Driving circuit, method for protecting the same, electro-optical apparatus, and electronic apparatus
View Patent ↗Aspects of the invention provide a driving circuit of an electro-optical panel that can include a plurality of power lines, a signal line, a driving device, and a protective circuit. The driving device can drive the electro-optical panel based on powers supplied from a power-supply circuit through the plurality of power lines and various signals input through the signal line. The protective circuit is provided between at least two power lines among the plurality of power lines, to which powers of different potentials are supplied, and can include an electrical path for dissipating static applied to one of the two power lines to the other. Accordingly, the driving circuit can increase resistance to static of an electro-optical apparatus, such as a liquid crystal apparatus.
1. A driving circuit for driving an electro-optical panel comprising:
a first power line for supplying a first power;
a second power line for supplying a second power;
a third power line for supplying a third power;
a fourth power line for supplying a fourth power;
a shift register that generates transfer pulses in synchronization with a clock signal when a transfer-starting pulse is input to the shift register and that outputs an end pulse from a last stage of the shift register, the shift register being connected to the first power line and the second power line;
a level shifter that shifts voltage of each of the transfer pulses from a voltage between potentials of the first power and the second power to a voltage between potentials of the third power and the fourth power and that outputs driving signals, the level shifter being connected to the third power line and the fourth power line;
a first protective circuit that is provided between the third power line and the fourth power line;
a first signal line for supplying the transfer-starting pulse;
a second signal line for supplying the end pulse;
second protective circuits that are provided between the first signal line and the first power line and between the first signal line and the second power line; and
third protective circuits that are provided between the second signal line and the first power line and between the second signal line and the second power line.
2. The driving circuit according to claim 1 , further comprising a fourth protective circuit that is provided between the first power and second power lines.
3. The driving circuit according to claim 1 , further comprising:
third signal lines, each of the signal lines for supplying each of the driving signals; and
fifth protective circuits that are provided between each of the third signal lines and the third power line and between each of the third signal lines and the fourth power line.
4. The driving circuit according to claim 1 , potentials of powers increasing in order of the fourth power, the second power, the first power, and the third power.
5. The driving circuit according to claim 1 , the first protective circuit including a diode or a diode-connected semiconductor device.
6. The driving circuit according to claim 1 , the first protective circuit comprising an N-type transistor, a P-type transistor, or a PIN junction transistor.
7. The driving circuit according to claim 1 , the first protective circuit comprising a resistor.
8. The driving circuit according to claim 7 , a resistance of the resistor being set so that a value of a current flowing between the third power line and the fourth power line is 10% or less of a value of a current consumed as the supplied powers.
9. An electro-optical apparatus, comprising the driving circuit according to claim 1 and the electro-optical panel.
10. An electronic apparatus, comprising the electro-optical apparatus according to claim 9 .
11. The electronic apparatus according to claim 10 , wherein the apparatus is selected from the group consisting of projection display apparatuses, liquid crystal television sets, mobile phones, electronic notepads, word processors, view-finder or monitor direct-view videotape recorders, work stations, television telephones, POS terminals, touch panels, and electrophoretic devices.
12. The driving circuit according to claim 1 , wherein at least one of the first, second and third protective circuits is configured to diffuse and eliminate static applied to the power lines through an electrical path included in the at least on protective circuit.
13. The driving circuit according to claim 12 , wherein the at least one protective circuit is energized to protect the driving circuit so that potentials on at least two power lines are maintained in a predetermined relationship when static is applied to the at least two power lines.
14. The driving circuit according to claim 1 , wherein at least one of the first, second and third protective circuits is configured to be energized so that potentials on the power lines corresponding to the at least one protective circuit are maintained in a predetermined relationship when the driving circuit is being driven.
15. The driving circuit according to claim 1 , wherein while the driving circuit is not receiving power and is not being operated, at least one of the first, second and third protective circuits is configured so that when static of a higher potential than the of a high-potential-side one of the power lines is applied to a low-potential-side one of the power lines, the at least one protective circuit discharges the static to the high-potential-side power line.
16. The driving circuit according to claim 1 , wherein the while the driving circuit is not receiving power and is not being operated, at least one of the first, second and third protective circuits is configured so that when static of a lower potential than that of a low-potential-side one of the power lines is applied to a high-potential-side one of the power lines, the at least one protective circuit discharges the static to the low-potential-side power line.
17. The driving circuit according to claim 1 , wherein while the driving circuit is receiving power, at least one of the first, second and third protective circuit is configured so that when static of a higher potential than the of a high-potential-side one of the power lines is applied to a low-potential-side one of the power lines, the at least one protective circuit discharges the static to the high-potential-side power line.
18. The driving circuit according to claim 1 , wherein while the driving circuit is receiving power, at least one of the first, second and third protective circuit is configured so that when static of a lower potential than that of a low-potential-side one of the power lines is applied to a high-potential-side one of the power lines, the at least one protective circuit discharges the static to the low-potential-side power line.
19. The driving circuit according to claim 1 , wherein at least one of the first, second and third protective circuits dissipates static applied to the power line corresponding to the at least one protective circuit by an electrical path included in the at least one protective circuit when the driving circuit is being operated and when the driving circuit is not being operated.
20. The driving circuit according to claim 19 , wherein the electrical path includes at least one of a path to the power line with the highest potential and a path to the power line with the lowest potential.