High current, low dropout driver circuit
AssigneeApple Inc.
InventorsCristian Grecu, Nicola Rasera, Bogdan-Eugen Matei, Fabio Ongaro
Life of this patent
Estimating the term…
Abstract
A high current, low dropout driver circuit is disclosed. The circuit includes a decoder configured to decode a plurality of control bits to generate a plurality of control signals, and a current source having a plurality of devices. The current source is configured to activate at least a subset of the plurality of devices using the control signals to provide a load current to a load circuit, such as a light-emitting diode (LED), using activated ones of the plurality of devices and a control voltage. A control circuit is configured to generate the control voltage based on the load current and a reference current.
Claims20
An apparatus, comprising:
- a decoder configured to decode a plurality of bits to generate a plurality of control signals;
- a current source including a plurality of devices, wherein the current source is configured to:
- activate at least a subset of the plurality of devices using the plurality of control signals;
- and
- provide a load current to a light-emitting diode (LED) using activated ones of the plurality of devices and a control voltage;
- and
- a control circuit configured to generate the control voltage based on the load current and a reference current.
A method comprising:
- generating a plurality of control signals, wherein the generating comprises a decoder circuit decoding a plurality of control bits;
- activating at least a subset of a plurality of devices of a current source based on the plurality of control signals;
- providing a load current to a load circuit based on a control voltage provided to activated ones of the plurality of devices;
- and
- generating, using a control circuit, the control voltage based on the load current and a reference current.
A system comprising:
- a current source configured to drive a load circuit with a load current, wherein the current source includes a plurality of devices;
- a decoder circuit configured to, based on an input code, selectively activate ones of the plurality of devices;
- and
- a control circuit configured to generate a control voltage provided to a gate terminal of a replica device and corresponding ones of the plurality of devices, wherein the control circuit is configured to generate the control voltage based on a reference current, and wherein the replica device and the plurality of devices of the current source have substantially equal electrical characteristics;
- wherein the replica device is configured to generate a replica current, and wherein the current source is configured to generate the load current based on the replica current and a number of the plurality of devices that are active.
Dependencies are inferred from the claim text.