Regulation circuit associated with synchronous rectifier providing cable compensation for the power converter and method thereof

Abstract

A regulation circuit of a power converter for cable compensation according to the present invention comprises a signal generator generating a compensation signal in accordance with a synchronous rectifying signal. An error amplifier has a reference signal for generating a feedback signal in accordance with an output voltage of the power converter. The compensation signal is coupled to program the reference signal. The feedback signal is coupled to generate a switching signal for regulating an output of the power converter. The regulation circuit of the present invention compensates the output voltage without a shunt resistor to sense the output current of the power converter for reducing power loss.

What is claimed is: 
     
         1 . A regulation circuit of a power converter, comprising:
 an error amplifier having a reference signal for generating a feedback signal in accordance with an output voltage of the power converter; and   a synchronous rectifying controller generating a synchronous rectifying signal;   wherein the feedback signal is coupled to generate a switching signal for regulating the output voltage of the power converter and a voltage drop on the output voltage is compensated in response to the synchronous rectifying signal.   
     
     
         2 . The regulation circuit as claimed in  claim 1 , wherein the reference signal is programmed in accordance with the synchronous rectifying signal. 
     
     
         3 . The regulation circuit as claimed in  claim 1 , wherein the reference signal is programmed in accordance with a demagnetization time of a transformer of the power converter; the transformer comprising a primary winding and a secondary winding. 
     
     
         4 . The regulation circuit as claimed in  claim 1 , wherein the synchronous rectifying signal is utilized to control a power transistor coupled to the power converter; the power transistor being used for a synchronous rectifier. 
     
     
         5 . The regulation circuit as claimed in  claim 1 , wherein the synchronous rectifying signal is correlated to an output current of the power converter. 
     
     
         6 . A regulation circuit of a power converter, comprising:
 an error amplifier having a reference signal for generating a feedback signal in accordance with an output voltage of the power converter, the feedback signal coupled to generate a switching signal for regulating the output voltage of the power converter; and   a power transistor used for a synchronous rectifier and coupled to a secondary side of the power converter;   wherein a voltage drop on the output voltage is compensated in response to a turn on period of the power transistor.   
     
     
         7 . The regulation circuit as claimed in  claim 6 , wherein the reference signal is programmed in accordance with the turn on period of the power transistor. 
     
     
         8 . The regulation circuit as claimed in  claim 6 , wherein the reference signal is programmed in accordance with a demagnetization time of a transformer of the power converter; the transformer comprising a primary winding and a secondary winding. 
     
     
         9 . The regulation circuit as claimed in  claim 6 , wherein the turn on period of the power transistor is correlated to an output current of the power converter. 
     
     
         10 . A power converter, comprising:
 a regulation circuit generating a feedback signal in accordance with a synchronous rectifying signal and an output voltage of the power converter;   wherein the feedback signal is coupled to generate a switching signal for regulating the output voltage of the power converter and a voltage drop on the output voltage is compensated in response to the synchronous rectifying signal.   
     
     
         11 . The power converter as claimed in  claim 10 , wherein the synchronous rectifying signal is utilized to control a power transistor coupled to the power converter; the power transistor being used for a synchronous rectifier. 
     
     
         12 . The power converter as claimed in  claim 10 , wherein the regulation circuit generates the feedback signal in accordance with an on-time of the synchronous rectifying signal and the output voltage of the power converter. 
     
     
         13 . The power converter as claimed in  claim 10 , wherein the regulation circuit has a reference signal for generating the feedback signal, and the reference signal is programmed in accordance with the synchronous rectifying signal. 
     
     
         14 . The power converter as claimed in  claim 10 , wherein the synchronous rectifying signal is correlated to an output current of the power converter. 
     
     
         15 . A power converter, comprising:
 a regulation circuit generating a feedback signal in accordance with a turn on period of a power transistor and an output voltage of the power converter;   wherein the feedback signal is coupled to generate a switching signal for regulating the output voltage of the power converter; a voltage drop on the output voltage being compensated in response to the turn on period of the power transistor; the power transistor being used for a synchronous rectifier.   
     
     
         16 . The power converter as claimed in  claim 15 , wherein the turn on period of the power transistor is correlated to an output current of the power converter.