Data interface with overvoltage protection for two-way digital control bus system
View Patent ↗A data interface with overvoltage protection circuitry includes a bus interface and power rectification stage configured to provide supply and return voltages for the data interface and overvoltage protection circuitry, a first power level overvoltage protection circuit, a second power level overvoltage protection circuit, a DALI endpoint power output port, a power supply for a DALI endpoint device drawing current from the power output port, a receiver configured to receive signals on the DALI bus, and, a transmitter configured to send signals on the DALI bus.
1. A data interface with overvoltage protection circuitry, the data interface comprising:
a bus interface and power rectification stage configured to provide supply and return voltages for the data interface and overvoltage protection circuitry;
a first power level overvoltage protection circuit configured to provide protection from high-current overvoltages on the DALI bus;
a second power level overvoltage protection circuit configured to provide protection from overvoltage conditions caused by power main voltages present on the DALI bus;
the first power level overvoltage protection circuit in parallel connection with the second power level overvoltage protection circuit across lines for the supply and return voltage;
a digital addressable lighting interface (DALI) endpoint power output port;
a power supply for a DALI endpoint device drawing current from the power output port;
a receiver configured to receive signals on the DALI bus; and
a transmitter configured to send signals on the DALI bus.
2. The data interface of claim 1 , including the bus interface configured to connect to a two-wire DALI data/control bus.
3. The data interface of claim 1 , including the power rectification stage including a diode bridge.
4. The data interface of claim 1 , including a receive port connected to a transmit output port of a microcontroller.
5. The data interface of claim 1 , including a transmit port connected to a data input port of a microcontroller.
6. The data interface of claim 1 , wherein the high-current overvoltages are caused by a current above a nominal transmit current.
7. A data interface with overvoltage protection circuitry, the data interface comprising:
a bus interface configured to be connectable to a digital addressable lighting interface (DALI) bus;
a first power level overvoltage protection circuit connected to a supply voltage line and a return voltage line, wherein the first power level overvoltage protection circuit is configured to protect the data interface from one or more DALI control voltages present on a DALI data bus;
a second power level overvoltage protection circuit connected in parallel with the first power level overvoltage protection circuit across the supply voltage and the return voltage lines;
a DALI endpoint power output port configured to provide a supply voltage to a DALI endpoint device;
a receiver configured to receive signals on the DALI bus; and
a transmitter configured to send signals on the DALI bus.
8. The data interface of claim 7 , including a power rectification stage configured to rectify a supply voltage received from the DALI bus.
9. The data interface of claim 7 , including:
a receive port connected to a transmit output port of a microcontroller; and
a transmit port connected to a data input port of a microcontroller.
10. The data interface of claim 7 , including:
a DALI transmitter connected to the DALI bus;
a power rectification stage configured to rectify a supply voltage received from the DALI bus;
the DALI transmitter and the power rectification stage each configured to be inhibited by activation of the first power level overvoltage protection circuit; and
the DALI transmitter and the power rectification stage each configured to be initialized by de-activation of the first power level overvoltage protection circuit following a removal of the one or more DALI control voltages present on the DALI data bus.
11. The data interface of claim 7 , including the second power level overvoltage protection circuit configured to protect the data interface from one or more overvoltage conditions on a main supply line.
12. The data interface of claim 11 , including:
a DALI transmitter connected to the DALI bus;
a power rectification stage configured to rectify a supply voltage received from the DALI bus;
the DALI transmitter and the power rectification stage each configured to be inhibited by activation of the second power level overvoltage protection circuit; and
the DALI transmitter and the power rectification stage each configured to be initialized by de-activation of the second power level overvoltage protection circuit following an end of the one or more overvoltage conditions.