Digital addressable lighting interface circuit method and apparatus
AssigneeKorrus, Inc.
InventorJUAN PABLO CASASOLA
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Abstract
This disclosure pertains to Digital Addressable Lighting Interface (DALI) circuitry, and particularly, to a DALI bus interface circuit for interfacing a device to a DALI bus.
Claims19
A circuit for interfacing a device to a Digital Addressable Lighting Interface (DALI) bus, the DALI bus comprising a first channel and a second channel, the circuit for interfacing comprising:
- a cascode circuit coupled between the DALI bus and a bus interface node of a DALI bus interface circuit, the cascode circuit configured to present a voltage at the bus interface node that tracks the voltage on the DALI interface bus up to a predetermined maximum voltage and to present the predetermined maximum voltage at the bus interface terminal when the voltage on the DALI bus exceeds the predetermined maximum voltage;
- a voltage ladder circuit coupled between the bus interface node and ground, the voltage ladder comprising a first voltage ladder resistor and a second voltage ladder resistor coupled in series between the bus interface node and ground;
- and
- a first transistor having a control terminal coupled to a node between the first voltage ladder resistor and the second voltage ladder resistor, a second current flow terminal coupled to ground, and a second current flow terminal coupled to an input node, the input node for coupling to a voltage mode processing device for receiving data from the DALI bus.
The circuit of claim 5 wherein the third resistor has a resistance adapted to cause a voltage at the input node to be close to zero volts when the second transistor is on.
A circuit for interfacing a device to a Digital Addressable Lighting Interface (DALI) bus, the DALI bus comprising a first channel and a second channel, the circuit for interfacing comprising:
- a cascode circuit coupled between the DALI bus and a bus interface node of a DALI bus interface circuit, the cascode circuit configured to present a voltage at the bus interface node that tracks the voltage on the DALI interface bus up to a predetermined maximum voltage and to present the predetermined maximum voltage at the bus interface terminal when the voltage on the DALI bus exceeds the predetermined maximum voltage;
- and
- a transistor having a first current flow terminal coupled to the bus interface node, a second current flow terminal coupled to ground and a control terminal for coupling to an output terminal coupled to an output terminal for coupling to the processing device for receiving data for placement on the DALI bus.
Dependencies are inferred from the claim text.