DC-DC converter with multiple outputs

A communication apparatus comprising:

• a plurality of modules, each module having a DC power supply input;
• a DC-DC converter comprising:
• a transformer having a primary winding and at least one secondary winding;
• a primary circuit comprising:
• an input that connects to a DC power supply source;
• the primary winding of the transformer;
• and
• a primary switch connected in series with the primary winding;
• a plurality of secondary circuits, wherein each of the plurality of secondary circuits comprises the secondary winding of the transformer or a respective winding of a plurality of secondary windings of the transformer, and wherein each of the plurality of secondary circuits includes an output stage for providing a DC power supply output, wherein at least one of the secondary circuits comprises a secondary switch;
• a digital controller that:
• monitors a respective output signal of each of the plurality of secondary circuits, wherein the digital controller receives one bit of feedback data for each respective output signal per monitoring period;
• generates, based on the monitored respective output signals and a respective digital representation a desired on-off duty cycle for each of the at least one secondary circuits, a respective secondary digital control signal for each of the at least one secondary switch and a primary digital control signal;
• and
• controls operation of the primary switch and the at least one secondary switch using control signals derived from the respective secondary digital control signals and the primary digital control signal;
• wherein the digital controller co-ordinates operation of the at least one secondary switch with the primary switch, such that the primary switch and the at least one secondary switch are switched on at the same time, or with a controlled offset;
• wherein the combined operation of the primary switch and the at least one secondary switch provides an on-off duty cycle matched to load demands of the at least one secondary switch, and wherein the controlled offset is selectable per said secondary circuit;
• and
• the DC-DC converter comprising a plurality of DC power supply outputs, wherein each DC power supply output of the DC-DC converter is connected to a respective DC power supply input of one of the plurality of modules.

A method of providing multiple DC outputs at a multiple output DC-DC converter comprising a transformer having a primary winding and at least one secondary winding, the method comprising:

• monitoring, by a digital controller, a respective output signal of each of a plurality of secondary circuits, wherein the digital controller receives one bit of feedback data for each respective output signal per monitoring period, wherein the multiple output DC-DC converter includes the plurality of secondary circuits, wherein each secondary circuit comprises the at least one secondary winding of the transformer or a respective winding of a plurality of secondary windings of the transformer, and an output stage for providing a DC power supply output;
• generating, based on the monitored respective output signals and a respective digital representation of a desired on-off duty cycle for each of the at least one secondary circuits, a respective secondary digital control signal for each of the at least one secondary switch and a primary digital control signal;
• controlling, by the digital controller, operation of a primary switch that is connected in series with the primary winding and at least one secondary switch using control signals derived from the respective secondary digital control signals and the primary digital control signal, wherein at least one of the plurality of secondary circuits comprises the at least one secondary switch, wherein the multiple output DC-DC converter also includes a primary circuit comprising an input for connecting to a DC power supply source, the primary winding of the transformer, and wherein each of the plurality of secondary circuits includes an output stage for providing a DC power supply output, wherein at least one of the secondary circuits comprises a secondary switch;
• wherein the controlling comprises co-ordinating operation of the at least one secondary switch with the primary switch, such that the primary switch and the at least one secondary switch are switched on at the same time, or with a controlled offset;
• and
• wherein the combined operation of the primary switch and the at least one secondary switch provides an on-off duty cycle matched to load demands of the at least one secondary switch, and wherein the controlled offset is selectable per said secondary circuit.

A non-transitory machine-readable storage medium storing instructions to co-ordinate control of a primary switch and at least one secondary switch of a multiple output DC-DC converter, the instructions that when executed by a DC-DC converter, cause the DC-DC converter to perform operations comprising:

• monitoring, by a digital controller, a respective output signal of each of a plurality of secondary circuits, wherein the digital controller receives one bit of feedback data for each respective output signal per monitoring period, wherein the multiple output DC-DC converter includes the plurality of secondary circuits, wherein each secondary circuit comprises the at least one secondary winding of a transformer or a respective winding of a plurality of secondary windings of the transformer, and wherein each of the plurality of secondary circuits includes an output stage for providing a DC power supply output, wherein at least one of the secondary circuits comprises a secondary switch;
• generating, based on the monitored respective output signals and a respective digital representation of a desired on-off duty cycle for each of the at least one secondary circuits, a respective secondary digital control signal for each of the at least one secondary switch and a primary digital control signal;
• controlling, by the digital controller, operation of the primary switch and the at least one secondary switch using control signals derived from the respective secondary digital control signal and the primary digital control signal, wherein at least one of the plurality of secondary circuits comprises the at least one secondary switch, wherein the multiple output DC-DC converter also includes a primary circuit comprising an input connected to a DC power supply source, the primary winding of the transformer, and the primary switch, wherein the primary switch is connected in series with the primary winding;
• wherein the controlling comprises a co-ordination operation of the at least one secondary switch with the primary switch, such that the primary switch and the at least one secondary switch are switched on at the same time, or with a controlled offset;
• and
• wherein the combined operation of the primary switch and the at least one secondary switch provides an on-off duty cycle matched to load demands of the at least one secondary switch, and wherein the controlled offset is selectable per said secondary circuit.