High efficiency standby power generation

A system to provide standby power, the system comprising:

• a switched-mode power supply comprising a primary stage and a standby stage, the primary stage and the standby stage sharing one or more switches, the primary stage comprising one or more switched-mode power supply stages;
• a switching module that adjusts an on-time and an off-time of the one or more switches for the primary stage and the standby stage of the switched-mode power supply, the switching module adjusting the on-time and the off-time based on a feedback signal;
• a shutoff module that, in response to a standby signal having a standby state, interrupts electric power flowing to the primary stage and, in response to the standby signal having an on state, allows electric power to flow to the primary stage;
• and
• a feedback module that provides the feedback signal to the switching module, the feedback module basing the feedback signal on an output of the primary stage in response to the standby signal having the on state and the feedback module basing the feedback signal on an output of the standby stage in response to the standby signal having the standby state.

A method to provide standby power, the method comprising:

• adjusting an on-time and an off-time of one or more switches for a primary stage and a standby stage of a switched-mode power supply based on a feedback signal, the primary stage and the standby stage sharing the one or more switches, the primary stage comprising one or more switched-mode power supply stages;
• interrupting electric power flowing to the primary stage in response to a standby signal having a standby state;
• allowing electric power to flow to the primary stage in response to the standby signal having an on state;
• basing the feedback signal on an output of the primary stage in response to the standby signal having the on state;
• and
• basing the feedback signal on an output of the standby stage in response to the standby signal having the standby state.

An apparatus to provide backup power, the apparatus comprising:

• a switching module that adjusts an on-time and an off-time of one or more switches for a primary stage and a standby stage of a switched-mode power supply, the switching module adjusting the on-time and the off-time based on a feedback signal, the primary stage and the standby stage sharing the one or more switches, the primary stage comprising one or more switched-mode power supply stages;
• a shutoff module that, in response to a standby signal having a standby state, interrupts electric power flowing to the primary stage and, in response to the standby signal having an on state, allows electric power to flow to the primary stage;
• a feedback module that provides the feedback signal to the switching module, the feedback module basing the feedback signal on the output of the primary stage in response to the standby signal having the on state and the feedback module basing the feedback signal on the output of the standby stage in response to the standby signal having the standby state;
• wherein the primary stage and the standby stage are electrically coupled to a load such that the primary stage provides electric power to the load and the load draws substantially no electric power from the standby stage in response to the shutoff module allowing electric power to flow to the primary stage and such that the standby stage provides electric power to at least a portion of the load in response to the shutoff module interrupting electric power flowing to the primary stage;
• and
• wherein a winding ratio of a primary stage transformer in the primary stage and a winding ratio of a standby stage transformer in the standby stage are selected such that the output of the standby stage, in response to the feedback module basing the feedback signal on the output of the primary stage, has a lower voltage than a standby setpoint voltage that the output of the standby stage has in response to the feedback module basing the feedback signal on the output of the standby stage, the output of the standby stage increasing from the lower voltage to the standby setpoint voltage in response to the feedback module basing the feedback signal on the output of the standby stage.