The infrared LED of an IrDA module transmits IR energy with a peak
wavelength (for example, 875 nm) appropriate for IrDA communication. This
peak wavelength is lower than is the wavelength (for example, 940 nm)
used in ordinary IR remote controls (RC). The IrDA LED does, however,
transmit some energy at the wavelength of the peak sensitivity of an RC
receiver. When making an IrDA transmission, the IrDA LED is driven with a
lower amount of current. When making an RC transmission, the IrDA LED is
driven with an increased amount of current such that higher wavelength
emissions received by the RC receiver are of adequate power to realize RC
communication. A passive circuit is disclosed for automatically
increasing IrDA LED current during RC transmissions. The circuit involves
an inductor that shunts current around a current-limiting resistor used
to limit LED drive current.