Power converter having a feedback circuit for constant loads

An apparatus, comprising:

• an LED array;
• and
• a power converter coupled to the LED array to provide an output current to the LED array, the power converter including:
• an input to be coupled to receive an input voltage and electrically coupled to the LED array;
• a switch coupled to the input;
• an input voltage sense circuit coupled to the input to generate an input voltage sense signal representative of the input voltage;
• a feedback circuit coupled to the LED array, wherein the feedback circuit generates a feedback signal representative of an output voltage of the power converter, wherein the feedback signal is a current signal and wherein the feedback circuit includes a voltage-controlled-current-source comprising a transistor coupled to generate the feedback signal in response to the output voltage;
• and
• a controller coupled to the feedback circuit and to the input voltage sense circuit to control switching of the switch to regulate the output current in response to the feedback signal and the input voltage sense signal.

An apparatus, comprising:

• an LED array;
• and
• a power converter coupled to the LED array to provide an output current to the LED array, the power converter including:
• an input to be coupled to receive an input voltage and electrically coupled to the LED array;
• a switch coupled to the input;
• an input voltage sense circuit coupled to the input to generate an input voltage sense signal representative of the input voltage;
• a sense circuit coupled to the LED array to sense the output voltage and to provide a second voltage substantially equal to the output voltage;
• a voltage-controlled-current-source coupled to the sense circuit to generate a feedback signal in response to the second voltage, wherein the feedback signal is a current signal representative of the output voltage, and wherein the voltage-controlled-current source includes:
• a first node coupled to generate a reduced voltage in response to the output voltage;
• and
• a transistor having a control terminal coupled to the first node, wherein the transistor is coupled to generate the feedback signal in response to the reduced voltage;
• and
• a controller coupled to the voltage-controlled-current source and to the input voltage sense circuit to control switching of the switch to regulate the output current in response to the feedback signal and the input voltage sense signal.