Detector based combination regulator
AssigneeAtmel Corporation
InventorsLouis Frew, Colin Bates
Life of this patent
Estimating the term…
Abstract
Methods and apparatus provide multiple input voltage regulation in which one regulator is selected for operation based on input power conditions. In one example, a dual input voltage regulator system in a combination smart card selects between contact and contactless (e.g., RF) operation based on which power source provides the highest available voltage level. A single transistor drop architecture provides low drop-out voltage regulation capability without substantially increased transistor size. In some implementations, multiplexed control of the regulators for each of a number independent power source inputs may be arranged to substantially reduce or prevent reverse current flow through regulators connected to inactive power inputs.
Claims23
A system comprising:
- a first regulator coupled to a first input node and operable in a first mode to regulate a voltage at an output node;
- a second regulator coupled to a second input node and operable in a second mode to regulate the voltage at the output node;
- a mode circuit that disables current flow through one of the first or the second regulator to the output node depending on the mode including generating a bias signal using a voltage provided by an operating regulator of the first or second regulator for a given mode applied through a pull up or pull down resistor to disable a pass transistor associated with a respective one of the first or the second regulator depending on the mode;
- and
- a controller to select the first mode or the second mode based on which of the first regulator or the second regulator has a highest voltage including to select the first mode when a first voltage level signal associated with the first input node is greater than a second voltage level signal associated with the second input voltage node, and to select the second mode when the first voltage level signal is less than the second voltage level signal.
A system comprising:
- a first regulator comprising a first transistor, wherein in a first mode the first transistor operates to regulate a voltage on an output node by modulating a voltage drop between a supply terminal connected to a first voltage supply node and an output terminal connected to the output node;
- a second regulator comprising a second transistor, wherein in a second mode the second transistor operates to regulate the voltage on the output node by modulating a voltage drop between a supply terminal connected to a second voltage supply node and an output terminal connected to the output node;
- a mode circuit to bias a control terminal of one of the first transistor or the second transistor to prevent a given transistor from conducting current in a respective other mode including generating a bias signal using a voltage provided by an operating one of the first or second regulator for a given mode and applied through a pull up or pull down resistance to bias the first or the second transistor given the mode;
- and
- a controller
- to select the first mode in response to the voltage at the first voltage supply node having the highest available voltage level;
- and
- to select the second mode in response to the voltage at the second voltage supply node having the highest available voltage level.
Dependencies are inferred from the claim text.