Primary side control circuit and method for ultra-low idle power operation

Abstract

A method and circuit for reducing power consumption during idle mode to ultra-low levels, such as about 1/10 th to 1/1000 th or less of active power is disclosed. An ultra-low idle power supply comprises a primary circuit, a secondary circuit and a control circuit. The control circuit monitors behavior of the primary circuit and determines whether an idle state or no load condition exists, and if so the primary circuit is disengaged. The control circuit may monitor at least one of a ripple current in an energy storage circuit, temperature of lossy components in the primary circuit, or a current flow through switch circuits within the primary circuit. By disengaging the primary circuit, the power consumption of the ultra-low idle power supply is reduced to ultra-low levels.

1 . A primary circuit configured to facilitate an ultra-low idle power mode in a power supply, said primary circuit comprising:
 a modulator configured for modulating input power to transfer power from a primary side of a transformer to a secondary side of said transformer; and   an energy storage circuit coupled to said modulator; and   a control circuit configured to monitor at least one of a ripple current in said energy storage circuit, temperature of lossy components in said primary circuit, or a current flow through switch circuits within said primary circuit and to control said primary circuit such that said primary circuit is substantially disabled in response to said control circuit determining that substantially no load exists.   
     
     
         2 . The primary circuit of  claim 1 , further comprising a standby switch configured to transition said power supply from said ultra-low idle power mode to an active mode or a normal idle mode. 
     
     
         3 . The primary circuit of  claim 1 , wherein said modulator comprises a PWM controller. 
     
     
         4 . The circuit of  claim 1 , wherein said control circuit comprises a logic control unit configured for monitoring said primary circuit and a power control unit configured for control of said primary circuit. 
     
     
         5 . The primary circuit of  claim 4 , wherein said logic control unit monitors said at least one of the ripple current in said energy storage circuit, the temperature of said lossy components in said primary circuit, or the current flow through said switch circuits within said primary circuit. 
     
     
         6 . The primary circuit of  claim 4 , wherein said primary circuit comprises at least one switch device coupled between said power control unit and said modulator, whereby said power control unit opens said at least one switch device to disable said modulator. 
     
     
         7 . A power supply comprising:
 a control circuit on a primary circuit of said power supply, wherein said control circuit is configured to monitor at least one of a ripple current in an energy storage circuit, temperature of lossy components in said primary circuit, or a current flow through switch circuits within said primary circuit and to control said primary circuit such that said primary circuit is substantially disabled in response to an idle power mode being detected.   
     
     
         8 . The power supply of  claim 7 , wherein said control circuit monitors said at least one of said ripple current in said energy storage circuit, the temperature of said lossy components, or the current flow through said switch circuits to determine whether a power level of said power supply is above or below a predetermined threshold. 
     
     
         9 . The power supply of  claim 8 , wherein said control circuit comprises a logic control unit configured for monitoring said primary circuit and a power control unit configured for control of said primary circuit. 
     
     
         10 . The power supply of  claim 9 , wherein said logic control unit and said power control unit comprise at least one of a combinational logic machine, a state machine or a microprocessor. 
     
     
         11 . The power supply of  claim 9 , wherein said primary circuit comprises a modulator circuit configured for driving at least one of a transformer or a dielectric isolation device. 
     
     
         12 . The power supply of  claim 11 , wherein said power control unit is configured to control at least one switch to control said modulator circuit. 
     
     
         13 . The power supply of  claim 11 , wherein said modulator circuit comprises a PWM controller. 
     
     
         14 . The power supply of  claim 7 , wherein said control circuit is configured to monitor and control said primary circuit solely in said primary circuit without a feedback signal from outside said primary circuit. 
     
     
         15 . The power supply of  claim 7 , further comprising a standby switch configured to transition said power supply to said ultra-low idle power mode from an active mode or a normal idle mode. 
     
     
         16 . A method for providing ultra-low power operation of a power supply comprising:
 monitoring, using a control circuit in communication with a primary circuit on a primary side of said power supply, at least one of a ripple current in an energy storage circuit, temperature of lossy components in said primary circuit, or a current flow through switch circuits within said primary circuit of said power supply and determining if substantially no load condition exists; and   substantially disabling, using said control circuit, said primary circuit of said power supply in response to said substantially no load condition being detected.   
     
     
         17 . The method according to  claim 16 , said method further comprising re-enabling said power supply after a lapsing of a predetermined time interval. 
     
     
         18 . The method of  claim 16 , wherein said determining if said substantially no load condition exists comprises detecting if at least one of a low ripple current rate, temperature, or current flow is present within said primary circuit. 
     
     
         19 . A power supply comprising:
 a control circuit on a primary side of said power supply, wherein said control circuit is configured to monitor a ripple current in an energy storage circuit within a primary circuit and to control said primary circuit such that said primary circuit is substantially disabled in response to an idle power mode being detected; and   a standby switch configured to transition said power supply from an ultra-low idle power mode to an active mode or a normal idle mode.