Infrared transmitter circuit and electronic device
US7359649B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 21, 2004 |
| Grant date | Apr 15, 2008 |
| Priority date | — |
| Expiry date | May 23, 2026 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B10/1141
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
An infrared transmitter circuit causes an output current to flow to a light emission diode via a current mirror circuit constituted of three transistors by using a current supplied from a power source circuit, so that the light emission diode emits light. When a voltage V1 varied by charging a capacitor with a current flowing from the power source circuit exceeds a reference voltage (voltage V2), an output of a comparator resets a D flip-flop, so that an output of the D flip-flop varies to “0”. Thus, an output of a NAND gate to which that output and a transmission signal are inputted causes a transistor (N-channel FET) to turn ON so as to stop operation of the current mirror circuit, and causes a transistor (P-channel FET) to turn OFF so as to cut a connection between the power source circuit and a power source line. Thus, it is possible to reduce power consumption in operation of a protection circuit which stops supplying the output current to the light emission diode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.