Stable voltage regulator having first-order and second-order output voltage compensation
First Claim
1. A voltage regulator circuit comprising a differential amplifier powered from a supply line at a nominal voltage level by being coupled between the supply line and a return line, a reference device coupled to a first input of the differential amplifier for defining a desired output voltage on an output line coupled to an output of the differential amplifier, and a feedback coupling from the output line to a second input of the differential amplifier, characterised in that the differential amplifier is coupled to the return line by a varying current source which feeds a varying bias current to the differential amplifier, and the varying current source has control means coupled to the supply line for controlling the magnitude of the varying bias current in accordance with variations in the nominal voltage level on the supply line and so to provide a first-order compensation of the output voltage for these variations in the nominal voltage level, a second-order compensation being provided by the feedback coupling from the output line to the second input of the differential amplifier.
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Accused Products
Abstract
A stable voltage regulator circuit of simple circuit configuration 174,222 includes a differential amplifier (M2, M3) which is powered from a supply line (1) at a nominal voltage level (Vin), by being coupled between the supply line and a return line (2). A reference device (M1) is coupled to a first input (4) of the differential amplifier (M2, M3) for defining a desired output voltage (Vca) on an output line (3) coupled to an output (6) of the differential amplifier (M2, M3). The differential amplifier (M2, M3) is coupled to the return line (2) by a varying current source (M4) which feeds a varying bias current to the differential amplifier (M2, M3) and which is controlled from the supply line (1) in accordance with variations in the nominal voltage level (Vin) on the supply line (1). The varying bias current to the differential amplifier (M2, M3) provides a first-order compensation of the output voltage (Vca) for these voltage variations on the supply line (1). A second-order compensation is provided by a feedback coupling (R7, R8) from the output line (3) to the second input (5) of the differential amplifier (M2, M3).
23 Citations
10 Claims
- 1. A voltage regulator circuit comprising a differential amplifier powered from a supply line at a nominal voltage level by being coupled between the supply line and a return line, a reference device coupled to a first input of the differential amplifier for defining a desired output voltage on an output line coupled to an output of the differential amplifier, and a feedback coupling from the output line to a second input of the differential amplifier, characterised in that the differential amplifier is coupled to the return line by a varying current source which feeds a varying bias current to the differential amplifier, and the varying current source has control means coupled to the supply line for controlling the magnitude of the varying bias current in accordance with variations in the nominal voltage level on the supply line and so to provide a first-order compensation of the output voltage for these variations in the nominal voltage level, a second-order compensation being provided by the feedback coupling from the output line to the second input of the differential amplifier.
Specification