Power control device configured to protect internal circuits and display device including the same
A power controller includes an inductor coupled to an input terminal to which an input voltage is input, a first switch coupled between the inductor and a first power source voltage output terminal, a second switch coupled between the inductor and a ground, a switch controller controlling a voltage output to the first power source voltage output terminal by controlling duties of the first and second switches according to a feedback voltage input to a feedback terminal corresponding to a voltage output to the first power source voltage output terminal, and a diode coupled between the first power source voltage output terminal and the feedback terminal, and preventing a voltage of the first power source voltage output terminal from increasing higher than a breakdown voltage of the first and second switches.
1. A power controller, comprising:
an inductor coupled to an input terminal to which an input voltage is input;
a first switch coupled between the inductor and a first power source voltage output terminal;
a second switch coupled to the inductor and the first switch;
a switch controller to control a voltage of the first power source voltage output terminal by controlling duties of the first and second switches according to a feedback voltage of a feedback terminal; and
a diode coupled between the first power source voltage output terminal and the feedback terminal, the diode to prevent the voltage of the first power source voltage output terminal from increasing higher than a breakdown voltage of the first and second switches when the feedback voltage is abnormal.
2. The power controller as claimed in claim 1 , wherein:
the diode is a single diode that is coupled to the first power source voltage output terminal and the feedback terminal, and
a threshold voltage of the diode corresponds to a voltage difference between the voltage of the first power source voltage output terminal and the feedback voltage when the voltage of the first power source voltage output terminal is lower by a predetermined level than the breakdown voltage of the first and second switches.
3. The power controller as claimed in claim 2 , wherein, when a voltage difference between the voltage of the first power source voltage output terminal and the feedback voltage reaches the threshold voltage of the diode, the feedback terminal is coupled to the first power source voltage output terminal through the diode.
4. The power controller as claimed in claim 1 , further comprising a first differential amplifier including a first input terminal to which the feedback voltage is input, a second input terminal to which a first reference voltage is input, and an output terminal outputting an over-voltage protection signal that corresponds to a voltage difference between the feedback voltage and the first reference voltage, wherein the diode has a first electrode that is coupled to a node between an electrode of the first switch and the first power source voltage output terminal, and the diode has a second electrode that is coupled to a node between the first differential amplifier and the feedback terminal.
5. The power controller as claimed in claim 4 , further comprising a third switch coupled between the first switch and the first power source voltage output terminal, wherein the switch controller controls turning on and off of the third switch according to the over-voltage protection signal.
6. The power controller as claimed in claim 1 , further comprising a first resistor and a second resistor coupled in series between the feedback terminal and a ground and by which a voltage corresponding to a voltage difference between the feedback voltage and a ground voltage is divided.
7. The power controller as claimed in claim 6 , further comprising a second differential amplifier including a first input terminal to which a voltage divided between the first resistor and the second resistor is input, a second input terminal to which a second reference voltage is input, and an output terminal outputting a voltage error signal that corresponds to a voltage difference between the divided voltage and the second reference voltage.
8. The power controller as claimed in claim 7 , further comprising a third differential amplifier including a first input terminal to which a first pulse width control signal is input, a second input terminal to which the voltage error signal is input, and an output terminal outputting a second pulse width control signal that corresponds to a voltage difference between the first pulse width control signal and the voltage error signal.
9. The power controller as claimed in claim 8 , wherein the switch controller controls the duties of the first and second switches according to the second pulse width control signal.
10. The power controller as claimed in claim 1 , further comprising a first capacitor including:
a first electrode coupled to the first power source voltage output terminal, and
a second electrode coupled to a ground.
11. The power controller as claimed in claim 1 , further comprising a second capacitor including:
a first electrode coupled to a second power source voltage terminal having a low level voltage relative to a high level voltage of the first power source voltage output terminal, and
a second electrode coupled to a ground.
12. The power controller as claimed in claim 1 , wherein:
when the feedback voltage is normal, the diode is turned off, and
when the feedback voltage is abnormal, the diode is turned on.