes:
• a first transistor having control, first and second terminals wherein its first terminal is coupled to the first output node, and its second terminal is coupled to the reference node;
• a second transistor having control, first and second terminals wherein its first terminal is coupled to the reference node, and its second terminal is coupled to the control terminal of the first transistor;
• a resistor having a first and second terminals wherein its first terminal is coupled to the first output node, and its second terminal is coupled to the control terminal of the first transistor;
• and
• a diode having first and second terminals wherein its first terminal is coupled to the control terminal of the second transistor, and its second terminal is coupled to the second output node.

An apparatus, comprising:

• a switch having a control terminal, an input terminal coupled to an input node, and an output terminal;
• a first device having a first terminal coupled to the output terminal of the switch, and a second terminal coupled to a first output node;
• a second device having a first terminal coupled to the first terminal of the first device, and a second terminal coupled to a second output node;
• an energy recovery device having a first terminal coupled to the second terminal of the second device and to the second output node, and a second terminal coupled to a reference node;
• a first charge storage device having a first terminal coupled to the second terminal of the first device, and a second terminal coupled to the reference node;
• a second charge storage device having a first terminal coupled to the second output node, and a second terminal coupled to the reference node;
• and
• a variable load control circuit having a first terminal coupled to the first output node, a second terminal coupled to the second output node, and a third terminal coupled to the reference node, wherein the variable load control circuit includes:
• a first transistor having control, first and second terminals wherein its first terminal is coupled to the first output node, and the second terminal is coupled to the reference node;
• a second transistor having control, first and second terminals wherein its first terminal is coupled to the reference node, and its second terminal is coupled to the control terminal of the first transistor;
• a first resistor having a first and second terminals wherein its first terminal is coupled to the first output node, and its second terminal is coupled to the control terminal of the first transistor;
• a second resistor having first and second terminals wherein its first terminal is coupled to the first output node, and its second terminal is coupled to the control terminal of the second transistor;
• and
• a diode having first and second terminals wherein its first terminal is coupled to the first output node, and its second terminal is coupled to the second output node.