Voltage Generator With Adjustable Slope

Abstract

A charging circuit includes a first current mirror including a first branch circuit, a second branch circuit and a third branch circuit for generating a first conduction current, a second conduction current and a third conduction current according to the input voltage, a second current mirror including a fourth branch circuit coupled to the first branch circuit and including a first channel width, and a fifth branch circuit coupled to the second branch circuit and including a second channel width, wherein a load circuit is coupled between the first current mirror and the second current mirror, and the first current mirror as well as the second current mirror correspondingly adjust values of the first conduction current, the second conduction current and the third conduction current according to the first channel width as well as the second channel width, so as to process a charging operation of the load circuit.

What is claimed is: 
     
         1 . A charging circuit comprising:
 a first current mirror comprising:
 a first branch circuit for generating a first conduction current according to an input voltage; 
 a second branch circuit for generating a second conduction current according to the input voltage; and 
 a third branch circuit for generating a third conduction current according to the input voltage; 
   a second current mirror comprising:
 a fourth branch circuit coupled to the first branch circuit and comprising a first channel width; and 
 a fifth branch circuit coupled to the second branch circuit and comprising a second channel width; 
   wherein a load circuit is coupled between the first current mirror and the second current mirror, and the first current mirror as well as the second current mirror correspondingly adjust values of the first conduction current, the second conduction current and the third conduction current according to the first channel width as well as the second channel width, so as to process a charging operation of the load circuit.   
     
     
         2 . The charging circuit of  claim 1 , wherein the second current mirror generates a fourth conduction current and a fifth conduction current passing through the fourth branch circuit and the fifth branch circuit, respectively, according to the first conduction current, the first channel width and the second channel width. 
     
     
         3 . The charging circuit of  claim 2 , wherein the first branch circuit and the second branch circuit both comprise two cascoded P-type MOS transistors, the fourth branch circuit and the fifth branch circuit both comprise two cascoded N-type MOS transistors, and a capacitive transistor comprises one end coupled to one end of a P-type MOS transistor of the first branch circuit and another end coupled to one end of a P-type MOS transistor of the second branch circuit. 
     
     
         4 . The charging circuit of  claim 3 , wherein a calculational result is obtained from subtracting the fifth conduction current from a sum of the second conduction current and the third conduction current such that the calculational result is utilized to process the charging operation of the load circuit. 
     
     
         5 . The charging circuit of  claim 4 , wherein the first current mirror further comprises a sixth branch circuit comprising two cascoded P-type MOS transistors. 
     
     
         6 . The charging circuit of  claim 5 , further comprising a bipolar transistor comprising an emitter coupled to one end of the sixth branch circuit, a base coupled to the load circuit as well as the one end of the P-type MOS transistor of the first branch circuit, and a collector coupled to a reference voltage source. 
     
     
         7 . The charging circuit of  claim 6 , wherein the bipolar transistor comprises a gain parameter. 
     
     
         8 . The charging circuit of  claim 7 , wherein the gain parameter is utilized to process a current multiplication operation of the calculational result, so as to process the charging operation of the load circuit. 
     
     
         9 . The charging circuit of  claim 1 , wherein the load circuit is a MOS transistor capacitor, a polysilicon capacitor or a passive circuit. 
     
     
         10 . The charging circuit of  claim 1 , wherein the charging operation provides a soft start operation for the load circuit. 
     
     
         11 . The charging circuit of  claim 1 , wherein the second branch circuit and the third branch circuit are integrated into an integration branch circuit providing an integration conduction current, and the integration conduction current is a sum of the second conduction current and the third conduction current.