Compensation for low drop out voltage regulator
First Claim
1. A voltage regulator, comprising:
- an error amplifier that amplifies a voltage difference between a reference voltage and a sampled output voltage of the voltage regulator;
a driver amplifier that receives said amplified voltage difference and that produces a gate driving voltage;
an output transistor that has a gate that receives said gate driving voltage and a source that outputs a regulated output voltage;
a Miller compensation capacitor that feeds a sample of said regulated output voltage back to an input of said driver amplifier; and
an Ahuja compensation circuit that feeds a portion of said regulated output voltage back to said input of said driver amplifier.
4 Assignments
0 Petitions
Accused Products
Abstract
A voltage regulator apparatus includes an error amplifier that amplifies a voltage difference between a reference and a sampled output voltage of the voltage regulator apparatus. A driver amplifier has an input that is responsive to the amplified voltage difference to produce a gate driving voltage at its output. An output transistor having a drain, a gate, and a source is also included. The gate is responsive to the gate driving voltage to produce a regulated output voltage at the source. To stabilize the voltage regulator apparatus, a Miller compensation capacitor is provided to feed a sample of the regulated output voltage back to the input of the driver amplifier; and additionally, an Ahuja compensation circuit is provided to feed back a portion of the regulated output voltage back to the input of the driver amplifier.
-
Citations
36 Claims
-
1. A voltage regulator, comprising:
-
an error amplifier that amplifies a voltage difference between a reference voltage and a sampled output voltage of the voltage regulator; a driver amplifier that receives said amplified voltage difference and that produces a gate driving voltage; an output transistor that has a gate that receives said gate driving voltage and a source that outputs a regulated output voltage; a Miller compensation capacitor that feeds a sample of said regulated output voltage back to an input of said driver amplifier; and an Ahuja compensation circuit that feeds a portion of said regulated output voltage back to said input of said driver amplifier. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. A voltage regulator apparatus comprising:
-
an outer loop including an error amplifier having an output that communicates with an input of a driver amplifier, a regulated voltage output responsive to an output of said driver amplifier, and an outer feedback path from said regulated voltage output to an input of said error amplifier that maintains said regulated voltage output based on a reference voltage; an inner loop including a first feedback path and a second feedback path around said driver amplifier, wherein said first and second feedback paths do not include said error amplifier, and wherein a zero produced by said first feedback path at least partially cancels, in said inner loop, a pole produced by said second feedback path. - View Dependent Claims (14, 15, 16)
-
-
17. A method for regulating voltage comprising:
-
comparing a sampled DC voltage to a reference voltage to generate a correction signal; amplifying the correction signal utilizing a driver amplifier; generating a regulated output voltage based on said amplified correction signal, wherein said sampled DC voltage is related to said regulated output voltage; feeding back said regulated output voltage to said driver amplifier utilizing Miller compensation; and feeding back said regulated output voltage to said driver amplifier utilizing Ahuja compensation. - View Dependent Claims (18, 19, 20, 21)
-
-
22. A voltage regulator, comprising:
-
error amplifying means for amplifying a voltage difference between a reference voltage and a sampled output voltage of the voltage regulator; driver amplifying means for receiving said amplified voltage difference and for producing a gate driving voltage; output means for receiving said gate driving voltage and for generating a regulated output voltage; first compensation means for feeding a sample of said regulated output voltage back to an input of said driver amplifying means; and second compensation means for feeding back a portion of said regulated output voltage back to said input of said driver amplifying means. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
-
-
33. A method for operating a voltage regulator, comprising:
-
amplifying a voltage difference between a reference and a sampled output voltage of the voltage regulator; producing a gate driving voltage based on said amplified voltage difference; receiving said gate driving voltage and outputting a regulated output voltage; feeding back a sample of said regulated output voltage to provide Miller compensation; and feeding back a portion of said regulated output voltage to provide Ahuja compensation. - View Dependent Claims (34, 35, 36)
-
Specification