Driver circuit for a light source and method of transmitting data over a power line
A driver circuit ( 21 ) for a light source ( 20 ) comprises an input configured for coupling to a power line ( 19 ). A control device ( 24 ) is configured to control at least one controllable switch ( 23 ) to control an output current or output voltage of the driver circuit ( 21 ). The control device ( 24 ) is configured to modulate a signal onto the power line ( 19 ) by setting a switching frequency of the at least one controllable switch ( 23 ) in dependence on data to be transmitted by the driver circuit ( 21; 121, 131 ) over the power line ( 19 ).
1. A driver circuit for a light source ( 20 ; 111 , 112 ), comprising:
an input ( 22 ; 22 a , 22 b ) configured for coupling to a power line ( 19 );
a switching circuit ( 23 a , 23 b , 141 - 150 ; 23 a , 23 b , 141 - 149 , 160 ) coupled to the input ( 22 ; 22 a , 22 b ) and comprising at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ); and
a control device ( 24 ) configured to control the at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ) to control an output current or output voltage of the driver circuit ( 21 ; 121 , 131 ),
the control device ( 24 ) being configured to modulate a signal onto the power line ( 19 ) by setting a switching frequency of the at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ) in dependence on data to be transmitted by the driver circuit ( 21 ; 121 , 131 ) over the power line ( 19 )
wherein the control device ( 24 ) is configured to control the output current of the driver circuit ( 21 ; 121 , 131 ) by setting the switching frequency to at least one frequency ( 30 - 32 ; 33 - 36 ; 51 , 52 ; 91 - 93 ; 94 - 96 ; 97 , 98 ) which is a function of both a target output current of the driver circuit ( 21 ; 121 , 131 ) and the data to be transmitted
wherein the control device ( 24 ) is configured to control the output current of the driver circuit ( 21 ; 121 , 131 ) by sequentially setting the switching frequency to plural frequencies ( 33 , 34 ; 35 , 36 ; 51 , 52 ; 91 - 93 ; 94 - 96 ; 97 , 98 ), the plural frequencies ( 33 , 34 ; 35 , 36 ; 51 , 52 ; 91 - 93 ; 94 - 96 ; 97 , 98 ) being a function of both the target output current ( 59 ) of the driver circuit ( 21 ; 121 , 131 ) and the data to be transmitted, and
wherein the control device ( 24 ) is configured to control the output current of the driver circuit ( 21 ; 121 , 131 ) by alternating the switching frequency between the plural frequencies ( 33 , 34 ; 35 , 36 ; 51 , 52 ; 91 - 93 ; 94 - 96 ; 97 , 98 ).
2. The driver circuit according to claim 1 , wherein
for transmitting a data bit having a first logical value, the plural frequencies are included in a first group of frequencies ( 35 , 36 ; 94 - 96 ), and
for transmitting a data bit having a second logical value, the plural frequencies are included in a second group of frequencies ( 33 , 34 ; 97 , 98 ),
wherein the first group of frequencies ( 35 , 36 ; 94 - 96 ) and the second group of frequencies ( 33 , 34 ; 97 , 98 ) are disjoint.
3. The driver circuit according to claim 1 , wherein the plural frequencies are included in a third group of frequencies ( 91 - 93 ) when no data are to be transmitted.
4. The driver circuit according to claim 1 , wherein the control device ( 24 ) is configured to detect a voltage ripple having a pre-defined frequency on the power line ( 19 ) to receive other data over the power line ( 19 ) from a master unit ( 10 ).
5. The driver circuit according to claim 1 , wherein the at least one controllable switch comprises a first switch ( 23 a ) and a second switch ( 23 b ).
6. A light source ( 20 ; 111 , 112 ), comprising:
the driver circuit according to claim 1 , and
at least one light emitting diode ( 29 ; 119 , 129 ), LED, connected to an output ( 27 ; 27 a , 27 b ) of the driver circuit ( 21 ; 121 , 131 ).
7. A system, comprising
a driver circuit for a light source ( 20 ; 111 , 112 ), comprising:
an input ( 22 ; 22 a , 22 b ) configured for coupling to a power line ( 19 );
a switching circuit ( 23 a , 23 b , 141 - 150 ; 23 a , 23 b , 141 - 149 , 160 ) coupled to the input ( 22 ; 22 a , 22 b ) and comprising at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ); and
a control device ( 24 ) configured to control the at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ) to control an output current or output voltage of the driver circuit ( 21 ; 121 , 131 ),
the control device ( 24 ) being configured to modulate a signal onto the power line ( 19 ) by setting a switching frequency of the at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ) in dependence on data to be transmitted by the driver circuit ( 21 ; 121 , 131 ) over the power line ( 19 ), and
and a master unit ( 10 ) configured to supply power to the driver circuit ( 21 ; 121 , 131 ) via a power line ( 19 ), wherein the master unit ( 10 ) comprises a power line demodulator ( 12 ) coupled to the power line ( 19 ) and configured to detect the data transmitted from the driver circuit ( 21 ; 121 , 131 ) over the power line ( 19 ),
wherein the power line demodulator ( 12 ) is configured to detect a data bit having a first logical value if a frequency of a voltage ripple ( 72 ) on the power line ( 19 ) is any one of plural frequencies included in a first group of frequencies.
8. The system according to claim 7 , wherein the power line demodulator ( 12 ) is configured to detect a data bit having a second logical value if the frequency of the voltage ripple ( 71 ) on the power line ( 19 ) is any one of plural frequencies included in a second group of frequencies, the first group and the second group being disjoint.
9. The system according to claim 7 , wherein the master unit ( 10 ) is configured to identify the driver circuit ( 21 , 121 , 131 ) transmitting the data based on the frequency of the voltage ripple ( 71 , 72 ).
10. A method of transmitting data over a power line ( 19 ), the method being performed by a driver circuit for a light source ( 20 ; 111 , 112 ), comprising:
an input ( 22 ; 22 a , 22 b ) configured for coupling to a power line ( 19 );
a switching circuit ( 23 a , 23 b , 141 - 150 ; 23 a , 23 b , 141 - 149 , 160 ) coupled to the input ( 22 ; 22 a , 22 b ) and comprising at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ); and
a control device ( 24 ) configured to control the at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ) to control an output current or output voltage of the driver circuit ( 21 ; 121 , 131 ),
the control device ( 24 ) being configured to modulate a signal onto the power line ( 19 ) by setting a switching frequency of the at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ) in dependence on data to be transmitted by the driver circuit ( 21 ; 121 , 131 ) over the power line ( 19 )
wherein the control device ( 24 ) is configured to control the output current of the driver circuit ( 21 ; 121 , 131 ) by setting the switching frequency to at least one frequency ( 30 - 32 ; 33 - 36 ; 51 , 52 ; 91 - 93 ; 94 - 96 ; 97 , 98 ) which is a function of both a target output current of the driver circuit ( 21 ; 121 , 131 ) and the data to be transmitted
wherein the control device ( 24 ) is configured to control the output current of the driver circuit ( 21 ; 121 , 131 ) by sequentially setting the switching frequency to plural frequencies ( 33 , 34 ; 35 , 36 ; 51 , 52 ; 91 - 93 ; 94 - 96 ; 97 , 98 ), the plural frequencies ( 33 , 34 ; 35 , 36 ; 51 , 52 ; 91 - 93 ; 94 - 96 ; 97 , 98 ) being a function of both the target output current ( 59 ) of the driver circuit ( 21 ; 121 , 131 ) and the data to be transmitted, and
wherein the control device ( 24 ) is configured to control the output current of the driver circuit ( 21 ; 121 , 131 ) by alternating the switching frequency between the plural frequencies ( 33 , 34 ; 35 , 36 ; 51 , 52 ; 91 - 93 ; 94 - 96 ; 97 , 98 ),
wherein the method comprises:
modulating a signal onto the power line ( 19 ) by setting a switching frequency of the at least one controllable switch ( 23 ; 123 , 133 ; 23 a , 23 b ) in dependence on the data to be transmitted over the power line ( 19 ).