| 摘要 |
PURPOSE:To enable both sink current and source current of flow as load current, by composing a load driving circuit of open-drain and open-source type MOSFETs. CONSTITUTION:Substrate-side terminal 6 and source terminal 7 are not connected together inside of IC and source terminal 7 is opened as well as drain terminal 5. Since MOS type FET is originally symmetric between the drain and source, it permits current to flow in both directions from the source to the drain and from the drain to the source. When display circuit 3 composed of common anode LED is driven, load current IL becomes sink current flowing from the drain to the source by connecting the drain to load 3 (i.e display circuit) while grounding the source of MOSFET. Further, when display circuit 3d made of common cathode LED is driven, load current IL becomes source current flowing from the source to the drain by connecting the source to power source VDD. |
