Circuit and method for regulating a voltage
AssigneeTexas Instruments Incorporated
InventorsMarco Corsi, Nicolas Salamina, Jeffrey W. Sanders, Michael R. Kay
Life of this patent
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Abstract
A voltage regulator circuit (10) is provided. Regulator circuit (10) includes an amplifier (18) with an emitter follower output stage (26). Emitter follower stage (26) is coupled to a gate of a PMOS transistor (28). The source of transistor (28) is coupled to an input voltage at a power supply rail (12). Regulator (10) provides an output at node (14) at a drain of transistor (28). The output at node (14) is divided by resistors (30 and 34) and provided in a negative feedback loop to an input of amplifier (18). A reference voltage (22) is also provided to a second input of amplifier (18) such that the output at node (14) is a regulated voltage.
Claims12
An integrated circuit for regulating an input voltage, said circuit comprising:
- an amplifier stage having first and second inputs and an output;
- a first emitter follower having a PNP bipolar junction transistor with a base coupled to the output of the amplifier stage, a collector coupled to ground, and an emitter coupled to the input voltage through a current source;
- a second emitter follower having a NPN bipolar junction transistor with a base coupled to the emitter of the first emitter follower circuit, a collector coupled to the input voltage, and an emitter coupled to ground through a current source, the first and second emitter followers forming an emitter follower stage having an output at the emitter of the NPN bipolar junction transistor;
- and
- an output stage having an MOS transistor with a gate coupled to said output of said follower stage, a drain coupled to said first input of the amplifier stage for providing negative feedback to said amplifier stage, and a source coupled to the input voltage such that the drain of the MOS transistor provides a regulated output voltage that is stable over a predetermined frequency range for a wide range of load impedances.
An integrated circuit for regulating an input voltage, said circuit comprising:
- an amplifier stage having first and second inputs and an output;
- a reference voltage power supply coupled to said second input of said amplifier stage;
- a bipolar emitter follower stage having an NPN bipolar junction transistor with a collector coupled to the input voltage, a base coupled to said output of said amplifier stage, and an emitter coupled to ground through a current source;
- a MOS transistor with a gate coupled to said emitter of said NPN transistor in said follower stage, a source coupled to the input voltage, and a drain;
- a voltage divider coupled between the drain of said MOS transistor and said first input of said amplifier stage for providing negative feedback to said amplifier stage such that the drain of the MOS transistor provides a regulated output voltage that is stable over a predetermined frequency range for a wide range of load impedances.
Dependencies are inferred from the claim text.