| 摘要 |
This invention realizes reduction in consumption of DC current in a level converter circuit by setting level shifters in an operating state only when necessary in accordance with hierarchical control, in which an output pulse of a level shifter ( 311 ) that is constantly in a power-ON state is used to set a level shifter ( 321 ) of the next hierarchical level in the operating state, then output pulses of the level shifter ( 311 ) and the level shifter ( 321 ) are used to generate control pulses LT 1 and LT 2 , which are used to set level shifters ( 341 to 346 ) of the next hierarchical level in the operating state, and an output pulse of one of the level shifters is used to set level shifters ( 351 ), ( 352 ) and ( 353 ) of the next hierarchical level in the operating state. Thus, a level converter circuit in which the consumption of DC current is reduced and which enables reduction in power consumption of the whole device, a display device equipped with this level converter circuit, and a portable telephone device using the display device as an output display unit can be constructed. |
