Display driving circuit and display device including the same
A display driving circuit comprising a level shift circuit, the level shift circuit including a level shift device configured to receive a source power applied thereto, and to generate an output signal by amplifying an input signal; a power switching circuit configured to provide any one of first to third selection powers as the source power to the level shift device, the first to third selection powers being different from one another; and a switch control circuit configured to change the first selection power to the second or third selection power based on a change of voltage levels of the first to third selection powers.
1. A display driving circuit comprising:
a level shift circuit including a level shift device, the level shift device configured to,
receive a source power applied thereto, and
generate an output signal by amplifying an input signal;
a power switching circuit configured to provide any one of first to third selection powers as the source power to the level shift device, the first to third selection powers being different from one another; and
a switch control circuit configured to change the first selection power to the second or third selection power based on a change of voltage levels of the first to third selection powers,
wherein the level shift circuit includes,
an operational amplifier configured to output source data to a display panel, and
a pull-down transistor configured to be gated by the output signal of the level shift device, and selectively connect an output terminal of the operational amplifier to a ground terminal.
2. The display driving circuit of claim 1 , wherein the power switching circuit comprises:
a first sub-circuit configured to provide the first selection power to a first node of the level shift circuit,
a second sub-circuit configured to provide the second selection power to the first node, and
a third sub-circuit configured to provide the third selection power to the first node.
3. The display driving circuit of claim 2 , wherein the first sub-circuit comprises a first sub-transistor having one terminal connected to the first selection power, a second sub-transistor connected in series to the first sub-transistor, a third sub-transistor having a terminal connected to the second sub-transistor and another terminal connected to the first node, and a fourth sub-transistor having one terminal connected between the first sub-transistor and the second sub-transistor and another terminal connected to a ground terminal.
4. The display driving circuit of claim 1 , further comprising:
a regulator configured to generate the third selection power based on the second selection power and to provide the generated third selection power to the power switching circuit.
5. The display driving circuit of claim 4 , wherein the regulator comprises:
an operational amplifier configured to receive an input of the second selection power and to output a converted voltage to a second node,
a first transistor configured to be gated by the input signal of the level shift device and to selectively connect the second node to a ground terminal,
a second transistor configured to be gated by a control signal based on the change of the voltage levels of the first to third selection powers and to selectively transfer a voltage of the second node to a third node, and
a capacitor connected between the third node and the ground terminal.
6. A display driving circuit comprising:
a level shift circuit including,
a level shift device configured to receive first and second source powers that are different from each other, and generate an output signal by amplifying an input signal, and
an operational amplifier configured to output source data to a display panel;
a pull-down transistor configured to be gated by the output signal of the level shift device, and to selectively connect an output terminal of the operational amplifier to a ground terminal;
a power switching circuit configured to provide any one of first to third selection powers that are different from one another as the first source power of the level shift device; and
a switch control circuit configured to determine an operating mode based on a change of voltage levels of the first and second source powers, and to change the first source power applied to the level shift circuit by changing a control signal for controlling the power switching circuit if the operating mode changes.
7. The display driving circuit of claim 6 , wherein the operating mode of the display driving circuit includes first to third modes of operation, the power switching circuit is configured to apply,
the first selection power to the level shift circuit as the first source power, in the first mode of operation, and
the second selection power to the level shift circuit as the first source power if the operating mode is changed from the first mode to the second mode.
8. The display driving circuit of claim 7 , wherein the level shift circuit is configured to pull down the second source power and the input signal, such that the output signal maintains a same value as the second mode of operation if the operating mode is changed from the second mode to the third mode of operation.
9. The display driving circuit of claim 6 , wherein the operating mode includes a normal mode and an abnormal mode, and the power switching circuit is configured to apply,
the first selection power to the level shift circuit as the first source power in the normal mode, and
the third selection power to the level shift circuit as the first source power in the abnormal mode.
10. The display driving circuit of claim 9 , wherein, if the operating mode is change from the normal mode to the abnormal mode, the level shift circuit is configured to
enable the input signal,
pull down the input signal together with the second source power, and
change a value of the output signal to have a slope that is equal to a slope of the third selection power.
11. The display driving circuit of claim 9 , wherein, if the operating mode is changed from the normal mode to the abnormal mode, the level shift circuit is configured to,
turn on the pull-down transistor, and
discharge an output terminal of the operational amplifier.
12. A display device comprising:
a display panel including a plurality of pixels; and
a display driving circuit configured to control the display panel, the display driving circuit includes,
a voltage generator configured to receive a power supply voltage from an outside of the display driving circuit and to generate first to third selection powers that are different from each other;
a level shift device configured to
receive any one of the first to third selection powers, and
generate an output signal by amplifying an input signal;
a pull-down transistor configured to be gated by the output signal of the level shift device and selectively connect the display panel to a ground terminal to pull down the plurality of pixels; and
a switch control circuit configured to change a selection power that is applied to the level shift device to another selection power based on a change of voltage levels of the first to third selection powers,
wherein the level shift device includes an operational amplifier that is configured to output source data to the display panel.
13. The display device of claim 12 , wherein the display driving circuit further comprises a source driver, the source driver configured to control data lines connected to the plurality of pixels, and the source driver includes the level shift device, the pull-down transistor, and the switch control circuit.
14. The display device of claim 12 , wherein the display driving circuit further comprises:
a first sub-circuit configured to transfer the first selection power to a first node, the first node is in the level shift device,
a second sub-circuit configured to transfer the second selection power to the first node, and
a third sub-circuit configured to transfer the third selection power to the first node.