Backlight unit and display apparatus including the same
AssigneeSamsung Display Co., Ltd.
InventorsTaegon Im, Min-gyu Kim, Youngsup Kwon
Life of this patent
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Abstract
A backlight unit includes a power converter which generates a light source power voltage at a first node in response to a voltage control signal, at least one light emitting diode string which is connected between the first node and a second node and receives the light source power voltage through the first node, and a controller connected to the second node where the controller detects current of a detection node varying based on a duty ratio of the power control signal, and controls current flowing through the second node when the detected current is greater than a reference value.
Claims16
A backlight unit, comprising:
- a power converter which generates a light source power voltage to a first node in response to a voltage control signal;
- at least one light emitting diode string which is connected between the first node and a second node, and receives the light source power voltage through the first node;
- and
- a controller connected to the second node,
- wherein the controller detects current of a detection node of the power converter varying based on a duty ratio of the voltage control signal, and controls current flowing through the second node when the detected current is greater than a reference value,
- wherein the controller comprises:
- a voltage controller which outputs the voltage control signal having a pulse width corresponding to a voltage level of the second node:
- and
- a current controller which detects the current of the detection node, and controls the current flowing through the second node when the detected current is greater than the reference value,
- wherein the current controller comprises:
- a comparison circuit which compares a feedback voltage corresponding to the current of the detection node and the reference value to output a detection voltage corresponding to a comparison result;
- and
- a feedback control circuit which controls the current flowing through the second node based on the detection voltage and the voltage level of the second node.
A display apparatus, comprising:
- a display panel including a plurality of pixels;
- a driving circuit which controls the plurality of pixels so as to display an image on the display panel;
- and
- a backlight unit which provides the display panel with light, wherein the backlight unit includes a power converter which generates a light source power voltage to a first node in response to a voltage control signal;
- at least one light emitting diode string connected between the first node and a second node, and which receives the light source power voltage through the first node;
- and
- a controller connected to the second node, wherein the controller detects current of a detection node of the power converter varying based on a duty ratio of the voltage control signal, and controls current flowing through the second node when the detected current is greater than a reference value,
- wherein the controller comprises:
- a voltage controller which outputs the voltage control signal having a pulse width corresponding to a voltage level of the second node;
- and
- a current controller which detects the current of the detection node and control the current flowing through the second node when the detected current is greater than the reference value,
- wherein the current controller comprises:
- a comparison circuit which compares a feedback voltage corresponding to the current of the detection node and the reference value to output a detection voltage corresponding to a comparison result;
- and
- a feedback control circuit which controls the current flowing through the second node b based on the detection voltage and the voltage level of the second node.
Dependencies are inferred from the claim text.