Universal dc power

Abstract

A power converter capable of providing a range of DC voltages to an external device and a method of providing a range of DC power are provided. The power converter comprises a supply circuit for receiving a request for DC power and for providing the requested DC power. The supply circuit comprises a detection circuit for sensing a connection to an external device, a source controller circuit for determining a DC output power required by the external device, and a converter circuit for generating the required DC output power. The external device comprises a device controller circuit for communicating the request for DC power. A first conductor provides a path for the device to communicate the required DC power to the power converter and for the power converter to supply the required DC power. A second conductor provides a common reference for conducting return current to the power converter.

1 . A DC-powered device requiring DC power, comprising: 
 a device controller circuit for communicating a request for DC power; and    first and second conductors for connecting the DC-powered device to a power converter, wherein the first conductor provides a path for the DC-powered device to communicate the required DC output power to the power converter and for the power converter to supply the required DC output power to the DC-powered device, and the second conductor provides a common reference for conducting return current to the power converter.    
   
   
       2 . The DC-powered device of  claim 1 , wherein the device controller circuit comprises: 
 a first circuit for establishing as DC output voltage required by the DC-powered device; and    a second circuit for establishing a maximum average current required by the DC-powered device.    
   
   
       3 . The DC-powered device of  claim 2 , wherein the first circuit comprises a zener diode and a first transistor connected in series between the first and second conductors.  
   
   
       4 . The DC-powered device of  claim 2 , wherein the first circuit comprises a resistor connected between the first and second conductors.  
   
   
       5 . The DC-powered device of  claim 2 , wherein the second circuit comprises a capacitor connected between the first and second conductors.  
   
   
       6 . The DC-powered device of  claim 2 , wherein the device controller circuit further comprises: 
 a switching circuit for detecting the DC output power supplied by the power converter and providing the supplied DC output power to the DC-powered device.    
   
   
       7 . The DC-powered device of  claim 2 , wherein the device controller circuit further comprises: 
 a loading circuit coupled to the first and second conductors for providing a disconnect signal to the power converter.    
   
   
       8 . The DC-powered device of  claim 7 , wherein the loading circuit comprises a resistor and a transistor connected in series between the first and second conductors.  
   
   
       9 . The DC-powered device of  claim 1 , wherein the device controller circuit comprises: 
 a first circuit for signaling the presence of the DC-powered device to the power converter;    a communications circuit for forming a communications packet indicating select electrical parameters of the required DC output power;    a switching circuit for detecting the DC output power supplied by the power converter and providing the supplied DC output power to the DC-powered device; and    a loading circuit coupled to the first and second conductors for providing a disconnect signal to the power converter.    
   
   
       10 . The DC-powered device of  claim 9 , wherein the first circuit comprises a first resistor and a first transistor connected in series between the first and second conductors.  
   
   
       11 . The DC-powered device of  claim 9 , further comprising: 
 a power supply circuit having an input coupled to the first conductor and an output coupled to the device controller circuit, wherein the output remains steady for short periods of time when power to the input is removed.    
   
   
       12 . The DC-powered device of  claim 1 , wherein the DC-powered device is implemented in a semiconductor device.