06377032 is referenced by 42 patents.

An apparatus and method for virtual current sensing in a DC-DC switched mode power supply. In a fixed frequency implementation, when a switching phase begins, the phase node goes high when the high-side switching transistor is turned on. At this point, a first programmable current source begins charging a current sensing capacitor and the voltage across the capacitor simulates the rising slope of the voltage across a conventional current sensing resistor. Simultaneously, a ramp capacitor beginning at a reference voltage is charged by a second programmable current source. When the sum of the voltages across the two capacitors exceeds an error voltage, the phase node goes low when the drive signal to the transistor is turned off. At this point, a third programmable current source begins discharging the current sensing capacitor and the voltage across the capacitor simulates the falling slope of the current across the conventional resistor.

Title
Method and apparatus for virtual current sensing in DC-DC switched mode power supplies
Application Number
9/620370
Publication Number
6377032 (B1)
Application Date
July 20, 2000
Publication Date
April 23, 2002
Inventor
William E Rader III
Cary
NC, US
John Fogg
Apex
NC, US
Joseph M Andruzzi
Raleigh
NC, US
Agent
Thelen Reid & Priest
US
Agent
David B Ritchie
US
Assignee
Semtech Corporation
CA, US
IPC
G05F 1/613
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